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Table 2 GRADE Summary of Findings Table

From: Relationship between caffeine intake and infertility: a systematic review of controlled clinical studies

Caffeine intakeLarge effectPlausible confoundingDose-response gradientAnticipated absolute effectsa (95% CI)Relative effect (95%CI)No of Participants (studies)Certainty of the evidence (GRADE)
Risk with non caffeineRisk with caffeine
Low dose (≤100 mg/d)NoNoNo197 per 1000189 per 1000
(161 to 221)
OR 0.95
(0.78–1.16)
4627
(2case-control studies + 1 cohort study)

Low
Medium dose (≥200 mg/d)NoNoNo194 per 1000215 per 1000
(143 to 309)
OR 1.14
(0.69–1.86)
5353
(2case-control studies + 1 cohort study)

Low
High dose (≥400 mg/d)NoNoNo186 per 1000298 per 1000
(60 to 736)
OR 1.86
(0.28–12.22)
2435
(1case-control study + 1 cohort study)

Low
  1. aThe risk in the intervention group (and its 95% confidence interval) is based on the assumed risk in the comparison group and the relative effect of the intervention (and its 95% CI)
  2. CI Confidence interval, OR Odds ratio
  3. GRADE Working Group grades of evidence
  4. High certainty: We are very confident that the true effect lies close to that of the estimate of the effect
  5. Moderate certainty: We are moderately confident in the effect estimate: The true effect is likely to be close to the estimate of the effect, but there is a possibility that it is substantially different
  6. Low certainty: Our confidence in the effect estimate is limited: The true effect may be substantially different from the estimate of the effect
  7. Very low certainty: We have very little confidence in the effect estimate: The true effect is likely to be substantially different from the estimate of effect