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Neuro- memory

Primary Care Corner with Geoffrey Modest MD: Intervention to Delay Functional Decline in Dementia

15 Jun, 16 | by EBM

By Dr. Geoffrey Modest

A recent review was done which looked at 23 systematic reviews (i.e., a systematic review of systematic reviews) of interventions to delay functional decline in patients with dementia, finding a few nonpharmacologic (exercise, dyadic interventions) and a few pharmacologic ones (especially donepezil and memantine) seemed to be effective (see doi:10.1136/bmjopen-2015-010767).

Details:

  • Background re: dementia
    • 6 million people are affected by dementia worldwide, including 5-7% of those >60yo
    • One of the leading causes of morbidity and mortality
    • Huge personal and social costs: reduced quality of life, increased care burdens on family, increased costs to society to provide supportive and medical care
  • Interventions:
    • Most patients in the reviews had mild-to-moderate dementia, 65% with any type of dementia and rest with Alzheimer’s
    • Nonpharmacologic (11 reviews).
      • Exercise (6 studies, 289 people, standardized mean difference (SMD) of those doing exercise was 0.68: the largest magnitude of effect of any intervention, though studies considered low quality because of risk of bias.
      • Dyadic interventions (interventions targeted to patient and caregiver to maximize the patient’s quality of life and meaningful activities): 8 studies, 988 patients, SMD 0.37. Somewhat mixed findings in the studies, and many with risk of bias, so considered low quality evidence
      • Those not reaching statistical significance included: cognitive training, cognitive stimulation therapy, light therapy, aromatherapy, nutritional supplements, validation therapy, psychological treatment, or music therapy
    • Pharmacologic (reviews)
      • Acetylcholinesterase inhibitors and memantine (12 studies, 4661 patients, including a variety of meds and doses: e.g. donepezil 5 or 10mg, galantamine 24mg, and rivastigmine 12mg): a pretty small but significant effect, with SMD in the 0.15-0.20 range). Moderate quality of evidence.
      • Selegiline also had small effect on Activites of Daily Living (ADL) function after 8-17 weeks (7 studies, 810 patients, SMD 0.27)
      • Other therapies (meds for sleep, latrepirdine, melatonin, statins, lecithin, nimodipine, acupuncture, vitamin B supplements) were ineffective. Gingko biloba and Huperzine A did have effect (which was really remarkable for Huperzine A, with SMD of 1.48), but these treatments had such low quality that they could not be recommended, and the latter one was based on 2 studies with a total of 70 people). The studies on Ginko Biloba were more extensive (7 studies with 2530 people, SMD 0.36), the quality was very low and the studies had mixed results.

COMMENTARY:

  • These types of reviews clearly are pretty large-scale data mining of studies of variable quality looking at different people (ages, types and severity of dementia), different interventions within the subgroups (different exercises, etc.), different outcomes measured (memory changes, or perhaps the more clinically/socially-relevant changes in ADL), sponsors (drug company vs not), sites (community-dwelling vs in institution), and qualities of the studies (as measured by the AMSTAR tool, assessing protocol data extraction, comprehensiveness, data synthesis, biases, documentation of conflicts of interest,…). But that’s all we got. Though I should mention again that unfortunately there are fewer studies and fewer patients in the non-pharmacologic arena, likely because of less available funding (most studies being funded by drug companies), with about ten-fold more patients in the pharmacologic studies reviewed.
  • Perhaps not so surprisingly, the two standouts here are exercise and dyadic therapies. In my limited experience, I have found that social day programs (these are adult day centers that I have many patients attend, with patients having social interactions, social activities, exercise, and some help with training family members in the care of patients) are really effective. I do need to lapse into one very recent anecdotal experience: a 78yo man who recently retired and after a short period of time, was forgetting how to find his house when either walking or driving (he soon stopped driving). I did start him on antidepressants, but the social day program was pretty immediately effective in both improving his mood dramatically and also improving his memory back to his baseline. Though I can’t draw unequivocal conclusions, I do find that overall one of the most important clinical interventions I do for my somewhat isolated older patients is to get them into these types of programs, encourage them to do more exercise, and help/support /get services for their caregivers.
  • So, bottom line to me: the most effective therapies for mild-to-moderate dementia (and perhaps those with the least potential for adverse effects) seem to be exercise and helping the patient/caregivers provide the most useful interventions to improve the ADLs, provide meaningful activities for the patient, etc.

Primary Care Corner with Geoffrey Modest MD: PPI Use and Dementia

25 Feb, 16 | by EBM

By Dr. Geoffrey Modest

A ​pharmacoepidemiological analysis, based on claims data, found an association between taking proton pump inhibitors (PPIs) and the risk of dementia in the elderly (see doi:10.1001/jamaneurol.2015.4791).

Details:

  • An observational database from 2004-2011 from the largest Germany health insurer insuring 1/3 of the population and 50% of the elderly, was used to assess inpatient and outpatient use of PPIs
  • 73679 participants, >=75yo and free of dementia at baseline. 2950 were on regular PPIs (mean age 83.8, 78% female), compared to 70,729 patients (mean age 83.0, 73.6% female)
  • 29510 patients received a diagnosis of dementia over the course of the study period (40% of the cohort)
  • Regular PPI use was defined as a prescription for a PPI each quarter of an 18-month interval during the study period

Results:

