A Cross-Sectional Study of Postpartum Changes in Bone Status in Indian Mothers

Abstract

Background: Bone turnover is high during lactation. However, studies on bone status of Indian urban mothers are scarce. Hence, the objective was to conduct a cross-sectional study on the lactation-related changes in bone health status of Indian mothers postpartum using Dual X-ray Absorptiometry (DXA) at 3 time points: within a week of delivery, at 1- and 3-years postpartum. We also explored the association of dietary calcium intake, physical activity, serum vitamin D status, and dietary traditional food supplements (Dietary Food supplements) with bone health.

Methods: A cross-sectional study was conducted; 300 full-term, healthy primiparous women (28.6 ± 3.4 year) were randomly selected and categorized into 3 groups: 128 mothers within 7 days of delivery (Group A), 88 with 1-year-old children (B), and 84 with 3-year-old children (C). Anthropometry, lactation history, physical activity, diet, biochemical tests (vitamin D, parathyroid hormone), body composition, areal bone mineral density (a-BMD) at total body (TB), AP spine (APS), and dual neck femur (DF) were assessed by DXA (GE-Lunar DPX).

Results: Significantly higher APS-BMD (mean ± SD) was observed in Group C (1.107 ± 0.098 g/cm(2)) than that in A (1.045 ± 0.131 g/cm(2)) (p < 0.05). When adjusted for breastfeeding practices, mean (±standard error) APS-BMD was lowest in women in Group A (1.024 ± 0.013 g/cm(2)), but was higher at 1-year (1.079 ± 0.02 g/cm(2)) and at 3-years postpartum (1.111 ± 0.019 g/cm(2)), though differences were significant only between groups A and C (p < 0.05). Most mothers from all 3 groups consumed inadequate amount of nutrients except dietary fat and showed low physical activity. Multiple regression analysis indicated that dietary calcium, moderate physical activity, serum vitamin D, and consumption of dietary food supplements were not significant predictors of APS-BMD (p > 0.1).

Conclusion: Prevalence of nutrient and vitamin D deficiencies, low physical activity, and poor sunlight exposure were major concerns in Indian lactating mothers; improvement in bone mass at APS was observed at 3-years which was most likely due to physiologic changes.

Keywords: Body composition; Bone health; Indian mothers; Lactation; Postpartum.