Ethnic admixture affects diabetes risk in native Hawaiians: the Multiethnic Cohort

• Published in: European journal of clinical nutrition 2016-09, Vol.70 (9), p.1022-1027
• Main Authors: Maskarinec, G, Morimoto, Y, Jacobs, S, Grandinetti, A, Mau, M K, Kolonel, L N
• Format: Article
• Language: English
• Subjects: 692/499; Admixtures; Aged; Asian; Body Mass Index; Body size; Body weight; China; Clinical Nutrition; Cohort Studies; Confidence intervals; Demographic aspects; Diabetes; Diabetes mellitus (non-insulin dependent); Diabetes Mellitus, Type 2 - ethnology; Diabetes Mellitus, Type 2 - genetics; Diet; Epidemiology; Ethnic factors; Ethnicity; Female; Genetic factors; Genetic Predisposition to Disease; Hawaii; Hawaiians; Health aspects; Health risk assessment; Health risks; Humans; Internal Medicine; Life Style; Male; Medicine; Medicine & Public Health; Metabolic Diseases; Middle Aged; Minority & ethnic groups; Native Hawaiian or Other Pacific Islander; Native peoples; Obesity; Obesity - ethnology; original-article; Overweight; Overweight - ethnology; Proportional Hazards Models; Public Health; Reference Values; Risk analysis; Risk Factors; Surveys and Questionnaires; Type 2 diabetes; White People
• ISSN: 0954-3007; 1476-5640
• DOI: 10.1038/ejcn.2016.32

Background/Objectives: Obesity and diabetes rates are high in Native Hawaiians (NHs) who commonly have mixed ancestries. People of Asian ancestry experience a high risk of type 2 diabetes despite the relatively low body weight. We evaluated the impact of ethnic admixture on diabetes risk among NHs in the Multiethnic Cohort (MEC). Subjects/Methods: On the basis of self-reports, 11 521 eligible men and women were categorized into NH/white, NH/other, NH alone, NH/Asian and the most common three ancestry admixture, NH/Chinese/white. Cox proportional hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated with the NH/white category as the reference group; covariates included known confounders—that is, body mass index (BMI), dietary and other lifestyle factors. Results: The NH alone category had the highest proportion of overweight and obese individuals and the NH/Asian category the lowest proportion. During 12 years of follow-up after cohort entry at 56 years, 2072 incident cases were ascertained through questionnaires and health plan linkages. All NH categories had higher HRs than the NH/white category before and after adjustment for BMI. In the fully adjusted models, the NH/Asian category showed the highest risk (HR=1.45; 95% CI: 1.27–1.65), followed by NH/other (HR=1.20; 95% CI: 1.03–1.39), NH/Chinese/white (HR=1.19; 95% CI: 1.04–1.37) and NH alone (HR=1.19; 95% CI: 1.03–1.37). The elevated risk by Asian admixture was more pronounced in normal weight than overweight/obese individuals. Conclusions: These findings indicate that Asian admixture in NHs is associated with a higher risk for type 2 diabetes independent of known risk factors and suggest a role for ethnicity-related genetic factors in the development of this disease.