Investigating whether smoking and alcohol behaviours influence risk of type 2 diabetes using a Mendelian randomisation study

This observational study examined whether there are causal effects of lifetime smoking and alcohol consumption on type 2 diabetes risk and continuous glycaemic traits of fasting glucose, fasting insulin and glycated haemoglobin (HbA1c). We conducted both two-sample and one-sample Mendelian randomisation analyses, using data from publicly available GWAS and UK Biobank. The analysis plan for this study was pre-registered on the Open Science Framework (https://osf.io/ygucn).