Dr. Keith Whitfield, associate professor of biobehavioral health and leader of the Penn State studies, says, "Our research team is working to understand why people seem to age differently on some things and not others. We hope to provide a better understanding of the role of genetics in health and mental health as well as looking at personality and cognitive functioning."
The team’s results were detailed in three posters presented at the Gerontological Society of America meeting in Chicago, Ill. Nov. 15 through 18. The posters are: Genetic Influences on Arthritis: Results from the Carolina African American twin Study of Aging; Personality As A Predictor of Cognitive Functioning; and Sources of Variance in Measures of Well-Being. The Penn State team includes Dr. Tamara A. Baker, who earned her doctorate under Whitfield’s direction, and Sebrina A. Wiggins and Dwayne T. Brandon, who are doctoral candidates.
Tamara A. Baker, who currently holds a postdoctoral appointment at the University of Michigan, is first author of the arthritis paper. She and the team found that genetics, age and depression were significant predictors of arthritis.
The subjects in the study included 70 identical twins and 88 fraternal twins ranging in age from 45 to 88 years of age from the Carolina African American Twin Study of Aging. The twins were asked to complete questionnaires and interviews in which they provided information on demographics, health, cognition and well-being. The rates of agreement in responses among the identical twin pairs was 69 percent and 58 percent among the fraternal twins, suggesting to the researchers that a genetic influence was present.
Whitfield notes that African Americans disproportionately experience arthritis and about 95 percent of the cases are osteo arthritis. He adds, while there is a significant body of evidence linking genetics to rheumatoid arthritis, there is less evidence for osteo arthritis. The findings of the current study, the first with African American twins, supports the genetic theory of the origin of both types of arthritis.
Baker writes, "The results suggest that even after known environmental measures are considered, genetic influences are still significant in accounting for individual variability in arthritis."
Sebrina A. Wiggins, a doctoral candidate in biobehavioral health at Penn State under Whitfield’s direction, is first author of the mental functioning paper. She and the team found that the personality trait that best predicted effective mental functioning among aging adult African Americans was openness. She says, "If a person indicated that they were open to new experiences and was flexible and adaptable, they also tended to maintain learning and memory, general intellectual ability and spatial ability. Attention and the ability to recall things on a short term basis didn’t vary with openness."
The data for the study was drawn from the Baltimore Study of Black Aging which Whitfield has been conducting since 1997. The subjects include 281 African American men and women from 47 to 90 years of age.
Whitfield notes that these findings could be useful when trying to select a retirement community, for example. If a person has a less open personality type, it might be best to select a retirement community that provides activities that foster openness in order to help maintain mental functioning.
Dwayne T. Brandon, National Institutes on Aging Pre-doctoral Fellow, is first author of the well-being study. He and the team found a strong genetic influence on several measures of well being including John Henryism or active coping, life satisfaction and depression. Perceived stress and locus or control or the extent that a person felt that things were under their own control were more affected by the environment.
Data for the study came from the Carolina African American Twin Study of Aging.
Whitfield adds, "Culture has varying degrees of environmental influence. So, next we will compare these results with results from Swedish and Russian studies."