DeCODE Genetics of Nicotine Dependence. DeCODE Genetics of Nicotine Dependence

A genome-wide association study on smoking behavior and nicotine dependence in Icelandic smokers, assessed by the number of cigarettes smoked per day, smoking initiation and degree of dependence on nicotine. The number of cigarettes smoked per day was ascertained through questionnaires given to individuals participating in multiple disease projects at deCODE Genetics (n=16,483). Smoking initiation was analyzed by comparing those that have ever smoked (n=16,483) versus those that have never smoked (n=21,667). The nicotine dependence analysis included 3,435 nicotine dependent cases (score 4 or higher on Fagerstrom Test for Nicotine Dependence (FTND) or endorsement of at least three of the seven Diagnostic and Statistical Manual of Mental Disorders 4th edition (DSM-IV) criteria) and 3,344 low-quantity smokers as controls.