Incidence and risk factors of type 2 diabetes mellitus in an overweight and obese population: a long-term retrospective cohort study from a Gulf state

OBJECTIVES: A high body mass index (BMI) is associated with risk of type 2 diabetes mellitus (DM). The United Arab Emirates (UAE) is experiencing a marked increase in obesity. Nonetheless, no data are available regarding the incidence of type 2 DM in the high-risk adult UAE population. Therefore, this study aimed to evaluate the incidence rate and risk of developing type 2 DM among individuals with above-normal BMI in the UAE. DESIGN: A retrospective cohort study. SETTING: Outpatient clinics at a tertiary care centre in Al Ain, UAE. PARTICIPANTS: Three hundred and sixty-two overweight or obese adult UAE nationals who visited outpatient clinics between April 2008 and December 2008. PRIMARY OUTCOME MEASURE: Patients with type 2 DM were identified based on diagnosis established by a physician or through glycated haemoglobin (HbA1c) levels ≥6.5% during the follow-up period (until April 2018). RESULTS: The overall incidence rate of type 2 DM during the median follow-up time of 8.7 years was 16.3 (95% CI 12.1 to 21.4) cases per 1000 person-years. Incidence rates in men and women were 17.7 (95% CI 11.6 to 25.9) and 15.0 (95% CI 9.8 to 22.2) cases per 1000 person-years, respectively. Multivariable Cox proportional hazard analysis determined older age and obesity in women and pre-diabetes in men to be independent risk factors for developing type 2 DM. CONCLUSIONS: The incidence rate of type 2 DM in overweight and obese UAE nationals is high. In addition to screening, current strategies should strongly emphasise lifestyle modifications to decrease HbA1c and BMI levels in this high-risk population.