“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,” notes study co-author Dr. Julie Locher, professor in the departments of medicine and health care organization and policy and associate director for enrichment of the Nutrition Obesity Research Center (NORC) at the University of Alabama at Birmingham. “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.”
[Photo: Dr. Julie Locher]
In this study conducted in collaboration with UAB’s Dr. Virginia Howard, professor in the department of epidemiology — as well as professor and lead author Dr. David L. Roth and associate professors Drs. Kimberly A. Skarupski and Deidra Candice Crews at Johns Hopkins University’s Center on Aging and Health — 12,181 African American and 17,436 White enrollees in the REasons for Geographic and Racial Differences in Stroke (REGARDS) study were assessed. Participants were aged 45 or older and had enrolled in REGARDS between 2003 and 2007. After adjusting for health history and demographics, the investigators found that African Americans participants had poorer SRH than their White counterparts, data which is consistent with results produced by previous studies. Survival analysis models showed that “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.”
The researchers determined that “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 conclusion suggests that other mechanisms, including behavioral, social, and cultural influences, should be evaluated toward greater understanding of the age-based mortality crossover effect as well as of other longevity disparities.
“Distinct Age and Self-Rated Health Crossover Mortality Effects for African Americans: Evidence from a National Cohort Study” was published online in March in the journal Social Science & Medicine.
Journal article: http://www.ncbi.nlm.nih.gov/pubmed/27015163?dopt=Abstract