The effect of dairy consumption on the prevention of cardiovascular diseases: A meta-analysis of prospective studies

Introduction: There is no global consensus on the relationship of dairy products with cardiovascular diseases. This study was conducted to evaluate the effect of the consumption of dairy products on cardiovascular diseases, including stroke and coronary heart disease (CHD). Methods: Important electronic databases such as the Scopus, Science Direct, and PubMed were evaluated up to September 2014. All prospective cohort studies that evaluated the relationship between dairy products consumption and cardiovascular diseases were included regardless of their publication date and language. The study participants were evaluated regardless of age, sex, and ethnicity. The STROBE checklist was used to assess quality of the study. Two investigators separately selected the studies and extracted the data. The designated effects were risk ratio (RR) and hazard ratio (HR). The random effect model was used to combine the results. Results: Meta-analysis was performed on 27 studies. There were 8648 cases of cardiovascular diseases (CVD), 11806 cases of CHD, and 29300 cases of stroke. An inverse association was found between total dairy intake and CVD (RR=0.90, 95% CI: 0.81-0.99) and stroke (RR=0.88, 95% CI: 0.82-0.95) while no association was observed between total dairy intake and CHD. The total diary intake was associated with decreased mortality of stroke (RR=0.80, 95% CI: 0.76-0.83) although it had no association with its incidence (RR=0.96, 95% CI: 0.88-1.04). Conclusion: This is the first meta-analysis of the relationship of total dairy intake with CVD. This study showed an inverse relationship between total dairy intake and CVD while no relationship was found for CHD. Considering the limited number of studies in this regard, more studies are required to investigate the effect of different factors on the association of dairy intake and CVD.