Bone mineral density and body composition in patients with airflow obstruction--the role of inhaled steroid therapy, disease and lifestyle.

Abstract

Inhaled steroid therapy has been shown to be associated with low bone mineral density (BMD) in asthmatic patients, but its effect in men has not been specifically studied; and the relative importance of therapy, disease and lifestyle leading to low BMD has not been investigated. The study was designed to compare BMD in women and men who had airflow obstruction (asthma or COAD with or without inhaled steroid therapy) with normal controls. The role of inhaled steroid treatment, disease severity and lifestyle was studied among patients. One hundred and fourty-four patients (106 on inhaled steroids and 38 not on inhaled steroids) and 212 age-matched controls were studied. Body composition and BMD (at the total body, hip and spine) were measured by dual-X-ray densitometry (DEXA). Forced expiratory volume (FEV1) was measured in patients. A validated questionnaire was administered to measure lifestyle factors. The body mass indices (BMI) (P < 0.001) and percentage of body fat (P < 0.001) were higher among female patients on inhaled steroids than controls. However, the BMD of the total body (P < 0.05) and spine (P < 0.001) were significantly lower in premenopausal and postmenopausal women than controls, respectively (P < 0.005). The BMD at the spine (P<0.01) and hip (P < 0.01) in male patients were significantly lower than the controls. By multiple regression, age and use of inhaled steroid was negatively associated with BMD at the hip (P < 0.01), but not at the spine (P>0.05). Cigarette smoking was associated with significantly lower BMD at the femoral neck (P < 0.05), and a low dietary calcium intake was associated with lower BMD at the spine (P<0.05). In women, use of inhaled steroid was not associated with significantly lower BMD. Men who had asthma and/or COAD had lower BMD, and this was not attributable entirely to steroid use. Cigarette smoking and a low dietary calcium intake may partially account for this difference. The difference in BMD between female patients and controls, even in those taking inhaled steroid, was small.