  • Those on PPIs had a 44% increased risk of incident dementia [HR 1.44 (1.36-1.52), p<0.001]
    • For males, HR 1.52 (1.33-1.74)
    • For females, HR 1.42 (1.33-1.51)
  • Other associations with dementia included: depression (HR 1.28), stroke (HR 1.37), and to a lesser extent, female sex (HR 1.15), diabetes (HR 1.05), polypharmacy (HR 1.16); all statistically significant
  • ​But, controlling for all these potentially confounding factors actually led to a higher association of dementia with PPI use [HR 1.66 (1.57-1.76)]
  • And, controlling for use of anticholinergics, itself a risk factor for dementia with its own HR of 1.80, did not change the association with PPIs (HR was still 1.44)
  • Looking at those patients who only occasionally used PPIs, there was a lower but significant HR of 1.16 (1.13-1.19).
  • Difference by type of PPI used: omeprazole had HR 1.51, pantoprazole HR 1.58, but somewhat higher with esomeprazole with HR 2.12
  • ​There was a slight decreasing effect with age: those 75-79 had HR 1.69, those 80-84 had HR 1.49 and those >84 had HR 1.32 (all significant)

A prior study by the same group, AgeCoDe (the German Study on Aging, Cognition and Dementia in Primary Care Patients), included 3327 community-dwelling persons >= 75 yo with 18-month neuropsychological assessments similarly found incident dementia to be associated with PPI usage, and with a similar HR of 1.38 (1.04-1.83), and with somewhat more dementia in the group on esomeprazole. All PPI associations controlled for age, sex, educational level, apoE4, depression, diabetes, stroke, ischemic heart disease, and polypharmacy.

So, this was a large computer-based study finding an association between PPI use and dementia; therefore it is not confirm a causal relationship. But a few points:

  • There is biological plausibility:
    • Mouse models find that PPIs increase the levels of b-amyloid in their brains, by affecting the enzymes b- and g-secretase; PPIs also could decrease the degradation of b-amyloid by lysosomes, which are pH-dependent, in microglia (and some PPIs cross the blood-brain barrier). Also, PPIs bind to tau.
    • PPIs are associated with vitamin B12 deficiency through malabsorption, and vitamin B12 deficiency is associated with cognitive decline
  • This study adds to the potential adverse effects of PPIs (see blogs below for some other problems with PPIs)
  • Of course, this study only finds an association. As above, they tried to account for many of the covariates for dementia (stroke, polypharmacy, depression, etc.), and they also found that there was not much difference in use of the health care system (all suggesting, but not proving, that the PPI-users and non-users were pretty similar in dementia risk). But the data are not so granular: i.e., even if the level of polypharmacy is the same in both groups, did those on PPIs might have more specific drugs that could affect cognition? And what about cigarette use, alcohol, or obesity which may be over-represented in the PPI-user group and may themselves be associated with dementia?
  • So, I think there are a couple of lessons here:
    • It is always important to remember that very few drugs really are targeted specifically to a single action. One might think (as perhaps most of us did) that a drug targeting acid release from the stomach’s parietal cells would not have potential widespread effects (other than collateral damage on nutrient absorption, etc.). The finding of clear effects on b-amyloid in mice brains and the potential effects of PPIs on human brains yet again brings us to the usual conclusion: use medications in their lowest dose and only if necessary, with an emphasis on helping patients try to make lifestyle changes as the primary approach to many medical problems.
    • As mentioned in prior blogs, it is really easy to just keep refilling PPI prescriptions since they work and it is sometimes a struggle to change paths with patients, and we often are quite busy just keeping up with the other more active medical problems. I.e., the approach of step-down therapy (moving from PPI to H2-blocker or just calcium) is in reality not done much in clinical practice. Which I think supports more of a step-up approach (staring with calcium then escalating to H2 blocker prior to PPI).

For a few of the recent blogs on PPIs, see

http://blogs.bmj.com/ebm/2014/12/03/primary-care-corner-with-geoffrey-modest-md-gastric-acid-suppression-and-the-microbiome/ which looks at microbiome changes with gastric acid suppression

http://blogs.bmj.com/ebm/2015/06/25/primary-care-corner-with-geoffrey-modest-md-ppis-associated-with-mis/ which looks at the possible association of PPIs with MIs

http://blogs.bmj.com/ebm/2016/01/15/primary-care-corner-with-geoffrey-modest-md-ppis-and-chronic-kidney-disease/ found an association of PPIs with chronic kidney disease

Primary Care Corner with Geoffrey Modest MD: Lifestyle Interventions and Cognition

14 Dec, 15 | by EBM

By Dr. Geoffrey Modest

There have been several recent articles on interventions to prevent cognitive decline, including

