- 1The Institute of Brain Science and Brain-inspired Research, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, China
- 2College of Environmental and Life Sciences, Murdoch University, Perth, WA, Australia
- 3College of Pharmacy, Shandong First Medical University, Jinan, China
- 4College of Life Sciences, Qingdao Agricultural University, Qingdao, China
- 5Chinese Academy of Agricultural Sciences, Beijing, China
Background: Diabetes mellitus (DM) has emerged as a rapidly growing global health problem, imposing substantial socioeconomic burdens and multidimensional health consequences, including adverse effects on male fertility. Although accumulating evidence suggests associations between DM and male reproductive dysfunction, comprehensive mechanistic insights, particularly through inflammatory pathways, remain inadequately elucidated.
Method: We conducted a systematic literature search on Web of Science, Embase, and PubMed databases (1972–2022) to investigate DM-related male infertility through meta-analysis. Following PRISMA guidelines, eight of 168 studies on type 1 diabetes (T1D) and nine of 185 studies on type 2 diabetes (T2D) were included to screen the relationship between diabetes and male infertility. In addition, 10 of 840 inflammation-related studies (1961–2022) underwent rigorous selection for mechanistic exploration. Meta-analysis was conducted to evaluate the summary relative risk (RR) and 95% confidence intervals (CIs) across the combined studies.
Results: Meta-analysis demonstrated a significant impairment of male fertility in diabetic populations. Subgroup analyses revealed that T2D is more likely to cause male infertility compared to T1D. Despite low between-study heterogeneity, inflammation biomarkers (e.g., TNF-α) were implicated in diabetes-induced male infertility. Transcriptomic analyses further identified enriched inflammatory pathways and altered expression of fertility-related genes.
Conclusion: Current evidence indicates that diabetes adversely affects male fertility through inflammatory pathways.
1 Introduction
Diabetes mellitus (DM) is a cluster of chronic disorders characterized by persistent hyperglycemia resulting from impaired insulin secretion (type 1 diabetes [T1D]) and/or insulin resistance (type 2 diabetes [T2D]) (1). According to the International Diabetes Federation (IDF), in 2021, DM affected over 1.2 million pediatric T1D cases, and 541 million adults were at high risk of T2D worldwide. DM has emerged as a critical global issue, with significant social, health, and economic consequences (2). T1D can develop at any age, but it is most prevalent among children and adolescents, who produce very little or no insulin. Conversely, T2D is more common in adults and accounts for approximately 90% of all diabetes cases, characterized by impaired insulin utilization (1, 71). Emerging evidence links DM to male reproductive dysfunction, particularly through sperm abnormalities (3, 32). Mechanistic studies implicate multiple pathways, including proinflammatory responses (4–6), oxidative stress (7, 8), hormone dysregulation (luteinizing hormone [LH], follicle-stimulating hormone [FSH], testosterone [T]) (9–12), increased glucose (13), and sperm DNA fragmentation (14, 15). However, significant heterogeneity across studies arises from differences in sample characteristics (age, disease duration, sizes), methodological variability (biomarker selection), and conflicting outcome measures, which hinders the conclusive synthesis of DM-mediated male infertility mechanisms.
Male infertility is defined as the inability to conceive following 1 year of twice-weekly unprotected intercourse (16). An increasing body of evidence indicates that male infertility may be a harbinger of future adverse health outcomes (17). Numerous factors contribute to male infertility, including genetic abnormalities (18, 19) and lifestyle risk factors (e.g., environment, nutrients, smoking, stress, and endocrine disruptors) (20). These factors may lead to immunologic disorders and sperm dysfunction (21), testicular disorders (16), and oxidative stress (22). Unhealthy lifestyles, including high-fat or high-sugar diets, are often accompanied by diabetes. Studies suggest that diabetes negatively impacts male fertility both directly and indirectly, affecting spermatogenesis, penile erection, and ejaculation (23–26).
As mentioned above, numerous studies have investigated the relationship between diabetes and male fertility. Despite growing recognition of DM-associated male infertility, current evidence remains fragmented due to inconsistent experimental designs and limited mechanistic integration. Meta-analysis, a robust statistical method for synthesizing heterogeneous datasets (27, 28), offers a solution by quantifying pooled effect sizes and identifying modulatory factors. In this study, we employed a systematic meta-analysis combined with bioinformatics validation to quantify the magnitude of DM-induced male fertility impairment across T1D/T2D subtypes, elucidate inflammation-centric mechanisms through pathway enrichment analysis, and establish evidence-based priorities for future therapeutic interventions.
