Time outdoors

hours / day

UV-B exposure, movement, and a SES-coded leisure habit.

Outdoor time is the hidden common cause of 25(OH)D and of 'having a life that looks healthy'. Desk-bound high earners in high latitudes can be rich and deficient; outdoor workers can be poorer and replete. That is why D is a terrible SES instrument.

Also called sun exposure, UV-B.