Heart Attack Risk Halved in Adults with Heart Disease Supplementing Vitamin D

One was that people who took Vitamin D were less likely to be symptomatic. The other was that people who smoke cigarettes were something like 80% less likely to experience severe respiratory complications.

I take Vitamin D every day and smoke like the devil, and I'm the only person I know who's never had covid (or at least never tested positive for it... and I'm a paranoiac who for several years tested anytime my nose itched). Confirmation bias of one right here.

Did either of those things have any truth to them? I do realize that daily smokers tend to underreport their smoking, which could lead the stats to lean toward showing that nonsmokers got severe disease at a higher rate than their percentage of the general population, if smokers lie at a rate of 5:1 on their hospital admission forms... but it never sat right with me that this wasn't followed up. I seem remember a similar thing with smokers / reduced risk of acute lung disease among the cleanup workers at Chernobyl, so in some way it made sense to me at the time.