title: Distinct age and self-rated health crossover mortality effects for African Americans: Evidence from a national cohort study.
abstract: The predictive effects of age and self-rated health (SRH) on all-cause mortality are known to differ across race and ethnic groups. African American adults have higher mortality rates than Whites at younger ages, but this mortality disparity diminishes with advancing age and may "crossover" at about 75-80 years of age, when African Americans may show lower mortality rates. This pattern of findings reflects a lower overall association between age and mortality for African Americans than for Whites, and health-related mechanisms are typically cited as the reason for this age-based crossover mortality effect. However, a lower association between poor SRH and mortality has also been found for African Americans than for Whites, and it is not known if the reduced age and SRH associations with mortality for African Americans reflect independent or overlapping mechanisms. This study examined these two mortality predictors simultaneously in a large epidemiological study of 12,181 African Americans and 17,436 Whites. Participants were 45 or more years of age when they enrolled in the national REasons for Geographic and Racial Differences in Stroke (REGARDS) study between 2003 and 2007. Consistent with previous studies, African Americans had poorer SRH than Whites even after adjusting for demographic and health history covariates. Survival analysis models indicated statistically significant and independent race*age, race*SRH, and age*SRH interaction effects on all-cause mortality over an average 9-year follow-up period. Advanced age and poorer SRH were both weaker mortality risk factors for African Americans than for Whites. These two effects were distinct and presumably tapped different causal mechanisms. This calls into question the health-related explanation for the age-based mortality crossover effect and suggests that other mechanisms, including behavioral, social, and cultural factors, should be considered in efforts to better understand the age-based mortality crossover effect and other longevity disparities.
authors.affiliation: Center on Aging and Health, Johns Hopkins University, USA; Division of Geriatric Medicine and Gerontology, Department of Medicine, School of Medicine, Johns Hopkins University, USA. Electronic address: droth@jhu.edu.
authors.forename: David L
authors.initials: DL
authors.lastname: Roth
authors.affiliation: Center on Aging and Health, Johns Hopkins University, USA; Division of Geriatric Medicine and Gerontology, Department of Medicine, School of Medicine, Johns Hopkins University, USA.
authors.forename: Kimberly A
authors.initials: KA
authors.lastname: Skarupski
authors.affiliation: Center on Aging and Health, Johns Hopkins University, USA; Division of Nephrology, Department of Medicine, School of Medicine, Johns Hopkins University, USA.
authors.forename: Deidra C
authors.initials: DC
authors.lastname: Crews
authors.affiliation: Department of Epidemiology, School of Public Health, University of Alabama at Birmingham, USA.
authors.forename: Virginia J
authors.initials: VJ
authors.lastname: Howard
authors.affiliation: Division of Gerontology, Geriatrics, and Palliative Care, Department of Medicine, University of Alabama at Birmingham, USA.
authors.forename: Julie L
authors.initials: JL
authors.lastname: Locher
mesh_terms: D001741:Black or African American / Q000706:statistics & numerical data*; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D059026:Diagnostic Self Evaluation; D005260:Female; D054624:Health Status Disparities; D006801:Humans; D008297:Male; D008875:Middle Aged; D009026:Mortality / Q000208:ethnology*; D014481:United States / Q000453:epidemiology; D044465:White People / Q000706:statistics & numerical data
keywords: Health disparities; Mortality; Mortality crossover effects; Race; Self-rated health