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poster
Serum insulin-like growth factor 1 (IGF-1) levels in preserved ratio impaired spirometry (PRISm)
Background Preserved ratio impaired spirometry (PRISm) and abnormal serum insulin-like growth factor 1 (IGF-1) levels are both associated with cardiopulmonary disease, diabetes, and mortality. However, the relationship between PRISm and serum IGF-1 levels is unclear and investigated in this study.
Methods Wave 4 (2008/2009) of the English Longitudinal Study of Ageing (ELSA), a large representative sample of adults 50 years and older in England, was analyzed. Participants were categorized into three pulmonary function groups: normal spirometry (NS) (FEV1/FVC≥0.7 and FEV1≥80% predicted), PRISm (FEV1/FVC≥0.7 and FEV1<80% predicted), and airflow obstruction (AO) based on Global Initiative for Chronic Obstructive Lung Disease (GOLD) criteria (FEV1/FVC<0.7). Serum IGF-1 levels were first collected in Wave 4. Multivariable linear and logistic regression were used to examine the association between the pulmonary function groups and serum IGF-1 levels. Models adjusted for age, sex, body mass index, race/ethnicity, education, occupation, smoking status, alcohol use, pulmonary medications, respiratory infection, asthma, heart disease, diabetes, hypertension, hypercholesterolemia, stroke, cancer, and physical activity level.
Results 5390 participants were included: 3246 (60.2%) NS, 667 (12.4%) PRISm, and 1477 (27.4%) AO. The mean serum IGF-1 level was 15.9 nmol/L overall, and 16.1 nmol/L, 15.2 nmol/L, and 15.8 nmol/L in the NS, PRISm, and AO groups, respectively. In multivariable linear regression, compared with NS, PRISm was associated with lower serum IGF-1 levels (-0.64 95% CI -1.12 to -0.16, p=0.009). In multivariable logistic regression, PRISm was associated with higher odds of membership in the lowest serum IGF-1 quartile (OR 1.36 95% CI 1.13, 1.64, p=0.001). The association was stronger in men compared with women.
Conclusions PRISm was significantly associated with lower serum IGF-1 levels after adjusting for various potential confounders. More studies are needed to explore this association, elucidate mechanistic pathways, and understand the potential clinical significance of this finding.