Birthweight, adult risk factors and incident coronary heart disease: The Caerphilly study

Objective: To determine the relationships between birthweight, the incidence of coronary heart disease, and a range of coronary heart disease risk factors that operate during adult life. Design: Cohort study with a 10-year follow-up period. Setting : The town of Caerphilly, South Wales, and five adjacent villages. Subjects: 1,258 men aged 45-59 at time of recruitment between 1979 and 1983. Main outcome measures : All deaths, coronary heart disease deaths, non-fatal CHD events. Results: The validity of the birthweight data was supported by the strong graded associations between birthweight and anthropometric measures in adulthood, particularly height, body mass index, triceps skinfold thickness and percentage body fat. An inverse relationship was found between birthweight and incident fatal and non-fatal CHD, (P = 0.01), though no relationship was found between birthweight and all-cause mortality. Amongst the major CHD risk factors, only fibrinogen shows a statistically significant relationship with birthweight (P = 0.008), fibrinogen levels being lower among the men with lower birthweights. When social and biological variables are included in models relating incident CHD and birthweight, the relationship between birthweight and incident fatal and non-fatal CHD remains essentially unchanged. Conclusion: A graded association between low birthweight and later CHD has been demonstrated in this cohort. This inverse association cannot be explained by the measured social or behavioural variables, or by other risk factors operating in adult life.