Abstract
Background: Association of diabetes with abnormal lung function was suggested by several studies. Reduced elastic recoil, reduced lung volume, diminished respiratory muscle performance, chronic low-grade inflammation, decrease in pulmonary diffusion capacity for carbon monoxide, and autonomic neuropathy involving respiratory muscles are some of the important changes occurring in diabetes mellitus (DM). Furthermore, metabolic disorders, especially diabetes that generally manifested with obesity, are associated with a substantial loss of pulmonary function in a restrictive pattern.

Aims and Objectives: The findings of the pulmonary function tests (PFTs) in Type 2 DM could guide the clinicians to modify the intervention and management strategies. The present study relates duration of diabetes and glycosylated hemoglobin (HbA1c) to lung function parameters among the Type 2 DM patients. It also compares the glycemic indices and lung function parameters of diabetics with those of the non-diabetics to reaffirm the results.

Materials and Methods: Glycemic indices and lung parameters are measured among diabetics and control non-diabetics.

Results: We found no effect of duration of diabetes on the mean values of the lung function parameters. All the lung function parameters showed negative correlation with HbA1c, especially for forced expiratory volume in 1 s (FEV1%) suggesting a decline in FEV1% with an increase in HbA1c. On comparing lung function parameters between diabetics and non-diabetics, we found statistically significant reduction in forced vital capacity, FEV1, peak expiratory flow rate, and forced expiratory flow 25–75 associated with an increase in FEV1% in both male and female diabetics which points to a restrictive type of pulmonary dysfunction.

Conclusions: Our study revealed restrictive pattern of lung function impairment in persons suffering from diabetes of both sexes. PFT can be used as a screening method to detect early changes in lung parameters in persons suffering from DM so as to prevent further restriction in functioning of respiratory system.

Key words: Diabetes; FBS; Forced Expiratory Volume in 1 Second; Glycosylated Hemoglobin; Lung Function; Peak Expiratory Flow Rate; Pulmonary Function