Digging deeper into tables in the paper, I realized there is actually even less data about non-smokers than I thought. Out of those 60 non-smokers with lung ca

Digging deeper into tables in the paper, I realized there is actually even less data about non-smokers than I thought. Out of those 60 non-smokers with lung cancer apparently just 20 were men (out of 14,208 study participants who were men and non-smokers => 0.14%) http://ascopubs.org/na101/home/literatum/publisher/asco/journals/content/jco/2017/jco.2017.35.issue-30/jco.2017.72.7735/20171005/images/large/jco.2017.72.7735t3.jpeg http://ascopubs.org/na101/home/literatum/publisher/asco/jour... ----- Curiously this also means non-smoking women have 1.28x higher chance to get lung cancer than non-smoking men (unrelated to vitamins). ----- For never-smokers vs smokers men risk ratios are then (again unrelated to vitamins): - current smoker: 31.7x higher risk - recent smoker (stopped < 10 years ago): 21.3x higher risk - past smoker (stopped > 10 years ago): 8.9x higher risk ----- Take home message: stop smoking! Precautionary principle: if you take B vitamin supplements, you can continue (for slight decrease of cancer risk), just make sure you aren't taking mega-doses (especially if you still smoke), but really - stop smoking - the sooner you do less cumulative harm you get.