Calcium Boost To Youths’ Bones Could Reduce Osteoporosis Risk

In the study at The Ohio State University Medical Center, which is the first clinical trial to track calcium’s effects on bone density in girls age 8-13 for as long as seven years, researchers found that calcium supplementation significantly increased bone mass development during a critical childhood growth spurt.

The findings suggest that elevated calcium use by pre-adolescent girls is likely to help prevent fractures and osteoporosis much later in life, said Velimir Matkovic, lead author of the study and director of the Osteoporosis Prevention and Treatment Center and the Bone and Mineral Metabolism Laboratory at OSU Medical Center.

The research is published in the January issue of the American Journal of Clinical Nutrition and the Journal of Nutrition.

“Because most bone mass is accumulated during this phase of growth, pre-adolescence may represent the time of highest need for calcium in a female’s lifetime,” said Matkovic, also a professor of physical medicine and rehabilitation and nutrition.

Matkovic pioneered research on the concept of calcium’s relationship to peak bone mass in the 1970s, when he documented differing fracture rates among populations that consumed contrasting levels of dairy products over their lifetime. His initial study, based in Croatia, is cited in “Bone Health and Osteoporosis,” a report of the U.S. Surgeon General associated with the federal declaration that 2002-2011 is the Decade of the Bone and Joint.

“The importance of preventing osteoporosis can’t be overstated,” Matkovic said. “Prevention of this disease will not only improve the population’s quality of life, but will also undoubtedly save on the skyrocketing health care costs associated with treatment.”

In patients with osteoporosis, the natural cycle of losing and adding minerals in healthy bone falls out of balance and the loss outpaces the gain, leading to low bone mass, structural deterioration of bone tissue, fragility and an increased susceptibility to fractures of the hip, spine and wrist. An estimated 30 million American women either have or are at risk for osteoporosis.

Though the risk of losing bone mass is part of aging, having the strongest skeleton possible as a youngster can tip the balance toward better bone health in later years, Matkovic said. The study also suggested that in addition to long-term benefits to women, high calcium intake during childhood shows signs of preventing bone fragility fractures in girls.

“We advocate development of a healthy skeleton throughout life,” Matkovic said.

Calcium exerts its action on bone accumulation during growth primarily by influencing the volumetric bone mineral density. The point of the clinical trial was to evaluate the effectiveness of calcium supplementation on bone mineral density during the period when most of the bone mass is accumulated. The pubertal growth spurt accounts for about 37 percent of the gain in the entire adult skeletal mass, meaning “inadequate calcium intake during this period compromises the bone mineral accumulation rate,” Matkovic said.

The seven-year length of the study allowed researchers to determine that calcium supplementation has the most significant effect on girls’ bone build-up during that growth spurt, and that over time, after the onset of menstruation, calcium supplementation’s effects on bone density decreased.

The calcium-supplemented group among the 354 girls in the trial showed a faster rate of bone mass development from the beginning of the study. The biggest difference in bone mineral density between the supplemented and nonsupplemented groups of girls occurred from between one year before and one year after the onset of menstruation. By young adulthood, significant effects remained at the metacarpals in the hands, the forearm and the hip.

The average dietary calcium intake among all study participants was 830 milligrams per day. The supplemented group took in an average of an additional 670 milligrams per day, equivalent to the calcium found in about 18 ounces of milk. The researchers noted that the calcium requirement for growth is body-size specific; taller individuals need more calcium during growth than shorter individuals.

Ohio State coauthors of the paper were Nancy Badenhop-Stevens, John Landoll, Eun-Jeong Ha and Albert Clairmont of the Osteoporosis Prevention and Treatment Center and Bone Mineral Metabolism Laboratory; Prem Goel and Bin Li of the Department of Statistics; and Larry Nagode of the Department of Veterinary Biosciences.

This work was supported by the National Institutes of Health, the U.S. Department of Agriculture, Procter & Gamble Co., the National Dairy Council, Ross Products Division Abbott Laboratories and General Mills Co.