>Results: Women with active sun exposure habits were mainly at a lower risk of cardiovascular disease (CVD) and noncancer/non-CVD death as compared to those who avoided sun exposure. As a result of their increased survival, the relative contribution of cancer death increased in these women. Nonsmokers who avoided sun exposure had a life expectancy similar to smokers in the highest sun exposure group, indicating that avoidance of sun exposure is a risk factor for death of a similar magnitude as smoking. Compared to the highest sun exposure group, life expectancy of avoiders of sun exposure was reduced by 0.6-2.1 years.
It's amazing that people take hopelessly confounded studies like this and infer anything from them.
Yes the study says they tried to remove confounders. But if people could effectively remove confounders, there'd be no need for randomized trials (which are enormously expensive). Despite doing everything possible, scientists' best efforts to remove confounders still don't effectively substitute for actual randomization.
This study is from 1990-1992. Even with all the sophisticated software today, we still cannot remove confounders, so how bad was it in 1992?
Yes think the replication crisis makes it pretty clear that even with all the fancy software, we still can't remove confounders today (and probably never will).
You can pretty safely translate we removed confounders to: we slightly cooked the data and got this significant result.
>Results: Women with active sun exposure habits were mainly at a lower risk of cardiovascular disease (CVD) and noncancer/non-CVD death as compared to those who avoided sun exposure. As a result of their increased survival, the relative contribution of cancer death increased in these women. Nonsmokers who avoided sun exposure had a life expectancy similar to smokers in the highest sun exposure group, indicating that avoidance of sun exposure is a risk factor for death of a similar magnitude as smoking. Compared to the highest sun exposure group, life expectancy of avoiders of sun exposure was reduced by 0.6-2.1 years.