  1. An op-ed piece in the NY Times (see http://www.nytimes.com/2015/10/25/opinion/sunday/can-you-get-smarter.html?emc=edit_th_20151025&nl=todaysheadlines&nlid=67866768&_r=0​ ) . A few of their points, expanded a bit with the references:
  • A 6-week on-line study with 11,430 participants trained several times a week on cognitive tasks: there were 3 groups–one with 6 training tasks emphasizing reasoning, planning and problem-solving; another group was exposed to a broader range of cognitive tasks including tests of short-term memory, attention, visuospatial processing and mathematics, as is found in commercially available brain training devices; and a control group who did not do specific cognitive tasks but answered obscure questions using online resources (i.e., like Google). They found that each of these tasks improved through this training, but “no evidence was found for transfer effects to untrained tasks, even when those tasks were cognitively closely related” – i.e., there is no evidence that regular use of computerized specific cognitive tasks improves general cognitive function (see Nature. 2010 June 10; 465: 775)
  • Exercise does seem to help:
    • Mice who have regular exercise have more neurons in their hippocampus (that is the site where new memories are formed and converted to long-term memories, and one of the first sites affected by Alzheimer Disease (AD)
    • A small study of 86 women with subjective memory complaints were assigned to 3 groups: resistance training, aerobic training, or balance/tone (the control group). Those in the aerobic training group remembered more items; both aerobic and resistance training led to better spatial memory performance; and there was a significant correlation between spatial memory performance and overall physical capacity (see doi: 10.1155/2013/861893)
    • A study of 155 community-dwelling women 65-75 yo were randomized to resistance training vs balance/tone (control group) and found that resistance training reduced the progression of brain MRI white matter lesions (which are associated with cognitive impairment, and are markers of cerebral small-vessel disease — see J Am Geriatr Soc 2015; 63(10): 2052)
  • They note that BNDF levels (brain-derived neurotrophic factor, which is released in response to neuronal activity) are associated with brain size and function, and is increased with exercise (more below).
  1. A JAMA perspective on mitigating cognitive decline (see doi:10.1001/jama.2015.15390​)
  • In assessing >1200 brains in 2 different aging studies, there was not a great correlation between anatomic findings and cognitive health:
    • The Rush Memory and Aging Project  [Curr Alzheimer Res. 2012; 9(6): 646] of 1556 elders without dementia enrolled from retirement communities beginning in 1997, tracked cognitive function, relying on clinical diagnoses and an array of 21 cognition tests, found that:
      • Physical activity was associated with cognition
      • Incident Alzheimer dementia (AD) was associated with a decline in motor function
      • Social engagement (social activity and support) was associated with global cognition and a slower rate of cognitive and motor decline and disability
      • But at autopsy, the correlation between anatomic changes and cognition were not great: 90% of those meeting clinical criteria of AD did meet pathologic criteria for AD, but 1/2 of those with mild cognitive impairment and 1/3 of those without cognitive impairment also met pathologic criteria for AD.
    • The Religious Orders Study [Curr Alzheimer Res. 2012; 9(6): 628], a study from 1994-2011 of 1162 Catholic nuns, priests, and brothers from 40 groups across the US initially without dementia, similarly used a battery of 21 cognitive tests, also found the same relatively poor correlation as the Rush study between anatomic pathology and AD.
    • ​And, overall overt brain pathology accounted for only 1/2 of the cognitive decline documented
  • Animal studies support the role of BDNF in improving neuronal survival and function (especially in the hippocampus and cortex), and improve synaptic plasticity and long-term memory. Human epidemiologic studies find a correlation between low BDNF levels and AD (though unclear which came first). In this light the community-based Framingham Study was reviewed to see if higher BDNF levels in cognitively healthy adults seemed to protect against future development of AD, found that in 10 years of followup, 140 people developed dementia (117 with AD), and each SD increase in BDNF levels was associated with a 33% decreased risk of dementia overall and AD in particular. Comparing the top to bottom quintile of BDNF levels, there was a 51% decrease in risk of dementia (HR49, p=0.01) and AD (HR.46, p=0.02),  specifically in subgroups of women, people >80 yo and those with college degrees (see  JAMA Neurol. 2014; 71(1): 55)
  • Depression is associated with lower BNDF levels and more hippocampal shrinkage, and antidepressants block the depression-induced drop in BDNF.
  • And what increases BDNF levels??? Increased physical activity, reduced caloric intake, social support (and lack thereof is associated with lower BDNF levels). A review found that aerobic exercise increases BDNF as well as improves hippocampal atrophy, improves memory function, and reduces depression [see Neuroscientist 2012: 18(1): 82].  By the way, there are also data showing exercise is associated with decreases in b-amyloid in a transgenic Alzheimer mouse model.
  • Increased BDNF also reduces risk of stroke (I could not find this reference to review the primary data).
  • Also there are data finding that blood VEGF levels (vascular endothelial growth factor) may be protective of brain function. For example, a study found that VEGF levels in the CSF were higher in those with higher cognitive abilities, in comparing those with normal cognition to mild cognitive impairment to those with AD. And, exercise boosts VEGF.. ​
  1. A more recent article undercut the exercise/dementia link: the LIFE trial (Lifestyle Interventions and Independence for Elders) looked at the effects of a 24-month physical activity program for 1635 community-living people in the US, aged 70-89, who were at risk for mobility disability but able to walk 400 meters (seeJAMA. 2015;314(8):781-790). They assessed cognitive function as a secondary outcome (though this study was not specifically powered for this outcome) using several instruments, especially the Digit Symbol Coding subtest of Wechsler Adult Intelligance Scale and the revised Hopkiins Verbal Learning Test (12-item word list recall), comparing those in the structured moderate-intensity physical activity program of walking, resistance training, and flexibility exercises, to those in a health education program. They found no overall benefit to exercise, except in those >80 yo and in those with poorer baseline physical performance, noting an improvement in executive function in these groups (p=0.01). However, they did not measure BDNF levels, which may be particularly important in a group of patients who were physically challenged at baseline and perhaps unable to exercise very much. Also, only 57 patients overall developed dementia though 132 developed mild cognitive impairment (this LIFE was a well-educated cohort, and therefore more likely to show less cognitive decline by the cognitive tests).

So, things are usually more complicated than they seem. We are all (myself certainly included) prone to look for simple solutions that make sense physiologically. It makes sense that AD and dementia in general are neurologic degenerative disorders associated with specific anatomic pathology, but the actual correlation is not so clear. It also makes sense that keeping the brain active, through suduko or other cognitive puzzles would help preserve brain function, but it seems that overall brain function does not improve (though performance of the specific task, suduko in this case, does get better….).  However, the above studies suggest that there do seem to be a large array of potential benefits from exercise, including decreased depression, improved memory, and decreased progression of cognitive decline. And the data also support the benefit of a Mediterranean diet. Bottom line: I think it is not so useful to try to break down the specific components of diet or exercise which is beneficial (a tad reductionist), that cognitive decline is undoubtedly multifactorial (again arguing against a reductionist approach), but that nutrition and exercise are very likely necessary for brain health and likely more so than the too-often-advertized easy fixes of on-line memory games, etc. And this realization is a bit of a game-changer, in that perhaps our primary therapeutic focus in elderly people concerned about cognitive decline really should be on a healthy diet and exercise, which not only are good for the body but also for the mind.

