Mothers' pelvic size, fetal growth, and death from stroke and coronary heart disease in men in the UK.

BACKGROUND

People who have a low birthweight show increased death rates from coronary heart disease and a higher prevalence for its risk factors. These findings have led to the hypothesis that the disease is programmed in fetal life. The aim of this study was to explore whether risk of stroke in adult life was linked to impaired fetal growth.

METHODS

We ascertained deaths from stroke and coronary heart disease in 13 249 men in two cohorts from Hertfordshire and Sheffield, UK. We related death rates from these disease to body size at birth, weight at 1 year, and to measurements of the mothers' pelvises.

FINDINGS

Death rates from both stroke and coronary heart disease tended to be highest in men whose birthweight had been low. Standardised mortality ratios (SMRs) for stroke fell by 12% (95% Cl 1-22) and for coronary heart disease by 10% (6-14) between each of five groupings of increasing birthweight (< or = 5.5 lb, 5.6-6.5 lb, 6.6-7.5 lb, 7.6-8.5 lb, and > 8.5 lb). Mortality from stroke was most strongly associated with low birthweight in relation to head size, and low placental weight in relation to head size. These patterns of growth occurred in offspring of mothers with flat bony pelvises. The SMR in sons of these women was 184 (67-396) compared with 104 (78-138) in the remainder of the cohort. In contrast, mortality from coronary heart disease was associated with small head circumference, thinness or shortness at birth and an altered ratio of placental weight to birthweight.

INTERPRETATION

Stroke may originate in poor nutrition during the mother's childhood, which deforms the bony pelvis and subsequently impairs her ability to sustain the growth of the placenta and fetus in late pregnancy. Coronary heart disease, on the other hand, seems to originate in adaptations made by the fetus to inadequate delivery of nutrients when it occurs for reasons other than failure of placental growth.