Vitamin D supplementation is relatively harmless at reasonable levels, so advising it makes sense. However, taking country wide averages is begging for confoun

Vitamin D supplementation is relatively harmless at reasonable levels, so advising it makes sense. However, taking country wide averages is begging for confounding factors, right? I bet you could find a higher correlation with lots of things than Vitamin D, for example amount of per capita olive oil usage (Spain and Italy are #2 and #3), time that dinner is eaten (Spain and Italy both tend towards 9pm, vs 6:30 for Germany), etc etc etc. It doesn't prove anything and there isn't a proposed mechanism of action, so it's just correlation bingo at this point.