The relationship between smoking cessation, depression and weight gain: a mixed method study

Introduction Public health measures have been effective in many countries including New Zealand in reducing the prevalence of smoking, but smokers with co-existing problems, including mental illnesses, are now becoming a focus for reducing smoking rates further. A key clinical dilemma is the inter-relationship between smoking cessation, depression and weight gain, on which there is currently limited understanding. Aims and Objective This study was aimed to investigate the relationship between smoking cessation, depression and weight gain; and also to explore the experiences of participants attending a smoking cessation program in Christchurch through the Smoking Cessation, Mood and Eating Study (SCeMES). Methodology The SCeMES was a mixed method study involving the quantitative study (SCeMES-QN) and the qualitative study (SCeMES-QL), conducted sequentially. Participants were recruited from an on-going clinical trial in Christchurch, the Zonnic and Patch Study (ZAP). Follow-up for SCeMES-QN were for one year and data collected at five separate occasions face-to-face. Information for depression, weight and both retention and abstinence rates were collected on all visits. Descriptive analysis was performed and where applicable univariate and multivariate analysis was conducted using the Statistical Package for Social Sciences (SPSS) version 20. Visits were grouped to baseline, EARLY and LATE. Participants for SCeMES-QL were recruited purposively from SCeMES-QN. Data was collected through individual and focus group interviews using a semi–structured interview guide. A general inductive approach was used for analysis with the assistance of the software NVivo. This study was approved by the local Ethics Committee. Results A total of 256 participants were recruited for SCeMES-QN and 25 for SCeMES-QL. The retention rate at EARLY follow-up (M = 94 days) was 48.4% and LATE follow-up (M = 380) was 37.6%; and the quit rate was 14.5% and 14.8% respectively. Thirty-five point seven percent reported a previous history of depression and current depression was low (2.3% and 6.6% using two different measures). The mean weight was 79.9kgs and the average BMI 27.4. Only 0.8% of the participants were considered to fulfil the criteria for food addiction at baseline with no significant cases detected at follow-ups. Overall, participants gained weight from baseline at EARLY and LATE follow-ups by 1.3kg and 5.1kg respectively (p <0.001) and those abstinent at follow up had gained more (p