2 Methods
Meta-analyses were carried out in accordance with the published guidelines of Meta-Analysis of Observational Studies in Epidemiology and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses.
We conducted a meta-analysis to explore the relationship between diabetes and male infertility. The literature included in this study was retrieved from PubMed, Embase, and Web of Science. The search terms diabetes or diabetes mellitus, male infertility or sterility, inflammation or immune response or cytokines or chemokines were used to search titles, keywords, and abstracts using the fuzzy search option. The studies included were published between 1961 and 2022. A flowchart of the selected papers is presented in Figure 1. Given the limited number of studies, statistical tests for publication bias were not performed. Heterogeneity was expressed using the I-squared test, where a higher I-squared indicates greater heterogeneity. The Z-test was used to represent the cumulative probability of the total effect. The formula for the Z-test is as follows (29):
Where: x is the sample mean; μ is the overall mean; ó is the overall standard deviation; and n is the sample size. Z-value represents the different probability (Z = ~ − ∞: 0%; Z = ~ 0: 50%; Z = ~ + ∞: 100%).
A total of 1,182 papers were initially retrieved. The titles and abstracts were screened, and studies containing information on diabetes mellitus and male fertility were selected. Among these, 840 experimental studies were first screened to ensure specific data support for the subsequent meta-analysis. Of these, 168 papers were related to type 1 diabetes, and 185 papers were related to type 2 diabetes. The publications were then assessed and selected if they met all the following criteria:
i. The aim of the study was to evaluate the influence of diabetes on male fertility.
ii. The full text of the study was available.
iii. The study was a primary research paper, not a review article.
iv. The study reported the number of individuals and included at least two groups (control and treatment).
v. Duplicate articles were excluded.
After the screening, 27 papers met the inclusion criteria. The selected articles were analyzed using RevMan v5.4 (Cochrane, London, UK). These studies were then divided into T1D (eight papers), T2D (nine papers), and inflammation (10 papers) groups. In this study, the fixed-effect model was applied as follows (30):
Where: Yi is the observed effect in the study; Θ is the true effect in the study; and ϵi is the difference between the true effect and the observed effect.
After the analysis, the value of the I-square was used for quantifying the heterogeneity, and the value of the Z-test was used for comparing the cumulative probability of the occurrence of the total effect amount.
Gene expression levels in RNA sequencing data were estimated using the fragments per kilobase of transcript per million mapped reads (FPKM) method. To screen differentially expressed genes (DEGs), the criteria were set at p < 0.05 and fold change > 2. Subsequently, enrichment analysis was performed on the identified DEGs to characterize their functional roles. The number of DEGs included in each functional term was counted, and the significance of enrichment (represented by p-value) was calculated using the hypergeometric distribution test. A smaller p-value indicates a higher likelihood that the DEGs are enriched in the corresponding functional term, suggesting a nonrandom association between the DEGs and the biological process/pathway. In this study, two RNA-seq databases (National Center for Biotechnology Information [NCBI]: GSE184025 and GSE179100) from the testes of diabetic male mice were further analyzed using Metascape to obtain the enriched pathways. Briefly, the gene list was first uploaded to the Metascape website, the species (human and mice) were selected, and expression analysis was then performed. The enriched pathways were subsequently obtained, as shown in Figure 2.
Figure 2. Bioinformatics pipeline (https://metascape.org/gp/index.html#/main/step1).
Correlation analysis between inflammation, male fertility parameters, and glucose levels was performed using the Pearson correlation coefficient by SPSS (IBM, V.20). The data were extracted from published papers (9, 12, 13). The formula was as follows (31):
Where: P(X, Y) is the Pearson correlation coefficient of two continuous variables (X, Y); cov(X, Y) is the covariance between them; and σX, σY are the standard deviations, respectively.
