Background and objectives: The extent to which health and survival inequality between indigenous and nonindigenous older Taiwanese is associated with diet is uncertain.
Methods and study design: Participants from the Elderly Nutrition and Health Survey in Taiwan (1999-2000) formed this cohort. Dietary information was collected by 24-hr recall and simplified food frequency questionnaire. Dietary quality was assessed by dietary diversity score (DDS, 0-6). Annual medical service utilization and expenditure were derived from National Health Insurance claims until 2006. Survivorship was ascertained from the National Death Registry until 2008. Cox proportional- hazards models were used to determine the association between aboriginality and mortality in conjunction with dietary diversity.
Results: Indigenes (n=156) compared with nonindigenes (n=1182) significantly differed in socio-demography, behaviors and chronic disease prevalences. For up to 8 years, indigenes had a higher mortality rate (46.2% vs 33.6%, p=0.003). Indigenes' nutrient intakes were less for polyunsaturated fat, dietary fiber, vitamins and minerals (but more sodium); food intakes more for meat, with less cooking oil, dairy products and fruits; and a lower DDS, (3.61 vs 4.54). They had a 41% higher mortality risk (HR: 1.41, 95% CI: 1.09-1.81, p=0.008). Control for demographic variables did not change the findings. However, the increase in HR was substantially attenuated by the inclusion of DDS (HR: 1.15, 95% CI: 0.88-1.49, p=0.316). There was no significant interaction between aboriginality and DDS on mortality (p=0.673).
Conclusions: Older indigenous Taiwanese have a higher mortality risk than their majority counterparts. Irrespective of aboriginality, the more diverse diet is associated with a lower risk of mortality.