Dairy fat and risk of cardiovascular disease in 3 cohorts of US adults

Abstract

Background: Few prospective studies have examined dairy fat in relation to cardiovascular disease (CVD).

Objective: We aimed to evaluate the association between dairy fat and incident CVD in US adults.

Design: We followed 43,652 men in the Health Professionals Follow-Up Study (1986-2010), 87,907 women in the Nurses' Health Study (1980-2012), and 90,675 women in the Nurses' Health Study II (1991-2011). Dairy fat and other fat intakes were assessed every 4 y with the use of validated food-frequency questionnaires.

Results: During 5,158,337 person-years of follow-up, we documented 14,815 incident CVD cases including 8974 coronary heart disease cases (nonfatal myocardial infarction or fatal coronary disease) and 5841 stroke cases. In multivariate analyses, compared with an equivalent amount of energy from carbohydrates (excluding fruit and vegetables), dairy fat intake was not significantly related to risk of total CVD (for a 5% increase in energy from dairy fat, the RR was 1.02; 95% CI: 0.98, 1.05), coronary heart disease (RR: 1.03; 95% CI: 0.98, 1.09), or stroke (RR: 0.99; 95% CI: 0.93, 1.05) (P > 0.05 for all). In models in which we estimated the effects of exchanging different fat sources, the replacement of 5% of energy intake from dairy fat with equivalent energy intake from polyunsaturated fatty acid (PUFA) or vegetable fat was associated with 24% (RR: 0.76; 95% CI: 0.71, 0.81) and 10% (RR: 0.90; 95% CI: 0.87, 0.93) lower risk of CVD, respectively, whereas the 5% energy intake substitution of other animal fat with dairy fat was associated with 6% increased CVD risk (RR: 1.06; 95% CI: 1.02, 1.09).

Conclusions: The replacement of animal fats, including dairy fat, with vegetable sources of fats and PUFAs may reduce risk of CVD. Whether the food matrix may modify the effect of dairy fat on health outcomes warrants further investigation.

Keywords: animal fat; cardiovascular disease; dairy fat; prospective; vegetable fat.

FIGURE 1

RR (95% CIs) for CVD (A), CHD (B), and stroke (C) associated with isocaloric substitutions of vegetable fat, other animal fat, PUFA, and carbohydrate for dairy fat. The 95% CIs are represented by horizontal lines, and gray bars represent overall estimates. The total sample size was 222,234 men and women at baseline with 5,158,337 person-years of follow-up. Substitution effects of substituting dairy fat with other sources of energy were estimated by the difference in the coefficients between fat sources and their covariances with the use of a time-dependent Cox proportional hazard regression model adjusted for age (continuous), BMI (8 categories), total energy intake (quintiles), race, smoking, physical activity, alcohol consumption, menopausal status and menopausal hormone use (NHS and NHS II participants only), oral contraceptive use (NHS II participants only), baseline hypertension, and baseline hypercholesterolemia, and dietary intakes of fruit, vegetables, coffee, and protein. CHD, coronary heart disease; CVD, cardiovascular disease; NHS, Nurses’ Health Study.