3 Results
3.1 Diabetes causes male infertility
To objectively evaluate the association between DM and male infertility, we conducted a meta-analysis approach utilizing the fixed-effect model. The included studies are presented in Tables 1, 2. Eight papers analyzed T1D vs. male infertility, involving 196 individuals in the diabetic group and 226 control individuals. Nine articles examined T2D vs. male infertility, including 410 diabetic individuals and 440 controls. According to the forest plot (Figure 3), there were more cases of male infertility in the diabetes group than in the control group. The total Z-test value (Z = 12.91; p < 0.00001) indicates that diabetes significantly reduces male fertility, and the heterogeneity was not significant (RR = 72.04; 95% confidence interval [CI] = 37.64, 137.90; I-square = 12%). Based on the Z-test of the subgroup meta-analysis, T2D (RR = 92.16; 95% CI = 37.73, 225.12; Z = 9.93; p < 0.00001) showed a higher probability of causing male infertility than T1D (RR = 49.18; 95% CI = 19.17, 126.22; Z = 8.10; p < 0.00001). Heterogeneity remained nonsignificant in T1D studies (I-square = 0%) and moderate in T2D studies (I-square = 44%), suggesting greater consistency in T1D-related infertility outcomes (Supplementary Figure S1).
Figure 3. Meta-analysis of the association between diabetes and male infertility. (T1D, type 1 diabetes; T2D, type 2 diabetes).
3.2 Inflammation assumes crucial roles in diabetes-induced male infertility
To identify the mechanisms of diabetes-induced male infertility, we summarized and calculated the frequency of the contributing factors. These included inflammation, oxidation, hormonal (e.g., FSH, testosterone), and apoptosis pathways involved in male infertility. Among them, inflammation was the most frequent factor, accounting for 20.4% (Figure 4). Given its predominance among the identified factors, inflammation was selected for in-depth meta-analytical validation. Eleven studies were included in the subsequent analysis (Table 3).
According to the forest plot (Figure 5), the Z-test for the overall effect showed significant statistics (Z = 7.82, p < 0.00001), indicating that inflammation is an important factor in diabetes-induced male infertility. Ten studies were included in the meta-analysis, involving 263 diabetes-induced infertility individuals, of whom 225 events showed increased inflammatory activity (RR = 35.98; 95% CI = 14.66, 88.29). The fixed-effects model revealed exceptional consistency across studies (I-square = 0%), eliminating concerns regarding interstudy heterogeneity (Supplementary Figure S2). This robust association underscores inflammation as a pivotal mediator in diabetes-associated male infertility.
3.3 Diabetes leads to male infertility through an inflammatory process
We searched two RNA-seq databases from the testes of diabetic male mice available at the NCBI related to diabetes-associated male infertility. Gene expression levels in the RNA sequencing data were estimated using the FPKM method. DEGs were screened using the criteria of p < 0.05 and fold change > 2.
Subsequently, the altered gene expression data from the diabetic and control groups were separated, combined, and further analyzed using an online analytical tool (http://metascape.org) (Figure 2). Based on the enriched pathways of the differentially expressed genes (Figure 6), most pathways were closely related to male fertility and included two notable pathways: innate immune response and inflammatory response. These findings suggest that diabetes can strongly influence male fertility through inflammatory pathways at the gene expression level.
Figure 6. Genetic pathway enrichment analysis (https://metascape.org/).
To explore interactions among diabetes, male infertility, and inflammation, we conducted a correlation analysis. The results demonstrated that the inflammatory pathway biomarker tumor necrosis factor alpha (TNF-α) was significantly negatively correlated with male fertility parameters, including testosterone, testis weight, sperm motility, and sperm concentration, particularly testosterone and sperm motility (Figure 7). In contrast, TNF-α was positively correlated with glucose levels. These findings provide further evidence of the role of inflammation in diabetes-induced male infertility. Diabetes disrupts the inflammatory system, contributing to male infertility.
Figure 7. Correlation analysis of the TNF-α inflammatory pathway. Different colors represent different correlations. (Blue represents negative correlation; yellow represents no correlation; red represents positive correlation).
4 Discussion
This is the first study to carry out a meta-analysis assessing the risk of male infertility in individuals with diabetes compared with controls. Based on the meta-analysis of the included studies, we propose that diabetes has a substantial impact on male reproduction. The underlying mechanisms are highly complex, and this paper primarily focuses on analyzing and discussing the role of inflammation.
