Pulmonary function phenotypes and bone health in older adults: a retrospective cross-sectional study

This study aims to investigate the association between pulmonary function phenotypes—including preserved ratio impaired spirometry (PRISm) and chronic obstructive pulmonary disease (COPD)—and bone health in older adults, by evaluating bone mineral density (BMD) and bone turnover markers (BTMs). This retrospective cross-sectional study enrolled 205 adults aged ≥ 60 years who completed spirometry, dual-energy X-ray absorptiometry, and laboratory testing. Participants had a median age of 68 years, a male proportion of 39%, and a median body mass index of 26.5 kg/m 2 . Participants were categorized into three phenotypes: normal spirometry, PRISm, and COPD. BMD at the lumbar spine, femoral neck, and total hip; and BTMs—including total procollagen type I N-terminal propeptide, osteocalcin, β -isomerized C-terminal telopeptide ( β -CTX), 25-hydroxyvitamin D and parathyroid hormone (PTH)—were compared across groups. Multivariable ordinal logistic regression was used to assess independent associations between lung function phenotypes and bone mass severity. Compared with the normal spirometry group, the COPD group showed significantly lower T-scores at all skeletal sites and a higher prevalence of osteopenia and osteoporosis ( P < 0.05). In unadjusted analyses, the PRISm group showed lower femoral neck and total hip BMD, but no significant association with ordered bone mass severity in the primary adjusted models. Individuals with COPD had higher C-reactive protein and PTH levels than those in other two groups. In fully adjusted models, the COPD group remained independently associated with more severe bone mass categories at the femoral neck (odds ratio [OR] 2.39, 95% confidence interval [CI] 1.18–4.83), total hip (OR 2.66, 95% CI 1.27–5.55), and lumbar spine (OR 2.54, 95% CI 1.20–5.39). Higher β-CTX levels, older age, and female sex were also independently associated with more severe bone mass categories. Impaired pulmonary function, particularly COPD, is robustly associated with reduced BMD and more severe skeletal deterioration in older adults. PRISm demonstrated a modest, site-specific association with hip bone measures, particularly in sensitivity analyses. These findings support skeletal risk assessment in individuals with abnormal spirometric patterns and underscore the need for longitudinal studies to clarify the temporal and biological pathways underlying the lung-bone association. not applicable.