Boys who are lean newborns but who gain significant weight between 8 and 15 years of age have an increased risk for hypertension as teenagers, according to an article in the February 11th rapid access issue of Hypertension.

“The boys who were thinnest at birth and who gained the most weight during childhood and adolescence were the ones who had the greatest risk of high blood pressure,” said lead author Linda S. Adair, Ph.D.

In contrast, adolescents with more rapid growth in the first 2 years of life rather than later in childhood were not at increased risk for hypertension in adolescence regardless of birth weight.

“Faster growth in infancy did not represent a risk for increased blood pressure in adolescence for either sex,” Adair said. “This period of weight gain may even be slightly protective against high blood pressure later. This is an important finding because pediatricians want to see improved growth in babies born small.”

For girls, large weight gains during ages 8 to 15 years increased risk for hypertension, but the risk was unrelated to birth weight. This finding surprised the researchers.

“The sex difference is a big question that we cannot answer,” Adair explained. “We thought the reason might be related to sexual maturity, but when we controlled for it in our analysis, it didn’t make a difference.”

Low birth weight in full-term infants may be evidence of fetal growth retardation, said Adair. The new findings are consistent with the fetal programming hypothesis, which states that a malnourished fetus will adapt its metabolism to survive until birth, but that these same changes put a person at increased risk of several chronic diseases - including cardiovascular ailments, diabetes and perhaps cancer - later in life.

For the current study, Adair and biostatistician Tim J. Cole, Sc.D., tested the hypothesis with use of data from the Cebu Longitudinal Health and Nutrition Survey, which follows more than 2,000 persons born between 1983 and 1984 in and near Cebu, the Philippines’ second largest city.

Adair noted that the long-lasting effects of birth weight remained important even after adjustment for other risk factors for hypertension. Adair concluded that the study results emphasize the need for pregnant women to receive adequate nutrition and health care before and during pregnancy to avoid fetal growth retardation.