Polygenic risk scores for nicotine use and family history of smoking are associated with smoking behaviour

Introduction Formal genetics studies show that smoking is influenced by genetic factors; exploring this on the molecular level can offer deeper insight into the etiology of smoking behaviours. Methods Summary statistics from the GWAS and Sequencing Consortium of Alcohol and Nicotine (GSCAN) Consortium were used to calculate polygenic risk scores (PRS) in a sample of ∼2,200 smokers/never-smokers. The association of PRS for Smoking Initiation (i.e. Lifetime Smoking; SI-PRS) with smoking status, and PRS for Cigarettes per Day (CpD-PRS) and Smoking Cessation (SC-PRS) with Fagerström Test for Nicotine Dependence (FTND) score were examined, as were distinct/additive effects of parental smoking on smoking status. Results SI-PRS explained 6.65% of variance (Nagelkerke-R2) in smoking status (p=1.71×10−24). In smokers, CpD-PRS (R2=3.15%, p=1.82×10−8) and SC-PRS (R2=2.01%; p=7.18×10−6) were associated with FTND score. Parental smoking alone explained R2=3.06% (p=2.43×10−12) of smoking status, and 1.39% when added to the most informative SI-PRS model (total R²=8.04%). Conclusion These results show the potential utility of molecular genetic data for research investigating smoking prevention. The fact that PRS explains more variance than family history highlights progress from formal to molecular genetics; the overlap and increased predictive value when using both suggests the importance of combining these approaches. Implications This study underlines the value of using PRS to predict smoking status/behaviour. It highlights the importance of molecular genetic methods in research investigating smoking prevention and points to the necessity of combining family history and molecular genetic data. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This research was supported by the German Research Foundation (DFG: TRR SPP1226, DFG Wa 731/8-1, Wi1316/9-1, DFG: TRR265 (Project-ID 402170461), and German Federal Ministry of Education and Research (BMBF: Target-OXY 031L0190A). ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The study was approved by the local ethics committees of the participating institutes (CIMH, Charite, Cologne). I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable. Yes All data produced in the present study are available upon reasonable request to the authors.