On 2014 Nov 19, Kaccie Li commented:

The authors of this study generalized the subjects from the United States to be white/Caucasian which is a serious oversight. A cursory look at US demographics would reveal that just over 75 percent of the population is white which is probably already questionable to generalize the entire group as white, but a closer look reveals even more concerning factors. Consider the populations in the studies classified under "white" in Table 2 of this article where the first two entries were studies done by Wang and colleagues (ref 13) and Porter and colleagues (ref 14). The first study was done at Baylor College of Medicine where a meager 43 percent of the student population is white. Suppose subject recruitment was done in the city Houston in general, the conclusions of Lim's study can be further put under scrutiny since only about 25 percent of Houston's population is white (non-hispanic). Similar things could be stated about individuals recruited in Porter's study (ref 14) at the University of Rochester where only about 76 percent of the student body is white. Lim and Fam does not mention the possibility of the presence of significant African and Asian Americans being an unknown factor that could have affected their results and conclusions.

On 2014 Nov 19, Kaccie Li commented:

The authors of this study generalized the subjects from the United States to be white/Caucasian which is a serious oversight. A cursory look at US demographics would reveal that just over 75 percent of the population is white which is probably already questionable to generalize the entire group as white, but a closer look reveals even more concerning factors. Consider the populations in the studies classified under "white" in Table 2 of this article where the first two entries were studies done by Wang and colleagues (ref 13) and Porter and colleagues (ref 14). The first study was done at Baylor College of Medicine where a meager 43 percent of the student population is white. Suppose subject recruitment was done in the city Houston in general, the conclusions of Lim's study can be further put under scrutiny since only about 25 percent of Houston's population is white (non-hispanic). Similar things could be stated about individuals recruited in Porter's study (ref 14) at the University of Rochester where only about 76 percent of the student body is white. Lim and Fam does not mention the possibility of the presence of significant African and Asian Americans being an unknown factor that could have affected their results and conclusions.