ABSTRACTBackgroundThe effect of long-term inhaled corticosteroid (ICS) therapy on the bone health of older adults remains unclear due to its possible impact on bone mineral density (BMD).ObjectiveTo evaluate, cross-sectionally and longitudinally, the impact of ICS use on BMD in postmenopausal women with asthma or chronic obstructive pulmonary disease (COPD).MethodsWe used a population-based bone densitometry registry linked with administrative health data of the province of Manitoba, Canada (1999–2013), to identify women with diagnosed asthma or COPD. ICS use was defined as cumulative dispensed days prior to baseline BMD (cross-sectional analysis), and medication possession ratio (MPR) between two BMD measurements (longitudinal analysis). Results were adjusted for multiple covariates including the underlying respiratory diagnosis and its severity.ResultsIn the cross sectional analysis, compared with non-users, women with the highest tertile of prior ICS exposure had lower baseline BMD at the femoral neck (-0.09 standard deviations [SD] below a healthy young adult, 95% CI: −0.16, −0.02) and total hip (-0.14 SD, 95% CI: −0.22, −0.05), but not at the lumbar spine. Longitudinally, the highest tertile of ICS exposure was associated with a slight decline in total hip BMD relative to non-users (-0.02 SD/year, 95% CI: −0.04, −0.01), with no significant effect at the femoral neck and lumbar spine. Middle and lower tertiles of ICS use had no significant effects.ConclusionHigh exposure to ICS was associated with a small adverse effect on baseline hip BMD and total hip BMD loss in post-menopausal women with asthma or COPD.