Copenhagen City Heart Study: longitudinal analysis of ventilatory capacity in diabetic and nondiabetic adults

The natural history of lung function in diabetes is unknown due to the lack of longitudinal observations. The decline of forced expiratory volume in one second (FEV 1 ) and forced vital capacity (FVC) was studied over 15 yrs in the 17,506 adult participants of The Copenhagen City Heart Study, which included 266 individuals with diabetes. Multiple linear regression and a mixed-effects model were used, taking into account correlation between repeated measurements and adjusting for relevant confounders. In both sexes, FEV 1 and FVC were consistently lower in diabetic individuals, compared with healthy individuals, with an average reduction of ∼8% of the predicted value. Longitudinal analyses showed that the decline of FEV 1 and FVC in diabetic individuals was similar to that observed in nondiabetic subjects. It was concluded that although diabetic subjects have, on average, a lower forced expiratory volume in one second and forced vital capacity than individuals without diabetes, this deficit seems not to be progressive in the long term. These observations may be of importance with regard to diabetes treatment with inhaled pulmonary insulin, which is likely to become available within a few years.