Bicycle helmets do protect against head injuries
Under Strict Embargo for
00.01hrs BST
Friday 27 October 2000
The number of serious head injuries among cyclists of all ages has fallen as a result of increasing helmet use, despite doubts about the effectiveness of helmets, report researchers from Imperial College in this week's BMJ (1).
Dr Aziz Sheikh and Adrian Cook of the Department of Primary Health Care and General Practice, Imperial College School of Medicine, analysed all cyclist hospital admissions in England between April 1991 and March 1995, a period of increasing helmet usage.
They divided patients into three age categories: junior (6-10 years), secondary (11-15 years), and adult (16 years and over).
The authors found that numbers of emergency admissions among cyclists changed little over the four-year study period, from a total of 8,678 in 1991-92 to 8,781 in 1994-95.
However the percentage admitted with head injuries fell significantly from 40% to 28% per month, and each age group showed a significant reduction: 9% among junior, 11% among secondary and 13% among adults.
These findings indicate that helmets are of benefit both to children and, contrary to popular belief, to adults, say the authors.
While previous reports have suggested that helmets confer benefit, doubts have been expressed about the accuracy of these findings because of the difficulties in adjusting for differences in risk-taking behaviours between helmet wearers and non-wearers.
Dr Sheikh points out that helmets are not designed to protect the rider in a fall which involves other vehicles. Most adult accidents involve other vehicles.
"The reasoning behind this is that when a cyclist is knocked off by another vehicle, this frequently results in the head being spun and subjected to torsional effects. One consequence of this is that they tend not to hit the ground as cleanly as children who are typically involved in low-impact, non-twisting injuries," said Dr Sheikh.
Dr Sheikh described the results from their study as among the strongest yet presented. "We've seen that cyclist head injuries fell sharply during a period of increased helmet wearing."
"Stronger evidence may never emerge, given the practical problems of comparing helmet wearers with non-wearers, and the ethical problems of conducting a randomised trial," he added.
Writing in the BMJ the authors conclude, "Local publicity campaigns encouraging the voluntary wearing of helmets have been effective and should accompany national drives to promote cycling."
But Dr Sheikh also revealed that while head injuries fell during the study period, other cycling injuries (limb and miscellaneous) increased.
"Cycle helmets are therefore only a partial solution to improving safety in this group of road-users," he said.
http://www.imperial.ac.uk/P2250.htm