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doi: 10.1111/1753-0407.12274
Journal of Diabetes 7 (2015) 590
LETTER TO THE EDITOR
Association between smoking and depression in patients with type 2 diabetes: A Response We thank Dr Kawada for his interest in our manuscript on smoking and depression in people with T2D. In his letter,1 the author questions the role of diabetes in the association between smoking and depression by highlighting a recent review that reports an association even in samples that do not have type 2 diabetes (T2D).2 We wish to clarify that although we reported on the association between smoking and depression in individuals with T2D, it was not our intention to imply that this association was: (i) unique to those with T2D; or (ii) specifically influenced by T2D. Instead, our results were meant to highlight the problem and risk of depression among moderate-heavy smokers with T2D, who are already vulnerable to a number of diabetes-related complications and health problems, even after controlling for a number of demographic and disease-related factors. Unfortunately, although we adjusted for depression at baseline, we did not have sufficient information to rule out a history of depression; thus, the association between smoking and depression may have already been established at an earlier time. The author highlights the different results reported between two of our papers.3,4 The main difference lies in the depression outcome that we assessed in each study. The first papaer3 focused on major depression as the main outcome, as assessed via the Patient Health Questionnaire (PHQ-9) and using Diagnostic and Statistical Manual of Mental Disorders, 4th Edition, Text Revision (DSM-IV-TR) criteria, whereas the second4 focused on depression syndrome. which includes major and minor depression. Previous studies (for a review, see Rodríguez et al.5) have highlighted the importance of investigating subthreshold depression; our group also recently published a paper on the relationship between minor depression and poor health outcomes in those with T2D,6 which led to the change in outcomes between papers. As Luger et al.2 reported, the choice of depression measure can have an important impact on the strength of the Correspondence Norbert Schmitz, Douglas Mental Health University Institute, McGill University, 6875 LaSalle Boulevard, Montreal,Quebec, Canada H4H 1R3. Tel.: +1514 761 6131 extn 3379 Fax: +1514 888 4064 Email: [email protected] Received 13 January 2015; accepted 14 January 2014.
590
association in question. Finally, we discussed a number of potential pathways in our paper, but agree with the author that further research is needed into the mechanisms that explain the association between smoking and depression. Through highlighting the persistence of this association, we also hoped to underscore to clinicians the potential dangers that concurrent smoking and depression can have in those with T2D. Both are associated with poor outcomes in diabetes and the presence of one can also negatively influence the other. Similarly, depression may impact the individual’s ability to successfully quit, or its presence may impact a health care provider’s willingness to counsel smoking. Disclosure None declared. References 1. Kawada T. Association between smoking and depression in patients with type 2 diabetes. J Diabetes. 2015 Jan 7. doi: 10.1111/1753-0407.12259. [Epub ahead of print] 2. Luger TM, Suls J, Vander Weg MW. How robust is the association between smoking and depression in adults? A meta-analysis using linear mixed-effects models. Addict Behav. 2014; 39: 1418–29. 3. Clyde M, Smith KJ, Gariepy G, Schmitz N. The association between smoking and depression in a Canadian community-based sample with type 2 diabetes. Can J Diabetes. 2013; 37: 150–5. 4. Clyde M, Smith KJ, Gariepy G, Schmitz N. Assessing the longitudinal associations and stability of smoking and depression syndrome over a 4-year period in a community sample with type 2 diabetes 24. J Diabetes. 2015; 7: 95–101. 5. Rodriguez MR, Nuevo R, Chatterji S, Ayuso-Mateos JL. Definitions and factors associated with subthreshold depressive conditions: A systematic review. BMC Psychiatry. 2012; 12: 181. 6. Schmitz N, Gariepy G, Smith KJ et al. Recurrent subthreshold depression in type 2 diabetes: An important risk factor for poor health outcomes. Diabetes Care. 2014; 37: 970–8.
