A Comparison of Variances in Age Cohorts to Understand Longevity in African Americans

African American life expectancy at age 65 is about 2 years less than that of Caucasians, but by age 85, African Americans may have a longevity advantage. One possible explanation for this cross-over effect is that African Americans who make it to the oldest ages have done so by handling stressful contextual and health disadvantages. The purpose of this study was to examine possible within group cohort differences that lead to exceptional longevity among older African Americans.

Data came from three cohorts of older African Americans: the Carolina African American Twin Study of Aging (CAATSA), the Baltimore Study of Black Aging-Patterns of Cognitive Aging (BSBA-PCA), and the Study of Longevity and Stress in African American Families (SOLSAA). Of the 533 participants, we compared two age cohorts (60-79 and 80+) with an average age of 73.2 (SD = 8.33) and 26.3% are men. Variables included measures of stress, depression, coping, cognition, and health indicators.

The variance for depression and average peak expiratory flow (APEF) was significantly larger for the older cohort but after controlling for demographic factors, the measure of depressive symptoms was not. The Alpha Span test showed a significant difference with the older cohort having larger variances after controlling for demographic factors.

The findings suggest that there are changes in the characteristics of who makes it to later life, but counter to our hypothesis, there was greater variability in the oldest group relative to the younger.