Low vital capacity was found to be associated with incident diabetes in health screening population of Japanese women.

Objective: There have been no previous studies regarding the relationship between the respiratory function and incident diabetes in East Asian women in whom obesity is not prevalent.

Methods: Using Cox regression models, hazard ratios (HRs) for incident diabetes for each one SD increase in the percent vital capacity (%VC), a parameter of restrictive pulmonary dysfunction, forced expiratory volume in one second over forced vital capacity (FEV1/FVC), a parameter of obstructive pulmonary dysfunction, and log high-sensitivity C-reactive protein (hs-CRP) were calculated in 1,704 men and 1,016 women among a Japanese health screening population.

Results: Over the four-year study period (mean of 3.4 years), 54 men (3.2%) and 19 women (1.9%) developed diabetes. The HRs [95% confidence intervals (CIs); p values] for incident diabetes for each one SD increase in %VC and log hs-CRP were 0.81 (0.61-1.06; 0.127) and 1.29 (0.97-1.73; 0.085), respectively in men, and 0.55 (0.35-0.88) 0.012 and 2.50 (1.37-4.57; 0.003), respectively in women adjusted for age, fasting glucose and body mass index. The FEV1/FVC was not found to be significantly associated with incident diabetes in any regression models. The Spearman's correlation coefficients between %VC and hs-CRP was -0.11 (p<0.001) in men and -0.08 (p=0.007) in women. The HRs (95% CIs; p values) for each one SD increase in %VC and hs-CRP were 0.86 (0.65-1.13; 0.278) and 1.26 (0.94-1.70; 0.125), respectively in men, and 0.56 (0.34-0.94; 0.028) and 2.95 (1.49-5.81; 0.002), respectively in women, further adjusted for each other, systolic blood pressure, triglycerides and HDL cholesterol.

Conclusion: A low %VC was found to be associated with incident diabetes, independent of hs-CRP in women among a Japanese health screening population.