Adolescents do not lose bone mineral density postpartum: comparative study with adult women

Objective.To analyze the pattern of bone mineral density (BMD), serum concentrations of estradiol and calcium levels, dietary calcium, body mass index (BMI), and lactation in adolescents and adult women at 15, 90, and 365 postpartum days (ppd). Material and Methods.A prospective cohort study was conducted of 33 adolescents and 39 adult women. Anthropometric and dietetic evaluations were performed, as well as evaluations of bone mineral density in L2-L4 and femur neck. Estradiol concentrations and calcium serum levels were determined. Results. L2-L4 BMD increased by 16% in adolescents, and 3% in adult women from day 15 to 365 ppd. While age was associated with this change (beta=13.779, EE=3.5, p=0.001), lactation was not (beta=-0.705, EE=0.647, p=0.283).The adult women had a higher L2-L4 BMD at 15, 90, and 635 ppd (1.151 vs 0.978g/cm(2), 1.195 vs 1.070g/cm(2), 1.195 vs 1.123g/cm(2), respectively) (p<0.003). Conclusions. Adolescents' BMD increased three times more than that of adult women. For all women, BMD was dependent of age and independent of lactation.