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Table 4 Assessment of study quality included in the meta-analysis by Newcastle Ottawa Scale (NOS) for cohort studies

From: Association between whole grain intake and breast cancer risk: a systematic review and meta-analysis of observational studies

Source Selection Comparabilitya Outcome Total scores
1 2 3 4 5A 5B 6 7 b 8 c  
Farvid et al * * * * * * * * 8
Egeberg et al. * * * * * * * 7
Sonestedt et al * * * * * * * * * 9
Nicodemus et al. * * * * * * * * 8
  1. 1 Representativeness of the exposed cohort. 2 Selection of the non-exposed cohort. 3 Ascertainment of exposure for cohort studies. 4 Demonstration that outcome of interest was not present at start of study for cohort studies. 5 Comparability of cohorts on the basis of the design or analysis. 6 Assessment of outcome. 7 Was follow-up long enough for outcomes to occur. 8 Adequacy of follow up of cohorts
  2. aStudies that controlled for age and traditional risk factors received one score, whereas studies that controlled for other important confounders received an additional score
  3. bstudy with follow-up time > 2 years was assigned one score
  4. cstudy with follow-up rate > 70% was assigned one score