For some other blogs on cognitive function, see:

http://blogs.bmj.com/ebm/2015/01/27/primary-care-corner-with-geoffrey-modest-md-chocolate-and-memory-this-time-reviewing-the-reference/ showing that chocolae improves cognitive function

http://blogs.bmj.com/ebm/2015/12/01/primary-care-corner-with-geoffrey-modest-md-mediterranean-diet-and-brain-volume/ reviewed the Mediterranean diet and cogntive decline, showing decreased AD and also larger brain volumes, which tracked with the degree of adherence to a Mediterranean diet. ​

 

Primary Care Corner with Geoffrey Modest MD: Atrial Fibrillation – Should We Look Harder For It?

2 Dec, 15 | by EBM

By Dr. Geoffrey Modest

Over the years, I have had several patients who have presented with significant strokes related to previously-undetected atrial fibrillation (AF). I have also had a couple of patients with dementia and no evident prior stroke, who on workup have had multiple small infarcts, again possibly related to AF. In this light, there was an interesting editorial in JAMA (see JAMA 2015; 314: 1911) ​ raising the question of whether we should be screening regularly for AF. Although not part of their argument, I think that the potential and not clearly well-defined relationship between AF and cognitive decline may be part of the incentive to screen (see below). Their argument is basically (all references are in the text):

  • AF is really common (1 in 4 lifetime risk in those >40, with 0.5% age 40, increasing to up to 15% at age 80)
  • Treatment is pretty effective: oral anticoagulation (OA) reduces stroke risk by 2/3 and mortality by 1/3, with relatively small risk of major bleeding (hence the use of pretty universal guidelines to anticoagulate if the CHA2DS2-VASc score is 2 or greater)
  • The effectiveness of OA is much more impressive than many of the other recommended screening activities/interventions
  • AF is a common cause of stroke: a recent Swedish Stroke survey of 94K patients with ischemic stroke found AF in 31K of them, which is probably an underestimate (see Stroke 2014; 45: 2599)
  • So, can asymptomatic AF be picked up by screening??
    • A systematic review found that in 123K patients, a single screen using either pulse palpation or EKG found undiagnosed AF in 1% of people overall and 1.4% of those >65yo.
    • The European Society of Cardiology 2012 guidelines on AF recommended routine checking the pulse of patients >=65 years of age, followed by an electrocardiogram as needed, for the timely detection of AF.
    • There are cheap handheld or smartphone EKG-type devices which may be useful. Preliminary studies suggest an AF pickup of 1.5-3.0%, all of whom qualified for OA.
  • Prognosis of incidental AF
    • A UK study found people with incidentally detected asymptomatic AF had stroke rate of 4% in 1.5 years and all-cause mortality of 7% in those untreated. Those on warfarin had stroke and death rates of 1% and 4% respectively
  • Cost-effectiveness
    • ​Smartphone based screening in those 65-85yo: $4066 per quality-adjusted life-year gained, $20,695 per stroke prevented (i.e., better than most preventative interventions). This age group has high incidence of AF and essentially all people >65 would qualify for OA
  • The authors suggest that we in the US follow the European guidelines and check the pulse during office visits.

So, AF has potentially devastating consequences, with significant morbidity and mortality. A few points:

  • The relationship between AF and multi-infarct dementia (MID) is not clear, and AF is not listed as a risk factor for MID by the NIH. But there was a population-based study (Rotterdam Study) which followed 6514 patients aged >55 and found a strong association between dementia and impaired cognitive function in those who developed AF and were <67 yo (see http://blogs.bmj.com/ebm/2015/10/30/primary-care-corner-with-geoffrey-modest-md-atrial-fibrillation-and-dementia/). A recent article on AF and cognition (see Stroke 2015;46:3316-3321) noted that:
    • The mechanism is unclear (?multiple small emboli, ?AF-associated cerebral hypoperfusion)– and, evidently, if the mechanism were the latter, it would be hard to attribute the cognitive decline to AF, since there would not necessarily be dectectable infarcts on brain imaging.
    • There have been meta-analyses (see Neurology 2011; 76:914, Ann Intern Med 2013; 158: 338) finding >2-fold increased risk of cognitive impairment in those with AF and subsequent stroke.
    • A few meta-analyses have found a 40% increased risk of dementia in those with AF and without stroke (see Heart Rhythm 2012; 9: 1761).
    • But, as we know, associations are not necessarily causal, and AF/dementia do have shared risk factors.
    • ​And, one of my concerns is that in many of these studies, our measurement of dementia (e.g. Mini-mental state exam) is a very blunt instrument and does not pick up subtle changes which may be very significant for the person at that time, and ultimately over years, progress to our definition of dementia.
  • Given the potential devastation of stroke/cognitive impairment, as well as the potential damage from other peripheral emboli, it seems to me that we should have a randomized controlled intervention study looking at treatment for AF and its overall effects. For that study, there would need to be some agreement on the following:
    • What is AF?  Is it a random pick-up on a routine exam (i.e., 1-minute evaluation for an irregular pulse and then followed by an EKG)? Is it a 24-hour Holter monitor, or a 30-day event monitor??? (clearly there are people with very intermittent, paroxysmal AF who have clinical emboli, and checking a pulse is going to find those with sustained AF predominantly)
    • ​What is cognitive decline? This study should include doing a more extensive evaluation for subtle cognitive decline (e.g., the Cardiovascular Health Study did look at a few instruments, including the Modified MMSE and Digit Symbol Substitution Test, as well as telephone interviews, finding those with incident AF had faster and earlier onset cognitive decline — see Neurology 2013; 81: 119).
  • But at this point, I will continue doing what I have been doing: pretty much always checking my own manual blood pressures on patients, after waiting several minutes in a reasonably relaxed atmosphere (as per prior blogs). In this setting I sometimes do pick up AF (and, by the way, the automated cuffs are pretty unreliable for blood pressure measurement in those with AF, further supporting checking manual blood pressures in those >50yo or so). But I will now add on checking the pulse for irregularities, and then follow the guidelines for treatment when I find AF. And, perhaps more aggressive assessments for AF than pulse-checking at the time of exams should be done (given the high prevalence of AF, especially in our aging population, a more intensive AF assessment such as Holter monitoring could be a very cost-effective strategy, especially given the dramatic quality-of-life issues associated with stroke/dementia). But this would need studies to determine.

