Breastfeeding and atherosclerosis - Intima-media thickness and plaques at 65-year follow-up of the Boyd Orr cohort

Objectives-The impact of breastfeeding in infancy on cardiovascular disease risk is uncertain. We related breastfeeding in infancy to atherosclerosis in adulthood. Methods and Results-A historic cohort study based on a 65-year follow-up of the Carnegie (Boyd Orr) survey of diet and health in prewar Britain, 1937 to 1939. A total of 732 eligible cohort members living in or around Aberdeen, Bristol, Dundee, Wisbech, and London were invited for follow-up examinations in 2002, and 405 (55%) participated. In models controlling for age and sex, breastfeeding was inversely associated with common carotid intima-media thickness (IMT; difference -0.03 mm; 95% CI, -0.07 to 0.01), bifurcation IMT (difference -0.19 mm; 95% CI, -0.37 to -0.01), carotid plaque (odds ratio [OR], 0.52; 95% CI, 0.29 to 0.92), and femoral plaque (OR, 0.54; 95% CI, 0.26 to 1.12), compared with bottle-feeding. Controlling for socioeconomic variables in childhood and adulthood, smoking and alcohol made little difference to effect estimates. Controlling for factors potentially on the causal pathway ( blood pressure, adiposity, cholesterol, insulin resistance, and C-reactive protein) made little difference to observed associations. Conclusions-Breastfeeding may be associated with a reduced risk of atherosclerosis in later life. Measurement error and power considerations limit the extent to which conclusions about the mechanisms underlying this relationship can be made.