Diabetes could lead to severe metabolic disease and complications (50). According to the IDF (71), diabetes rates are increasing worldwide. As early as 500–600 bc, two Indian physicians described the distinction between types 1 and 2 diabetes: type 1 being associated with onset in youth, and type 2 linked to obesity (51). Although types 1 and 2 diabetes show different characteristics, this study found that both have a substantial adverse effect on male fertility (3, 14, 26, 45, 52–55). This study included 27 papers for meta-analysis. Eight articles involving 422 individuals evaluated the risk of T1D on male fertility, yielding statistically significant results (p < 0.00001). Nine papers involving 850 individuals evaluated T2D in male fertility, also showing statistically significant results. Although some included studies had small sample sizes, the meta-analysis findings are consistent with our previous studies (56, 57). These results suggest that diabetes has a detrimental impact on male fertility. Interestingly, we found that type 2 diabetes was associated with a higher risk of male infertility than type 1 diabetes. This may be because type 2 diabetes is characterized by insulin resistance as its core feature and is accompanied by various complications, such as chronic hyperglycemia, lipid metabolism disorders (58), and systemic low-grade inflammation (59). These complications could negatively impact male reproductive function (26, 60).
Studies have established an association between inflammatory biomarkers and the occurrence of diabetes and its complications (61–63). According to our results, diabetes may induce male infertility through several pathways. Among them, inflammation (20.4%) was observed more frequently than hormonal (16.7%), apoptotic (13%), and oxidative (9.3%) pathways. The 10 studies included here involved 263 diabetes-induced male infertile individuals and 208 controls. The forest plot indicated that inflammatory reactions were active in diabetes-induced male infertility. These data consistently confirm that inflammatory pathways (TNF-α) serve as important mechanisms mediating male infertility in diabetes. Moreover, TNF-α showed a significant negative correlation with core male fertility indicators, such as sperm motility, sperm concentration, and testosterone levels, highlighting the causal role of inflammatory pathways in diabetes-induced male infertility and providing critical evidence for subsequent mechanistic research. Despite the strong consistency of the results, the inclusion of both animal and human studies introduced limitations and heterogeneity. A major limitation was the overreliance on rodent models in the included studies, which may reduce the applicability of the findings to human male fertility. This limitation primarily arises from significant differences between rodents and humans in physiological characteristics, metabolic mechanisms, and reproductive system structure. For instance, the spermatogenic cycle of mice (35 days) is much shorter than that of humans (74 days) (64, 65), and the ratio of Sertoli cells to germ cells in the seminiferous tubules also differs from that in humans (66). Such structural disparities may lead to variations in the duration and intensity of inflammatory effects on spermatogenesis. More importantly, the species-specificity of inflammatory pathways may limit the extrapolation of results. Here, we demonstrated that inflammation is a high-risk factor through which diabetes can cause male infertility. This analysis clarifies the mechanism by which diabetes induces male infertility via inflammatory pathways; however, the limitations of rodent models indicate that these findings require further validation in humans. In addition, genetic disorders were observed in diabetic male mice. Metascape analysis of gene expression in fertility pathways and inflammatory pathways further confirmed that inflammation plays a vital role in diabetes-induced male infertility. Pearson coefficient analysis showed the relationships among inflammation, diabetes, and male infertility. TNF-α is a cytokine with tumor necrosis activity and plays a role in inflammation (67). This study found that TNF-α is positively associated with diabetes and negatively associated with male fertility parameters, including testosterone, testis weight, sperm motility, and sperm concentration, confirming the results of the meta-analysis and gene expression pathway analysis. Another notable finding was that TNF-α was positively correlated with glucose levels. Studies have confirmed that elevated glucose is an important pathological feature of metabolic diseases such as type 2 diabetes and obesity (68). This association was not merely a concomitant phenomenon. The feedback regulation of TNF-α by glucose in the diabetes model creates a vicious cycle: high glucose levels stimulate the secretion of TNF-α, forming a vicious cycle of hyperglycemia→increased TNF-α→more severe hyperglycemia (69). Importantly, oxidative stress induced by high-sugar conditions negatively impacts sperm quality, which in turn indirectly affects normal male reproductive function (70). In addition, oxidative stress and hormonal imbalance are important contributors to male infertility in diabetes (54). The cycle of diabetes→oxidative stress→inflammation activation→hormonal imbalance→aggravated oxidative stress and inflammation→continuous damage to reproductive function→male infertility represents the core mechanism of male infertility in diabetes. Therefore, not only anti-inflammatory approaches, but also strategies targeting oxidative stress and hormonal imbalance, may be potential treatment directions for improving male infertility in diabetes. Consequently, comprehensive interventions addressing these three aspects—including anti-inflammatory therapy, antioxidant treatment, and testosterone supplementation—may become the key strategies for enhancing fertility in diabetic men in the future. Of course, this study represents a preliminary exploration in this field, and further high-quality studies are needed to validate these conclusions.
