A diabetes prevalence study on an isolated urbanized Central Pacific Island has established a prevalence rate of 34.4% in individuals aged 15 years and over. Of these, 10.4% had previously known diabetes; in the others the diagnosis was made on the basis of a plasma glucose level of at least 160 mg/100 ml 2h after a 75 gm oral glucose load. A further 11.3% of the subjects had borderline diabetes as judged by a 2-h plasma glucose of between 140 and 159 mg/100 ml. Of the diabetics, 72% had a positive family history of diabetes. The high prevalence rate appears to be related to a number of factors including a diabetic genotype, urbanization, and obesity.

The incidence of LEAs in diabetic Nauruans was higher than in other populations after adjusting for age and duration. Given the apparent success of the Nauruan footcare program in reducing amputation rates, other populations with high rates of NIDDM and LEAs should consider population-wide prevention strategies.

Summary. Genetic factors play a major role in predisposition to diabetes in the Micronesian population of Nauru. In people aged 60years and older, 83% of full-blooded Nauruans were diabetic compared with 17% of those with ancestral foreign admixture, as detected by HLA typing. HLA distributions also showed a small increased risk for early onset of diabetes (< 46 years) associated with HLA-Bw22 (Bw56). Variation in the restriction fragment length of DNA near the insulin gene was found, but was not associated with diabetes. The distribution in fragment lengths, previously reported in Caucasoids, was observed in healthy Polynesians, Melanesians and Micronesians.

Summary: The effect of westernization on native populations. Studies on a Micronesian community with a high diabetes prevalence. A diabetes prevalence study in 1975 on an isolated urbanized Central Pacific island (Nauru) showed rates comparable to the American Pima Indians—the highest yet recorded in the world literature. This paper reports the results of a follow‐up study and the high prevalence has been confirmed. In this survey of 417 people aged ten years and over, 9‐8% were known diabetics. With a plasma glucose of 160 mg/100 ml or over at two hours after a 75 gram oral glucose load as the criterion of diagnosis, diabetes was detected in a further 19‐2%, making a total diabetic population of 29% in the population studied. The prevalence of diabetes was 44% in people aged 20 years and over. A further 7% had borderline diabetes on the basis of a two‐hour plasma glucose of 140–159 mg/100 ml. Parity did not appear to be a causative factor in relation to the high diabetes prevalence. However, obesity is common in this community and is more marked than that seen in other Pacific or Caucasian communities. The high prevalence of diabetes in this population appears to be related to the inter‐action of environmental factors, such as obesity, with a diabetic genotype. The results confirm the possible detrimental effects of westernization on native populations.

SUMMARY An analysis of mortality data for the years 1982-5 was carried out for the Micronesian population (aged 15 years and over) of the central Pacific Island, Nauru. Among males, the most common causes of death were circulatory system disorders (33 3%), accidents (25-2%), and diabetes mellitus (12 1 %). The majority ofaccidents occurred in the 15-34 year age group and involved motor vehicles. Among females, neoplasms (almost all lung and cervix) (22A4%), circulatory system disorders (20-7%), and diabetes mellitus (17.2%) were the most common causes of death. When accidents are excluded, 59 4% of deaths were in persons with diabetes. Compared with Australia, mortality rates in almost all age groups were at least five times higher for males and females for a comparable period. Nauruan life expectancy (39 5 years for men and 48 5 years for women) is one of the lowest in the world. These data confirm the high mortality associated with diabetes mellitus in Nauruans as evidenced in earlier studies. Modernisation of this society through the affluence acquired by the mining of phosphate has led to serious public health problems relating to non-communicable diseases so that the mortality trends now mirror those of developed societies.