Use of hormone replacement therapy among Danish nurses at increased risk of osteoporosis.

Observational studies and recent randomized trials have shown that postmenopausal hormone replacement therapy (HRT) may reduce the risk of osteoporotic fractures by about 30 to 40%. In this study we used a log linear graphical model to determine whether women with a known increased risk of osteoporosis were more likely to use HRT than other women and to examine whether women at increased risk modified this risk through their lifestyle. Cox regression analysis was used to analyze if women at risk of osteoporosis used HRT longer than women not at risk. Participants were Danish female nurses who, in 1993, were between 50 and 69 years of age (N=14,865). Data were collected from postal questionnaires. We concluded that nurses with a known family history of osteoporosis more often used HRT than nurses without this risk. No other direct associations were found between biological risk factors and ever use of HRT. The presence of biological risk factors of osteoporosis was not consistently modified by a healthier lifestyle. Nurses with a low body mass index (BMI) with a known family history of osteoporosis continued to use HRT longer than nurses without these risk factors.