The effect of antioxidant supplementation on dysmenorrhea and endometriosis-associated painful symptoms: a systematic review and meta-analysis of randomized clinical trials

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Obstet Gynecol Sci. 2024;67(6):586-587
Publication date (electronic) : 2024 November 4
doi : https://doi.org/10.5468/ogs.24228
Infertility and Reproductive Health Research Center, Health Research Institute, Babol University of Medical Sciences, Babol, Iran
Corresponding author: Parvaneh Mirabi, PhD Infertility and Reproductive Health Research Center, Health Research Institute, Babol University of Medical Sciences, Babol 47176-47745, Iran E-mail: parvaneh_mirabi@yahoo.com
Received 2024 August 19; Revised 2024 September 30; Accepted 2024 October 20.

We are writing this letter to express concerns regarding a systematic review and meta-analysis by Baradwan et al. [1] published in your journal entitled, “The effect of antioxidant supplementation on dysmenorrhea and endometriosisassociated painful symptoms: a systematic review and metaanalysis of randomized clinical trials”.

The authors stated that the eligibility criteria required participants to have “clinically and/or histologically confirmed endometriosis;” however, upon reviewing the included studies, we noted that a study by Lasco et al. [2] did not include women with confirmed endometriosis. This study focused on women with primary dysmenorrhea without laparoscopic confirmation of endometriosis. Primary dysmenorrhea characteristically begins as adolescents attain ovulatory cycles, usually within 6-12 months of menarche. Secondary dysmenorrhea refers to painful menses caused by a pelvic pathology or recognized medical condition. Endometriosis is the most common cause of secondary dysmenorrhea.

Additionally, the inclusion criteria were as follows; supplementation with antioxidants (vitamins D, C, E, and A, melatonin, curcumin, omega-3 fatty acids, resveratrol, zinc, copper, chromium, and selenium, separately or in different combinations) comparators; antioxidant versus no treatment, antioxidant versus placebo. Moreover, we noted that Sesti et al. [3] did not meet the eligibility criteria. They compared gonadotropin-releasing hormone-a, continuous estroprogestin, and dietary therapy containing vitamins, minerals, lactic acid ferments, and fish oil, rather than focusing solely on antioxidant supplementation. Interventions involving complex dietary therapies may have different action mechanisms and outcomes than those involving pure antioxidant supplementation.

The inclusion of a study population that does not meet the stated eligibility and intervention criteria affects the validity of the results and conclusions drawn from this meta-analysis. Patients with primary dysmenorrhea may have different pathophysiologies and responses to interventions than those with endometriosis-associated pain.

Additionally, the principle of comprehensiveness is important in systematic reviews. Some studies, although in the search range of this systematic study, were excluded in this meta-analysis, including the studies of Santanam et al. [4] and Ibrahim Abd El-Fadil Sehsah et al. [5].

Excluding relevant studies and those that did not meet the stated eligibility and intervention criteria may have affected the overall findings of this meta-analysis. Adherence to welldefined eligibility criteria and a comprehensive literature search are crucial to ensure the integrity and reliability of systematic reviews and meta-analyses.

We would kindly request that the authors re-evaluate the eligibility of the included studies, consider the inclusion of potentially relevant studies that may have been excluded, and clarify these deviations from the stated inclusion criteria that may have impacted the overall findings. Addressing these concerns is essential to ensure the validity and reliability of the conclusions drawn from this systematic review and meta-analysis.

To address our concerns, we referenced the key AMSTAR guidelines; the need for a clear a priori design regarding the inclusion/exclusion criteria, importance of a comprehensive search strategy to identify all relevant studies, and requirement for clear disclosure of the included study characteristics to assess their fit within the eligibility criteria.

Notes

Conflict of interest

The authors declare that they have no competing interests.

Ethical approval

Not applicable.

Patient consent

Not applicable.

Funding information

Not applicable.

References

1. Baradwan S, Gari A, Sabban H, Alshahrani MS, Khadawardi K, Bukhari IA, et al. The effect of antioxidant supplementation on dysmenorrhea and endometriosisassociated painful symptoms: a systematic review and meta-analysis of randomized clinical trials. Obstet Gynecol Sci 2024;67:186–98.
2. Lasco A, Catalano A, Benvenga S. Improvement of primary dysmenorrhea caused by a single oral dose of vitamin D: results of a randomized, double-blind, placebocontrolled study. Arch Intern Med 2012;172:366–7.
3. Sesti F, Pietropolli A, Capozzolo T, Broccoli P, Pierangeli S, Bollea MR, et al. Hormonal suppression treatment or dietary therapy versus placebo in the control of painful symptoms after conservative surgery for endometriosis stage III-IV. A randomized comparative trial. Fertil Steril 2007;88:1541–7.
4. Santanam N, Kavtaradze N, Murphy A, Dominguez C, Parthasarathy S. Antioxidant supplementation reduces endometriosis-related pelvic pain in humans. Transl Res 2013;161:189–95.
5. Ibrahim Abd El-Fadil Sehsah F, Taha Abd El-Fattah A, Mohammed Saeed A. The role of antioxidant supplementation in reducing the endometriosis related chronic pelvic pain in women. AMJ 2022;51:121–34.

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