In poor countries, taller moms' kids are healthier

NEW YORK (Reuters Health) - In developing countries, taller moms tend to give birth to healthier kids who are less likely to die in infancy, be underweight or have stunted growth, a new study finds. At the same time, good nutrition in adolescence and delaying marriage and childbirth appear to lead to taller adults.

“This is the first time we’re seeing an effect of the mother’s health -- as captured through her attained height -- being transferred well into the childhood of her offspring,” study author Dr. S. V. Subramanian of the Harvard School of Public Health told Reuters Health.

Subramanian and colleagues looked at health data from 54 developing countries gathered between 1991 and 2008 of nearly 3 million births to more than three quarters of a million women between the ages of 15 and 49.

The mothers were separated into 5 height categories, ranging from under four feet nine inches to taller than five feet three inches.

Overall, almost 12 percent of the children in the study died before the age of five years. With each drop in height category, the risk of child mortality increased “substantially,” the researchers found.

Children born to the shortest moms had about a 40 percent higher risk of dying during childhood than those born to the tallest mothers. The risk of death among those born to the tallest mothers was about one in 14, compared to about one in seven for those born to the shortest mothers.

More pronounced discrepancies were noted in children’s failure to flourish physically. Each lower height category in the moms was associated with a “substantially higher” risk of their children being underweight and having stunted growth.

Maternal height was the “most important factor” in determining risk of growth failure, twice the effect of a mother’s education and 1.5 times the effect of her income.

“What surprised me the most was the consistency of the findings,” Subramanian said.

Whether the results would be the same in wealthier nations is unclear, but Subramanian said it was unlikely, given the extremely different environment into which children in developed nations are born. Even extremely premature infants, for example, can be saved using expensive technology available in richer countries. If researchers looked at other effects, such as mental functioning, they might find similarities, he said.

Still, “there are certainly underserved populations (with higher rates of maternal and child undernutrition than the national averages) in high income countries to whom these results/associations would apply,” Dr. Parul Christian, of the Johns Hopkins Bloomberg School of Public Health, who was not involved in the research, told Reuters Health.

Writing in the April 21 issue of the Journal of the American Medical Association, the Harvard researchers argue that the data suggest nurture impacts nature from one generation to the next.

“Past research has shown the benefits of height on life expectancy and income; this is the first study to show the intergenerational passing on of advantage in physical health,” Subramanian said.

Because adult height “reflects the stressful nutritional environment of the mother in early life,” the results could have implications for how nutrition programs are designed and targeted.

“We need to focus on interventions that have an intergenerational payoff, which happens only when you invest in children -- especially girl children between ages 5 and 15,” Subramanian said.

In an editorial accompanying the study, Christian writes that the study underscores the “vast challenge” and value of addressing maternal undernutrition and short stature in turning around child mortality and undernutrition in the developing world.

“It could take multiple generations to turn around, but you have to start somewhere,” Christian told Reuters Health. “The next generation will be slightly better.”

SOURCE: Journal of the American Medical Association, April 21, 2010.