Familial influences on adolescent smoking.

The family unit is the primary source of transmission of basic social, cultural, genetic, and biological factors that may underlie individual differences in smoking. Existing information on the role of familial factors in tobacco use is characterized by two separate, but somewhat overlapping, lines of research: genetic epidemiological studies and risk-factor research. The present paper summarizes and evaluates studies assessing the association between adolescent smoking and parent and sibling smoking behaviors. A review of 87 studies reveals that methods are limited by a lack of standardized instruments, failure to measure important confounding and mediating factors, reliance on cross-sectional designs and the use of inconsistent definitions of tobacco-related behavior and assessment procedures. Moreover, there are no systematic family studies of the acquisition and continuation of smoking that have employed contemporary methodological standards for examining familial aggregation of tobacco behaviors among adolescents. Findings across studies show weak and inconsistent associations between parent and adolescent smoking; inconsistent findings may be attributed to methodological issues or associated factors that may complicate the relation between parent and adolescent smoking. Sibling and peer smoking show greater associations with adolescent smoking. Suggestions for future research include contemporary family studies that delineate meaningful phenotypes of tobacco use and prospective work on the later stages of tobacco use and the timing of the influence and valence of parent and family factors. Integration of the risk factor approach within the family study design may enrich both approaches to elucidate familial influences on smoking.