Primary Care Corner with Geoffrey Modest MD: Mediterranean Diet and Brain Volume

1 Dec, 15 | by EBM

By Dr. Geoffrey Modest

I sent out a recent blog on a Spanish intervention trial of a Mediterranean Diet, which was associated with a decrease in breast cancer risk. This same study (the PREDIMED study) also found decrease likelihood of developing atrial fibrillation, coronary artery disease, diabetes and improved cognition (see prior blogs: http://blogs.bmj.com/ebm/2014/06/24/primary-care-corner-with-geoffrey-modest-md-olive-oil-and-atrial-fibrillation/ , http://blogs.bmj.com/ebm/2014/01/21/primary-care-corner-with-geoffrey-modest-md-mediterranean-diet-and-cad-primary-prevention/,http://blogs.bmj.com/ebm/2014/01/21/primary-care-corner-with-geoffrey-modest-md-mediterranean-diet-for-diabetes-prevention/ ). The PREDIMED substudy on cognitive decline looked at 522 participants at high vascular risk, randomized them to 2 Mediterranean diets (one high in extra-virgin olive oil and the other high in nuts) vs a low-fat control. They tracked participants with the Mini-Mental State Exam (MMSE) and Clock Drawing Test for 6.5 years and found that, controlling for apo E genotype, family history of cognitive impairment/dementia, depression and the array of cardiovascular risk factors, participants in either of the Mediterranean diets did better (though those on the high extra-virgin olive oil did a little better than the high nut one) –see J Neurol Neurosurg Psychiatry 2013;84:1318–1325.

There was a recent study which looked at Mediterranean diet and brain structure. Patients were in the Washington Heights-Inwood Columbia Aging Project (WHICAP), following 2,258 community-dwelling non-cognitively impaired individuals in New York and prospectively evaluating them for Alzheimer’s Disease every 1.5 years. They found 262 incident cases of Alzheimer’s over 4 years, and found an overall 9% decreased risk of Alzheimer’s with greater adherence to a Mediterranean diet, with a 40% decreased risk in comparing the highest to the lowest tertile of consuming a Mediterranean diet, in a multivariate analysis controlling for the usual suspects (seeAnn Neurol 2006;59:912–921​). These results have been confirmed in several observational studies, but not all.

In the current study, researchers looked at adherence to a Mediterranean diet and several MRI-determined variables of brain architecture (see doi.10.1212/WNL.0000000000002121). They scored adherence to the Mediterranean diet from 0-9.

Details:

  • 674 subjects of whom 370 had lower adherence to Med diet (score 0-4) and 304 with higher adherence (score 5-9)
  • Mean age 80.1, 10.7 years of education, 67% female, 25% apo e-4 positive, 28% white/35% black/36% Hispanic, BMI 27.8, 21% with diabetes, 74% hypertension, 10.5% stroke.

Results:

  • ​Those with higher total brain volume were younger, had higher education, more often male, less likely to have diabetes, and had lower BMI.
  • Those with higher Med diet adherence (5-9) vs lower (0-4) had:
    • Higher total brain volume by 13.11 ml (p=0.007)
    • Higher total gray matter volume by 5.00 ml (p=0.05)
    • Higher total white matter volume by 6.41 ml (p=0.05)
  • Specific components of the Mediterranean Diet:
    • Higher fish consumption and lower meat consumption were associated with higher total gray matter volume
    • Lower meat intake was associated with larger total brain volume
    • Higher fish intake was associated with a 0.019 mm larger mean cortical thickness (p=0.03)
    • Volumes of the cingulate cortex, parietal lobe, temporal lobe, and hippocampus, and cortical thickness of the superior-frontal region were associated with dietary factors, esp. higher fish and lower meat intakes
  • Overall, Med Diet adherence was associated with less brain atrophy, equivalent to the effects of 5 years of aging, with higher fish and lower meat intakes being the most significant association.

So, this is yet another study confirming the benefits of eating well. The constellation of findings, whether related to developing diabetes, heart afflictions, or cognitive decline, reinforce that diet is important for the whole body, and that in some ways our reductionist approach (looking just at coronary artery disease, for example) can lead to the wrong conclusions (just put people on statins and aspirin and don’t worry). So, I bring up this study mostly to reinforce overall the benefits of healthy lifestyle and that it probably is one of the most important messages we in primary care can impart on our patients. Of course, some of these suggestions are structurally difficult in our society (eating well requires access to affordable healthy foods, exercise requires access to safe neighborhoods in which to walk, etc.), but, at least in Boston, there are lots of grassroots initiatives to improve access to food and safe neighborhoods, from which my patients have benefited significantly. [And it would be great to generalize/develop access to good foods and safe neighborhoods more broadly…..]

Primary Care Corner with Geoffrey Modest MD: Atrial Fibrillation and Dementia

30 Oct, 15 | by EBM

By Dr. Geoffrey Modest

The studies on the relationship between atrial fibrillation (AF) and dementia are inconsistent. This long-term, prospective population-based observational Rotterdam Study provided insight into this relationship (see doi:10.1001/jamaneurol.2015.2161).

