Anthropometric and metabolic differences and distribution of ABCG2 rs2231142 variant between lowland and highland Papuans in West Papua, Indonesia.

BACKGROUND

Papuan people inhabiting the island of New Guinea are the most ancient population living outside Africa, having resided in the region for at least 50,000 years. The arrival of Austronesian speakers and other group from mainland Asia around 3000 years or so created a peculiar genetic mixture, particularly in lowland/coastal areas. We investigated the anthropometric and blood chemical differences alongside the population structure of the ABCG2 rs2231142 genetic variant of West Papuans from lowland/coastal and highland areas to understand metabolic risk differences between these two populations.

RESULTS

We studied West Papuan students from lowland/coastal areas (n = 78, 45 males, 33 females) and from highland areas (n = 65, 40 males, 25 females). We found the following: (1) The lowland/coastal Papuans were taller, with lower BMI, central obesity, and triceps. Contrarily, highland Papuans have a more gynoid body shape, with higher WC, HC, WHR, and WHtR. The skinfolds were significantly thicker in women from the highlands. (2) There was actually a negative correlation between BMI and central adiposity with UA and FBG to those from the highlands. The lowland/coastal Papuans indicated an Asian-type metabolic traits, with higher fasting glucose levels at lower BMI and lower central adiposity. (3) UA concentration and DBP were strongly correlated with obesity of the Papuans from lowlands/coasts and not in the Papuans from highlands. (4) There was a striking difference in the ABCG2 rs2231142 > T allele frequency in those from the lowlands/coasts (22%) compared to those from the highlands of West Papua (7%). The T variant in the latter is all heterozygous.

CONCLUSIONS

The higher adiposity and thicker skinfolds observed in highland Papuans are thought to be adaptive responses to the high-altitude environment, enabling greater adipose tissue expandability and energy storage capacity while maintaining metabolic homeostasis. In contrast, the lowland/coastal Papuans exhibit an Asian metabolic phenotype, which is more prone to metabolic derangements at lower adiposity. Our findings on the population distribution of the ABCG2 rs2231142 > T variant support the idea that its presence in the Papuan highlands is through demic diffusion of the variant from ISEA, indicating that the two populations are separate entities displaying differences in metabolic risks.