SNPs in the <i>nAChR</i> cluster and OR (95%CI) for quitting smoking in subjects who smoke (upper graph), and OR (95%CI) for restarting to smoke in ex-smokers (lower graph).

<p>Nr. of pairs = number of paired observations in which the subject stopped respectively restarted smoking/ total number of paired observations included in the analysis; Circles represent the odd ratio (OR) and vertical bars represent 95% confidence interval (CI); Wild type was set to one as the reference category; Different total number of paired observations for the SNP genotypes are due to missing data on genotype or smoking habits. The analyses are adjusted for gender and the time between 2 successive surveys. rs569207 TT = wild-type, TC = heterozygote, CC = homozygote variant rs1051730 CC = wild-type CT = heterozygote TT = homozygote variant rs8034191 GG = wild-type, GA = heterozygote, AA = homozygote variant.</p

SNPs in the <i>nAChR</i> cluster and annual FEV₁ decline (ml/year) in smokers, ex-smokers and never smokers.

<p>B = regression coefficient from the linear mixed-effect model, adjusted for 1 = quitting smoking, 2 = restarting smoking, 3 = never smoker, gender, height and age at the first of two successive surveys and time between two successive surveys. “Smokers” refer to those paired observations in which the subject was a smoker at the first of two successive surveys and quitted smoking or continued smoking at the nearest follow-up survey. “Ex-smokers” refer to those paired observations in which the subject was an ex-smoker at the first of two successive surveys and continued being an ex-smoker or restarted smoking at the nearest follow-up survey. “Never smoker” refer to those paired observations in which the subject was a never smoker at the first of two successive surveys and continued being a never smoker at the nearest follow-up survey. a = heterozygotes vs. wild-type; b = homozygote variant vs. wild-type.</p

Summary of the observed associations in the current study.

<p>SNPs = single nucleotide polymorphisms; COPD = Chronic Obstructive Pulmonary Disease; <i>nAChR</i> = <i>nicotinic acetylcholine receptor</i>; + = association; − = no association.</p

SNPs in the <i>nAChR</i> cluster with cigarettes smoked per day in current smokers, and packyears in ever smokers at the last survey.

<p>B = regression coefficient derived from linear regression model, adjusted for age and gender;</p>*<p>only current smokers at the last survey;</p>**<p>ever smokers are current smokers and ex-smokers together.</p><p>a = heterozygote vs. wild-type.</p><p>b = homozygote variant vs. wild-type.</p