Genetic and environmental contributions to initiation of cigarette smoking in young African-American and European-American women.
BACKGROUND
Distinctions in the relative contributions of genetic and environmental factors to initiation of cigarette smoking may explain, in part, the differences between African Americans and European Americans in the prevalence of smoking. The current investigation is the first to compare heritable and environmental influences on smoking initiation between African-American and European-American women.


METHODS
Data were drawn from Missouri Adolescent Female Twin Study participants and female Missouri Family Study participants (n=4498; 21% African-American, the remainder European-American). Mean ages at first and last assessments were 17.0 (SD=3.5) and 24.0 (SD=3.2), respectively. Twin-sibling modeling was conducted to estimate the proportion of variance in smoking initiation (i.e., ever trying a cigarette) attributable to additive genetic, shared environmental, special twin environmental, and unique environmental factors.


RESULTS
Additive genetic influences accounted for approximately half of the variance in smoking initiation in both African-American and European-American women. In the African-American subsample, the remaining variance was attributable primarily to unique environmental factors (46%; 95% CI: 28-71%). In the European-American subsample, only 12% (95% CI: 8-16%) of the variance was attributable to unique environmental factors, with the remainder accounted for by shared environmental (13%; 95% CI: 0-41%) and special twin environmental (24%; 95% CI: 0-52%) factors.


CONCLUSIONS
The estimated heritability of smoking initiation is substantial and nearly identical for African-American and European-American women, but the type of environmental factors that contribute to risk differ by race/ethnicity. Whereas the primary environmental influences on European-American women's smoking initiation are at the family level, those that impact African-American women's smoking initiation are primarily individual-specific.
Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA; Department of Psychiatry, Washington University School of Medicine, St. Louis, MO, USA. Electronic address: carolyn.sartor@yale.edu.
Carolyn E
CE
Sartor
Department of Psychiatry, Washington University School of Medicine, St. Louis, MO, USA.
Julia D
JD
Grant
Department of Psychiatry, Washington University School of Medicine, St. Louis, MO, USA.
Arpana
A
Agrawal
Department of Psychiatry, Yale University School of Medicine, New Haven, CT, USA; Department of Psychiatry, Washington University School of Medicine, St. Louis, MO, USA.
Brooke
B
Sadler
Department of Psychiatry, Washington University School of Medicine, St. Louis, MO, USA.
Pamela A F
PA
Madden
Department of Psychiatry, Washington University School of Medicine, St. Louis, MO, USA.
Andrew C
AC
Heath
Department of Psychiatry, Washington University School of Medicine, St. Louis, MO, USA.
Kathleen K
KK
Bucholz
D000293:Adolescent; D001741:Black or African American / Q000235:genetics* / Q000523:psychology*; D016739:Behavior, Addictive / Q000235:genetics / Q000523:psychology; D004777:Environment; D005192:Family Health; D005260:Female; D006801:Humans; D008923:Missouri / Q000453:epidemiology; D015995:Prevalence; D012306:Risk; D012907:Smoking / Q000453:epidemiology* / Q000235:genetics* / Q000523:psychology; D014427:Twins / Q000235:genetics / Q000523:psychology; D014481:United States; D044465:White People / Q000235:genetics* / Q000523:psychology*; D055815:Young Adult
African Americans; Smoking; Twins; Women