5 Conclusions
In summary, this meta-analysis demonstrates a significant risk of male infertility in diabetic populations, with T2D exhibiting greater reproductive toxicity than T1D. Mechanistically, chronic inflammation appears to be an important mediator, as indicated by correlation analysis and transcriptomic signatures. In the future, targeting inflammation may become a potential therapeutic strategy for diabetic male infertility.
Data availability statement
The datasets presented in this study can be found in online repositories. The names of the repository/repositories and accession number(s) can be found in the article/Supplementary Material.
Author contributions
YH: Conceptualization, Formal analysis, Funding acquisition, Writing – original draft. ZY: Formal analysis, Writing – original draft. YF: Writing – review & editing. YZ: Supervision, Writing – review & editing. YR: Supervision, Writing – review & editing.
Funding
The author(s) declare that financial support was received for the research and/or publication of this article. This research was supported by the Brain Science and Brain Research Institute of Shandong First Medical University- 2024 Talent Funding (YS24-0001686 to YH).
Conflict of interest
The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
Generative AI statement
The author(s) declare that no Generative AI was used in the creation of this manuscript.
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Supplementary material
The Supplementary Material for this article can be found online at: https://www.frontiersin.org/articles/10.3389/fendo.2025.1600565/full#supplementary-material
Supplementary Figure 1 | The funnel plot corresponding to Figure 3.
Supplementary Figure 2 | The funnel plot corresponding to Figure 5.
References
1. American Diabetes Association. Diagnosis and classification of diabetes mellitus. Diabetes Care. (2011) 34:S62–9. doi: 10.2337/dc11-S062
2. Kaul K, Tarr JM, Ahmad SI, Kohner EM, and Chibber R. Introduction to diabetes mellitus. Adv Exp Med Biol. (2012) 771:1–11. doi: 10.1007/978-1-4614-5441-0_1
3. Condorelli RA, Vignera SL, Mongioì LM, Alamo A, and Calogero AE. Diabetes Mellitus and infertility: Different Pathophysiological effects in Type 1 and Type 2 on sperm Function. Front Endocrinol. (2018) 9:268. doi: 10.3389/fendo.2018.00268
4. Bakhshwin D, Faddladdeen KAJ, Ali SS, Alsaggaf SM, and Ayuob NN. Nanoparticles of Costus speciosus Ameliorate Diabetes-Induced Structural Changes in Rat Prostate through Mediating the Pro-Inflammatory Cytokines IL 6, IL1β and TNF-α. Molecular. (2022) 27:1027. doi: 10.3390/molecules27031027
5. Jiang QK, Maresch CC, Petry SF, Paradowska-Dogan A, Bhushan S, Chang YS, et al. Elevated CCL2 causes Leydig cell malfunction in metabolic syndrome. JCI Insight. (2020) 5:e134882. doi: 10.1172/jci.insight.134882
6. Naylor AJ, Desanti G, Saghir AN, and Hardy RS. TNFα depleting therapy improves fertility and animal welfare in TNFα-driven transgenic models of polyarthritis when administered in their routine breeding. Lab Anim. (2018) 52:59–68. doi: 10.1177/0023677217707985
7. Nna VU, Bakar ABA, Ahmad A, Eleazu CO, and Mohamed M. Oxidative stress, NF-κB-mediated inflammation and apoptosis in the testes of streptozotocin–induced diabetic rats: combined protective Effects of Malaysian propolis and metformin. Antioxidants. (2019) 8:465. doi: 10.3390/antiox8100465