Details:

  • 6514 participants (mean age 68, 59% female, BMI 26, 10% diabetic, BP 139/74, chol/HDL ratio of 290/54, 42% former/23% current smokers, 8% with coronary artery disease, and 3% with heart failure)
  • 318 (5%) had prevalent AF at start of study; 994 (15%) developed incident dementia over 20 years of follow-up

Results:

  • Prevalent AF was associated with increased risk of dementia, with HR 1.33 (1.02-1.73), meaning a 33% increase vs those without prevalence AF
  • Of 6196 without prevalent AF (79K person-years of follow-up), 723 (12%) developed incident AF and 932 (15%) developed incident dementia
  • Incident AF was associated with an increased risk of dementia in those <67yo, with HR 1.81 (1.11-2.94), but was not significant in those >67yo
  • The risk of dementia was strongly related to the duration of exposure to AF:  those younger patients with the longest exposure had HR 3.30 (1.16-9.38, with p=0.003 for trend), though not in those >67yo
  • The above relationships were independent of clinical stroke, and didn’t vary by whether the dementia was classified as “Alzheimer” or “non-Alzheimer”

The above study found an impressive relationship between AF and dementia in those <67yo, with an apparent dose-response curve (the longer the AF exposure, the more dementia). There are some important caveats:

  • The definition of dementia was basically a clinical one, relying on the MIni-Mental State Exam and Geriatric Mental State Schedule, with further clinical differentiation of Alzheimer vs non-Alzheimer. These tests are insensitive to picking up early dementia, especially in high-functioning adults
  • There was no systematic neuroimaging, so unclear if there were either subclinical strokes, or even asymptomatic emboli (lacunar strokes are associated with cognitive decline)
  • The above study did not have any information about whether the patients with AF were anticoagulated (nor how good the level of anticoagulation was)
  • ​It is difficult to attribute causality in an observational study: was the issue that the AF caused cerebral hypoperfusion (AF is associated with decreased cardiac output) or small cerebral emboli leading to cognitive decline? Or that both AF and cognitive decline share similar causes (those who had AF were more likely to be smokers, have lower HDL levels, be on treatment for hypertension, be diabetics)?
  • ​AF is often undetected in asymptomatic individuals, since it is often intermittent. In a study as the above one, with clinic visits/EKGs done every 3-4 years, we may well miss asymptomatic intermittent AF. Perhaps we should have a more aggressive approach to AF diagnosis?? 24 or more hour monitoring every year??

So, the real issues in primary care are:

  • AF is really common and increasing as the population ages
  • The data on rhythm control (e.g., reverting to normal sinus rhythm) vs rate control (just controlling the ventricular rate) did not assess long-term cognitive issues (e.g. the AFFIRM and RACE trials, which somewhat favored rate control, basically assessed mortality, strokes/hemorrhages, serious arrhythmias, and used somewhat toxic antiarrhythmics and did not maintain full anticoagulation in those with rhythm control). It is certainly possible that restoration of normal sinus rhythm is in fact better in the prevention of cognitive decline.
  • But, it is hard to maintain normal sinus rhythm with these pretty toxic meds. Even with radiofrequency ablation, there are not-so-infrequent AF recurrences (meta-analysis of ablation found only about 50% were in NSR after 3 years with a single ablation, though increases to about 80% with multiple ablations, though ablations themselves are also associated with emboli –e.g., see JACC 2013; 62:531 or Circ 2010; 122:1667.) and who knows how sustained normal rhythm will actually be in longer-term studies? Or even if some who have “NSR” still have occasional episodes of AF which could be associated with small, inapparent emboli? Maybe we should aim for sinus rhythm but continue with anticoagulation??
  • And, it would be very interesting to know if either rhythm control (as best as we can measure it) or adequate anticoagulation diminishes cognitive decline (one possible study might be in those with low CHA2DS2-VASc scores, who are not generally given anticoagulation, to be randomized to anticoagulation vs not, to see if there is a long-term cognitive difference. There is a study lending some support to this — those in AF on anticoagulants and more often in therapeutic range had less dementia –see  Heart Rhythm 2014: 11:2206 — though this was not a randomized control study, so there may have been important differences in those achieving better control than the others.)
  • But, the finding above that the duration of AF being associated with more cognitive decline, is somewhat reassuring since it is likely that those with less evident AF seem to be at lower risk, supporting the concept that decreasing the numbers of episodes of AF may be helpful.
  • In some ways the real value of a quick-and-dirty study as the Rotterdam one above serves to raise a much bigger issue: we perhaps should not be so complacent with just achieving rate control, the current general approach, but should pursue studies to see if another very important endpoint (cognitive decline) might be better achieved by more aggressive attempts to reinstate sinus rhythm.​

Primary Care Corner with Geoffrey Modest MD: Too low blood pressure and cognitive decline in elderly

23 Apr, 15 | by EBM

By: Dr. Geoffrey Modest 

An Italian prospective cohort study of elderly patients (>65 yo) with baseline cognitive impairment assessed the association between achieved blood pressure in those who were hypertensive and the rate of cognitive decline (see JAMA Intern Med. 2015;175(4):578-585​).

elderly

Details:

–172 patients followed in 2 outpatient memory clinics, mean age 79, 63.4% female, mean mini-mental status exam (MMSE) baseline score of 22.1 (normal range 0-30, with scores of 21-24 indicating mild cognitive impairment, MCI, and 10-21 indicating moderate impairment). MMSE was assessed again after 9 months.

