B44-16 Association Between Preserved Ratio Impaired Spirometry (PRISm) and Vitamin D Deficiency in Community-Dwelling Older Adults

Rationale Preserved ratio impaired spirometry (PRISm) and vitamin D deficiency are both associated with cardiopulmonary disease and increased mortality. However, the relationship between PRISm and vitamin D deficiency remains poorly understood. We investigated the association between PRISm and vitamin D deficiency and examined factors associated with vitamin D deficiency among individuals with PRISm. Methods We analyzed data from Wave 6 (2012/2013) of the English Longitudinal Study of Ageing (ELSA), a prospective cohort of adults ≥50 years old in England. Pulmonary function was computed using the Global Lung Function Initiative (GLI) equations and categorized as normal spirometry (NS) (FEV1/FVC ≥0.7 and FEV1 ≥80% predicted), PRISm (FEV1/FVC ≥0.7 and FEV1 <80% predicted), or airway obstruction (AO) (FEV1/FVC <0.7) based on Global Initiative for Chronic Obstructive Lung Disease (GOLD) criteria. Serum 25-hydroxyvitamin D [25(OH)D] was measured and defined as deficient if < 30 nmol/L based on Institute of Medicine guidelines. Multivariable linear and logistic regression assessed associations between pulmonary function categories and 25(OH)D, adjusting for sociodemographic, clinical, behavioral, and seasonal covariates selected a priori. Among participants with PRISm, multivariable logistic regression identified factors associated with vitamin D deficiency. Results Among 5177 participants, 59.8% had NS, 7.8% had PRISm, and 32.5% had AO. Mean serum 25(OH)D levels were 49.8 nmol/L in NS, 42.4 nmol/L in PRISm, and 49.6 nmol/L in AO. Vitamin D deficiency prevalence was 21.0% in NS, 34.0% in PRISm, and 23.3% in AO. In multivariable regression analysis, compared with NS, PRISm was independently associated with lower 25(OH)D levels (adjusted coefficient -2.68, 95% confidence interval -4.91 to -0.45) and higher odds of vitamin D deficiency (adjusted odds ratio 1.34, 95% confidence interval 1.04 to 1.74). Among those with PRISm, factors associated with vitamin D deficiency included current smoking, diabetes, low physical activity, depression, and higher BMI (Figure 1). Protective factors included summer or autumn season (compared with winter), vitamin D supplementation, and self-reported White race. AO was not associated with 25(OH)D levels or vitamin D deficiency. Conclusion Vitamin D deficiency is highly prevalent among individuals with PRISm, affecting over one-third of participants. PRISm is independently associated with lower vitamin D levels and higher odds of vitamin D deficiency compared with NS. Specific modifiable factors such as smoking cessation, sun exposure, and vitamin D supplementation may represent intervention targets. Future studies should evaluate mechanisms linking vitamin D deficiency to clinical outcomes in PRISm and the impact of treating vitamin D deficiency on disease trajectory.