So my toot about helmet laws increasing heart disease has got a few replies by people wondering wtf. The way it works is that mandatory helmet laws reduce cycling, fewer people cycling results in an increase in obesity related illnesses like heart disease and diabetes.
One of, if not rhe best, things that a government can do to improve health at a population level is increasing active travel (walking and cycling).
1/n
https://theconversation.com/ditching-bike-helmets-laws-better-for-health-42
@quixoticgeek Peter Walker's "Bike Nation" book has some very good discussion about the "trauma surgeon" vs "population health" on the topic of helmet.
Short summary in the Grauniad by it's author
https://www.theguardian.com/lifeandstyle/2017/mar/21/bike-helmet-cyclists-safe-urban-warfare-wheels
The question of whether cyclists should wear helmets provokes fury – often from those on four wheels. But which has the bigger benefit: increased physical safety, or creating a better environment for people to cycle helmet-free?
Quixoticgeek
JF 
Jfrench