Fish on a bike
Any casual observer standing aside an arterial road leading into any major town or city in UK would attest to the incontrovertible fact that commuting cyclists are usually super fit with a healthy BMI and usually recipients of envious glances from the less well endowed. So it is not at all surprising that the cyclists are healthy..
The old and infirm on a bicycle would be like a fish out of water. People with high BMI cannot even buy a decent comfortable bicycle seat, let alone ride one to work.
This study might a good example to illustrate the statistical fallacy that underlying baseline differences could be somehow adjusted by statistical modelling, design and computations. Statistical sleight of hand cannot turn Apples into Pears. .
1 Celis-Morales CA, Lyall DM, Welsh P, et al. Association between active commuting and incident cardiovascular disease, cancer, and mortality: prospective cohort study. BMJ 2017;357:j1456. doi:10.1136/bmj.j1456
2 Song M, Hu FB, Wu K, et al. Trajectory of body shape in early and middle life and all cause and cause specific mortality: results from two prospective US cohort studies. BMJ 2016;353:i2195. doi:10.1136/bmj.i2195
Competing interests: No competing interests