Lower frailty incidence in older Mexican Americans than in Older European Americans: The San Antonio longitudinal study of aging

OBJECTIVES: To directly compare frailty incidence of older Mexican American (MA) and European American (EA) adults. DESIGN: Longitudinal, observational cohort study. SETTING: Socioeconomically diverse neighborhoods in San Antonio, Texas. PARTICIPANTS: Three hundred one older MA and 305 older EA adults in the San Antonio Longitudinal Study of Aging (SALSA) who were nonfrail at baseline. MEASUREMENTS: Frailty was assessed at baseline, and three follow-ups conducted over an average of 9.9 years using well-established criteria from the Cardiovascular Health Study. Covariates were baseline age, sex, socioeconomic status (SES), prefrailty status, diabetes mellitus, and comorbidity. The adjusted ethnic odds (MA vs EA) of incident frailty were estimated using generalized estimating equations. RESULTS: There was no ethnic difference in the unadjusted incidence of frailty over the three follow-up examinations (odds ratio (OR)=0.97, 95% confidence interval (CI)=0.62-1.52), even though baseline SES was significantly lower in MAs than EAs. After covariate adjustment, the odds of incident frailty were significantly lower for MAs than EAs (OR=0.40, 95% CI=0.23-0.72). Other significant predictors of frailty in the adjusted model were pre-frailty (present vs absent OR=3.19, 95% CI=1.86-5.47), education (1-year increment OR=0.89, 95% CI=0.83-0.96), and income (1-year increment OR=0.88, 95% CI=0.79-2.04). CONCLUSION: These findings lend support to the Hispanic Paradox and suggest that MAs who live to older ages are less likely than similarly aged EAs to become frail. Further research is needed to identify the underlying biological and social mechanisms that explain this finding to enhance the development of interventions for the prevention and treatment of this clinical geriatric syndrome.