Matthew Clyde,1,2 Kimberley J. Smith,3 Geneviève Gariépy2,4 and Norbert Schmitz1,2,4,5 1 Department of Psychiatry, 4Epidemiology and Biostatistics, McGill University, 2Douglas Mental Health University Institute, 5Montreal Diabetes Research Centre, Montreal, Canada, and 3Department of Life Sciences, Brunel University, Middlesex, UK
© 2015 Ruijin Hospital, Shanghai Jiaotong University School of Medicine and Wiley Publishing Asia Pty Ltd
doi: 10.1111/1753-0407.12274
Journal of Diabetes 7 (2015) 590
LETTER TO THE EDITOR
Association between smoking and depression in patients with type 2 diabetes: A Response We thank Dr Kawada for his interest in our manuscript on smoking and depression in people with T2D. In his letter,1 the author questions the role of diabetes in the association between smoking and depression by highlighting a recent review that reports an association even in samples that do not have type 2 diabetes (T2D).2 We wish to clarify that although we reported on the association between smoking and depression in individuals with T2D, it was not our intention to imply that this association was: (i) unique to those with T2D; or (ii) specifically influenced by T2D. Instead, our results were meant to highlight the problem and risk of depression among moderate-heavy smokers with T2D, who are already vulnerable to a number of diabetes-related complications and health problems, even after controlling for a number of demographic and disease-related factors. Unfortunately, although we adjusted for depression at baseline, we did not have sufficient information to rule out a history of depression; thus, the association between smoking and depression may have already been established at an earlier time. The author highlights the different results reported between two of our papers.3,4 The main difference lies in the depression outcome that we assessed in each study. The first papaer3 focused on major depression as the main outcome, as assessed via the Patient Health Questionnaire (PHQ-9) and using Diagnostic and Statistical Manual of Mental Disorders, 4th Edition, Text Revision (DSM-IV-TR) criteria, whereas the second4 focused on depression syndrome. which includes major and minor depression. Previous studies (for a review, see Rodríguez et al.5) have highlighted the importance of investigating subthreshold depression; our group also recently published a paper on the relationship between minor depression and poor health outcomes in those with T2D,6 which led to the change in outcomes between papers. As Luger et al.2 reported, the choice of depression measure can have an important impact on the strength of the Correspondence Norbert Schmitz, Douglas Mental Health University Institute, McGill University, 6875 LaSalle Boulevard, Montreal,Quebec, Canada H4H 1R3. Tel.: +1514 761 6131 extn 3379 Fax: +1514 888 4064 Email: [email protected] Received 13 January 2015; accepted 14 January 2014.
590
association in question. Finally, we discussed a number of potential pathways in our paper, but agree with the author that further research is needed into the mechanisms that explain the association between smoking and depression. Through highlighting the persistence of this association, we also hoped to underscore to clinicians the potential dangers that concurrent smoking and depression can have in those with T2D. Both are associated with poor outcomes in diabetes and the presence of one can also negatively influence the other. Similarly, depression may impact the individual’s ability to successfully quit, or its presence may impact a health care provider’s willingness to counsel smoking. Disclosure None declared. References 1. Kawada T. Association between smoking and depression in patients with type 2 diabetes. J Diabetes. 2015 Jan 7. doi: 10.1111/1753-0407.12259. [Epub ahead of print] 2. Luger TM, Suls J, Vander Weg MW. How robust is the association between smoking and depression in adults? A meta-analysis using linear mixed-effects models. Addict Behav. 2014; 39: 1418–29. 3. Clyde M, Smith KJ, Gariepy G, Schmitz N. The association between smoking and depression in a Canadian community-based sample with type 2 diabetes. Can J Diabetes. 2013; 37: 150–5. 4. Clyde M, Smith KJ, Gariepy G, Schmitz N. Assessing the longitudinal associations and stability of smoking and depression syndrome over a 4-year period in a community sample with type 2 diabetes 24. J Diabetes. 2015; 7: 95–101. 5. Rodriguez MR, Nuevo R, Chatterji S, Ayuso-Mateos JL. Definitions and factors associated with subthreshold depressive conditions: A systematic review. BMC Psychiatry. 2012; 12: 181. 6. Schmitz N, Gariepy G, Smith KJ et al. Recurrent subthreshold depression in type 2 diabetes: An important risk factor for poor health outcomes. Diabetes Care. 2014; 37: 970–8.
Matthew Clyde,1,2 Kimberley J. Smith,3 Geneviève Gariépy2,4 and Norbert Schmitz1,2,4,5 1 Department of Psychiatry, 4Epidemiology and Biostatistics, McGill University, 2Douglas Mental Health University Institute, 5Montreal Diabetes Research Centre, Montreal, Canada, and 3Department of Life Sciences, Brunel University, Middlesex, UK
© 2015 Ruijin Hospital, Shanghai Jiaotong University School of Medicine and Wiley Publishing Asia Pty Ltd
