Childhood dairy and calcium intake and cardiovascular mortality in adulthood: 65-year follow-up of the Boyd Orr cohort.

BACKGROUND Dairy consumption in childhood may have long-term effects on cardiovascular mortality through influencing the development of risk factors or programming effects. OBJECTIVE To investigate whether dairy and calcium consumption in childhood is associated with adult mortality due to coronary heart disease (CHD), stroke and all causes. METHODS In 1937-9, 4999 children in England and Scotland participated in a study of family food consumption, assessed from 7-day household food inventories. Cause of death was ascertained between 1948 and 2005 in 4374 traced cohort members with complete data. Per capita household intake estimates for dairy products and calcium were used as proxies for individual intake. RESULTS No strong evidence that a family diet in childhood high in dairy products was associated with CHD or stroke mortality was found. However, childhood calcium intake was inversely associated with stroke mortality (multivariable adjusted hazard ratio (HR) for highest versus lowest calcium group: 0.41; 95% confidence interval (CI) 0.16 to 1.05; p for trend = 0.04), but not CHD mortality. All-cause mortality was lowest in those with the highest family dairy (HR = 0.77; 95% CI 0.61 to 0.98; p for trend = 0.04) and calcium intake (HR = 0.77, 95% CI 0.60 to 0.98; p for trend = 0.05). CONCLUSIONS Children whose family diet in the 1930s was high in calcium were at reduced risk of death from stroke. Furthermore, childhood diets rich in dairy or calcium were associated with lower all-cause mortality in adulthood. Replication in other study populations is needed to determine whether residual confounding explains part of these findings.