Association between lung function and risk of microvascular diseases in patients with diabetes: A prospective cohort and Mendelian randomization study.

BACKGROUND AND AIMS: To investigate causal relationships of lung function with risks microvascular diseases among participants with diabetes, type 2 diabetes mellitus (T2DM) and type 1 diabetes mellitus (T1DM), respectively, in prospective and Mendelian randomization (MR) study.

METHODS AND RESULTS: 14,617 participants with diabetes and without microvascular diseases at baseline from the UK Biobank were included in the prospective analysis. Of these, 13,421 had T2DM and 1196 had T1DM. The linear MR analyses were conducted in the UK Biobank with 6838 cases of microvascular diseases and 10,755 controls. Lung function measurements included forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1). The study outcome was microvascular diseases, a composite outcome including chronic kidney diseases, retinopathy and peripheral neuropathy. During a median follow-up of 12.1 years, 2668 new-onset microvascular diseases were recorded. FVC (%predicted) was inversely associated with the risk of new-onset microvascular diseases in participants with diabetes (Per SD increment, adjusted HR = 0.86; 95%CI:0.83-0.89), T2DM (Per SD increment, adjusted HR = 0.86; 95%CI:0.82-0.90) and T1DM (Per SD increment, adjusted HR = 0.87; 95%CI: 0.79-0.97), respectively. Similar results were found for FEV1 (%predicted). In MR analyses, genetically predicted FVC (adjusted RR = 0.55, 95%CI:0.39-0.77) and FEV1 (adjusted RR = 0.48, 95%CI:0.28-0.83) were both inversely associated with microvascular diseases in participants with T1DM. No significant association was found in those with T2DM. Similar findings were found for each component of microvascular diseases.

CONCLUSION: There was a causal inverse association between lung function and risks of microvascular diseases in participants with T1DM, but not in those with T2DM.