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

Objectives

This study estimates type 2 diabetes (T2DM) incidence in Samoans aged 25–64 years from sequential, irregularly spaced, cross-sectional population prevalence surveys.

Methods

T2DM prevalence from eight population surveys conducted over 1978–2013 (n = 12,516) was adjusted for census region, sex, and 5-year age group to the nearest previous census. Annual T2DM incidence was calculated from adjusted prevalences (by sex), using birth cohorts constructed from age-period matrices. Projections of T2DM incidence to 2020 were estimated, based on various scenarios of population weight change using Poisson regression.

Results

Over 1978–2013, T2DM incidence was estimated to increase from 1.12 to 8.44 per 1000 person-years in men and from 2.55 to 8.04 per 1000 in women. Based on regression modeling, if mean population weight was stabilized from 2013, absolute incidence reductions of 0.9 per 1000 person-years (7% lower) are predicted in 2020, compared to the current period trend in weight gain.

Conclusions

T2DM incidence can be calculated from irregularly conducted population risk factor surveys which may be useful in developing countries with limited resources.

Electronic supplementary material

The online version of this article (doi:10.1007/s00038-017-0961-x) contains supplementary material, which is available to authorized users.

Prevalence of adiposity and associated cardiometabolic risk factors in the Samoan genome-wide association study

OBJECTIVE

To describe the prevalence of obesity-related noncommunicable diseases (NCDs) and associated risk factors in a sample of Samoan adults studied in 2010 as part of a genome-wide assocation study (GWAS) for obesity related traits.

METHODS

Anthropometric and biochemical data collected from n = 3,475 participants (n = 1,437 male; n = 2,038 female) aged 24.5 to <65 years were used to describe the prevalence of obesity, diabetes, hypertension, and dyslipidemia within the study sample. One way analysis of variance, χ(2) tests, and binary logistic regression were used to identify differences in disease and risk factor prevalence by 10-year age group, gender, or by census region of residence.

RESULTS

Obesity was highly prevalent among the study sample; 64.6% of females and 41.2% of males were obese according to Polynesian cutoffs (BMI ≥ 32 kg/m(2) ). Females were less likely than males to have hypertension (31.7% vs. 36.7%) but equally likely to have diabetes (17.8% vs. 16.4%). With the exception of obesity and low HDL-cholesterol in females only, there were significant differences in the prevalence of all NCDs and associated risk factors by age group, with the oldest age group (55 to <65 years) most affected. In both sexes, residents of the Apia Urban Area were at significantly greater risk of obesity, diabetes, low HDL-cholesterol, and high triglycerides than residents of the more rural Savaii region.

CONCLUSIONS

The phenotypic characteristics of this sample provide evidence of a continuation of previously reported temporal trends toward obesity and its associated disorders. Attention must be paid to the critical NCD situation in Samoa.