Do maternal and intrauterine factors influence blood pressure in childhood?

It has been proposed that maternal health and nutrition may be important in the development of adult cardiovascular risk, and that blood pressure may be an important intermediate step in this process. To examine the relevance of this hypothesis in contemporary British children, the relationships of several maternal factors to blood pressure were studied in 3360 children of European origin aged 5-7 years. Maternal age, height, and body mass index were all positively related to blood pressure in childhood but these relationships were abolished once the child's body build was taken into account. Maternal social class, educational attainment, and history of smoking in pregnancy showed no relationship with blood pressure in childhood. Parity showed an inverse association with blood pressure, but this appeared to be due to an association between total sibship size and blood pressure, suggesting a postnatal rather than a prenatal origin. Blood pressure was higher in children whose mothers had a history of high blood pressure but this association was no stronger than that for paternal history. Both birth weight and gestational age were inversely related to blood pressure at 5-7 years. The association between birth weight and blood pressure was attenuated by standardisation for gestational age, and the relationships between birth weight and blood pressure were similar in preterm and full term infants. No specific association between blood pressure and the maternal factors studied have been observed in this population. Hypotheses relating maternal factors to cardiovascular risk need to specify the timing and nature of their effects more precisely. Although the relationship between birth weight and blood pressure is not fully understood, it appears to reflect size at birth rather than fetal growth rate.

Intermittent ambulatory blood pressure recordings in children. Methodological aspects and influence of family history on hypertension

In 100 children of different school classes (10-12 years, participation rate ca. 50%) ambulatory blood pressure (BP) was recorded by a semi-automatic non-invasive device (Remler system). BP was measured every 1/2 h between 2 and 7.30 p.m. During each measurement the children protocolled their activity. These BP recordings were repeated five times at monthly intervals in 86 children. In the same children casual and near basal BP was determined. The mean ambulatory BP was 103/64 +/- 7/6 mm Hg. The average retest reliability of the monthly mean values was r = 0.57 for systolic and r = 0.45 for diastolic BP. The variability of BP (standard deviation) was not reproducible. Data recording failed in 32% of all single systolic and in 42% of all single diastolic BP measurements. These drop-outs were caused by inappropriate use rather than technical problems. There was a relationship between procolled activities and systolic BP. On average, ambulatory BP was lower than BP under standardized conditions. Under all conditions, children with hypertensive parents exhibited a 6 mm Hg higher systolic BP than children without a similar family history. No sex differences were found.

Behavioral response to induced conflict in families with a hypertensive father

To clarify the possible environmental mediation of familial aggregation of blood pressure (BP), we examined whether the behavior of family members differed between families with a hypertensive (n = 16) or a normotensive (n = 15) father. Three-member families consisting of a father, mother, and a boy or girl aged 8-13 years were videotaped as they interacted under standard conditions calling for disagreement or conflict. Their BPs were recorded before and after interactions. The videotaped material was reliably coded into behavioral categories by independent observers. The aggregate of all three members of families with hypertensive fathers, as well as normotensive mothers and the children in these families, showed significantly more negative nonverbal behavior than their counterparts in families with normotensive fathers.

Muscle strength and body composition as determinants of blood pressure in young men

The correlations of blood pressure to various indices of muscularity and fatness were studied in 183 young healthy men (mean age 19.7, SD 2.1 years). Systolic pressure showed significant positive correlations with body fat percentage, isometric strength of trunk extensors, body mass index, lean body mass, strength of leg extensors, heart rate, and the sum of four skinfolds. Diastolic pressure had significant positive correlations with body mass index, lean body mass, body fat percentage, sum of skinfolds, strength of leg extensors, strength of trunk extensors, and age. A stepwise selective multiple regression analysis for systolic pressure resulted in four significantly correlating variables: body fat percentage (p less than 0.001), heart rate (p less than 0.01), lean body mass (p less than 0.05), and strength of trunk extensors per kg body weight (p less than 0.05). For diastolic pressure the analysis resulted in two explaining variables: body mass index (p less than 0.001) and age (p less than 0.05). In a regression equation with 13 variables the strength of trunk flexors was negatively correlated with diastolic pressure. It is concluded that both fatness and muscularity are factors related to blood pressure in young men. The muscularity effect is more clearly associated with trunk and leg extensor strength.

Hypertension and arterial development. Long-term considerations

A considerable body of evidence supports the view that haemodynamic factors, acting during growth and development, affect the ultimate form of the larger arteries. Many of the changes induced in vessels by high pressure or flow are adaptive and effectively minimise alterations in vessel function, but these changes may predispose to degenerative disease. 'Early intervention' in arterial disease implies intervention in the first and second decades of life.