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EBM Author Blog: Diet Quality Inversely Associated with the Risk of COPD

26 Oct, 15 | by Kelly Horwood, BMJ

Evidence-Based Medicine Author Blog


Dr Rania A Mekary, Department of Social and Administrative Sciences, MCPHS University 

A higher overall diet quality is inversely associated with the risk of chronic obstructive pulmonary disease (COPD) in men and women

The obvious association between some modifiable risk factors such as tobacco smoke, chemicals, and dust and chronic obstructive pulmonary disease (COPD) has long been established.  Other well-established non-modifiable risk factors include age and genetics.  The question is whether there are other non-modifiable risk factors that we, and in particular physicians, need to be aware of.

According to recent prospective cohort studies, the answer is yes.  It is overall diet quality.

What is meant in here is not a specific food, a food group, or a few food groups per se; it is rather the overall diet quality as reflected by the Alternate Healthy Eating Index 2010 (AHEI-2010).  The AHEI-2010 is based on food and nutrients consistently associated with a lower risk of cardiovascular diseases, diabetes, or cancer.  More specifically, a higher AHEI-2010 diet score reflects high intakes of of whole grains, polyunsaturated fatty acids, nuts, and long chain omega-3 fats and low intakes of red/processed meats, refined grains, and sugar sweetened drinks.

A recent prospective cohort study assessed the relationship between AHEI-2010 diet score and COPD risk in men and women.


  • Data was collected from the Nurses’ Health Study cohort with 73,228 females and 1137,106 person-years and from the Health Professionals Follow-Up Study with 47,026 males and 521,764 person-years
  • The AHEI-2010 was identified from the different Food Frequency Questionnaires. Self-reported newly diagnosed COPD was defined by the affirmative response to a physician’s diagnosis of chronic bronchitis or emphysema and by the report of a diagnostic test at diagnosis.


  • Among women: 723 cases of newly diagnosed COPD; incidence rate= 64/100,000 person-years;
  • Among men: 167 cases of newly diagnosed COPD; incidence rate= 32/100,000 person-years;
  • Pooled analysis of men and women, AHEI-2010 diet score was inversely associated with newly diagnosed COPD [Multivariate-adjusted HR=0.67; 95%CI= 0.53 to 0.85 comparing top to bottom quintiles; P-trend<0.001)
  • Similar results were seen in women (RR=0.69; 95%CI= 0.53 to 0.90) and men (RR=0.60; 95%CI= 0.34 to 1.03), although the results were not significant in men; this could be due to lack of power.
  • Similar results were seen among ex-smokers and current smokers.

So what are we to take from this?

It is important to realize that the overall diet quality is an important risk factor for COPD; physicians need to stress the importance of an overall healthy diet when consulting their patients.  Whether these findings (AHEI-2010 & COPD) could differ between men and women remains unclear and merits further studies.

In fact, the root of the question is whether we have less incidence of COPD among men than women.

Read the full commentary here.



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