It is very possible there is a health concern. It is also very possible, as stated in the very beginning of the article, that this is a socio-economic/lifestyle

It is very possible there is a health concern. It is also very possible, as stated in the very beginning of the article, that this is a socio-economic/lifestyle correlation, and not causative or even involved in the health issues. In other words, people who have no alternatives or through lack of education or other cause make poor health choices suffer the consequences broadly. There are things one can do to rule this out in a study, and these authors have not done them. Perhaps later studies will take that on.