Association between insulin resistance and lung function trajectory over 4 years in South Korea: community-based...

Hyperglycemic conditions are associated with respiratory dysfunction. Although several studies have reported that insulin resistance (IR) is related to decreased lung function, the association between IR and change in lung function has been rarely studied. This study aimed to investigate the potential association of IR on annual change in lung function using a community-based prospective cohort in Korea.

We selected 4827 Korean participants whose serial lung functions were assessed over 4 years using 1:3 propensity score matching. Exposure was baseline IR estimated with homeostatic model assessment (HOMA-IR), and outcomes were annual changes in lung function determined by calculating the regression coefficient using least-square linear regression analysis.

In the multivariate linear regression, per one unit increased log transformed HOMA-IR was associated with decline in FEV₁%-predicted (β: - 0.23, 95% CI: - 0.36 to - 0.11) and FVC %-predicted (β: - 0.20, 95% CI: - 0.33 to - 0.08), respectively. In the generalized additive model plot, HOMA-IR showed a negative linear association with annual changes in FEV₁%-predicted and FVC %-predicted. The suggested threshold of HOMA-IR for decline in lung function was 1.0 unit for annual change in FEV₁%-predicted and 2.2 unit for annual change in FVC %-predicted. Age showed statistically significant effect modification on the relationship between HOMA-IR and annual change in FEV₁%-predicted. Increased HOMA-IR was associated with the decreased annual change in FEV₁%-predicted, particularly in older people.

In South Korea, increased HOMA-IR was associated with decline in lung function. Since IR was related to decline in FEV₁%-predicted, particularly in older people, tailored approaches are needed in these populations. The potential pulmonary hazard of IR needs to be confirmed in future studies.