Association of Insulin Resistance With Radiographic Lung Abnormalities and Incident Lung Disease: The Framingham Offspring Study

Abstract

OBJECTIVE Insulin resistance (IR) may be a risk factor for lung disease, but objective evidence is limited. We sought to define the relationship of longitudinal IR with radiographic imaging outcomes and examiner-identified incident lung disease in the Framingham Offspring Study. RESEARCH DESIGN AND METHODS Participants without baseline lung disease underwent repeated measurements of fasting insulin and glucose levels over an average period of 13.6 years, from which time-weighted average HOMA-IR was calculated. Each participant then underwent a cardiac gated whole-lung computed tomography scan, which was analyzed for the presence of emphysema, interstitial lung abnormalities (ILAs), and quantitative airway features. Incident lung disease was determined by a study examiner. The relationship of HOMA-IR to these outcomes was estimated in models adjusted for demographics, BMI, and lifetime smoking. RESULTS A total of 875 participants with longitudinal IR data and outcomes were identified. Their mean age was 51.5 years, and BMI was 26.7 kg/m2. HOMA-IR was temporally unstable, with a within-person SD approximately two-thirds of the between-person SD. In adjusted models, a 1 SD increase in log(HOMA-IR) z score was associated with higher odds of qualitative emphysema (odds ratio [OR] 1.33; 95% CI 1.04–1.70), ILAs (OR 1.35; 95% CI 1.05–1.74), and modest increases in airway wall thickness and wall area percentage. These radiographic findings were corroborated by a positive association of HOMA-IR with incident lung disease. CONCLUSIONS IR is associated with radiographic lung abnormalities and incident lung disease. Deeper phenotyping is necessary to define mechanisms of IR-associated lung injury.