Birth weight linked to high blood pressure risk
|
|
Men born at below-average weight are slightly more likely to have high blood pressure as young adults, a relationship that does not appear to be related to genetics or socioeconomic factors, the results of a large study from Sweden shows.
The findings support the theory that poor growth in the womb may cause disorders of the metabolism, such as high blood pressure (hypertension) or diabetes, known as the “fetal programming hypothesis,” Dr. Niklas Bergvall of the Karolinska Institutet in Stockholm and colleagues report in the September issue of Epidemiology.
While past research has linked low birth weight to high blood pressure, most studies have not taken socioeconomic and genetic factors into account. Since both are tied to the risk of low birth weight as well as high blood pressure in adulthood, the relationship could be due to these factors, Bergvall and his team note.
To look at the effect of low birth weight independently, the researchers studied a group of Swedish men conscripted for military service, nearly 90,000 of whom had at least one brother available for comparison. Because brothers share half of their genes, on average, grow up in the same environment and have the same socioeconomic status, this allowed the researchers to control for the effect of these factors on the relationship between low birth weight and high blood pressure.
The researchers defined low birth weight as below 2,806 grams (6 pounds, 3 ounces) for babies born at 40 weeks gestation, and high systolic blood pressure as 140 mm/Hg or greater. Systolic pressure is the top number in a blood pressure reading.
The National Institutes of Health has further defined high blood pressure. These categories are for people 18 years and older who do not take medication for high blood pressure and do not have a short-term serious illness. These categories are as follows.
- Normal blood pressure is a systolic blood pressure of less than 130, and a diastolic pressure of less than 85.
- High normal blood pressure is a systolic blood pressure of 130 to 139, and a diastolic pressure of 85 to 89.
- Stage 1 high blood pressure is a systolic blood pressure of 140 to 159, and a diastolic pressure of 90 to 99.
- Stage 2 high blood pressure is a systolic blood pressure of 160 to 179, and a diastolic pressure of 100 to 109.
- Stage 3 high blood pressure is a systolic blood pressure of 180 or higher, or a diastolic blood pressure of 110 or higher.
After adjusting for these other factors, the researchers found that men born at low birth weight had a 14-percent greater risk of high systolic blood pressure in young adulthood.
“Our results lend some support to the fetal programming hypothesis, which states that metabolic disorders originate through adaptations in the malnourished fetus,” they conclude.
SOURCE: Epidemiology, September 2005.
Print Version
Tell-a-Friend comments powered by Disqus
