Serum ferritin contributes to racial or geographic disparities in metabolic syndrome in Taiwan

Abstract

Objectives: Asians and Pacific Islanders have higher circulating serum ferritin (SF) compared with Caucasians but the clinical significance of this is unclear. There is a higher prevalence of metabolic syndrome (MetS) in Taiwanese Indigenous than Han Chinese. Genetically, Indigenous are related to Austronesians and account for 2 % of Taiwan's population. We tested the hypothesis that accumulation of Fe in the body contributes to the ethnic/racial disparities in MetS in Taiwan.

Design: A population-based, cross-sectional study.

Setting: National Nutrition and Health Survey in Taiwan and Penghu Island.

Subjects: A total of 2638 healthy adults aged ≥19 years. Three ethnic groups were included.

Results: Han Chinese and Indigenous people had comparable levels of SF. Austronesia origin was independently associated with MetS (OR = 2·61, 95 % CI 2·02, 3·36). After multiple adjustments, the odds for MetS (OR = 2·49, 95 % CI 1·15, 5·28) was significantly higher among Indigenous people in the highest SF tertile compared with those in the lowest tertile. Hakka and Penghu Islanders yielded the lowest risks (OR = 1·08, 95 % CI 0·44, 2·65 and OR = 1·21, 95 % CI 0·52, 2·78, respectively). Indigenous people in the highest SF tertile had increased risk for abnormal levels of fasting glucose (OR = 2·34, 95 % CI 1·27, 4·29), TAG (OR = 1·94, 95 % CI 1·11, 3·39) and HDL-cholesterol (OR = 2·10, 95 % CI 1·18, 3·73) than those in the lowest SF tertile.

Conclusions: Our results raise the possibility that ethnic/racial differences in body Fe store susceptibility may contribute to racial and geographic disparities in MetS.

Fig. 1

Distribution of serum ferritin (SF) level by decade of age for healthy Taiwanese men and women aged ≥19 years (n 2638) stratified by ethnicity (Nation: (men), (women); Hakka: (men), (women); Indigenous: (men), (women); Penghu Islander: (men), (women))

Fig. 2

Association between serum ferritin (SF) level (, men; , women) and metabolic syndrome (MetS) prevalence (, men; , women) by decade of age for healthy Taiwanese men and women aged ≥19 years (n 2638) according to ethnic group: (a) Indigenous; (b) Hakka; (c) Penghu Islanders