Current research - The relationship of dietary and lifestyle factors to bone mineral indexes in children

Objective To identify factors related to children's bone mineral indexes at age 8 years, and to assess bone mineral indexes in the same children at ages 6 and 8 years. Design Bone mineral content (BMC [g]) and bone mineral density (BMD; calculated as g/cm(2)) were measured by dual-energy x-ray absorptiometry (DEXA) in children and their mothers when the children were 8 years of age. A subset of children had an earlier DEXA assessment at age 6 years. Children's dietary intake, height, weight, and level of sedentary activity were assessed as part of a longitudinal study from ages 2 months to 8 years. Subjects/setting Fifty-two healthy white children (25 male, 27 female) and their mothers. Main outcome measures Children's total BMC and BMD at age 8 years. Statistical analyses performed Correlations and stepwise multiple regression analyses. Results Factors positively related to children's BMC at age 8 years included longitudinal intakes (ages 2 to 8 years) of protein, phosphorus, vitamin K, magnesium, zinc, energy, and iron; height; weight; and age (P <=.05). Factors positively related to children's BMD at age 8 years included longitudinal intakes of protein and magnesium (P <=.05). Female sex was negatively associated with BMC and BMD at age 8 years (P <=.05). Children's bone mineral indexes at ages 6 and 8 years were strongly correlated (r=0.86, P <.0001 for BMC; r=0.92, P <.0001 for BMD). Conclusions Because many nutrients are related to bone health, children should consume a varied and nutrient-dense diet.