Size at birth and blood pressure: cross sectional study in 8-11 year old children
BMJ 1997; 314 doi: https://doi.org/10.1136/bmj.314.7079.475 (Published 15 February 1997) Cite this as: BMJ 1997;314:475
- Stephanie J C Taylor (staylor{at}rfhsm.ac.uk), honorary research fellow in public health medicinea,
- Peter H Whincup, senior lecturer in clinical epidemiologya,
- Derek G Cook, reader in epidemiologyb,
- Olia Papacosta, research statisticiana,
- Mary Walker, honorary research fellowa
- a Cardiovascular Research Group Department of Primary Care and Population Sciences Royal Free Hospital School of Medicine London NW3 2PF
- b Department of Public Health Sciences St George's Hospital Medical School London SW17 0RE
- Correspondence to: Dr Taylor
- Accepted 29 November 1996
Abstract
Objective: To identify which patterns of fetal growth, represented by different measurements of size at birth, are associated with increased blood pressure in children aged 8-11 years.
Design and setting: School based, cross sectional survey conducted in 10 towns in England and Wales in 1994.
Subjects: 3010 singleton children (response rate 75%) with physical measurements and information on birth weight from parental questionnaires. Hospital birth records were examined for 1573.
Main outcome measures: Systolic and diastolic blood pressure at age 8-11 years.
Results: In the whole group birth weight was inversely related to systolic pressure (regression coefficient -1.48 mm Hg/kg; 95% confidence interval -2.20 to -0.76) after adjustment for current body size. There was no significant association between birth weight and diastolic pressure. The association with systolic pressure was much stronger in girls (-2.54 mm Hg/kg; -3.60 to -1.48) than in boys (-0.64 mm Hg/kg; -1.58 to 0.30), with a significant difference between the sexes (P=0.006). Among the other neonatal measures, head circumference and placental weight were inversely associated with subsequent blood pressure in girls, and placental ratio (placental weight:birth weight) was positively associated with blood pressure in boys. Neither ponderal index at birth nor length:head circumference ratio was related to blood pressure in either sex.
Conclusions: In these contemporary children the association between birth weight and blood pressure was apparent only in girls. There was no evidence that measures of size at birth, which may be related to nutrition at critical periods of pregnancy (thinness at birth or shortness in relation to head circumference), are related to blood pressure in the offspring.
Key messages
This study confirms the well established inverse association between birth weight and childhood blood pressure, but there seems to be a strong difference between the sexes towards the end of the first decade of life—the association being strong in girls and weak or absent in boys
Only highly correlated, simple measures of size at birth seem to be associated with blood pressure in girls; more complex measures of size at birth, including ponderal index and shortness in association to head circumference, are not associated with childhood blood pressure in either sex at 8-11 years
The association between placental weight and placental ratio and blood pressure in children of 8-11 years is inconsistent
These findings do not support the hypothesis that fetal undernutrition “programmes” raise blood pressure in the second and third trimesters
Current body size is a much more important determinant of blood pressure in childhood than size at birth
Footnotes
- Accepted 29 November 1996