Letter - Response to Rissel and Wen: ?The possible effect on frequency of cycling if mandatory bicycle helmet legislation was repealed in Sydney, Australia: a cross sectional survey?

Abstract

Rissel and Wen?s article boldly proclaims that repealing mandatory helmet legislation (MHL) would greatly increase cycling uptake. However, closer examination of their results reveals that odds ratios are interpreted incorrectly several times and some findings were curiously omitted. They state that people 'aged 16-24 years...were significantly more likely to ride more if they did not have to wear a helmet'. This is only found to be true when compared to those aged 55+ but is not shown to be the case compared to the broader adult population. If the intent is to state those aged 16-24 years are significantly more likely than not to cycle more, this is clearly not true as significantly more people responded to the contrary (0.341, 95%CI: 0.235-0.447). Also, significantly more people in the other age groups responded they would not ride more, with an apparent downward trend in proportion by age.