–baseline: 68.0% had dementia, 32.0% had MCI, and 73.3% had hypertension with 69.8% were on antihypertensive drugs. They also assessed an array of common morbidities (including diabetes, CHF, CAD, CKD) as well as ADLs/IADLs (activities of daily living, instrumental ADLs)

–primary outcome: assess the role of office BP, ambulatory blood pressure monitoring (ABPM), and BP meds in changes in cognitive function and progression of disabilities. Secondary outcome: effect of office and ABPM on adverse events.

–patients in the lowest tertile of daytime systolic blood pressure by ABPM, SBP <=128 mmHg, had greater decrease in MMSE (-2.8) vs those in the intermediate tertile (SBP 129-144, with MMSE -0.7, p=0.002) vs highest tertile (SBP >=145, with MMSE -0.7, p=0.003)

–the association between SBP and MMSE decline was significant only in those on antihypertensive drugs, for both subgroups of those with MCI and dementia.

–in multivariate model (controlling for age, baseline MMSE, vascular comorbidities), interaction between daytime SBP and use of antihypertensives was independently associated with greater cognitive decline, for both MCI and dementia subgroups

–the association between office-based SBP and MMSE change was weaker than the ambulatory SBP, not reaching statistical significance.

–for the secondary outcome: both ADL and IADL decreased, but there was no relationship between any of the blood pressure measurements.

–adverse events were pretty high: 26.2% had at least one fall, 6.8% had syncope, 23.7% were hospitalized. There was a nonsignificant trend for a higher incidence of syncope and hospitalization with decreasing daytime SBP (eg, the rates of syncope went from 10.5% in the lowest SBP tertile to 6.8% in the intermediate to 3.4% in the highest tertile. for hospitalizations, it went from 33.3% to 21.7% to 17.2%).  My guess is that this was too small a study to achieve statistical significance for these outcomes.

So, a few points:

–This was not an RCT, where patients were stratified to different blood pressure goals and cognitive decline was measured. So it is hard to draw firm conclusions. ie, did those with lower achieved SBP have more cognitive decline because those patients had their blood pressure lowered more easily (eg, their vasculature was fundamentally different, leading to lower achieved blood pressure in those having more cognitive decline — and, by the way, there are some data finding that the onset of overt dementia is associated with spontaneous lowering of blood pressure)? And would the same group with more blood pressure lowering/more cognitive decline have had less cognitive decline if they were randomized to higher target blood pressures? One possible model is that more aggressively treating early hypertension is cognitively beneficial; but later on, the vascular changes from long-standing hypertension and its effects on cerebral blood flow autoregulation, endothelial function, etc could lead to impaired cognitive function, especially in the presence of dementia (ie, in the absence of cerebral blood flow autoregulation, lowering the blood pressure leads to more cerebral hypoperfusion and decreased functioning). So, there might be different BP targets in people of the same age group who have normal cognition, MCI, or dementia.

–This study reinforces the utility of ambulatory blood pressure monitoring. I posted many blogs over the past 3-4 years with data showing the superiority of ABPM — for diagnosis (about 30% of those in the mild hypertension range by office-based blood pressure do not have hypertension on ABPM), for cardiovascular clinical outcomes (the correlation between hard clinical cardiovascular endpoints in several studies were only significant for APBM and not for office-based blood pressure), and now this study suggests ABPM is a better predictor of cognitive decline. For more extensive discussion of ABPM, see here​.

–This study also reinforces the significance of the JNC8 targets being increased in elderly to <150/90 (see here for my previous blog on JNC8).

–And, again, I would like to reinforce that in elderly patients postural blood pressure changes should be assessed pretty regularly. Given changes in vasculature as noted above and increases in autonomic neuropathy with aging, it is very common (at least in my practice) to see older patients with even somewhat high SBP but having dramatic BP decline on standing. The immediate concern is falling, but I am also concerned about cardiovascular events (decreased myocardial perfusion) and cerebrovascular effects (hypoperfusion, or more vascular dementia from micro or macro infarcts).

Primary Care Corner with Geoffrey Modest MD: Chocolate and memory, this time reviewing the reference

27 Jan, 15 | by EBM

By: Dr. Geoffrey Modest

So, the paper did come through on the internet, showing that chocolate (actually dietary epicatechin) does increase the dentate gyrus function on functional MRI and improve cognitive testing in only 3 months (see doi:10.1038/nn.3850). A couple of other observations from the paper.

Chocolate

–Data in mice show a synergy between flavanols and aerobic exercise in enhancing dendritic spine density in the dentate gyrus
–This increase in both function (mice have improved cognitive performance with flavanols) and structure occur in association with an increase in capillary density in the dentate.
–The researchers developed a cognitive test, which mostly was looking at a large series of complex images, then 1 second after each image they asked which of 2 similar objects was present in the complex image, timing the subjects’ responses. Each time the test was performed, different images were used.
–They tested this cognitive eval in undergraduates and in healthy subjects aged 21-69, finding that there was a worsening with aging. And this was worsening was associated with the images on functional MRI.
–Then, as per the NY Times, they had their dietary flavonoid intervention in people aged 50-69. But, not in the Times, they also did so in both sedentary state and with exercise (1h/day of aerobic exercise, 4 days/week). So, there were 37 individuals distributed into the 4 groups (high vs. low flavanol diet, and with vs. without exercise), comparing before and after.
— The high flavanol diet led to significant cognitive improvement independent of exercise. No effect of exercise, but rather unexpectedly, the VO2 max was no different between the groups with and without the exercise (???). The changes in cognitive function was “equivalent to improvements in cognition by approximately three decades of life”
–The changes in the cognitive function correlated with changes in cerebral blood volume on imaging
–The improvements in blood flow have been shown in several prior studies of flavanols (and also with exercise, in several other studies).
–Prior studies (including by this group) have shown that aerobic exercise typically improves hippocampal function

So, there it is. A small study with multiple components that are (it seems to me) pretty impressive. Data from animals and humans provide many of the pieces: flavanoids increase blood flow, including cerebral blood flow in the hippocampus; there is an association in mice with flavonoids increasing neural density in the dentate gyrus, which was tied into increasing blood flow; and functionally there are impressive changes in cognition in humans and mice. Bigger studies would be useful. As well as chocolate bars with high and known levels of flavonoids. I’m game to try them…..

