Both genetic and lifestyle factors likely contribute to disease risks.
A new genetic study of Native Hawaiians by Charleston Chiang at the University of Southern California and colleagues finds that people who have a greater proportion of Polynesian ancestry in their genomes face a higher risk of obesity, Type-2 diabetes and heart failure. The study was published in the journal PLOS Genetics.
Previous studies have shown that Native Hawaiians appear to have high rates of cancers and chronic health conditions, especially when compared to other people living in Hawaii. In their genes, Native Hawaiians carry a mix of Polynesian, European and Asian ancestry, but due to the group’s small size, there have been few studies of their genetics. To help fill this gap, Chiang and his team examined genome-wide genetic data of about 4,000 self-reported Native Hawaiians to identify regions inherited from Polynesian ancestors, and to find connections to health conditions experienced by the study participants. They found that for every 10% increase in a person’s Polynesian genetic ancestry, their odds of being diabetic and having heart failure rose by 8.6%, and 11.0% respectively. A greater amount Polynesian genetic ancestry also was linked to a higher body mass index (BMI), a measure of body fat. These associations could be attributed to both genetic and lifestyle or other non-genetic factors linked with Polynesian ancestry.
The researchers emphasize that they don’t endorse using genetic information to define Polynesian ancestry and community membership–that should be determined through self-identity or genealogical records. But they hope that further studies may be able to identify genetic variants and underlying biological factors specific to Polynesian populations, which would allow the election of lifestyle or pharmaceutical interventions to reduce their higher risk of these diseases.
The authors add, “While this study focused on the genetics of an underserved population, we want to stress that genetic factors are not the sole, or even necessarily the major, determinant of complex diseases such as obesity and chronic illness in any ethnic group — lifestyle, socioeconomic, and other environmental factors could play as big or a bigger role. However, we hope the genetic studies will be a window into understanding the biology behind these diseases, in a way that is targeted and eventually be beneficial to the health of the underserved population.”
Reference: “The impact of global and local Polynesian genetic ancestry on complex traits in Native Hawaiians” by Hanxiao Sun, Meng Lin, Emily M. Russell, Ryan L. Minster, Tsz Fung Chan, Bryan L. Dinh, Take Naseri, Muagututi‘a Sefuiva Reupena, Annette Lum-Jones, the Samoan Obesity, Lifestyle, and Genetic Adaptations (OLaGA) Study Group, Iona Cheng, Lynne R. Wilkens, Loïc Le Marchand, Christopher A. Haiman and Charleston W. K. Chiang, 11 February 2021, PLOS Genetics.
Funding: The Multiethnic Cohort was funded through grants from the National Cancer Institute (U01CA164973, P01CA168530) and National Human Genome Research Institute (U01HG007397). Whole genome sequencing (WGS) for the Trans-Omics in Precision Medicine (TOPMed) program was supported by the National Heart, Lung and Blood Institute (NHLBI). NHLBI TOPMed: Genome-wide Association Study of Adiposity in Samoans was funded by NHLBI (R01HL093093 [S.T. McGarvey] and (R01 HL133040 [R.L.M.]); WGS (phs000972) was performed at the University of Washington Northwest Genomics Center (HHSN268201100037C) and the New York Genome Center (HHSN268201500016C). Centralized read mapping and genotype calling, along with variant quality metrics and filtering were provided by the TOPMed Informatics Research Center (3R01HL-117626-02S1; contract HHSN268201800002I). Phenotype harmonization, data management, sample-identity QC, and general study coordination were provided by the TOPMed Data Coordinating Center (3R01HL-120393-02S1; contract HHSN268201800001I). This research is also supported by Samoan Ministry of Health and the Samoa Bureau of Statistics. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.