“…Twenty-three studies 16,32,33,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58 remained for quantitative data synthesis ( Figure 1 and Table 2). There were 7 cohort studies, with follow-ups ranging from 4.3 to 15 years, and 16 case-control studies, 10 hospital-based, 5 populationbased, and one with no specified study base.…”