Trends in cycling and cycle related injuries and a calculation of prevented morbidity and mortality

Abstract

The objectives were to describe trends in cycling and cycle related injuries in Denmark overall and in the four largest Danish cities to see if changes in cycling trips and injuries were associated. Further, we compared number of prevented deaths, type 2 diabetes (T2D), cardiovascular diseases (CVD) and cancers with registered injuries. We analyzed cycling trends over past 17 years in Denmark based on national statistics from 56 electronic counters as an ecological study. Cycle related injuries were collected by Statistics Denmark from hospital records. We also calculated the annual prevented disease and mortality accrued from the health benefits of physical activity in cycling based on relative risk (RR) of cycling derived from population studies, number of cyclists, and number of death, T2D, CVD and cancers in Denmark. Since 1998 till 2015, cycling has increased by 10% in the whole country; the cycling related injuries however, have gradually declined and were only 45% in 2015 as compared to 1998 level. In Copenhagen specifically, cycling even increased more than 30% since 1998 while cycling related injuries decreased during the same period to one third. Diseases prevented in Denmark by cycling were annually 3328 T2D cases, 5742 CVD cases and 2076 cancer cases and prevented deaths were 6190. In comparison, in 2015, 26 cyclists were killed in the traffic, 512 were seriously injured and 297 experienced light injuries in the whole country. In conclusion, in Denmark, the number of cycling trips have steadily increased over the past 17 years while cycling related injuries show a concomitant decline. Intuitively one might expect cycle related injuries to increase with increased cycling, but a decrease was observed in injuries. Health benefits of cycling calculated from cohort studies were 21 times higher than risk of injuries and for mortality alone the ratio was 238.