Search

Fetal growth retardation has been linked to elevated blood pressure in adult life. This association between birth weight and blood pressure is present in childhood and is amplified with age. However, the mechanisms that underlie this association are largely unknown. We examined the relationship between birth weight and forearm vascular resistance and forearm blood flow in children aged 9-12.7 years. A total of 58 children were randomly selected from a cohort of 1610 born at the University Hospital of the West Indies in Jamaica where adequate antenatal and delivery records were available. Blood pressure, heart rate and forearm blood flow (by venous occlusion plethysmography) were measured at rest and after cold pressor and mental arithmetic tests. There was a significant inverse correlation between birth weight and the change in the vascular resistance for the cold pressor test (r=-0.47; P<0.001) and the mental arithmetic stress test (r=-0.26; P=0.05). The log ratio of vascular resistance under stress to resting decreased by 0.289 units per kg of birth weight (95% CI: 0.145-0.434; P=0.0002). Lower birth weight is associated with increased vascular responsiveness. Increased vascular resistance might be one mechanism linking fetal growth to subsequent elevated blood pressure.

Percent body fat (%BF) was estimated in 50 males and 50 females aged 8-21 y by using hydrodensitometry (%BFd) and a bioelectrical-impedance analyzer (%BF-BIA). The sample population was racially heterogeneous, though predominantly of African origin. Percent body fat was computed from density by using an equation derived specifically for blacks. The BIA predicted %BF with r2 = 0.77 (SEE = 3.7%BF), underestimating by a mean of 1.7%BF. Residuals (%BFd - %BF-BIA) were normally distributed but were significantly correlated with age (P less than 0.01), although this effect was small. The theoretical bases for impedance analysis and for hydrodensitometry would appear for different reasons to impair applicability of these techniques to the present population and age group. However, for our population sample the BIA estimated %BF as precisely as other simple techniques applied to other populations.