Diabetes and obesity trends in Fiji over 30 years

Abstract

Background: No systematic comparison has been conducted in Fiji using all suitable surveys of type 2 diabetes mellitus (T2DM) and obesity prevalence after standardizing methodology and definitions. Methods: Unit records from six surveys of Fiji adults were variously adjusted for age, ethnicity (Fiji Melanesians, i-Taukei, and Fijians of Asian Indian descent [Indians]) and urban-rural by sex to previous censuses. Trends were assessed using meta-regression (random effect models) and estimates projected to 2020. Poisson regression of strata was used to assess the effect of body mass index (BMI) increases on T2DM period trends. Results: Over 1980-2011, T2DM prevalence increased in i-Taukei men (3.2% to 11.1%; 1.32%/5 years) and women (5.3% to 13.6%; 1.40%/5 years) and Indian men (11.1% to 17.9%; 1.24%/5 years) and women (11.2% to 19.9%; 1.71%/5 years). Projected T2DM prevalence in 2020 is 13.3% and 16.7% in i-Taukei men and women, and 23.4% and 24.1% in Indian men and women, respectively. Obesity prevalence increased in i-Taukei men (12.6% to 28.9%; 2.99%/5 years) and women (30.1% to 52.9%; 3.84%/5 years) and in Indian men (2.8% to 9.4%; 1.21%/5 years) and women (13.2% to 26.6%; 2.61%/ 5 years). Projected obesity prevalence in 2020 is 34.0% and 60.0% in i-Taukei and women, and 11.4% and 31.0% in Indian men and women, respectively. After age-adjustment, an estimated 27%, 25%, 16% and 18% of the T2DM period trend is attributable to BMI in i-Taukei men and women and Indian men and women, respectively. Conclusions: Prevalence of T2DM in Fiji is projected to continue increasing, driven by rising obesity, with consequences for premature mortality and life expectancy.

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

“…Compared to incidence of T2DM found by McGarvey (2001) over 1991–1995 (5.3 per 1000 person-years in each sex), estimated national T2DM incidence rates in the present study for 1993 are similar for men (4.0 per 1000 person-years) and women (4.3 per 1000 person-years). The T2DM incidence estimates for Samoa are higher than the estimated Fiji Melanesian incidence rate of 2.3 per 1000 person-years (men) and 2.8 per 1000 person-years (women) in 1993 (Morrell et al 2016), which is congruent with the higher T2DM prevalence in Samoa (2013: men 27.0%, women 22.6%) (Lin et al 2016a) compared to Fiji Melanesians (2011: men 11.1%, women 13.6%) (Lin et al 2016b). The present analysis has added to the previous incidence study in Fiji by provision of empirical cohort data in Samoa to enable external validation which also extends the method to a population with markedly higher levels of BMI and T2DM.…”

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

“…In Tonga, BMI increases explained 76% (men) and 73% (women) of T2DM prevalence increases over 1973–2012 [23]. BMI increases in Samoa, Fiji [22] and Tonga [23] have been attributed to changes in way of life, including a shift away from farming and fishing towards more sedentary occupations; and increased consumption of energy dense imported foods [24]. …”

Diabetes incidence and projections from prevalence surveys in Fiji

“…The lower annual incidence in Fiji i-Taukei compared to Samoans and American Samoans may be related to lower levels of obesity in Fiji [12] compared to Samoa and American Samoa. 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].…”

“…In each sex-specific model, T2DM (FBG ≥6.1 mmol/L [whole blood glucose] and/or on medication) was modeled with ethnicity, age, BMI, and self-reported doctor-diagnosed T2DM status and/or on T2DM medication (for 2004 NNS), or self-reported, doctor-diagnosed T2DM status only (for 1993 NNS). Further details on the methods used to adjust self-reported T2DM data have been published previously [12]. …”

“…In Fiji no prospective cohort study of T2DM has been conducted, but prevalence surveys have been performed over the last three decades. Analysis of T2DM prevalence trends based on six population surveys in Fiji indicates an increase from 7.7 to 15.6% between 1980 and 2011, with projection to 2020 estimated to be 19.3% [12]. Fiji’s population, approximately 828,000 at the most recent 2007 census, comprises 57% Melanesian (i-Taukei) and 38% Indian.…”