Regular Long‐Term Intakes of Total Dairy and Yogurt are Linked with a Lower Risk of Incident High Blood Pressure in Middle‐Aged Adults

Background Observational studies have found beneficial effects of increased dairy intake on risk of high blood pressure (HBP). While it has been suggested that fermented dairy may provide even greater benefits, the independent effects yogurt, cheese, and milk have not been demonstrated. Objective To estimate the independent effects of total dairy, as well as yogurt, cheese, and milk, on risk of incident HBP among adults. A secondary objective was to evaluate effect modification by healthy diet patterns. Methods Data from three prospective studies of middle‐aged adults were used: the Nurses' Health Study (NHS) (ages 30–55 years, n=66,987), NHS II (ages 25–42, n=84,368), and the male Health Professionals Follow‐up Study (HPFS) (ages 40–75, n=30,512). Subjects without prevalent HBP, cardiovascular disease, cancer, or diabetes but with valid food frequency questionnaire data were included. NHS, NHS II, and HPFS participants were followed for a maximum of 30, 20, and 24 years, respectively, for development of physician diagnosed HBP self‐reported on biennial questionnaires. Time‐dependent Cox proportional hazards models were used to calculate hazard ratios (HR) and 95% confidence intervals (CI), controlling for age, race, family history of HBP, smoking, physical activity, energy intake, protein, fruits and vegetables. Updated BMI was added in separate models to evaluate its potential mediating effect on HBP risk. A DASH (Dietary Approaches to Stop Hypertension) diet score was calculated to explore effect modification by diet quality. Fixed effects meta‐analysis was used to combine the results across the three cohorts. Results There were 81,909 total cases of incident HBP in the three cohorts; 41,585 cases occurred in the NHS, 26,134 cases in the NHS II, and 14,190 cases in the HPFS. Regular yogurt consumers (≥5 servings/week vs. <1 serving/month) in the NHS, NHS II, and HPFS cohorts respectively had 19% (95% CI: 0.75–0.86), 17% (95% CI: 0.76–0.89), and 7% (95% CI: 0.82–1.05) reductions in HBP risk. In pooled analyses, higher yogurt intake led to an 18% (95% CI: 0.78–0.86) reduction in risk of HBP. In contrast, we found 17% (95% CI: 0.80–0.85), 13% (95% CI: 0.85–0.89) and 8% (95% CI: 0.88–0.96) reductions in HBP risk with higher intakes of total dairy (3–<6 servings/day), milk (2–<6 servings/day), and cheese (1–4 servings/day), respectively. Controlling for BMI slightly attenuated (<5%) the effect of dairy in all forms. There was evidence of additive interaction between diet quality and yogurt intake; those with the highest yogurt intake and in the highest tertile of the DASH score across all three cohorts had a statistically significant 30% (95% CI: 0.65–0.74) lowered HBP risk. Conclusion Higher usual intakes of total dairy and all dairy subtypes (milk, cheese, and yogurt) were associated with a lower risk of HBP across three longitudinal cohorts. Yogurt consumption tended to confer a greater benefit than other forms of dairy. Our study adds solid evidence that higher long‐term dairy intake, and especially yogurt consumption, is linked with lower risk of HBP in middle‐aged adults. Support or Funding Information National Dairy Council and the Boston Nutrition and Obesity Research Center