A study of blood pressure in children in nine british towns.

The age at which differences in blood pressure between populations emerge may have important implications for the primary prevention of high blood pressure. This thesis describes a study of blood pressure in childhood, conducted in nine British towns in 4056 children aged between 5.00 and 7.50 years to determine whether the pattern of geographic differences previously described in middle-aged men was also present in childhood. Standardization of blood pressure measurement was facilitated by the use of an automated oscillonetric blood pressure recorder, the Dinamap 1846SX. Cuff bladder size had a marked effect on blood pressure measurement and was taken into account in the analyses. Significant differences between the mean systolic and diastolic blood pressures of children in the different towns were observed. The pattern of town mean blood pressures was related both to the blood pressure pattern in adults in the same towns and to standardized mortality ratios for adult cardiovascular disease. However, these findings were strongly dependent on the observations in Guildford, a town with exceptionally low average blood pressure levels both in children and in adults. Blood pressure levels were strongly related to age, weight and height but not to social factors. Birth weight was inversely related to blood pressure at 5-7 years but only when standardized for current body build. Maternal age, birth order and a parental history of hypertension were all strongly related to blood pressure; average blood pressures were higher in subjects with higher maternal age, in firstborn children and in those with a parental history of high blood pressure. These effects were largely independent of one another and of age and social class. The results suggest that geographic differences in blood pressure in British men may have their origins in the first years of life. The relationship between birthweight and blood pressure in childhood may reflect the influence of either intrauterine or factors or, more likely, weight gain in infancy. New studies to investigate these findings further are outlined