People with diabetes are at risk of developing health-related complications, including cardiovascular disease, cerebrovascular events, and cardiac insufficiency, as well as other accompanying diseases, such as retinopathy, nephropathy, and neuropathy. “Although there is already a lot of evidence pointing to the association between physical activity and the prevention of type 2 diabetes, this was not the case for the association between physical activity and diabetes-related complications,” says the principal investigator, Dr. Sabrina Schlesinger from the Institute for Biometrics and Epidemiology at the German Diabetes Center. “Furthermore, we wanted to identify the optimal amount of physical activity required to achieve the largest possible risk reduction”. The World Health Organization (WHO) currently recommends that adults with chronic diseases do at least 150-300 minutes of moderate aerobic physical activity per week2. This corresponds to a metabolic equivalent of 8.25 to 16.5 MET per week.
In total, the researchers identified 31 relevant studies published between 1995 and 2021, which investigated populations in the USA, Europe, Asia, Australia, and a cohort of 20 different countries. The results of this review, including the meta-analyses, provided moderate evidential certainty that physical activity was associated with a relative reduction in the risk of cardiovascular disease incidence and mortality and overall microvascular complications, such as retinopathy (see Fig.1 below). The evaluations showed a dose-response relationship, i.e., as physical activity increased, the risk of diabetes complications decreased. “The results indicate that even a level of physical activity below the amount recommended by the WHO reduces the relative risk of diabetes-related complications,” summarizes Dr. Schlesinger. The most pronounced risk reduction was observed at 20 to 40 MET hours per week.
Fig. 1: Reduction in the risk of cardiovascular disease incidence and mortality as well as subsequent microvascular complications associated with people with diabetes mellitus achieved via physical activity levels below the WHO recommendations (gray areas).
Every Step Counts
It can be stressful for people with diabetes when they are unable to successfully implement the specified amount of physical activity. However, sometimes the goals are unachievable – especially at the beginning or for physically inactive people with a high BMI. Stressing the scientific implications of the study, Schlesinger states that “these findings could encourage people with diabetes to be physically active because, as the results of the dose-response meta-analysis have shown, even a modest degree of physical activity is effective in preventing diabetes-related complications”.
Relevance of the Findings
A meta-analysis goes beyond the work of a purely systematic review and uses statistical methodologies to quantitatively summarize the findings of several individual studies into a global result. Meta-analyses have become an increasingly significant component of systematic reviews and constitute a pillar of evidence-based medicine. They can be used to derive practical recommendations for those affected. “For example, taking into account our dose-response meta-analysis, one hour of Nordic walking per week, corresponding to 4.8 MET hours, could reduce the risk of cardiovascular mortality by approx. 10%,” recommends the expert.
1 Original publication:
Rietz M, Schlesinger S et al. Physical Activity and Risk of Major Diabetes-Related Complications in Individuals With Diabetes: A Systematic Review and MetaAnalysis of Observational Studies
Diabetes Care 2022;45(12):3101–3111; https://doi.org/10.2337/dc22-0886