Primary Care Corner with Geoffrey Modest MD: Diabetes and cognitive decline

5 Jan, 15 | by EBM

By: Dr. Geoffrey Modest 

A recent analysis of the Atherosclerosis Risk in Communities study (ARIC, a prospective community-based cohort study from 4 communities across the US) assessed 13351 black and white adults aged 48-67 in 1990-92, and assessed changes in cognitive function over the next 20 years.

nurse-527615_640

Baseline:

–Population: average age 57, 56% female, 24% black, 13.3% with diabetes

–Cognitive assessment: 3 tests — delayed word recall test (DWRT, a test of verbal learning and recent memory); digit symbol substitution test (DSST, a test of executive function and processing speed), a component of the Weschler adult intelligence scale-revised; and the word fluency test (WFT, a test of executive function and language), all checked at baseline and at least 2 more times.

–They assessed stored blood for A1c values and controlled for age, race, education level, smoking, alcohol, BMI, hypertension, history of CAD, history of stroke, and apolipoprotein e4 genotype

Results:

–20-year decline in cognitive function:

–The adjusted difference in those with and without diabetes was pretty consistent: all of the tests were lower in diabetics, though only the DSST and ​WFT reached statistical significance (ie, most significant decreases were in the tests of executive function/processing speed)

–The composite (global Z score) unadjusted was -0.15, and on adjusted analysis was -0.23 (a score of -0.15 is equivalent to the cognitive difference of a 60-year old vs a 55-year old)

​–There was a significant trend per A1c: the most dramatic decline was in those with A1c>7.0, less so in those with 6.5-7, and pretty similar in those either 5.7-6.4 as in those 6.5-7. all of these (including those 5.7-6.4) were significantly different from controls

–Longer duration of diabetes was associated with greater late-life decline in cognitive function

–No difference between black and white patients

So, this was an observational study, making it hard to reach clear-cut conclusions (ie, was the cognitive decline related to untested variables? Are the patients with pre-diabetes or diabetes fundamentally different from normoglycemic patients, such that they are predisposed to cognitive decline? are both diabetes and cognitive decline, for example, associated with lack of exercise, eating fewer anti-oxidant vegetables or other lifestyle variables??). However, there is important biological plausibility for the association between diabetes and cognitive decline: the decline in executive functioning/processing speed involves the subcortical microvasculature, causing damage in white matter pathways and subcortical gray matter, as is more likely to be prevalent in diabetics (eg, those with other microvascular diabetic disease, such as retinopathy, in some studies, have higher likelihood of cognitive dysfunction. macrovascular atherosclerotic disease can be associated with decreased cerebral perfusion). One of my blogs done 6/21/12 reviewed a lancet review (see Lancet 2012; 379: 2291–99), noting similar findings. Data on reversal of cognitive decline by improved diabetes control are paltry (the ACCORD MIND study did not find anything, but was only a 3-year study in patients already age 63 and with frequent hypoglycemic episodes). One thing new in the current study is the association with prediabetes. this really brings up the issue that the primary goal is to prevent prediabetes and diabetes. several studies have shown that people at high risk of developing diabetes, or who have prediabetes, can significantly delay developing diabetes by around 10 years through lifestyle changes. i have personally had several patients revert from prediabetes (and even a few with diabetes) to a totally normal A1c through diet and exercise. but the “lifestyle” issue, as noted previously, is always complex, ranging from issues of personal preferences (shaped by a society that reinforces driving a few blocks instead of walking), access to safe and pleasant exercise venues (safe neighborhoods, sidewalks, etc), access to good food (issues of access in the “food deserts” of the inner city), income inequalities (less money for poorer patients to buy the more expensive fresh fruits and vegetables), etc etc etc — ie, there really needs to be a clear social/public health imperative to focus on these “lifestyle” issues, which of course in the longrun are better for people and undoubtedly save lots of money from decreased medical costs of caring for the resultant medical disabilities.

 

Primary Care Corner with Geoffrey Modest MD: Chocolate and Memory

5 Nov, 14 | by EBM

Sorry, but I can’t help myself….  a story published in NY Times recently found that chocolate improves memory in healthy 50-69 year olds. Partially-sponsored by drug company (Mars, maker of lots of chocolate products) and published by Nature Neuroscience, they found that drinking a high-flavanol drink with flavanols extracted from cocoa beans (especially with epicatechin) improved memory.

CHOCOLATE

 

Details:

–37 healthy volunteers aged 50-69 given either high-flavanol diet (900mg/d) vs. low-flavanol diet (10 mg/d) for 3 months, with reference being one bar of chocolate containing 40mg/d

–Memory improved 25% (by pattern recognition test: testing, for example, issues like remembering where you parked your car or the face of a person you just met), equivalent to the memory of a 30-40 year old if one had the memory of a normal 60 year old.

–Flavanols associated with increased metabolic activity in the dentate gyrus of the hippocampus and important in memory formation, which is generally reduced with aging, but no change in the entorhinal cortex of the hippocampus which is affected by early Alzheimers.

So, I thought it was important to bring this up in the context of the last week’s Halloween. One caveat is that most cocoa-processing methods remove a lot of flavanols (so hard to know which candy bar works best). But the dose in the study is equivalent to eating 300 grams of regular dark chocolate (approx. 7 average-sized bars) or 100 grams of baking chocolate or unsweetened chocolate powder (again, depending on how it was processed).

Geoff

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