Drinking Milk as Teens May Not Protect Men's Bones
Instead, research found boys who consumed more milk had higher risk of hip fractures as adults
By Alan Mozes
TUESDAY, Nov. 19, 2013 (HealthDay News) -- Boys who drink more milk during their teenage years might not see any drop in their risk for hip fractures as adults, new research suggests. Just the opposite: Their risk actually might rise.
The finding, which was not observed among women, is based on the fracture history of nearly 100,000 white men and women, middle-aged and older, who recounted their milk-drinking habits decades earlier.
"I don't consider this to be a definitive finding that would change the public-health message concerning milk at this point," said lead study author Diane Feskanich. "But even though we're very focused on milk in this country, we don't really have studies that have documented how people drink milk as kids and then have waited 50 to 60 years to see what happens to their bones.
"What we found was a little surprising. Teen milk consumption was associated with a higher fracture risk among men, but not women," said Feskanich, an assistant professor in the department of medicine at Brigham and Women's Hospital and Harvard Medical School, in Boston.
Feskanich and her colleagues discussed their findings in the Nov. 18 online issue of the journal JAMA Pediatrics.
The researchers said milk has long been touted as an essential part of teen diets. The most recent dietary guidelines from the U.S. Department of Agriculture recommend that adolescents drink at least three glasses of milk (or a dairy equivalent) each day.
The guidelines' goal is to ensure proper skeletal growth and health during adolescence, the time during which boys and girls amass roughly 95 percent of their future adult bone mineral content, the researchers said.
But they also said growing taller -- which can be spurred by drinking milk -- has itself has been linked to a greater risk for fractures, perhaps complicating milk's overall protective role regarding hip-fracture risk.
The investigators analyzed teen milk-consumption patterns that had been reported in 1986 by women participating in the Nurses' Health Study, and in 1988 by men participating in the Health Professional Follow-Up Study.
All participants were white, and milk-consumption histories (primarily involving whole milk) focused on the ages of 13 to 18. The participants' histories were provided solely on the basis of personal recall.
More than 35,000 men and nearly 62,000 women were tracked for 22 years. During this time, 490 hip fractures occurred among men and more than 1,200 occurred among women.
First, the researchers accounted for a number of possible influencing factors, such as current diet, weight, smoking history, exercise patterns, prescription drug use and current milk-consumption habits. They then determined that a man's risk for a hip fracture actually increased 9 percent for every additional daily glass of milk he had consumed while a teen.