Does parity and duration of lactation have any effect on the bone mineral density of the femur and lumbar spine in Indian women? A cross-sectional study from the Northeast region of India.

Abstract

The effects of multiple pregnancies and period of lactation on bone density have not been studied till date and there is very less data available, especially from developing countries like India. Lumbar spine and femoral neck were used to measure BMD and results were recorded. To find out the effect of parity and period of lactation on occurrence of osteoporosis in spine and femoral neck in women of the Northeast region of India. The cross-sectional study included 294 perimenopausal and postmenopausal women aged 30-65 year old. Age, body mass index (BMI), parity, total lactation period, menopausal status, duration of menopause socioeconomic status, and nutritional history were noted. The dual-energy X-ray absorptiometry system was used to measure the BMD of lumbar and femoral neck BMD. Multiple regression analysis was done for finding out the association of parity and lactation with BMD. The parity was inversely related with BMD of lumbar spine (<i>β</i> = -0.138, <i>P</i> = 0.00423) and BMD of femoral neck (<i>β</i> = -0.142, <i>P</i> = 0.00487). This relation remained significant after adjusting for age, BMI, and duration of menopause. Period of lactation was also inversely correlated with BMD for lumbar spine (<i>β</i> = -0.0812, <i>P</i> = 0.0012) and BMD of femoral neck (<i>β</i> = -0.033, <i>P</i> = 0.0031). The number of parity and prolonged period of lactation have a negative effect on BMD in both regions especially in the lower socioeconomic strata with poor nutritional intake. Our data supports that parity and duration of lactation can be associated with future osteoporosis.