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

Abstract

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/m 2 . 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.

Reproductive health, obesity, and cardiometabolic risk factors among Samoan women

“…Given the continual temporal rise in adiposity in Samoans (Lin et al 2016), our cross-sectional findings may also underestimate the impact of duration of adiposity on women’s reproductive health. We suggest that attempts to further understand the mechanisms influencing adiposity, insulin resistance, androgen levels, menstrual regulation, and PCOS must proceed with longitudinal designs, improved biomarkers, and, if possible, clinical markers of these processes.…”

Diabetes incidence and projections from prevalence surveys in Samoa over 1978–2013

“…The higher T2DM incidence in American Samoa likely relates, in part, to greater levels of obesity: the 2004 STEPS surveys in American Samoa found that 69% of men and 80% of women were obese (WHO 2007), compared to 53% (men) and 73% (women) in Samoa in 2013 (Lin et al 2016a). …”

Diabetes incidence and projections from prevalence surveys in Fiji

“…Between 1980 and 2011, obesity prevalence (BMI ≥30 kg/m 2 ) increased at a rate of 3.0% per five years in i-Taukei men (from 12.6 to 28.9%) and 3.8% per five years in i-Taukei women (30.1–52.9%) [13]. For a similar period (1978–2013), the rate of obesity increase in Samoans was 3.6% per five years in men (from 23.5 to 53.1%), and 4.6% per five years in women (43.7 to 73.4%) [42], with higher baseline obesity prevalence in Samoans also indicating a longer duration of obesity than in Fiji. Both magnitude and duration of obesity have been shown to affect increases in T2DM incidence, which has been demonstrated in Pima Indians [43], American men and women [34, 35], British men [44], and Japanese men [45].…”