Cognitive therapies targeting change in two or more health behaviours at the same time: a systematic review
We evaluated the effect of cognitive therapies targeting two or more lifestyle habits. The included studies involved different patient groups and sedentary and/or overweight persons.
Physical inactivity, unhealthy diets or tobacco use increase risk of disease. Many people engage in two or more such unhealthy behaviours. Cognitive therapies may increase physical activity, but we do not know the effects of targeting two or more health behaviours at the same time.
We evaluated the effect of cognitive therapies targeting two or more lifestyle habits. The included studies involved different patient groups and sedentary and/or overweight persons. We included 14 randomised controlled trials, however few studies followed up the participants beyond four months.
We found that:
- Cognitive therapies, targeting two or more health behaviours at the same time, probably lead to small improvements in physical activity and dietary habits, compared to no intervention or usual care, based on moderate-quality evidence.
- We are uncertain whether cognitive therapies, when targeting two or more health behaviours at the same time, change physical activity, diet, or tobacco use compared to other interventions.
In 2013, 37% of all deaths in Norway could be attributed to behavioural risk factors, of which unhealthy diets, tobacco use, and physical inactivity were the most important. Many people engage in two or more of these unhealthy behaviours. Cognitive therapies are considered effective treatments for a range of disorders such as depression, anxiety, insomnia, and chronic pain. There are also documented effects of cognitive therapies when used to increase physical activity, but we do not know the effects of targeting two or more health behaviours at the same time.
In this report, the term cognitive therapies includes cognitive behavioural therapies.
Our objective was to answer the question “What is the effect of cognitive therapies to change two or more health behaviours in adults 18 years or older, compared to no intervention, usual care or another intervention?”
We searched systematically in five electronic databases for systematic reviews and subsequently for primary studies. In addition, we searched the reference lists of included studies. Two reviewers independently screened titles and abstracts, selected studies based on full text publications, and assessed risk of bias in the included studies. One person extracted data from the studies and another person verified the data extraction. We summarized the results for each health behaviour by random-effects meta-analyses, presented as standardized mean differences or relative risk and 95% confidence intervals. We rated our confidence in the effect estimates using GRADE (Grading of Recommendations Assessment, Development and Evaluation) and presented the results in summary of findings tables. In the GRADE system, high quality means that we are very confident that the true effect is close to that of the estimate of the effect; moderate quality that the true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different; low quality that the true effect may be substantially different from the estimate of the effect; and very low quality that the true effect is likely to be substantially different from the estimate of effect.
We did not find any systematic reviews that could answer our question. We found 14 randomized controlled trials that fulfilled our inclusion criteria. Nine studies included sedentary and/or overweight persons. Five studies included different patient groups, such as persons with cancer, type 2 diabetes, or coronary heart disease. Twelve studies used cognitive therapies to alter physical activity and diet, while the remaining two studies focused on other behaviours. The control groups received either no intervention, usual care or other interventions, and the studies measured several behavioural outcomes. Few studies had follow-up times beyond four months after the end of the intervention. We judged 11 studies to have an unclear risk of bias, two studies to have a low risk of bias, and one study to have a high risk of bias.
We found small effects of cognitive therapies targeting physical activity and diet compared to no intervention or usual care.
- For physical activity, the standardized mean change difference based on nine studies with 1401 participants was 0.19 with a 95% confidence interval of 0.03 to 0.35, indicating increased physical activity. According to GRADE, we rated our confidence in the effect estimate as moderate.
- For diet based on types of foods or food groups consumed, the standardized mean change difference based on three studies with 562 participants was 0.23 with a 95% confidence interval of 0.06 to 0.39, indicating improved dietary quality. We rated our confidence in the effect estimate as moderate.
- For diet based on energy intake, the standardized mean change difference based on three studies with 588 participants was -0.19 with a 95% confidence interval of -0.38 to -0.03, indicating reduced energy intake. We rated our confidence in the effect estimate as moderate.
The results of cognitive therapies targeting physical activity and diet, or physical activity and tobacco use, as compared to other interventions were associated with large uncertainty. According to GRADE, we rated our confidence in the effect estimates as very low. Thus, we are uncertain whether cognitive therapies change these outcomes compared to other interventions.
The study participants in this review were diverse and included both patients and healthy persons with risk factors such as overweight or a sedentary lifestyle. The interventions involved basic elements of cognitive therapies, such as goal setting and skills development related to self-regulation of behaviour, problem solving, and relapse prevention. Several different health professions delivered the interventions, with great variation in the duration and frequency of the therapy sessions.
The strict exclusion criteria applied in several of the studies, for example exclusion of persons with co-morbidities or mental health problems, may limit the applicability of the results. Our results may not capture how effective cognitive therapies targeting two health behaviours will be under routine clinical practice. Another possible limitation was that all studies except one measured the outcome as self-reported behaviours using questionnaires. Such methods are known to have limited ability to detect behavioural change from one point in time to another in a reliable way. Another limitation is that the studies used many different methods to measure the outcome, and therefore we had to standardise the scales for the meta-analyses. Thus, the connection with the original measurement scales, such as minutes per day of physical activity or units of fruit, is lost. We can only describe effects in terms of direction (advantage of the intervention or control group or showing little or no difference) and magnitude (small, moderate, or large). This makes it difficult to interpret the results. Finally, few studies had follow-up beyond four months post-intervention.
Research gaps include lack of studies targeting tobacco use together with other health behaviours, few studies comparing cognitive therapies to other interventions, lack of common outcomes measurements for heath behaviours, and lack of follow-up for at least 12 months post-intervention.
Cognitive therapies targeting at least two health behaviours at the same time probably lead to small short-term improvements in physical activity level and diet when they are compared to no intervention or usual care. Compared to other interventions, the evidence is too uncertain to indicate whether cognitive therapies targeting multiple behaviours at the same time change physical activity, diet, and tobacco use.