I haven't read the original study, but might they not be mixing together cause and effect here? Instead of taking vitamins causing people to get sick, it might be people with riskier genetics/lifestyles are more likely to take vitamins to hedge against that?
Reminds me of a news article that interpreted statistics to say "People who drink low fat milk are fatter! Clearly this means that low fat milk makes you fat!" instead of the obvious conclusion that people who are fat would drink low fat milk to try to get slimmer.
Reminds me of a news article that interpreted statistics to say "People who drink low fat milk are fatter! Clearly this means that low fat milk makes you fat!" instead of the obvious conclusion that people who are fat would drink low fat milk to try to get slimmer.