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Purpose: To determine the genetic and environmental influences exerted on arthritis by measuring the distribution of self-reported arthritis diagnoses among monozygotic (MZ) and dizygotic (DZ) African American twins., Methods: A cross-sectional study was conducted on 97 MZ and 113 DZ twin pairs recruited into the Carolina African American Twin Study of Aging (CAATSA). The sample had a mean age of 47 +/- 13.9 years. A twin design was used to determine correlations in arthritis diagnosis for MZ and DZ twins and to estimate the contribution of genes and environment to the variation in an arthritis diagnosis., Results: The concordance rate for being diagnosed with arthritis was 42% for MZ twins, and 20% for DZ twins, resulting in a 2.1:1 ratio of MZ to DZ concordance. These results indicate a significant proportion of individual variability was due to genetic factors (43%) on an arthritis diagnosis as well as 57% of variance due to nonshared environmental influences., Conclusion: This research suggests that while there are genetic influences on arthritis diagnosis, environmental factors, such as infections, dietary factors, urbanization, and pollutants, also play a role in accounting for variability in the diagnosis and treatment of arthritis among diverse populations.

Objectives: Despite greater negative environmental influences such as lower socioeconomic status, less parental education, more single-parent households and urban dwelling, African Americans are less likely to begin smoking than European Americans. The goal of the current investigation was to examine the proportion of genetic and environmental influences on smoking in a sample of adult African-American twins., Design: Birth records from North Carolina Register of Deeds Offices were used to identify participants for the Carolina African-American Twin Study of Aging (CAATSA). Participants completed an in-person interview that included measures of health status, cognition and psychosocial measures., Participants: Data for the analysis come from 200 pairs of same-sex twins (97 identical pairs and 113 fraternal), with a mean age = 46.9 years (SD = 13.9) and 38% of the sample being men., Results: Compared to previous research on smoking, our estimates are very similar with genetics, accounting for about 60% of the individual variance in current smoking. We did find that there was a significant amount of genetic variance in pack years but no shared environmental influences., Conclusion: Similarity in proportions of genetic influences lead to larger questions about the genes involved in smoking among African Americans working in the same manner as in Caucasians or other groups. Additionally, this same question holds for the environmental variance. It is perhaps most likely that while the proportions of environmental variance are similar between groups that the actual source of variance (e.g., poverty, urban rural context, socioeconomic status, attitudes of family and friends) may differ when comparing ethnic groups.

Objectives: The primary objective of this investigation was to examine the relationship between physical functioning and various clinical (pain intensity, pain locations, medications, comorbidities) and psychosocial (depression, locus of control) variables in a sample of older blacks., Methods: Data were collected from community-dwelling black adults (N=247), with a mean age of 69.4 +/- 9.4 years. Participants were recruited from several senior high-rise facilities located in an urban community in Baltimore, MD. A multivariate regression model was tested to determine the relationship between selected clinical, psychosocial and demographic characteristics, and physical functioning; and to assess the amount of unique variance in functional status accounted for by specific psychosocial, clinical and demographic indicators (independently and collectively)., Results: It was established that reporting more depressive symptoms (beta=0.18, p<0.05), multiple pain locations (beta=0.25, p<0.01) and pain intensity (beta=0.30, p<0.01) was a significant indicator of physical impairment and accounted for 36% of its variation., Conclusion: Identifying indicators of physical impairment is critical in providing baseline information on the functional well-being in older blacks. This emphasizes the need for further studies to rigorously examine the relationship between physical functioning, and clinical and psychosocial indicators within defined race and ethnic groups in order to develop data that provide meaningful comparisons between different race and ethnic groups.

Objectives: To decompose sources of individual differences in coping as measured by John Henryism among African Americans., Methods: Analyses described in this study are based on the pairwise responses from 180 pairs of same-sex, African-American twin pairs who participated in the Carolina African-American Twins Study of Aging (CAATSA). The sample consisted of 85 monozygotic (MZ) and 95 dizygotic (DZ) twin pairs., Results: Environmental factors account for most of the variance (65%) in John Henryism scores, with the remaining variance attributable to additive genetic factors (35%). The test of the genetic component suggested that the 35% represented a statistically significant proportion of variance., Conclusions: The vast majority of recent studies on African Americans and health outcomes have focused on the impact of psychosocial factors on diseases such as hypertension and diabetes, with relatively little attention to possible genetic contributors. Previous research on psychosocial indices and their relationship to cardiovascular health among African Americans has focused on assessment and epidemiological explorations rather than understanding the etiology of variability in such measures.

The development and testing of explanatory hypotheses about the underlying mechanisms that create health disparities among ethnic minorities will be crucial in identifying solutions for reducing the current differentials. This paper addresses the potential for using genetic information as a useful and necessary addition to approaches to measures of the "environment" in the study of the origins of health disparities. Approaches and theoretical perspectives on the integration of social science and genetic findings are discussed.