Table 2.

Quality assessment tool for observational cohort and cross-sectional studies

References	Item 1	Item 2	Item 3	Item 4	Item 5	Item 6	Item 7	Item 8	Item 9	Item 10	Item 11	Item 12	Item 13	Item 14	Scores
Andrade et al. [44]	Yes	Yes	NA	Yes	No	No	No	NA	NA	NA	Yes	NA	NA	No	4/8
Andrade Nogueira et al. [25]	Yes	Yes	NA	Yes	Yes	No	No	NA	NA	NA	Yes	NA	NA	No	5/8
Barnes et al. [19]	Yes	Yes	NA	Yes	Yes	No	No	NA	NA	NA	Yes	NA	NA	Yes	6/8
Barroso et al. [26]	Yes	Yes	NA	Yes	Yes	No	No	NA	NA	NA	Yes	NA	NA	No	5/8
Barroso et al. [38]	Yes	Yes	NA	Yes	Yes	No	No	NA	NA	NA	Yes	NA	NA	No	5/8
Brink et al. [5]	Yes	Yes	NA	Yes	Yes	No	No	NA	NA	NA	Yes	NA	NA	No	5/8
Brink et al. [39]	Yes	Yes	NA	Yes	Yes	No	No	NA	NA	NA	Yes	NA	NA	Yes	6/8
Cruz et al. [27]	Yes	Yes	NA	Yes	Yes	No	No	NA	NA	NA	Yes	NA	NA	No	5/8
Doeven et al. [40]	Yes	Yes	NA	Yes	Yes	No	No	NA	NA	NA	Yes	NA	NA	No	5/8
Figueiredo et al. [15]	Yes	Yes	NA	Yes	Yes	No	No	NA	NA	NA	Yes	NA	NA	Yes	6/8
Foster et al. [17]	Yes	Yes	NA	Yes	Yes	No	No	NA	NA	NA	Yes	NA	NA	No	5/8
Ieno et al. [28]	Yes	Yes	NA	Yes	Yes	No	No	NA	NA	NA	Yes	NA	NA	No	5/8
Imamura et al. [41]	Yes	Yes	NA	Yes	Yes	No	No	NA	NA	NA	Yes	NA	NA	No	5/8
Inoue et al. [29]	Yes	Yes	NA	Yes	Yes	No	No	NA	NA	NA	Yes	NA	NA	No	5/8
Kraft et al. [30]	Yes	Yes	NA	Yes	Yes	No	No	NA	NA	NA	Yes	NA	NA	No	5/8
Lupo et al. [45]	Yes	Yes	NA	Yes	Yes	No	No	NA	NA	NA	Yes	NA	NA	Yes	6/8
Medina et al. [42]	Yes	Yes	NA	Yes	No	No	No	NA	NA	NA	Yes	NA	NA	No	4/8
Murphy et al. [49]	Yes	Yes	NA	Yes	Yes	No	No	NA	NA	NA	Yes	NA	NA	Yes	6/8
Nogueira et al. [31]	Yes	Yes	NA	Yes	Yes	No	No	NA	NA	NA	Yes	NA	NA	No	5/8
Oytun et al. [46]	Yes	Yes	NA	Yes	Yes	No	No	NA	NA	NA	Yes	NA	NA	No	5/8
Rabelo et al. [20]	Yes	Yes	NA	Yes	Yes	No	No	NA	NA	NA	Yes	NA	NA	No	5/8
Redkva et al. [16]	Yes	Yes	NA	Yes	Yes	No	No	NA	NA	NA	Yes	NA	NA	No	5/8
Rodrigues-Marroyo et al. [47]	Yes	Yes	NA	Yes	Yes	No	No	NA	NA	NA	Yes	NA	NA	No	5/8
Scantlebury et al. [32]	Yes	Yes	NA	Yes	Yes	No	No	NA	NA	NA	Yes	NA	NA	Yes	6/8
Sinnott-O'Connor et al. [33]	Yes	Yes	NA	Yes	Yes	No	No	NA	NA	NA	Yes	NA	NA	No	5/8
Vaquera et al. [43]	Yes	Yes	NA	Yes	Yes	No	No	NA	NA	NA	Yes	NA	NA	No	5/8
Viveiros et al. [48]	Yes	Yes	NA	Yes	Yes	No	No	NA	NA	NA	Yes	NA	NA	No	5/8
Voet et al. [34]	Yes	Yes	NA	Yes	Yes	No	No	NA	NA	NA	Yes	NA	NA	No	5/8
Wallace et al. [18]	Yes	Yes	NA	Yes	Yes	No	No	NA	NA	NA	Yes	NA	NA	No	5/8

Item 1: Was the research question or objective in this paper clearly stated?; Item 2: Was the study population clearly specified and defined?; Item 3: Was the participation rate of eligible persons at least 50%?; Item 4: Were all the subjects selected or recruited from the same or similar populations (including the same time period)? Were inclusion and exclusion criteria for being in the study prespecified and applied uniformly to all participants?; Item 5: Was a sample size justification, power description, or variance and effect estimates provided?; Item 6: For the analyses in this paper, were the exposure(s) of interest measured prior to the outcome(s) being measured?; Item 7: Was the timeframe sufficient so that one could reasonably expect to see an association between exposure and outcome if it existed?; Item 8: For exposures that can vary in amount or level, did the study examine different levels of the exposure as related to the outcome (e.g., categories of exposure, or exposure measured as continuous variable)?; Item 9: Were the exposure measures (independent variables) clearly defined, valid, reliable, and implemented consistently across all study participants?; Item 10: Was the exposure(s) assessed more than once over time?; Item 11: Were the outcome measures (dependent variables) clearly defined, valid, reliable, and implemented consistently across all study participants?; Item 12: Were the outcome assessors blinded to the exposure status of participants?; Item 13: Was loss to follow-up after baseline 20% or less?; Item 14: Were key potential confounding variables measured and adjusted statistically for their impact on the relationship between exposure(s) and outcome(s)?; NA: Not applicable. Items 6 and 7 were answered with “No” in all 29 studies according to the guidelines of the National Institutes of Health Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies. Items 3, 8, 9, 10, 12, and 13 were considered not applicable to the cross-sectional studies included in this review