Genetic and environmental contributions to alcohol dependence risk in a national twin sample: consistency of findings in women and men.
BACKGROUND
Genetic influences on alcoholism risk are well-documented in men, but uncertain in women. We tested for gender differences in genetic influences on, and risk-factors for, DSM-III-R alcohol dependence (AD).


METHODS
Diagnostic follow-up interviews were conducted in 1992-3 by telephone with twins from an Australian twin panel first surveyed in 1980-82 (N = 5889 respondents). Data were analysed using logistic regression models.


RESULTS
Significantly higher twin pair concordances were observed in MZ compared to DZ same-sex twin pairs in women and men, even when data were weighted to adjust for over-representation of well-educated respondents, and for selective attrition. AD risk was increased in younger birth cohorts, in Catholic males or women reporting no religious affiliation, in those reporting a history of conduct disorder or major depression and in those with high Neuroticism, Social Non-conformity, Toughmindedness, Novelty-Seeking or (in women only) Extraversion scores; and decreased in 'Other Protestants', weekly church attenders, and university-educated males. Controlling for these variables, however, did not remove the significant association with having an alcoholic MZ co-twin, implying that much of the genetic influence on AD risk remained unexplained. No significant gender difference in the genetic variance in AD was found (64% heritability, 95% confidence interval 32-73%).


CONCLUSIONS
Genetic risk-factors play as important a role in determining AD risk in women as in men. With the exception of certain sociocultural variables such as religious affiliation, the same personality, sociodemographic and axis I correlates of alcoholism risk are observed in women and men.
Heath
A C
AC
Department of Psychiatry, Washington University School of Medicine, St Louis, MO 63110, USA.
Bucholz
K K
KK
Madden
P A
PA
Dinwiddie
S H
SH
Slutske
W S
WS
Bierut
L J
LJ
Statham
D J
DJ
Dunne
M P
MP
Whitfield
J B
JB
Martin
N G
NG
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000437:Alcoholism / Q000453:epidemiology / Q000235:genetics*; D001315:Australia / Q000453:epidemiology; D002410:Catholicism; D004200:Diseases in Twins / Q000453:epidemiology / Q000235:genetics*; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D008957:Models, Genetic; D016017:Odds Ratio; D010551:Personality / Q000145:classification; D015995:Prevalence; D012042:Registries; D012307:Risk Factors; D012720:Severity of Illness Index; D012737:Sex Factors; D014429:Twins, Dizygotic; D014430:Twins, Monozygotic