Table 2.
NOS for risk of bias assessment of included longitudinal studies
| Study | Domains a | Results b | |||
|---|---|---|---|---|---|
| Selection (4) | Comparability (2) | Outcome (3) | Score | Risk | |
| Purdy et al. 32 | 4 | 3 | 2 | 9 | Low |
| Verghese et al. 34 | 3 | 3 | 2 | 8 | Low |
| Chen et al. 33 | 4 | 3 | 1 | 8 | Low |
a
Domains of Newcastle‐Ottawa Scale (NOS): Selection (representativeness of the exposed cohort; selection of the non‐exposed cohort; ascertainment of exposure and demonstration that outcome of interest was not present at start of study); Comparability (principal factor and any additional factor); and Outcome (assessment of outcome; if the follow‐up was long enough for outcomes to outcome occurs; and adequacy of follow‐up of cohorts).
b
Studies were categorized as high (<5), moderate (5–7), or low risk of bias (≥8) on the scale of 0 to 9 for longitudinal studies.