A Swedish study shows that men born with below-average birth weight have a slightly higher risk of developing high blood pressure (BP) as young adults, compared with men born within the average weight range.
The findings support the theory that poor fetal growth may cause metabolic disorders, such as high BP or diabetes. This theory is known as the "fetal programming hypothesis," according to a report by Niklas Bergvall, PhD, of the Karolinska Institutet in Stockholm, which appeared in the September 2005 issue of Epidemiology.
Although past research has linked low birth weight (LBW) to high BP, most studies have not taken socioeconomic and genetic factors into account. Because both are linked to the risk of LBW as well as the risk of high adult BP, the relationship could be due to these factors.
The study included adult men, nearly 90,000 of whom had at least 1 brother to use for a comparison. Because brothers share an average of half their genes, grow up in the same environment, and have the same socioeconomic status, researchers were able to control for the effect of these factors on the relationship between LBW and high BP.
The researchers defined LBW as a weight below 6 lb 3 oz for babies born at 40 weeks' gestation, and high systolic BP as 140 mm Hg or higher. After adjusting for genetic and socioeconomic factors, they found that men born with LBW had a 14% greater risk of developing high BP in young adulthood.