Serum insulin is associated with right ventricle function parameters and lung volumes in subjects free of cardiovascular disease

BACKGROUND: Diabetes mellitus is an established risk factor for cardiovascular diseases. Even impaired levels of glucose and insulin might harm organ function prior to diabetes onset. Whether serum glucose or insulin plays a direct role in cardiac dysfunction or lung volume reduction remains unclear. The aim was to investigate the relationship between glucose and insulin with the right ventricle and lung volumes within KORA-MRI FF4 study. METHODS: From the KORA-MRI FF4 cohort study 337 subjects (mean age 55.7 ± 9.1 years; 43% women) underwent a whole-body 3T MRI scan. Cardiac parameters derived from a cine-steady-state free precession sequence using cvi42. MRI-based lung volumes derived semi-automatically using an in-house algorithm. Fasting serum glucose, fasting insulin levels, and HOMA index were calculated in all study subjects. Linear regression analyses were performed to assess the relationships between glucose and insulin levels with right ventricle volumes and lung volumes adjusted for age, sex, BMI, and cardiovascular risk factors. RESULTS: In univariate and multivariate-adjusted models, high serum insulin was inversely associated with end-diastolic volume (β = -12.43, P < 0.001), end-systolic volume (β = -7.12, P < 0.001), stroke volume (β = -5.32, P < 0.001), but not with ejection fraction. The association remained significant after additional adjustment for lung volumes. Similarly, serum insulin was inversely associated with lung volume (β = -0.15, P = 0.04). Sensitivity analysis confirmed results after excluding subjects with known diabetes. CONCLUSIONS: Serum insulin was inversely associated with right ventricle function and lung volumes in subjects from the general population free of cardiovascular disease, suggesting that increased insulin levels may contribute to subclinical cardiopulmonary circulation impairment.