Combined effect of body mass index and waist-height ratio on incident diabetes; a population based cohort study

We investigated the impact of combined effect of body mass index and waist-to-height ratio on risk of diabetes. Overweight and abdominal obesity were defined as body mass index ≥23 kg/m2 and waist-to-height ratio ≥0.5, respectively. We divided participants into four groups according to presence of overweight and/or abdominal obesity. About 20% individuals with overweight did not complicated with an abdominal obesity. Among 3,737 participants, 286 participants had diabetes at baseline-examination. Adjusted odds ratios for prevalence of diabetes compared with non-overweight participants without abdominal obesity were as follow: 1.87 (95% confidence interval 1.09-3.14, p = 0.024) in non-overweight participants with abdominal obesity, 1.51 (0.87-2.55, p = 0.141) in overweight participants without abdominal obesity and 3.25 (2.37-4.52, p<0.001) in overweight participants with abdominal obesity. In the follow-up examination, 86 participants were diagnosed as diabetes among 2,263 participants. Adjusted odds ratios for incident diabetes were as follow: 2.59 (0.98-6.44, p = 0.056) in non-overweight participants with abdominal obesity, 1.65 (0.64-4.00, p = 0.288) in overweight participants without abdominal obesity and 2.77 (1.55-5.15, p<0.001) in overweight participants with abdominal obesity. Non-overweight individuals with abdominal obesity as well as overweight individuals with abdominal obesity was associated with diabetes compared with non-overweight individuals without abdominal obesity.