TABLE 1

Quality assessment with the Newcastle–Ottawa Scale [13]

First author [ref.]Selection#ComparabilityOutcome/exposure+Total score§
Cohort/case–control
 Chen [14]4037
 Guan [3]4037
 Han [15]4037
 Huang [1]4037
 Tang [16]4037
 Tang [17]4037
 Wang [18]4037
 Wang [19]4239
 Wu [6]4037
 Yin [20]3036
 Zhang [21]4037
 Zhou [22]4239
 Zhang [23]3036
Cross-sectional
 Zhang [24]4026
 Li [25]3025
 Wan [26]4026

#: range 0–4 for cohort/case–control, 0–5 for cross-sectional; : range 0–2 for all studies; +: range 0–3 for all studies; §: range 0–9 for cohort/case–control, 0–10 for cross-sectional.