The methodology mentions nothing about randomization so its unclear if there was any selection bias here.
If you look a table 2, the control group was on average 6 years older and had more co-morbidities. This suggests that there was some selection bias and that other undocumented factors could have greatly affected this experiment.
Doing multi-variate analysis with such a small sample size gives rise to huge uncertainties. In all, this study is only very weak evidence.
If you look a table 2, the control group was on average 6 years older and had more co-morbidities. This suggests that there was some selection bias and that other undocumented factors could have greatly affected this experiment.
Doing multi-variate analysis with such a small sample size gives rise to huge uncertainties. In all, this study is only very weak evidence.