8. Zhao YG, Song WJ, Wang ZY, Wang ZQ, Jin X, Xu JC, et al. Resveratrol attenuates testicular apoptosis in type 1 diabetic mice: Role of Akt-mediated Nrf2 activation and p62-dependent Keap1 degradation. Redox Biol. (2018) 14:609–17. doi: 10.1016/j.redox.2017.11.007
9. Kermani J, Goodarzi N, and Bakhtiari M. An experimental study to evaluate the protective Effects of solanum lycopersicum seed essential oil on diabetes-induced testicular injuries. Medicina. (2019) 55:499. doi: 10.3390/medicina55080499
10. Kharazi U, Keyhanmanesh R, Hamidian GR, Ghaderpour S, and Ghiasi R. Voluntary exercise could reduce sperm malformations by improving hypothalamus-hypophysis-gonadal axis and kisspeptin/leptin signaling in type 2 diabetic rats. Iranian J Basic Med Sci. (2021) 24:1624–31. doi: 10.22038/IJBMS.2021.58740.13048
11. Rakhshandeh H, Khasevan HR, Saviano A, Mahdinezhad MR, Rahimi VB, Ehtiati S, et al. Protective effect of portulaca oleracea on streptozotocin-induced type I diabetes-associated reproductive system dysfunction and inflammation. Molecules. (2022) 27:6075. doi: 10.3390/molecules27186075
12. Tsounapi P, Honda M, Dimitriadis F, Kawamoto B, Hikita K, Muraoka K, et al. Impact of antioxidants on seminal vesicles function and fertilizing potential in diabetic rats. Asian J Andrology. (2017) 19:639–46. doi: 10.4103/1008-682X.186871
13. Annie L, Jeremy M, Gurusubramanian G, Derkach KV, Shpakov AO, and Roy VK. Effect of metformin on testicular expression and localization of leptin receptor and levels of leptin in the diabetic mice. Mol Reprod Dev. (2020) 87:620–9. doi: 10.1002/mrd.23342
14. Ding GL, Liu Y, Liu ME, Pan JX, Guo MX, Sheng JZ, et al. The effects of diabetes on male fertility and epigenetic regulation during spermatogenesis. Asian J Andrology. (2015) 17:948–53. doi: 10.4103/1008-682X.150844
15. Simas JN, Mendes TB, Fischer LW, Vendramini V, and Miraglia SM. Resveratrol improves sperm DNA quality and reproductive capacity in type 1 diabetes. Andrology. (2021) 9:384–99. doi: 10.1111/andr.12891
16. Sharma A, Minhas S, Dhillo WS, and Jayasena CN. Male infertility due to testicular disorders. J Clin Endocrinol Metab. (2021) 106:e442–59. doi: 10.1210/clinem/dgaa781
17. Choy JL and Eisenberg ML. Male infertility as a window to health. Fertility Sterility. (2018) 110:810–4. doi: 10.1016/j.fertnstert.2018.08.015
18. Coutton C, Fissore RA, Palermo GD, Stouffs K, and Touré A. Male infertility: genetics, mechanism, and therapies. BioMed Res Int. (2016) 2016:7372362. doi: 10.1155/2016/7372362
19. Krausz C and Riera-Escamilla A. Genetics of male infertility. Nat Rev. (2018) 15:369–84. doi: 10.1038/s41585-018-0003-3
20. Bisconti M, Simon JF, Grassi S, Leroy B, Martinet B, Arcolia V, et al. Influence of risk factors for male infertility on sperm protein composition. Int J Mol Sci. (2021) 22:13164. doi: 10.3390/ijms222313164
21. Hamada A, Esteves SC, Nizza M, and Agarwal A. Unexplained male infertility: diagnosis and management. International Brazilian Journal of Urology. (2012) 38:576–594. doi: 10.1590/S1677-55382012000500002
22. Bisht S, Faiq M, Tolahunase M, and Dada R. Oxidative stress and male infertility. Nat Rev. (2017) 14:470–85. doi: 10.1038/nrurol.2017.69
23. Barkabi-Zanjani S, Ghorbanzadeh V, Aslani M, Ghalibafsabbaghi A, and Chodari L. Diabetes mellitus and the impairment of male reproductive function: possible signaling pathways. Diabetes Metab Syndrome: Clin Res Rev. (2020) 14:1307–14. doi: 10.1016/j.dsx.2020.07.031
