Relationship between caffeine intake and infertility: a systematic review of controlled clinical studies
Background: Previous studies showed that high dose of caffeine intake may induce some specific human reproductive system diseases, even lead to infertility. This review is aimed to systematically review the evidence from all controlled clinical studies of caffeine intake for infertility.
Methods: Relevant randomized/quasi-randomized controlled trials, non-randomized clinical studies, cohort studies, and case-control studies were included. Participants were either those without a history of infertility who are willing to have a baby (for prospective studies) or infertile patients with confirmed diagnosis (for retrospective studies). Caffeine or caffeine-containing beverage was observed as the exposure factor. The key outcome was the diagnosis of infertility.
Results: Four studies (one cohort study and three case-control studies) involving 12912 participants were included. According Newcastle - Ottawa Scale (NOS), the average score of case-control studies was 6, and the cohort study achieved 9. Meta-analysis and subgroup analysis were conducted. The results showed that low (OR 0.95, 95%CI 0.78-1.16), medium (OR 1.14, 95%CI 0.69-1.86) and high doses (OR 1.86, 95%CI 0.28-12.22) of caffeine intake may not increase the risk of infertility. The GRADE method was used to assess the certainty of the evidence and the results showed that the quality of the three evidence bodies were all low.
Conclusion: Our study provides low quality evidence that regardless of low, medium and high doses of caffeine intake do not appear increase the risk of infertility. But the conclusion should be treated with caution.
Systematic review registration: PROSPERO CRD42015015714
Figure 1
Figure 2
Figure 3
Figure 4
This is a list of supplementary files associated with this preprint. Click to download.
Posted 13 May, 2020
On 22 Apr, 2020
Received 17 Apr, 2020
On 17 Apr, 2020
Received 17 Apr, 2020
On 24 Mar, 2020
Received 01 Mar, 2020
On 17 Feb, 2020
Invitations sent on 12 Feb, 2020
On 06 Feb, 2020
On 05 Feb, 2020
On 05 Feb, 2020
Relationship between caffeine intake and infertility: a systematic review of controlled clinical studies
Posted 13 May, 2020
On 22 Apr, 2020
Received 17 Apr, 2020
On 17 Apr, 2020
Received 17 Apr, 2020
On 24 Mar, 2020
Received 01 Mar, 2020
On 17 Feb, 2020
Invitations sent on 12 Feb, 2020
On 06 Feb, 2020
On 05 Feb, 2020
On 05 Feb, 2020
Background: Previous studies showed that high dose of caffeine intake may induce some specific human reproductive system diseases, even lead to infertility. This review is aimed to systematically review the evidence from all controlled clinical studies of caffeine intake for infertility.
Methods: Relevant randomized/quasi-randomized controlled trials, non-randomized clinical studies, cohort studies, and case-control studies were included. Participants were either those without a history of infertility who are willing to have a baby (for prospective studies) or infertile patients with confirmed diagnosis (for retrospective studies). Caffeine or caffeine-containing beverage was observed as the exposure factor. The key outcome was the diagnosis of infertility.
Results: Four studies (one cohort study and three case-control studies) involving 12912 participants were included. According Newcastle - Ottawa Scale (NOS), the average score of case-control studies was 6, and the cohort study achieved 9. Meta-analysis and subgroup analysis were conducted. The results showed that low (OR 0.95, 95%CI 0.78-1.16), medium (OR 1.14, 95%CI 0.69-1.86) and high doses (OR 1.86, 95%CI 0.28-12.22) of caffeine intake may not increase the risk of infertility. The GRADE method was used to assess the certainty of the evidence and the results showed that the quality of the three evidence bodies were all low.
Conclusion: Our study provides low quality evidence that regardless of low, medium and high doses of caffeine intake do not appear increase the risk of infertility. But the conclusion should be treated with caution.
Systematic review registration: PROSPERO CRD42015015714
Figure 1
Figure 2
Figure 3
Figure 4