Table 2.

Characteristics of African-American and European-American samples

Characteristic	African- American	European- American
No. of nuclear families	402	200
Avg. members/family	3.14 ± 0.75	3.17 ± 0.69
No. of subjects	1,366	671
% female	66.1	69.5
Age (years)	39.4 ± 14.4	40.5 ± 15.5
No. of smokers	1,053	515
Age of smoking onset (years)	17.3 ± 4.7	15.5 ± 4.4
Years smoked	20.4 ± 12.5	23.2 ± 13.5
CPD	19.4 ± 13.3	19.5 ± 13.4
HSI	3.7 ± 1.4	3.9 ± 1.4
FTND score	6.26 ± 2.15	6.33 ± 2.22

CPD number of cigarettes smoked per day, HSI Heaviness of Smoking Index, FTND Fagerström test for ND