Biking Linked With Reduced All-Cause, CVD Mortality Among Patients With Diabetes

Results of a cohort study indicate cycling is linked with lower all-cause and cardiovascular disease (CVD) mortality risk among individuals with diabetes, independent of other types of physical activity. Findings were published in JAMA Internal Medicine.

“Premature death from all causes and CVD is higher among people with diabetes,” the authors wrote, and although regular physical activity represents a main target in diabetes management, “only structured exercise, in contrast with advice only, has been shown to improve CVD risk factors,” they explained.

To address this knowledge gap, the researchers investigated the influence of unstructured physical activities, in particular cycling, on premature mortality among patients with diabetes.

Data were gleaned from the European Prospective Investigation into Cancer and Nutrition study cohort, which consists of participants from 23 centers in 10 Western European nations.

At baseline (between 1992 and 1998) participants’ medical, sociodemographic, and lifestyle information was collected. A second examination took place between 2006 and 2011, while only participants with diabetes at baseline assessments were included in the current analysis.

As part of the study, individuals’ body mass indexes (BMI) were measured, and diet and physical activity behaviors were assessed via questionnaires.

Change in total cycling from baseline to the second examination was categorized based on total time spent cycling at the 2 examinations: noncycling, stopped cycling, started cycling, or maintained cycling, the authors said.

A total of 10,995 individuals with diabetes were included in final analyses, while the analytic sample consisted of 7459 participants. Of these, 4701 (63%) had confirmed diabetes and 4699 (63%) were noncyclists.

The mean (SD) participant age was 55.9 (7.7) years, patients had a mean diabetes duration of 7.7. (8.1) years, and a majority (52.6%) of participants were female. Throughout 110,944 person-years of follow-up, a total of 1673 deaths were recorded for all causes and 811 were attributed to CVD.

Analyses revealed:

• Compared with the reference group of people who reported no cycling at baseline (0 min/week [wk]), the multivariable-adjusted HRs for all-cause mortality were 0.78 (95% CI, 0.61-0.99), 0.76 (95% CI, 0.65-0.88), 0.68 (95% CI, 0.57-0.82), and 0.76 (95% CI, 0.63-0.91) for cycling 1 to 59, 60 to 149, 150 to 299, and 300 or more min/wk, respectively
• The 10-year cumulative mortality risk difference relative to 0 min/wk of cycling for ascending cycling categories (1-59, 60-149, 150-299, and ≥300 min/wk) were −1.9%, −2.0%, −2.7%, and −2.1% for all-cause mortality and −1.2%, −1.2%, −2.2%, and −1.0% for CVD mortality, respectively
• In an analysis of change in time spent cycling with 57,802 person-years of follow-up, 975 deaths from all causes were recorded
• Compared with people who reported no cycling at both examinations, the multivariable-adjusted HRs for all-cause mortality were 0.90 (95% CI, 0.71-1.14) in those who cycled and then stopped, 0.65 (95% CI, 0.46-0.92) in initial noncyclists who started cycling, and 0.65 (95% CI, 0.53-0.80) for people who reported cycling at both examinations

Overall, “cycling was associated with at least a 24% lower all-cause mortality rate when compared with noncyclists, independent of other physical activity and putative confounders,” the authors wrote.

In addition, “taking up cycling over a 5-year period was associated with at least a 35% lower risk of all-cause mortality when compared with consistent noncyclists.”

Those reporting the lowest time category of cycling consistently also exhibited the highest cumulative mortality, but the dose-response relationships were ambiguous. The researchers noted high volumes of cycling can also be associated with risk of fatal injuries, while the benefits of physical activity on CV risk factors may be attenuated by increasing air pollutants.

“However, the health benefits of cycling may outweigh the increased risk of injuries owing to a decreased risk of morbidities in cyclists,” they said.

The observational design of the study precludes any causal inferences from being drawn, marking a limitation to the investigation. Although the data did not specify between type 1 and type 2 diabetes (T2D), the authors point out T2D accounts for over 90% of all diabetes in adults. Results may also not be generalizable to those using electric bicycles.

“The present investigation extends the level of evidence within this field by documenting that cycling and taking up cycling may offer specific health benefits in people with diabetes over and above other physical activities, including walking,” the researchers said.

“Studies with repeated measurement of cycling and documentation of cycling-related accidents are needed to elaborate on the dose-response relationship between cycling and mortality,” they concluded.

Reference

Ried-Larsen M, Rasmussen MG, Blond K, et al. Association of cycling with all-cause and cardiovascular disease mortality among persons with diabetes: the European prospective investigation into cancer and nutrition (EPIC) study. JAMA Intern Med. Published online July 19, 2021. doi:10.1001/jamainternmed.2021.3836