Calcium supplementation, bone mineral density and bone mineral content. Predictors of bone mass changes in adolescent mothers during the 6-month postpartum period

Abstract

We determined the effect of calcium supplementation on bone mineral density (BMD) and bone mineral content (BMC) and identified predictors of bone mass changes in adolescent mothers 6 months postpartum. A prospective, analytical, clinical study was performed in adolescent mothers (< or = 19 years old; n = 37) from La Plata, Argentina. At 15 days postpartum, mothers were randomly assigned into one of two groups and started with calcium supplementation; one group received dairy products (932 mg Ca; n = 19) and the other calcium citrate tablets (1000 mg calcium/day; n = 18). Weight, height and dietary intake were measured and BMD was determined by DEXA at 15 days (baseline) and 6 months postpartum. BMC, total body BMD and BMD were assessed in lumbar spine, femoral neck, trochanter and total hip. Regression models were used to identify the relationship of total body BMD and BMC with independent variables (calcium supplementation, months of lactation, weight at 6 months, percent weight change, lean mass at 6 months, percent lean mass change, total calcium intake). Results showed that changes in BMD and BMC at the different sites were similar in both groups, and changes in percent body weight and total calcium intake were the main predictive factors. In conclusion, the effect of calcium was similar with either form of supplementation, i.e., dairy products or tablets, and changes in percent body weight and total calcium intake were predictors of total body BMD and BMC changes.