Low Vital Capacity Was Associated with Incident Diabetes in a Japanese Health Screening Population in Whom Obesity Was Not Prevalent.

Objectives: There have been few studies regarding the relationship between respiratory function and incident diabetes in East Asian populations in whom obesity is not prevalent.

Methods: This is a 6-year follow-up study in a Japanese health-screening population that included 1874 men and 1093 women. Using Cox regression models, hazard ratios (HRs) of incident diabetes for percent vital capacity (%VC) and forced expiratory volume in 1 second divided by forced vital capacity (FEV1/FVC) were calculated. Diabetes was defined as simultaneous fasting plasma glucose (FPG) ≥7.0 mmol/L and glycated hemoglobin (A1C) ≥6.5% or use of antidiabetic medications.

Results: During the 6-year follow-up period (mean of 4.8 years), 71 men (3.8%) and 18 women (1.7%) developed diabetes. The HRs (95% confidence intervals [CIs]) of incident diabetes for each 1 SD increase in %VC and the lowest tertile of %VC compared with the highest tertile were 0.81 (0.66 to 1.00) (p=0.045) and 1.78 (1.01 to 3.16) (p=0.048), respectively, adjusted for sex, age, body mass index, antihypertensive drug use and A1C levels. After further adjustment for log high-sensitivity C-reactive protein, the HRs (95% CI) of incident diabetes for each 1 SD increase in %VC and the lowest tertile of %VC were 0.82 (0.67 to 1.01) (p=0.063) and 1.69 (0.95 to 3.01) (p=0.073), respectively. The association between FEV1/FVC and incident diabetes was not significant.

Conclusions: %VC, but not FEV1/FVC, was significantly associated with incident diabetes in a Japanese health-screening population in whom obesity was not prevalent.