Impact of lactational performance on bone mineral density in marginally-nourished Bangladeshi women.

This cross-sectional study, carried out during July 1997-June 1998, evaluated the effects of prolonged breast-feeding and lactational amenorrhoea on bone mineral density (BMD) in 400 marginally-nourished Bangladeshi women aged 20-81 years. A bone densitometer was used for measuring BMD in the distal and ultra-distal end of radius and ulna. The results showed that the women who breastfed for 60 months or less had a higher mean BMD compared to those who breastfed for 61-120 months and for over 120 months. There was a significantly higher BMD in the women who had a shorter duration of lactational amenorrhoea compared to those having a longer duration of lactational amenorrhoea. BMD was significantly and negatively correlated with total duration of lactational amenorrhoea (slope -0.024, p<0.05) after controlling for parity, physical workload, and total duration of breast-feeding. The study concluded that there was a negative correlation between longer duration of breast-feeding and BMD, but it was not found when other factors were controlled in multivariate analysis. The duration of lactational amenorrhoea, which is a proxy indicator of breast-feeding, showed a negative correlation with BMD. It is recommended that all lactating women be given diet with adequate calcium to support breast-feeding for maintaining good nutrition of their bones.

Comparison of bone mineral density between premenopausal and postmenopausal women in Bangladesh.

This cross sectional study was conducted in the department of Obstetrics and Gynaecology at Bangabandhu Sheikh Mujib Medical University, Dhaka during July 1997 to June 1998. Two hundred and twenty (220) Bangladeshi premenopausal and post-menopausal women aged from 35 to 55 years were studied to compare the effect of age, parity, socioeconomic status and nutritional status on bone mineral density (BMD) of distal and ultra distal ends of radius and ulna. A bone densitometer (Single photon X-ray absorptiometry, DTX100, USA) was used to measure the BMD. BMD was calculated by taking the mean of the two sites and is expressed in g/cm2. Bone mineral density in post-menopausal women (0.48 +/- 0.1 g/cm2) was significantly lower than pre-menopausal women (0.61 +/- 0.06 g/cm2, p<0.001). Parity and number of family members were significantly greater in post-menopausal women compared to pre-menopausal women (6.5 +/- 2.9 vs. 4.2 +/- 2.3 and 8.1 +/- 2.5 vs. 6.2 +/- 2.3 respectively, p<0.001). Height was significantly lower in post-menopausal women (148.6 +/- 6.9 vs. 151.8 +/- 5.7 cm, p<0.001). After adjustment of various biological factors in multiple linear regression, body mass index (BMI) showed negative relationship with age (slope -0.0068, p<0.001) and positive relationship with weight (slope 0.0011, p<0.05). Peak BMD was observed upto the age of 40 years and thereafter declined and sharply after menopause. The study concluded that bone mineral density is greater in pre-menopausal women than post-menopausal women and remains high up to 35-40 years of age, and declines to older age. BMD positively correlates with weight of women. Premenopausal women have higher height than postmenopausal women though height does not have correlation with BMD in this study.