Exercise as it relates to Disease/Effects from a supervised exercise intervention for depressed female smokers

The following is a critique on the original investigation Supervised, Vigorous Intensity Exercise Intervention for Depressed Female Smokers: A Pilot Study, published by Nicotine & Tobacco Research, 2017.

What is the background to the research?
In 2016 more than 6% of women above the age of 15 were smoking worldwide. This was significantly lower than males (34%), however, women have shown to find it more difficult to quit than men. Female smokers have also been reported to have psychiatric comorbidities such as depression. Higher levels of depression are shown more prevalent in smokers than non-smokers, and smokers with depressive symptoms find it harder to draw back from nicotine use. More research should be conducted to explore better methods in smoking cessation treatments that can treat female smokers with depressive symptoms. The addition of vigorous-intensity exercise as part of a smoking cessation intervention may be an effective form of treatment for depressed female smokers.

This research was a pilot study, designed to evaluate the potential role that supervised vigorous exercise has as part of a smoking cessation intervention for depressed females.

Where is the research from?
The author of this research, Christi A. Patten is from the Department of Psychiatry and Psychology, Mayo Clinic, Rochester, Minnesota, USA. Christi A. Patten has been involved in many studies that have been acknowledged by other experts in the field and are related to disease and exercise. The study was approved by Mayo Clinic Institutional Review Board. Funding was granted by a Mayo Clinic National Institutes of Health relief award and a small grant award from the Department of Psychiatry and Psychology. The data was collected from September 2013 to April 2015.

What kind of research was this?
This study was a randomised controlled trial with blinding. Randomised controlled trials prevent systematic differences between the intervention group and the control group – limiting the effects of biased treatment effects. Blinding tests further increases the unlikelihood of bias by hiding information that may negatively influence a test’s validity. In this trial, participants, wellness coaches, and the study coordinator were blinded. Coaches who were blindly assigned to the control group or the intervention group adhered to 90% and 95% of their training treatment protocols, respectively.

This was also a pilot study, not designed to find significant differences in smoking cessation rates, but aimed to find enough evidence to proceed for a definitive trial.

What did the research involve?
30 women, aged between 18-55 were eligible to participate; all of whom had to have smoked at least 10 cigarettes/day during the previous year, intentions of quitting, clinical identification of depression and were not following the American College of Sports Medicine (ACSM) exercise guidelines. Depression score was measured using the 10-item Centre for Epidemiological Studies Depression Scale and participants had to receive a score >16 which indicated moderate-severe depression. Other preventative measures were done to prevent skewing of data such as not enrolling those who have cardiovascular disease or major thought disorder. Participants gave written consent to partake in all parts of the study.

The intervention group (n = 15) included supervised, vigorous-intensity exercise sessions along with smoking cessation counselling and pharmacotherapy. The controlled group (n = 15) had no exercise intervention but instead received health education sessions including smoke cessation counselling and pharmacotherapy. Both groups would consist of 12 weeks of treatment (3 sessions each week) followed by a 6-month post-target quit date.

The exercise intervention followed a similar procedure taken from research from Marcus et al which supported – but needs further investigation – the benefits that exercise has on smoking cessation. The research also saw the possibility that vigorous exercise is more beneficial than moderate exercise for smoking cessation, but limitations to their study did not allow them to come to a definitive conclusion for this matter. The 12-week exercise intervention from Christi et al included 3 sessions a week, each consisting 20-30 minutes of aerobic exercise. Each week, an increase of 2-4 minutes of vigorous exercise was added to each session as a way for the exercisers to gradually reach 30 minutes of vigorous exercise by Week 12. The coaches delivered exercise counselling while participants exercised. The intervention group were encouraged to attend all sessions and exercise in their free time. The controlled group were not given council about how exercise may help with depression or smoking cessation.

Depressive symptoms were measured at Week 12 using the 9-item Patient Health Questionnaire (PHQ-9) – a validated clinical diagnoses tool for depressive disorders. Self-reported, smoking status was obtained at Week 12 and 6 months follow up – taking participant’s saliva at certain time points to verify if they have been smoking. This biochemical method is more integral than just having participants doing recall entries. A participant who had not been smoking for the past 7 days would be deemed a non-smoker. A doubling of smoking cessation rates for the intervention versus the control groups would be seen clinically significant and would consider warranting a more definitive trial.

What were the basic results?
13 participants from both groups (total = 26/30) finished the whole trial, meaning that the study retention was good (87%). The control group completed a mean of 24 sessions (SD = 10, range 5-36) whereas the intervention group had a mean of 26 (SD = 10, range 5-36); p = 0.028.

The abstinence rates for smoking were significantly higher in the intervention group (73% [11/15]) than the control (33% [5/15]) at Week 12. Participants in the intervention group averaged 22 minutes (SD = 10, range 3-30) of vigorous exercise on their final session. This was lower than the recommended guidelines (30 minutes) but feasible enough to say that the intervention was of influence to the smoking absence outcomes. The 6-month follow up showed no significant differences in smoking absence rates for the intervention group (27% [4/15]) against control (40% [6/15]); p = 0.439. The PHQ-9 measurements showed no significant changes in depression levels between baseline and Week 12 results.

What conclusions can we take from these outcomes?
This pilot study was a well-designed and credible source for providing evidence that supports the benefits that supervised, vigorous-intensity exercise has in enhancing smoking cessation on depressed females. Statistically, this study showed no long-term benefits that exercise has on smoking cessation and therefore exercise must be continually practised throughout the week. Since depression levels had no change pre and post-intervention, the relationship between depression, female smokers and exercise should be further investigated.

Practical Advice
Female smokers with depression should commonly practice vigorous exercise, following the ACSM guidelines of >20 minutes on >5 days/week, to enhance smoking cessation. Just like the study intervention, exercise can start at moderate intensity and gradually increase to vigorous. Coach supervision may reinforce exercise for those who have low self-efficacy and is recommended alongside counselling and pharmacotherapy.

Further information/resources

 * https://www.who.int/news-room/fact-sheets/detail/tobacco
 * https://www.health.gov.au/health-topics/smoking-and-tobacco/how-to-quit-smoking
 * https://www.beyondblue.org.au/