[Relations between blood pressure at 3-4 years of age and body mass at birth: a population-based study].

BACKGROUND

To study the association between blood pressure of 3-4 year-old children and birth corpulence estimated from birth ponderal index (body weight/length3), a school based, cross sectional survey was conducted in the Rhône department.

METHODS

1296 randomly selected children were examined at the time of a school medical visit. Physicians abstracted information on pregnancy and measurements at birth from the Child Health Handbook and from parents interview. Systolic and diastolic blood pressure measurements were carried out by using an automated oscillometric device.

RESULTS

Multiple linear regression analyses revealed an inverse association between systolic blood pressure and birth ponderal index (converted into Z-score adapted to gestational age), this was obtained after adjustment for current length and for current body mass index (body weight/length2--converted into Z-score), for child emotion and for linked study factors. Such a model provided an assessment of regression coefficient: -0.67 mmHg/birth ponderal index Z-score unit (95% confidence interval: -1.24 to -0.11). So, estimation of systolic blood pressure difference between two 3-4 year-old children, one at -2 SD birth ponderal index and another at +2 SD, was obtained: 2.6 mmHg. No evidence of an association between diastolic blood pressure and birth ponderal index was observed.

CONCLUSION

In this large population with a limited range of age, our results show that, at age 3-4 years, systolic blood pressure is higher with lower birth ponderal index, suggesting that thinness at birth might be a risk factor of hypertension in adulthood.