The number of bicycle accidents that resulted in hospitalizations increased significantly in the past 15 years, with the largest proportion of the injuries occurring in adults over the age of 45. What's more, bike-auto fatalities among people between the ages of 35 and 74 have increased as well.
Researchers at the University of California San Francisco looked at biking-related injuries and hospital admissions and reported those results in the Sept. 1 issue of JAMA.
During the period between 1998 and 2013, hospital admissions due to bicycling injuries increased by 120 percent. Women accounted for nearly 35 percent of the injuries, and head injuries increased from 10 to 16 percent.
More significantly, the proportion of injuries in adults older than 45 grew from 23 percent to 42 percent, and the proportion of hospital admissions in that age group increased from 39 percent to 65 percent.
Along with more middle-aged cyclists participating in the sport, other factors that led to the increase in injuries and hospital admissions included more street accidents and more sport cycling at faster speeds, the researchers wrote.
"These injury trends likely reflect the trends in overall bicycle ridership," the authors wrote. With the shift to an "older demographic, further investments in infrastructure and promotion of safe riding practices are needed to protect bicyclists from injury."
Since nonfatal bike accidents aren't usually reported to police agencies, researchers used data compiled by the National Electronic Surveillance System to track the number of injuries. The NESS gathers product-related injury data from 100 emergency departments. The researchers queried the NESS for injuries associated with bicycles from 1998 to 2013.
Another recent study found that middle-aged cyclists are killed more often in bike-auto collisions.
The study by the Centers for Disease Control and Prevention found that overall, the rate of cyclists killed in accidents involving bikes and cars declined between the years of 1975 and 2012. Notably, the rates of death among children younger than 15 decreased 92 percent during those years, from 1.18 deaths per 100,000 in 1975 to 0.09 deaths per 100,000 in 2012.
However, the number of people between the ages of 35 and 74 who were killed increased significantly. According to the study, the largest increase was among adults aged 35-54 years, with the mortality rate increasing nearly threefold, from 0.11 to 0.31 per 100,000 cyclists.
Additionally, men are six times more likely to be killed in a bicycle-automobile-related crash than women, the study found. In 2012, males accounted for 87 percent of total bicycle deaths in the United States.
"Although bicycles account for a relatively small share of trips across all modes of transportation, the share of total household trips taken by bicycle has doubled over the last 35 years, and in 2009, bicycling accounted for approximately 1 percent of trips in the United States," the study authors wrote. "Changes in cyclist mortality rates vary by sex, age and state. Many factors likely contribute to trends in bicycling fatalities, including prevalence of bicycling, road design and engineering, traffic law enforcement, driver and bicyclist behavior, helmet use and traffic volume."
The authors noted that while cycling rates have increased among many age groups — specifically men between 25 and 64 — fewer children are biking, which could partially account for the drop in fatalities.
"Thus, the decline in bicyclist mortality among children might be attributable to fewer child bicycle trips rather than a result of safer road conditions," they wrote. "Increased use of helmets among children might also have contributed to reduced child bicyclist mortality."
