Relationships between glycaemic abnormalities, obesity and insulin resistance in nondiabetic Polynesians of New Caledonia

Abstract

Objective: Polynesians in New Caledonia have an increased risk for developing diabetes, compared to Melanesians or Europeans. They are also more prone to obesity. The aim of this study was to analyse differences in the pre-diabetic state that may explain the varying susceptibility to diabetes between these three ethnic groups, focusing on the balance between insulin resistance and capacity of pancreatic cells to secrete insulin. Design and subjects: The CALDIA Study is a population-based cross-sectional survey of diabetes prevalence conducted in New Caledonia. All participants who did not have diabetes, according to the results of a 0-2 h oral glucose tolerance test (n ¼ 392), were selected for analysis. Results: Compared to Europeans, Polynesians and Melanesians had significantly higher body mass indices (BMI) and waist-tohip ratios (WHRs). Polynesians had higher fasting plasma glucose values than Europeans or Melanesians (6.03 mmol/l, vs 5.78 and 5.46, respectively; Po0.0001). Fasting plasma insulin level and the estimate of insulin resistance by homeostasis model assessment were not significantly different between the three ethnic groups. Homeostasis model assessment estimate of b-cell secretory capacity was lower in Polynesians compared to the two other ethnic groups (83.1 mU/mmol, vs 119.3 and 125.2, respectively; Po0.02). Conclusion: Despite a high prevalence of central obesity, as judged by high BMI and WHR, in Polynesians of New Caledonia, their high risk of diabetes may be more strongly related to a defect in insulin secretion capacity than to insulin resistance.

Impact of modernization on adult body composition on five islands of varying economic development in vanuatu

“…Our observation that prevalence of obesity is greater among adults on Futuna than on Ambae is consistent with patterns observed in other studies directly comparing Polynesians and Melanesians in other parts of the Pacific: Defay et al (2007) found that Polynesians living in New Caledonia demonstrated a slightly higher prevalence of obesity than Melanesians (41.7% versus 38.3%), and Heightmann et al (1997) reported that Samoans of Polynesian origin demonstrated greater prevalence of high BMIs than Torres Strait Islanders of Melanesian descent.…”

Paradoxical Relationships Between Anthropometric Variables and Phenotypic Expression of the Metabolic Syndrome in Nondiabetic Polynesians of New Caledonia

“…In a previous study, we have shown in accordance with Simmons et al (3) that Polynesians had low fasting insulin levels and HOMA-IR values (6). This may be due to their high physical activity or other environmental factors, such as diet, or to genetic factors.…”

“…Polynesians also exhibit high rates of obesity (2,3), known to be a risk factor for insulin resistance and type 2 diabetes (4,5). However, recent analyses of the CALDIA Study showed that despite high indexes of abdominal obesity, Polynesians had low fasting plasma insulin levels and homeostasis model assessment of insulin resistance (HOMA-IR) (6). Since abdominal obesity is usually associated with impaired fasting glucose, dyslipidemia, and/or hypertension, forming the metabolic syndrome (7,8), we investigated whether these features were present in this group, in comparison with Melanesians and Europeans.…”

The 2009 pandemic H1N1 influenza and indigenous populations of the Americas and the Pacific

“…Almost all indigenous populations considered in this paper have greater prevalence of diabetes, obesity and chronic respiratory diseases such as asthma and chronic obstructive pulmonary disease [19][20][21][22][23][24][25][26][27][28][29] (Table 2).…”