Dairy Product Consumption and Cardiovascular Health: A Systematic Review and Meta-analysis of Prospective Cohort Studies

Abstract

The association between dairy product consumption and cardiovascular health remains highly debated. We quantitatively synthesized prospective cohort evidence on the associations between dairy consumption and risk of hypertension (HTN), coronary heart disease (CHD), and stroke. We systematically searched PubMed, Embase, and Web of Science through August 1, 2020, to retrieve prospective cohort studies that reported on dairy consumption and risk of HTN, CHD, or stroke. We used random-effects models to calculate the pooled RR and 95% CI for the highest compared with the lowest category of intake and for a 1-serving/d increase in consumption. We rated the quality of evidence using NutriGrade. Fifty-five studies were included. Total dairy consumption was associated with a lower risk of HTN (RR for highest compared with lowest level of intake: 0.91, 95% CI: 0.86, 0.95, I² = 73.5%; RR for 1-serving/d increase: 0.96, 95% CI: 0.94, 0.97, I² = 66.5%), CHD (highest compared with lowest level of intake: 0.96, 95% CI: 0.92, 1.00, I² = 46.6%; 1-serving/d increase: 0.98, 95% CI: 0.95, 1.00, I² = 56.7%), and stroke (highest compared with lowest level of intake: 0.90, 95% CI: 0.85, 0.96, I² = 60.8%; 1-serving/d increase: 0.96, 95% CI: 0.93, 0.99, I² = 74.7%). Despite moderate to considerable heterogeneity, these associations remained consistent across multiple subgroups. Evidence on the relation between total dairy and risk of HTN and CHD was of moderate quality and of low quality for stroke. Low-fat dairy consumption was associated with lower risk of HTN and stroke and high-fat dairy with a lower risk of stroke. Milk, cheese, or yogurt consumption showed inconsistent associations with the cardiovascular outcomes in high compared with low intake and dose-response meta-analyses. Total dairy consumption was associated with a modestly lower risk of hypertension, CHD, and stroke. Moderate to considerable heterogeneity was observed in the estimates, and the overall quality of the evidence was low to moderate.

Keywords: cheese; coronary heart disease; dairy; hypertension; milk; stroke; yogurt.

FIGURE 1

Association of total dairy consumption with hypertension risk, for high compared with low intake, using random-effects meta-analysis. Weights of each estimate are represented by the size of the square. Black diamonds represent the individual estimate effects, and black lines represent the 95% CI. The x-axis is the relative risk. The overall effect estimates and 95% CIs are represented by the diamond and dotted line. I² refers to the proportion of heterogeneity between studies. M, risk estimate among men; W, risk estimate among women.

FIGURE 2

Association of total dairy consumption with coronary heart disease risk, for high compared with low intake, using random-effects meta-analysis. Weights of each estimate are represented by the size of the square. Black diamonds represent the individual estimate effects, and black lines represent the 95% CI. The x-axis is the relative risk. The overall effect estimates and 95% CIs are represented by the diamond and dotted line. I² refers to the proportion of heterogeneity between studies. M, risk estimate among men; W, risk estimate among women.

FIGURE 3

Association of total dairy consumption with stroke risk, for high compared with low intake, using random-effects meta-analysis. Weights of each estimate are represented by the size of the square. Black diamonds represent the individual estimate effects, and black lines represent the 95% CI. The x-axis is the relative risk. The overall effect estimates and 95% CIs are represented by the diamond and dotted line. I² refers to the proportion of heterogeneity between studies. M, risk estimate among men; W, risk estimate among women.