Available reports have shown genetic liability for cigarette smoking. No prior study has compared the relative familial risk for different phenotypic definitions of nicotine dependence despite the importance of optimal identification of phenotype for genetic studies. Data come from the Health and Adjustment of Young Adults Study, a longitudinal study of 1,007 adults, 21-30 years of age. Family history of 'regular smoking' was assessed for biological parents and full siblings. Familial loading was measured as the proportion of 1st degree relatives with a lifetime history of regular cigarette smoking. Proband nicotine dependence was assessed by daily smoking, the Fagerstrom Test for Nicotine Dependence and the Diagnostic and Statistical Manual version-III-R. Probands who had never smoked or smoked but never daily had similar levels of mean familial loading (0.38, 0.39) that were significantly lower (p < 0.01) than current daily smokers (regardless of their dependence status) and former smokers who were DSM-III-R dependent (range 0.58 - 0.61). Former daily smokers who were never DSM-III-R dependent did not differ from low or high familial risk groups (0.48). Requiring relatives to have smoked at least 20 cigarettes per day, examining only siblings and inclusion of psychiatric comorbidity did not alter these results. Results suggest that familial risk of nicotine dependence might not be highly sensitive to phenotypic definition among daily smokers.
|Number of pages||1|
|Journal||American Journal of Medical Genetics - Neuropsychiatric Genetics|
|State||Published - Aug 7 2000|