The average age of the subjects was 40.8 ± 14.8 years for EAs and 39.9 ± 14.6 years for AAs. The average family size was 3.16 ± 0.69 for EAs and 3.10 ± 0.75 for AAs. Of these families, 60.5% had at least one biological parent recruited, 50.4% had two full sibs, and 44.6% had three or more full sibs. If a family had no biological parents recruited, we had at least three full sibs. The average Fagerstrom test for ND (FTND) score was 6.4 ± 2.2 for EA and 6.3 ± 2.1 for AA smokers. The average CPD was 19.8 ± 13.6 for EA and 19.5 ± 13.0 for AA smokers.
