Blood pressure in Jamaican children: relationship to body size and composition.

Blood pressure levels in adults and children are related to body size and composition, but some of these relationships are unclear and they have been incompletely described in the Jamaican population. In a cross-sectional survey of 2,332 school children (6-16 years old; 1,046 boys, 1,286 girls), we measured systolic and diastolic blood pressure and pulse rate, and explored their relationship to weight, height, and waist, hip and mid-upper arm circumferences. The effect of these and other derived measures of body composition on blood pressure was explored in univariate and multivariate analysis. Blood pressure increased with age in both boys and girls, although the increase was greater for systolic than for diastolic blood pressure. The increase of systolic blood pressure among boys continued after age 11 years, but that for girls levelled off. Height and weight were the major predictors of blood pressure, but were highly correlated with each other and with all measures of body composition. Age, height and height-sex interaction explained 11.4% of systolic blood pressure variation, and the largest incremental contribution to this model was provided by the addition of body mass index or hip circumference, each explaining an additional 2.6% of the variance. Lean body mass made a larger contribution to blood pressure than percent fatness. Blood pressure in Jamaican children rises with age and this rise may be steeper in boys than girls. Blood pressure variation is significantly related to several measures of body composition including measures of fatness and fat free mass.