Background: A higher milk consumption may be associated with a lower stroke risk. We conducted a comprehensive systematic review and dose-response meta-analysis of milk and other dairy products in relation to stroke risk.
Methods and results: Through a systematic literature search, prospective cohort studies of dairy foods and incident stroke in stroke-free adults were identified. Random-effects meta-analyses with summarized dose-response data were performed, taking into account sources of heterogeneity, and spline models were used to systematically investigate nonlinearity of the associations. We included 18 studies with 8 to 26 years of follow-up that included 762 414 individuals and 29 943 stroke events. An increment of 200 g of daily milk intake was associated with a 7% lower risk of stroke (relative risk 0.93; 95% CI 0.88-0.98; P=0.004; I(2)=86%). Relative risks were 0.82 (95% CI 0.75-0.90) in East Asian and 0.98 (95% CI 0.95-1.01) in Western countries (median intakes 38 and 266 g/day, respectively) with less but still considerable heterogeneity within the continents. Cheese intake was marginally inversely associated with stroke risk (relative risk 0.97; 95% CI 0.94-1.01 per 40 g/day). Risk reductions were maximal around 125 g/day for milk and from 25 g/day onwards for cheese. Based on a limited number of studies, high-fat milk was directly associated with stroke risk. No associations were found for yogurt, butter, or total dairy.
Conclusions: Milk and cheese consumption were inversely associated with stroke risk. Results should be placed in the context of the observed heterogeneity. Future epidemiological studies should provide more details about dairy types, including fat content. In addition, the role of dairy in Asian populations deserves further attention.
Keywords: dairy products; meta‐analysis; prospective cohort study; stroke; systematic review.
© 2016 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.