Trends in diabetes and obesity in Samoa over 35 years, 1978–2013

Aims Population surveys of Type 2 diabetes mellitus and obesity conducted in Samoa over three decades have used varying methodologies and definitions. This study standardizes measures, and trends of Type 2 diabetes mellitus and obesity for 1978–2013 are projected to 2020 for adults aged 25–64 years. Methods Unit records from eight surveys (n = 12 516) were adjusted to the previous census for Division of residence, sex and age to improve national representativeness. Type 2 diabetes mellitus is defined as a fasting plasma glucose ≥ 7.0 mmol/l and/or on medication. Obesity is defined as BMI ≥ 30 kg/m2. Random effects meta‐regression was employed to assess time trends following logit transformation. Poisson regression from strata was used to assess the effects of mean BMI changes on Type 2 diabetes mellitus period trends. Results Over 1978–2013, Type 2 diabetes mellitus prevalence increased from 1.2% to 19.6% in men (2.3% per 5 years), and from 2.2% to 19.5% in women (2.2% per 5 years). Obesity prevalence increased from 27.7% to 53.1% in men (3.6% per 5 years) and from 44.4% to 76.7% (4.5% per 5 years) in women. Type 2 diabetes mellitus and obesity prevalences increased in all age groups. From period trends, Type 2 diabetes mellitus prevalence in 2020 is projected to be 26% in men and women. Projected obesity prevalence is projected to be 59% in men and 81% in women. Type 2 diabetes mellitus period trends attributable to BMI increase are estimated as 31% (men) and 16% (women), after adjusting for age. Conclusion This is the first study to produce trends of Type 2 diabetes mellitus and obesity in Samoa based on standardized data from population surveys. Type 2 diabetes mellitus is equally prevalent in both sexes, and obesity is widespread. Type 2 diabetes mellitus prevalence in Samoa is likely to continue to increase in the near future. What's new? This is the first study to standardize previously conducted, disparate population‐based measures of Type 2 diabetes mellitus and obesity from unit records of empirical surveys to produce period trends in Samoa. Prevalences of Type 2 diabetes mellitus and obesity have increased over 35 years (1978–2013), and are projected to continue to increase in the near future. The increase in Type 2 diabetes mellitus is partially attributed to the rise in obesity and effective interventions to reduce obesity are urgently required.