Drinking more milk as a teenager does not lower risk of hip fracture later
Drinking more milk as a teenager apparently does not lower the risk of hip fracture as an older adult and instead appears to increase that risk for men, according to a study published by JAMA Pediatrics, a JAMA Network publication.
While drinking milk during adolescence is recommended to achieve peak bone mass, milk’s role in hip fractures later in life has not been established. Drinking more milk is associated with attaining greater height, which is a risk factor for hip fracture, according to the study background.
Diane Feskanich, Sc.D., of Brigham and Women’s Hospital and Harvard University, Boston, and colleagues examined the association between remembered teenage milk consumption and risk of hip fracture at older ages in a study of more than 96,000 men and women with a follow-up of more than 22 years. During the follow-up, 1,226 hip fractures were reported by women and 490 by men.
Study findings indicate teenage milk consumption (between the ages of 13-18 years) was associated with an increased risk of hip fractures in men, with each additional glass of milk per day as a teenager associated with a 9 percent higher risk. Teenage milk consumption was not associated with hip fractures in women. The association between drinking milk and hip fractures in men was partially influenced by height, according to the study
“We did not see an increased risk of hip fracture with teenage milk consumption in women as we did in men. One explanation may be the competing benefit of an increase in bone mass with an adverse effect of greater height. Women are at higher risk for osteoporosis than men, hence the benefit of greater bone mass balanced the increased risk related to height,” the authors comment.
Cheese intake during teenage years was not associated with the risk of hip fracture in either men or women.
Diane Feskanich, an assistant professor at Harvard Medical School in Boston, and her team tested the assumption by looking at hip fractures among more than 61,000 women and 35,000 men over 22 years.
“We questioned the belief that drinking more milk in earlier life would help to avoid these fractures in older adults,” Feskanich said in an interview.
In Monday’s issue of the journal JAMA Pediatrics, Feskanich and her co-authors said milk consumption during teenage years was not associated with a lower risk of hip fracture in the group of older adults they studied.
The researchers analyzed findings from white participants from the Nurses’ Health Study and Health Professional Followup Study.
Health Canada recommends 1,300 milligrams of calcium for children aged nine to 18.
“It does make you stop and ponder and want to see better evidence for our dietary recommendations,” Feskanich said of the study’s findings.
The authors suggest that further research needs to be done to examine the roles of early milk consumption and height in preventing hip fractures in older adults.
“Dietary Guidelines for Americans, 2010 recommends the consumption of three cups of milk or equivalent dairy foods per day to promote maximal bone mass in adolescents. In this investigation, higher milk consumption at this age did not translate into a lower risk of hip fracture for older adults, and a positive association was observed among men,” the study concludes.
(JAMA Pediatr. Published online November 18, 2013. doi:10.1001/jamapediatrics.2013.3821. )
Editor’s Note: This research was supported by a grant from the National Institute on Aging. Please see the articles for additional information, including other authors, author contributions and affiliations, financial disclosures, funding and support, etc.
In the UK, one in three women and one in twelve men over 50 will develop osteoporosis. However, this statistic could be improved by adequate intake of calcium during the critical teen years.
What is taken in during adolescence makes a big difference in the health of bones during the golden years. Almost 50 per cent of bone mass is acquired during the teenage years. By age 20, the amount of bone is at its greatest (called the peak bone mass), and then it slowly but steadily decreases. So, if not enough calcium is taken in during this critical period, less is available in the bones for the rest of life.
Daily dose
Nine out of ten teenage girls do not take in enough daily calcium. The recommended amount cannot be agreed upon: the Reference Nutrient Intake (RNI) is 800 milligrams of calcium per day for girls aged seven to 11 (1,000 for boys of the same age), but the National Osteoporosis Society recommends 1,000 milligrams generally (1/3 pint milk contains 230mg calcium.)
But how does one get a teenage girl to care about a problem that won’t haunt her for another 40 years? Many young women worry that milk and other dairy products will make them put on weight. Others simply have not had milk as a major part of their diets even before the teenage years, so they do not naturally drink this as a part of their meals when they are away from their parents. In addition, milk is not readily available as a part of the fast-food culture, so even those with good intentions are unable to drink milk due to lack of convenience.
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By Robert Steele, MD
Editorial: Milk Consumption, Bone Health
In a related editorial, Connie M. Weaver, Ph.D., of Purdue University, West Lafayette, Ind., writes: “A main tenet of Feskanich and colleagues is that milk consumption in teens may have led to an increase in height as an adult. Height has been identified as a risk factor for osteoporosis. It is not clear why this would be true in men but not women, and especially given that men experience about one-fourth the hip fractures that women do.”
“The investigators could have tested the contribution of other dietary protein sources (eggs, meat) to height and subsequent fracture risk to help confirm the impact of dietary protein more generally,” Weaver continues.
“Practically speaking, does the study by Feskanich and colleagues offer a solution to osteoporosis? Without dairy, dietary quality is compromised. If milk intake in teens contributes to height, and therefore fracture risk in older men, who among men aspire to be shorter?” Weaver concludes.
(JAMA Pediatr. Published online November 18, 2013. doi:10.1001/jamapediatrics.2013.4239. )
Editor’s Note: Weaver disclosed that she has received funding from the Dairy Research Institute and Nestlé. Please see the articles for additional information, including other authors, author contributions and affiliations, financial disclosures, funding and support, etc.
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Jessica Maki
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