Predictors of bone mineral density in female workers in Morelos State, Mexico

Although several studies have identified factors associated with bone mineral density (BMD), little research is available on Mexican women.

A cross-sectional study was conducted in 1,622 female workers between 20 and 80 years of age at the Mexican Social Security Institute (IMSS), an integral part of the Mexican health system. It was carried out in Morelos, a Mexican state that borders Mexico City. Women were recruited to participate in this study from their workplaces. Body mass index (BMI) was measured and BMD was assessed using dual-energy x-ray absorptiometry of dominant forearm. Predictors of BMD (age, reproductive factors, BMI, diet, and physical activity) in pre- and postmenopausal women were assessed by questionnaire and analyzed using generalized additive models.

In premenopausal women, older age, higher BMI, younger age at menarche, and greater vitamin D intake were associated with higher BMD (R(2)=0.06, null deviance reduction=6.9%). In postmenopausal women, determinants of BMD were older age, higher BMI, greater height, later initiation of menopause, longer time of use of hormonal replacement therapy (HRT), and greater calcium intake from dairy products (R(2)=0.39, null deviance reduction=40.7%).

As observed in other populations, age, BMI, height, age at menopause, time of use of HRT, and calcium intake derived from dairy products in these Mexican women are factors associated with higher forearm BMD during postmenopausal period. Age, BMI, age at menarche, and vitamin D are associated with higher forearm BMD in premenopausal women. Some of these factors are not linearly associated with BMD. This was a limited population study carried out in a large group of female healthcare workers whose reproductive and lifestyle factors potentially agreed with those of female workers from urban areas of Mexico.