Ceri Woolsgrove, ECF Policy Officer for Road Safety & Technical Issues, 21/5/2012
ECF policy Officer Ceri Woolsgrove examines a recent study on Helmets from the International Journal “Risk Analysis”.
A new study has appeared in the International Journal, “Risk Analysis” by Prof. de Jong, concluding that “a helmet law is likely to have a large unintended negative health impact”.
It shows algebraically that even very small reductions in cycle use due to helmet legislation* would almost certainly mean lives being lost annually due to physical inactivity than helmets could possibly save, regardless of their effectivenes. The paper importantly takes into account the health benefits of cycling as well as the risks of cycling.
For instance, a widely quoted figure suggests that the health benefits of cycling in the UK outweigh the injury risks by 20:1 (from the Mayer Hillman Study though other more recent calculations from elsewhere in Europe give even higher values). From this, it follows that a helmet law would have a net disbenefit to public health if just 1 person was put off cycling for every 20 who continue (i.e. a reduction of 4.7% in cycle use), even if those 20 people were 100% protected by a helmet against every kind of cycling injury.
In other words a very small drop in numbers of cyclists will shorten more lives than the helmets themselves will save, even if helmets are 100% effective. This figure becomes closer to zero if we take a more realistic figure regarding helmet effectiveness and take into account the fact that helmets obviously do not protect against all injury. For example if they were 15% effective then a 0.3% loss of cyclist numbers brings about a net health disbenefit.
*There has been a great deal of evidence to show that cycling numbers decrease greatly with the introduction of mandatory helmet laws. More details can be found here