Table 3.

Factors Affecting the Risk of Developing Alcohol Dependence and Habitual Smoking in Siblings of Alcohol-Dependent COGA Probands

	Risk Ratio (95% Confidence Interval)
	Alcohol Dependence	Habitual Smoking
Sibling Characteristics
Birth Cohort
Born before 1950	1.00	1.00
Born 1950–1959	1.53 (1.23–1.90)	0.63 (0.53–0.77)
Born 1960 or later	2.07 (1.65–2.60)	0.50 (0.41–0.61)
Gender
Male	1.00	1.00
Female	0.48 (0.42–0.55)	0.86 (0.75–0.98)
Alcohol Dependence	NA	2.06 (1.78–2.39)
Habitual Smoking	1.92 (1.68–2.20)	NA
Proband Characteristics
Gender
Male	1.00	1.00
Female	1.09 (0.94–1.26)	1.09 (0.91–1.30)
Alcohol Dependence	2.60 (1.60–4.01)	1.66 (0.99–2.79)
Habitual Smoking	0.98 (0.85–1.12)	1.77 (1.48–2.12)

COGA = Collaborative Study on the Genetics of Alcoholism.

Probands = alcohol-dependent patients and control subjects initially recruited for the COGA study.

SOURCE: Adapted in part from Bierut et al. 1998.