title: The association between quitting smoking and weight gain: a systematic review and meta-analysis of prospective cohort studies.
abstract: This systematic review and meta-analysis aimed to quantify weight gain after smoking cessation and the difference in weight gain between quitters and continuing smokers. Five electronic databases were searched before January 2015. Population-based prospective cohort studies were included if they recorded the weight change of adult smokers from baseline (before smoking cessation) to follow-up (at least 3 months after cessation). Thirty-five cohort studies were identified, including 63,403 quitters and 388,432 continuing smokers. The mean weight gain was 4.10 kg (95% confidence interval [CI]: 2.69, 5.51) and body mass index (BMI) gain was 1.14 kg m(-2) (95% CI: 0.50, 1.79) among quitters. Compared with continuing smoking, quitting smoking was significantly associated with absolute weight (adjusted mean difference [MD]: 2.61 kg; 95% CI: 1.61, 3.60) and BMI gain (adjusted MD: 0.63 kg m(-2) ; 95% CI: 0.46, 0.80). Subgroup analyses using geographic region found that the difference in weight gain was considerably greater in studies from North America than from Asia. Follow-up length was identified as a source of heterogeneity, such that studies with longer follow-up showed greater difference in weight gain. Effective strategies are needed to encourage smokers to quit irrespective of potential weight gain and to help quitters avoid excess weight gain.
authors.affiliation: Menzies Institute for Medical Research, University of Tasmania, Hobart, Tasmania, Australia.
authors.forename: J
authors.initials: J
authors.lastname: Tian
authors.affiliation: Menzies Institute for Medical Research, University of Tasmania, Hobart, Tasmania, Australia.
authors.forename: A
authors.initials: A
authors.lastname: Venn
authors.affiliation: Menzies Institute for Medical Research, University of Tasmania, Hobart, Tasmania, Australia.
authors.forename: P
authors.initials: P
authors.lastname: Otahal
authors.affiliation: Menzies Institute for Medical Research, University of Tasmania, Hobart, Tasmania, Australia.
authors.forename: S
authors.initials: S
authors.lastname: Gall
mesh_terms: D015992:Body Mass Index; D006801:Humans; D008969:Molecular Sequence Data; D009765:Obesity / Q000209:etiology* / Q000378:metabolism / Q000523:psychology; D011446:Prospective Studies; D012907:Smoking / Q000009:adverse effects* / Q000378:metabolism / Q000523:psychology; D016540:Smoking Cessation / Q000523:psychology*; D013997:Time Factors; D015430:Weight Gain
keywords: Cohort studies; meta-analysis; smoking cessation; weight gain