Insulin Resistance and Truncal Obesity as Important Determinants of the Greater Incidence of Diabetes in Indian Asians and African Caribbeans Compared With Europeans

Abstract

OBJECTIVETo determine the extent of, and reasons for, ethnic differences in type 2 diabetes incidence in the U.K.RESEARCH DESIGN AND METHODSPopulation-based triethnic cohort. Participants were without diabetes, aged 40–69 at baseline (1989–1991), and followed-up for 20 years. Baseline measurements included fasting and postglucose bloods, anthropometry, and lifestyle questionnaire. Incident diabetes was identified from medical records and participant recall. Ethnic differences in diabetes incidence were examined using competing risks regression.RESULTSIncident diabetes was identified in 196 of 1,354 (14%) Europeans, 282 of 839 (34%) Indian Asians, and 100 of 335 (30%) African Caribbeans. All Indian Asians and African Caribbeans were first-generation migrants. Compared with Europeans, age-adjusted subhazard ratios (SHRs [95% CI]) for men and women, respectively, were 2.88 (95%, 2.36–3.53; P < 0.001) and 1.91 (1.18–3.10; P = 0.008) in Indian Asians, and 2.23 (1.64–3.03; P < 0.001) and 2.51 (1.63–3.87; P < 0.001) in African Caribbeans. Differences in baseline insulin resistance and truncal obesity largely attenuated the ethnic minority excess in women (adjusted SHRs: Indian Asians 0.77 [0.49–1.42]; P = 0.3; African Caribbeans 1.48 [0.89–2.45]; P = 0.13), but not in men (adjusted SHRs: Indian Asians 1.98 [1.52–2.58]; P < 0.001 and African Caribbeans, 2.05 [1.46–2.89; P < 0.001]).CONCLUSIONSInsulin resistance and truncal obesity account for the twofold excess incidence of diabetes in Indian Asian and African Caribbean women, but not men. Explanations for the excess diabetes risk in ethnic minority men remains unclear. Further study requires more precise measures of conventional risk factors and identification of novel risk factors.

The clinical characteristics at diagnosis of type 2 diabetes in a multi-ethnic population: the South London Diabetes cohort (SOUL-D)

“…It matches the known increased risk for type 2 diabetes. Recent data from the Southall And Brent REvisited Study (SABRE) study confirm that, given similar environmental influences, the prevalence of type 2 diabetes is equally elevated in black and South Asian ethnic groups [30].…”

Associação entre cor/raça, obesidade e diabetes em idosos da comunidade: dados do Estudo FIBRA

“…Authors further emphasize that racial differences in obesity 15 and diabetes 29 result from a complex interaction that encompasses, beyond socioeconomic and environmental factors (lifestyle), biological/physiological conditions that include: lower resting and total energy output among black individuals (especially women) than in white individuals 29 ; lower levels of adiponectins (associated with higher body fat and metabolic syndrome) in black individuals (versus white individuals) 15 ; in addition to a possible predisposition of ethnic minorities to insulin resistance 29,49,50 . However, further studies are necessary in order to clarify these associations.…”

Ethnic-Specific Obesity Cutoffs for Diabetes Risk: Cross-sectional Study of 490,288 UK Biobank Participants

“…Both obesity and diabetes are increasing in prevalence, particularly among people from nonwhite ethnic groups (6,7). Type 2 diabetes is up to six times more common in people of South Asian descent and up to three times more common among people of African and African-Caribbean origin (7,9), compared with white populations.…”

“…Epidemiological studies carried out in North America, Europe, and Australia suggest that South Asian, black, and Chinese people experience a higher risk of diabetes at lower levels of obesity than whites (9)(10)(11)(12)(13)(14)(15)(16)(17)(18). This suggests that conventional clinical thresholds for obesity that were originally derived from populations of white European descent, namely BMI $30 kg/m 2 (19) or a waist circumference $88 cm in women or $102 cm in men (20), may not be appropriate for nonwhite groups (15)(16)(17)(18).…”