Size at Birth, Infant Growth, and Blood Pressure at Three Years of Age
Received 7 December 2006; received in revised form 16 March 2007; accepted 1 May 2007. published online 13 August 2007.
Objectives
Our aim was to determine the extent to which infant growth—in weight-for-length—from birth to 6 months is associated with systolic blood pressure (SBP) at 3 years and to determine whether this association varies with birth size.
Study design
In 530 children from the prospective cohort Project Viva, we measured birth length and 6-month weight and length with research standard instruments and SBP at age 3 years with a Dinamap automated recorder. We derived weight-for-length z-scores (WFL-z) and analyzed data with mixed effects regression models.
Results
The mean (SD) WFL-z was 0.47 (0.75) at birth and 0.70 (0.96) at 6 months. Mean (SD) SBP at 3 years was 91.7 (9.4) mm Hg. After adjusting for confounding variables and birth WFL-z, child SBP was 1.0 mm Hg (95% CI 0.2, 1.8) higher for each z-score increment in 6-month WFL-z. The SBP of children in the lowest birth WFL-z quartile and the highest 6-month WFL-z quartile was 5.5 mm Hg (95% CI 2.6, 8.4) higher than that of children in the highest birth and lowest 6-month WFL-z quartiles.
Conclusions
More rapid increase in weight-for-length, a measure of adiposity, in the first 6 months of life is associated with higher early childhood SBP, particularly in children who are thin at birth.
aDepartment of Ambulatory Care and Prevention, Harvard Medical School/Harvard Pilgrim Health Care, Boston, MA
bDivision of Newborn Medicine, Children’s Hospital Boston, Boston, MA
cDivision of Women’s Health, Brigham and Women’s Hospital, Boston, MA
dDepartment of Epidemiology, Harvard School of Public Health, Boston, MA
eDepartment of Nutrition, Harvard School of Public Health, Boston, MA.
Reprint requests: Mandy B. Belfort, MD, MPH, Division of Newborn Medicine, Hunnewell 437, Children’s Hospital Boston, 300 Longwood Ave, Boston, MA 02115.
Supported by NIH (HD 34568, HL 64925, HL 68041), Harvard Medical School, Harvard Pilgrim Health Care Foundation, and Harvard Pediatric Health Services Research Fellowship Program (HRSA T32 HP10018).
ABSTRACT