A genetic analysis of smoking behavior in family members of older adult males.

AIMS: To conduct a genetic study of smoking behavior in 493 three-generation families.

DESIGN

Complex segregation analysis and maximum likelihood statistics were used to describe the familial clustering of ever-smoking under several transmission models.

SETTING

The Western Collaborative Group Study, an ageing and health study currently in its 39th year of follow-up.

PARTICIPANTS

Probands were male participants who were of mean age 71.6 years at the time of the family history interview in 1986-88.

MEASUREMENTS: Data were collected via an interview that focused on the family smoking history of participants. Smoking histories of all first-degree relatives were obtained from probands.

FINDINGS: Evidence for genetic transmission was indicated by rejection of both the environmental and sporadic models in favor of a Mendelian genetic model with residual familial effects from spouses and both parents.

CONCLUSIONS

The best-fitting model was that of a dominant major gene with low estimated frequency and residual familial correlations. This is the first study to date to model the familial transmission of ever-smoking in three-generation families.