Table S1.
NIH Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies
| Study ID 1. | Was the research question or objective in this paper clearly stated? | 2. Was the study population clearly specified and defined? | 3. Was the participation rate of eligible persons at least 50%? | 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 pre-specified and applied uniformly to all participants? | 5. Was a sample size justification, power description, or variance and effect estimates provided? | 6. For the analyses in this paper, were the exposure(s) of interest measured prior to the outcome(s) being measured? | 7. Was the time frame sufficient so that one could reasonably expect to see an association between exposure and outcome if it existed? | 8. For exposures that can vary in amount or level, did the study examine different levels of the exposure as related to the outcome (eg, categories of exposure, or exposure measured as continuous variable)? | 9. Were the exposure measures (independent variables) clearly defined, valid, reliable, and implemented consistently across all study participants? | 10. Was the exposure(s) assessed more than once over time? | 11. Were the outcome measures (dependent variables) clearly defined, valid, reliable, and implemented consistently across all study participants? | 12. Were the outcome assessors blinded to the exposure status of participants? | 13. Was loss to follow-up after baseline 20% or less? | 14. Were key potential confounding variables measured and adjusted statistically for their impact on the relationship between exposure(s) and outcome(s)? | Total Score | Quality rating: good (11–14 points) or fair (7.5–10.5 points) or poor (0–7 points) |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
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| Yes/No/Not reported (NR) or cannot determine (CD) or not applicable (NA) | Yes/No/Not reported (NR) or cannot determine (CD) or not applicable (NA) | Yes/No/Not reported (NR) or cannot determine (CD) or not applicable (NA) | Yes/No/Not reported (NR) or cannot determine (CD) or not applicable (NA) | Yes/No/Not reported (NR) or cannot determine (CD) or not applicable (NA) | Yes/No/Not reported (NR) or cannot determine (CD) or not applicable (NA) | Yes/No/Not reported (NR) or cannot determine (CD) or not applicable (NA) | Yes/No/Not reported (NR) or cannot determine (CD) or not applicable (NA) | Yes/No/Not reported (NR) or cannot determine (CD) or not applicable (NA) | Yes/No/Not reported (NR) or cannot determine (CD) or not applicable (NA) | Yes/No/Not reported (NR) or cannot determine (CD) or not applicable (NA) | Yes/No/Not reported (NR) or cannot determine (CD) or not applicable (NA) | Yes/No/Not reported (NR) or cannot determine (CD) or not applicable (NA) | Yes/No/Not reported (NR) or cannot determine (CD) or not applicable (NA) | |||
| Jerger, 2018 | Yes | Yes | Yes | No | No | Yes | CD | NA | NA | NA | CD | NR | Yes | CD | 6 | Poor |
| Silva, 2013 | Yes | Yes | Yes | Yes | Yes | Yes | CD | NA | NA | NA | CD | NR | Yes | CD | 7 | Poor |
Reviewers used the study rating tools on the range of items included in each tool to judge each study to be of “good,” “fair,” or “poor” quality. The ratings on the different items were used by the reviewers to assess the risk of bias in the study due to flaws in study design or implementation. In general terms, a “good” study has the least risk of bias, and results are considered to be valid. A “fair” study is susceptible to some bias deemed not sufficient to invalidate its results. The fair quality category is likely to be broad, so studies with this rating will vary in their strengths and weaknesses.
A “poor” rating indicates significant risk of bias. Studies rated poor were excluded from the body of evidence to be considered for each CQ. The only exception allowed was if there was no other evidence available, then poor quality studies could be considered. However, this exception was not applied in this project because there were no situations found where only poor quality studies were available for a body of evidence for a particular CQ.