Association of restrictive ventilatory dysfunction with insulin resistance and type 2 diabetes in koreans

Aims: To investigate associations of obstructive and restrictive patterns of ventilatory dysfunction with insulin resistance and type 2 diabetes mellitus (DM) in Koreans.

Methods: We cross-sectionally examined clinical, laboratory, and pulmonary function data on 35,456 Korean adults (age 18-93 years, 40% women) recorded during regular health check-ups. Insulin resistance (IR) was determined from fasting serum insulin concentration and homeostasis model assessment (HOMA).

Results: Individuals with type 2 DM and those with pre-diabetes (impaired fasting glucose levels) showed a higher prevalence of both restrictive (18% and 11%, respectively, VS. 8%; P<0.01) and obstructive (4.3% and 3.2%, respectively, VS. 2.3%; P<0.01) ventilatory dysfunction than did individuals with normal fasting glucose levels. Compared to subjects with normal ventilatory function, those with restrictive or obstructive ventilatory dysfunction were older, had higher systolic and diastolic blood pressure, and had elevated glucose and HbA1c levels. However, serum triglyceride, fasting insulin, and HOMA-IR were higher only in subjects with restrictive ventilatory dysfunction, and not in those with obstructive ventilatory dysfunction. On logistic regression analysis, the age and gender-adjusted odds ratio (OR) of restrictive ventilatory dysfunction for type 2 DM was 1.59 (95% confidence interval, 1.43-1.78). The increased OR remained significant after controlling for exercise, drinking, and smoking habits, presence of hypertension, body mass index, and waist circumference (OR=1.38 [1.23-1.55]). However, further adjustment for HOMA-IR attenuated the OR (1.11 [0.97-1.26]), making the OR statistically insignificant. In contrast, obstructive ventilatory dysfunction was not independently related to type 2 DM status.

Conclusion: Restrictive ventilatory dysfunction is independently associated with type 2 DM, probably VIA insulin resistance.