25-Hydroxyvitamin D, calcium intake, and bone mineral content in adolescents and young adults: analysis of the fourth and fifth Korea National Health and Nutrition Examination Survey (KNHANES IV-2, 3, 2008-2009 and V-1, 2010).

CONTEXT

The amount of calcium and vitamin D needed to support bone development is still uncertain.

OBJECTIVE

We examined the association of 25-hydroxyvitamin D [25(OH)D] and calcium intake with bone mineral content (BMC).

DESIGN

A total of 2918 subjects (1345 males and 1573 females) aged 10 to 29 years from the 2008-2010 Korea National Health and Nutrition Examination Survey were stratified into 3 age groups: early adolescents, late adolescents, and young adults.

OUTCOME MEASURES

BMC of femoral neck, total hip, and lumbar spine were evaluated in each group according to quartiles of serum 25(OH)D concentration and calcium intake.

RESULTS

Mean serum 25(OH)D for all males and females were 43.4 and 39.2 nmol/L, and calcium intakes were 524.4 and 437.2 mg/d, respectively. Early adolescent and young adult males had strong and significant associations of serum 25(OH)D with BMC at each skeletal site. The association was not linear, and a step up was observed at a 25(OH)D concentration of 53.0 nmol/L. Although the impact of calcium intake on BMC was not evident, the top quartile of both serum 25(OH)D and calcium intake had a higher BMC than those in the top quartile of either nutrient alone in these subjects. In late adolescent males and in females, 25(OH)D and BMC associations were inconsistent.

CONCLUSIONS

This cross-sectional study indicates a significant association of serum 25(OH)D concentration with BMC and a supportive role of calcium on bone mass for early adolescents and young adult males. We believe that a large proportion of young Koreans would attain greater BMC if they increased their 25(OH)D concentrations and calcium intake.