Objectives: To examine chewing ability and survival in older adults after 8 years of follow-up and consider any interaction with the metabolic syndrome (MetS).
Design: Prospective cohort.
Setting: The Elderly Nutrition and Health Survey in Taiwan during 1999/00, a nationally representative sample of Taiwanese aged 65 and older.
Participants: One thousand four hundred ten people (729 men and 681 women).
Measurements: Chewing ability and food intake were ascertained using a questionnaire, supplemented by 24-hour dietary recall. The MetS was defined according to National Cholesterol Education Program Adult Treatment Panel III criteria for Asians. Death according to the National Death Registry by December 31, 2006, was the outcome measure.
Results: During follow-up, 368 subjects died. A significantly higher age- and sex-adjusted hazard ratio (HR=1.44, 95% confidence interval (CI)=1.10-1.78, P=.009) for mortality was found in those who had unsatisfactory chewing ability. Age, sex, and appetite together explain the effect of chewing on mortality. Dietary diversity, body mass index, and health status may also play a role in mediating a possible mortality effect of chewing. Significant interactions between chewing ability and the MetS and mortality were found (P=.04 for five components and .006 for three energy-related components). Jointly, those who had unsatisfactory chewing ability and the MetS were at higher risk of death than those who had satisfactory chewing ability without the MetS (HR=1.65, 95% CI=1.11-2.46 for 5 MetS components; HR=2.58, 95% CI=1.58-4.23 for 3 MetS components).
Conclusion: Self-reported unsatisfactory chewing ability is associated with greater mortality risk in older adults, and MetS increases the risk of mortality in people with chewing difficulty.