Concordance rates for smoking among African-American twins

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.

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.

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.

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.

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.