Bone mineral status of lactating mothers of different ages

Abstract

To determine the effect of age on the bone mineralization of lactating mothers, 48 healthy mothers were evaluated at 2 and 16 weeks post partum. All mothers were divided into three age groups: ≤18 years, 19 to 30 years, and >31 years old. At 2 and 16 weeks post partum, blood was drawn for measurement of serum calcium, phosphorus, alkaline phosphatase, and 25-hydroxy vitamin D. Bone mineral content was measured by photon absorptiometry. Dietary history was also recorded. At both 2 and 16 weeks, there were no differences in the serum values or bone mineral content among the three age groups. However, there was a decrease in the bone mineral content between the 2 and 16 weeks' values in the ≤18 years age group, 1.049 ± 0.088 versus 0.895 ± 0.051 gm/cm (p < 0.05). Dietary intakes were similar among the three groups, but only one of seven mothers ≤18 years of age met the recommended dietary allowance for calcium or phosphorus, as compared to six of seven older mothers who met the recommended dietary allowance for calcium or phosphorus (p < 0.01). We conclude that young lactating mothers ≤18 years old are at risk for bone demineralization because of low dietary intakes of calcium or phosphorus.