It is not known whether asthma constitutes a risk factor for osteoporosis or what the impact is of inhaled corticosteroids on bone mineral density (BMD). The study population (n = 3,222) was a random stratified sample from the Kuopio Osteoporosis Study, which included all women 47 to 56 yr of age residing in Kuopio Province, Eastern Finland. Spinal and femoral BMDs were measured using dual-energy X-ray absorptiometry. The BMD values of 119 asthmatics were cross-sectionally compared with those of 3,103 nonasthmatics. Of the 119 asthmatic women, 28 had not used corticosteroids, 65 had used oral corticosteroids, and 26 had used only inhaled corticosteroids. The asthmatics with no hormone replacement therapy (HRT) (n = 83) had lower mean spinal and femoral BMD value than did the corresponding nonasthmatics (spinal BMD, 1.083 +/- 0.150 [SD] versus 1.128 +/- 0.160 g/cm2, p < 0.05; femoral BMD, 0.894 +/- 0.112 [SD] versus 0.929 +/- 0.128 g/cm2, p < 0.05). Although BMDs were not significantly decreased in the asthmatics who had used inhaled corticosteroids, the duration of use correlated negatively with spinal BMD and was also associated with spinal BMD in multiple regression analysis. In perimenopausal women, asthma is associated with decreased bone density. This may be due to the corticosteroids rather than to the disease itself. However, HRT appears to be protective against bone loss also in asthmatics.