Commuter Bicycling Lowers Risk of Incident CVD, Obesity

Actively commuting to work by bicycling has been linked to lower rates of incident obesity, hypertension, hypertriglyceridemia, and impaired glucose tolerance, according to research published in the Journal of the American Heart Association.

Researchers in Denmark, Sweden, and the United States conducted a population-based health study of 23,732 Swedish men and women (mean age: 43.5 years) over a 10-year period. Study participants received individual counseling sessions and health examinations, and baseline data were collected on patients’ leisure time exercise, occupational physical activity, and work commuting method. These commuting methods were then divided into passive travel, irregular travel, walking, and cycling categories. Weight, height, and BMI were also measured, as well as cardiovascular disease risk factors including blood pressure, hypertension, and triglyceride levels.

At baseline, the most common method of commuting was passive travel (59%), followed by bicycling (24%), walking (11%), and irregular traveling (6%); percentages remained similar at follow up. The odds of participants cycling to work at follow-up was 10.4 times higher (95% confidence interval [CI], 9.6-11.3) when comparing noncyclists to cyclists at baseline.

Overall, participants who reported bicycling to work were healthier, better educated, and more likely to be female. Participants who bicycled to work had lower odds of incident obesity, hypertension, hypertriglyceridemia, and impaired glucose tolerance, compared to those who undertook passive travel modes on a daily basis.

Adjustment for additional cardiovascular risk factors did not significantly change results. In fully adjusted models, the researchers found that bicycling to work was associated with lower body mass index (BMI), triglycerides, systolic and diastolic blood pressure, and 2-hour glucose levels.

The investigators also examined the associations of changes in commuting method with cardiovascular risk. Specific analyses of patients who, at baseline, reported using a passive travel method to commute but who later reported cycling to work during follow up were conducted; odds of incident obesity (odds ratio [OR]: 0.64; 95% CI, 0.49-0.84, P <.001), hypertension (OR: 0.88; 95% CI: 0.75-1.03), hypertriglyceridemia (OR: 0.76; 95% CI: 0.62-0.92, P =.006), and impaired glucose tolerance (OR: 0.79; 95% CI: 0.68-0.93, P =.005) were lower compared to participants who continued to use passive travel.

Additionally, participants who reported cycling at both baseline and follow up had lower odds of incident obesity (OR: 0.43; 95% CI, 0.30-0.63, P<.001). The odds of incident risk factors were significantly lower in participants compared to those who did not cycle to work at either baseline or follow-up or those who switched from cycling to a passive method of transportation. Relationships were similar between men and women, and across educational status and smoking status.

“The attributable fraction percentage for obesity was 24%, suggesting that approximately a quarter of new cases of obesity occurring during these 10 years of follow-up could be prevented in this population if all participants remained or switched to cycling to work,” the researchers wrote.

“We are unaware of any long-term randomized controlled trial examining the effect of commuter cycling with other forms of transport on cardiovascular risk factors,” they added, noting that several modest-sized, short-term randomized trials support the idea that commuter cycling is “an important causal factor that can be used for primordial prevention of cardiovascular risk, including maintaining or improving cardiorespiratory fitness.”

The researchers concluded that public health efforts to encourage population-wide active commuting may be an effective CVD prevention strategy in the general population.

Study Limitations

• Researchers were unable to quantify the contribution that bicycling to work had on participants’ total physical activity level.
• Residual and unknown confounding factors may have contributed to results.
• Findings may not be generalizeable to populations living in areas with varied infrastructure.

Disclosures: The researchers report no conflicts of interest. Dr Grøntved received support from the Lundbeck Foundation (R151-2013-14641 and the Danish Council for Independent Research (DFF-4004-00111). This study was supported by grants from the Novo Nordisk Foundation, among others.

Reference

Grøntved A, Koivula RW, Johansson I, et al. Bicycling to work and primordial prevention of cardiovascular risk: a cohort study among Swedish men and women. J Am Heart Assoc. 2016 Oct 31;5:e004413. doi:10.1161/jaha.116.004413 [Epub ahead of print].