The FINRISK studies are population surveys of the Finnish adult population conducted every five years since 1972 [31], examining risk factors of chronic diseases. The FINRISK2007 study consists of 6258 men and women aged 25–74 years drawn from the national population register in five large geographical areas in Finland at the end of 2006. The sample was stratified by sex, 10-year age category, and area. FINRISK2007 includes a smoking-specific questionnaire given to a subsample of ever-smokers who attended an in-person clinical examination and blood draw. Cotinine and 3-hydroxycotinine were measured among self-identified current smokers and recent quitters as part of an analysis of the validity of self-reported smoking status. A total of 419 subjects with cotinine above 10ng/ml and 1000Genomes imputed genome-wide genotype data available were included in the NMR GWAS analyses. For scrutiny of linkage disequilibrium (LD) patterns and allele frequencies, as well as for Genetic Risk Score analyses, additional non-overlapping samples from FINRISK cohorts 1992, 1997, 2002, and 2007 (N = 19857 after individuals with pi-hat>0.4 were excluded; cotinine and 3-hydroxycotinine not available in these) with 1000Genomes imputed genome-wide genotype data available were used.
