Older men tend to father low birthweight infants

By Anne Harding

NEW YORK (Reuters Health) - A study conducted in an urban U.S. population found that men over the age of 35 were more likely to father low birth weight infants than their younger peers.

"This is just one more study that's indicating that fathers matter too," co-author Dr. Nancy E. Reichman of the University of Medicine and Dentistry of New Jersey in New Brunswick, told Reuters Health. The findings also suggest that poverty and living in an urban environment can be damaging to men's health.

While a number of studies have linked advanced paternal age to birth defects and pregnancy complications, the current study is the first to examine the effect of a father's age on low birth weight in an urban context, Reichman her co-author, Dr. Julien O. Teitler of Columbia University in New York, note in their report in the American Journal of Public Health.

Birth weight below 2500 grams (about 5.5 pounds) increases an infant's risk of disorders such as cerebral palsy, deafness and attention deficit disorder, the researchers point out.

Reichman and Teitler evaluated a population-based sample of 4,621 births to first-time parents in 18 U.S. cities. Sixty-five percent of mothers were on Medicaid. Forty-seven percent of the women were black, 27 percent were Hispanic, and 21 percent were white.

Men 35 years of age or older were 90 percent more likely than men between 20 and 34 years old to father a low birth weight baby, while teenage fathers were 20 percent less likely to father a low birth weight baby. The relationship between a father's age and low birth weight was the same for all ethnic groups.

Men's age had the same influence on the risk of low birth weight as the mother's age did, the researchers found, with women 35 or older about twice as likely to have underweight infants than younger women.

Reichman and Teitler say the findings support the concept of "weathering," meaning that poorer people age more quickly and show declines in health faster than relatively wealthy individuals.

"Basically health declines as men age, but the decline appears to be accelerated among men who are socioeconomically disadvantaged," Reichman told Reuters Health. "The health status of a well-off man at age 50 might be the same as a poor man at age 35, for example."

Also poor men living in urban areas may have greater exposure to dangerous chemicals on the job, more life stresses, or be more likely to smoke, drink or use drugs, the researchers suggest.

"What we don't want the message to be is that women shouldn't be having children with older men," Teitler told Reuters Health. Instead, the findings should spur investigation into poverty's effects on the health of both men and women.

SOURCE: American Journal of Public Health, May 2006.