Article Text
Abstract
Objective To investigate whether: (1) smoking predicts suicide-related outcomes (SROs), (2) prior SRO predicts smoking, (3) smoking abstinence affects the risk of SRO and (4) psychiatric comorbidity modifies the relationship between smoking and SRO.
Design Retrospective analysis of longitudinal data obtained in wave 1 (2001–2002) and wave 2 (2004–2005) of the National Epidemiologic Survey on Alcohol and Related Conditions.
Setting Face-to-face interviews conducted with persons in the community.
Participants US adults (N=43 093) aged 18 years or older were interviewed in wave 1 and reinterviewed (N=34 653) 3 years later. For the present study, the sample was the subset of persons (N=7352) who at the wave 2 interview reported low mood lasting 2 weeks or more during the past 3 years and were further queried regarding SRO occurring between waves 1 and 2.
Outcome measures SRO composed of any of the following: (1) want to die, (2) suicidal ideation, (3) suicide attempt, reported at wave 2. Current smoking reported at wave 2.
Results Current and former smoking in wave 1 predicted increased risk for wave 2 SRO independently of prior SRO, psychiatric history and socio-demographic characteristics measured in wave 1 (adjusted OR (AOR)=1.41, 95% CI 1.28 to 1.55 for current smoking; AOR=1.32, 95% CI 1.21 to 1.43 for former smoking). Prior SRO did not predict current smoking in wave 2. Compared with persistent never-smokers, risk for future SRO was highest among relapsers (AOR=3.42, 95% CI 2.85 to 4.11), next highest among smoking beginners at wave 2 (AOR=1.82, 95% CI 1.51 to 2.19) and lowest among long-term (4+ years) former smokers (AOR=1.22, 95% CI 1.12 to 1.34). Compared with persistent current smokers, risk for SRO was lower among long-term abstainers (p<0.0001) but not among shorter-term abstainers (p=0.26).
Conclusions Smoking increased the risk of future SRO independently of psychiatric comorbidity. Abstinence of several years duration reduced that risk.
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Footnotes
The study is a secondary analysis of data collected by the National Institute of Health–National Institute of Alcohol and Alcohol Abuse of the US government. Before data collection, each respondent was informed of the nature of the survey and its potential uses, ensured of confidentiality and told that participation was voluntary. All participants signed a consent form prior to participating in the interviews. Individual data files are deidentified to prevent full anonymity of participants. Approval for conducting this secondary analysis of previously collected data was not required.
To cite: Covey LS, Berlin I, Hu MC, et al. Smoking and suicidal behaviours in a sample of US adults with low mood: a retrospective analysis of longitudinal data. BMJ Open 2012;2:e000876. doi:10.1136/bmjopen-2012-000876
Contributors LSC and IB conceptualised this study and together with M-CH designed the analysis. JKH had full access to all the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis. LSC was the lead writer of the manuscript. All authors participated in the interpretation of findings and writing of the manuscript. All authors had full access to the statistical reports, tables and the manuscript and take responsibility for the integrity of the data and the accuracy of the data analysis. The US Census Bureau, National Institute on Alcohol Abuse and Alcoholism (NIAAA) and other employers of the authors had no role in the study design, implementation of the study, analysis and interpretation of data, in the writing of the report and the decision to submit the article for publication.
Funding The National Epidemiologic Survey on Alcohol and Related Conditions was sponsored by the NIAAA and funded in part by the Intramural Program, NIAAA, National Institutes of Health, with additional support from the National Institute on Drug Abuse. No funding was obtained for this secondary analysis.
Competing interests All authors have completed the Unified Competing Interest form (www.icmje.org/coi_disclosure.pdf). (1) JKH received support from NIAAA through the US Census Bureau for the submitted work; (2) LSC, IB and M-CH received no specific support for this work; (3) IB received occasional honoraria for participating in advisory panels of Pfizer Ltd during the past 3 years; (4) in February 2011, LSC provided educational consultation to a law firm regarding mood effects of smoking cessation; (5) JKH and M-CH had no relationships with any company that might have an interest in the submitted work in the previous 3 years; (6) none of the spouses of the authors had financial relationships that may be relevant to the submitted work; (7) none of the authors had a non-financial interest that may be relevant to the submitted work.
Ethics approval Ethics approval was provided by the US Census Bureau and the US Office of Management and Budget.
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement In order to safeguard sensitive personal information, data are not available for public use. The restricted use data sets are maintained by the US Census Bureau on behalf of NIAAA, and any requests to use NESARC data for replication or other purposes may be directed to the NIAAA coordinator for NESARC, Aaron White (whitea4{at}mail.nih.gov).