24. Eisenberg ML, Sundaram R, Maisog J, and Buck Louis GM. Diabetes, medical comorbidities, and couple fecundity. Hum Reprod. (2016) 31:2369–76. doi: 10.1093/humrep/dew200
25. Maresch CC, Stute DC, Alves MG, Oliveira PF, Kretser DM, and Linn T. Diabetes-induced hyperglycemia impairs male reproductive function: a systematic review. Hum Reprod Update. (2018) 24:86–105. doi: 10.1093/humupd/dmx033
26. Tobias DK, Gaskins AJ, Missmer SA, Hu FB, Manson JE, Buck Louis GM, et al. History of infertility and risk of type 2 diabetes mellitus: a prospective cohort study. Diabetologia. (2015) 58:707–15. doi: 10.1007/s00125-015-3493-z
27. ArchMiller AA, Bauer EF, Koch RE, Wijayawardena BK, Anil A, Kottwitz JJ, et al. Formalizing the definition of meta-analysis in Molecular Ecology. Mol Ecol. (2015) 24:4042–51. doi: 10.1111/mec.13264
28. Fagard RH, Staessen JA, and Thijs L. Advantages and disadvantages of the meta-analysis approach. J Hypertension. (1996) Supplement 14:9–S12. doi: 10.1097/00004872-199609002-00004
29. Zaykin DV. Optimally weighted Z-test is a powerful method for combining probabilities in meta-analysis. J Evolutionary Biol. (2011) 24:1836–41. doi: 10.1111/j.1420-9101.2011.02297.x
30. Spineli LM and Pandis N. Meta-analysis: fixed-effect model. Am J Orthodontivs Dentofacial Orthopedics. (2020) 157:134–7. doi: 10.1016/j.ajodo.2019.10.008
31. Armstrong RA. Should Pearson’s correlation coefficient be avoided? Ophthalmic Physiol Optics. (2019) 39:316–27. doi: 10.1111/opo.12636
32. Vignera SL, Condorelli RA, Mauro MD, Presti DL, Mongioì LM, Russo G, et al. Reproductive function in male patients with type 1 diabetes mellitus. Andrology. (2015) 3:1082–7. doi: 10.1111/andr.12097
33. Shi GJ, Zheng J, Wu J, Qiao HQ, Chang Q, Niu Y, et al. Protective effects of Lycium barbarum polysaccharide on male sexual dysfunction and fertility impairments by activating hypothalamic pituitary gonadal axis in streptozotocin-induced type-1 diabetic male mice. Endocrine J. (2017) 64:907–22. doi: 10.1507/endocrj.EJ16-0430
34. Alves MG, Martins AD, Moreira PI, Carvalho RA, Sousa M, Barros A, et al. Metabolic fingerprints in testicular biopsies from type 1 diabetic patients. Cell Tissue Res. (2015) 362:431–40. doi: 10.1007/s00441-015-2217-5
35. Ballester J, Muñoz MC, Domínguez J, Rigau T, Guinovart JJ, and Rodríguez-Gil JE. Insulin-dependent diabetes affects testicular function by FSH- and LH-linked mechanisms. J Andrology. (2004) 25:706–19. doi: 10.1002/j.1939-4640.2004.tb02845.x
36. Akondi RB, Kumar P, Annapurna A, and Pujari M. Protective effect of rutin and naringin on sperm quality in streptozotocin (STZ) induced type 1 diabetic rats. Iranian J Pharm Res. (2011) 10:585–96. doi: 10.5414/CP201376
37. Diniz A, Alves MG, Candeias E, Duarte AI, Moreira PI, Silva BM, et al. Type 2 diabetes induces a pro-oxidative environment in rat epididymis by disrupting SIRT1/PGC-1α/SIRT3 pathway. Int J Mol Sci. (2022) 23:8912. doi: 10.3390/ijms23168912
38. Long LL, Qiu H, Cai B, Chen NN, Lu XF, Zheng SH, et al. Hyperglycemia induced testicular damage in type 2 diabetes mellitus rats exhibiting microcirculation impairments associated with vascular endothelial growth factor decreased via PI3K/Akt pathway. Oncotarget. (2018) 9:5321–36. doi: 10.18632/oncotarget.23915
39. Ahangarpour A, Oroojan AA, Heidari H, Ehsan G, and Nooshabadi MRR. Effects of hydro-alcoholic extract of rhus coriaria (Sumac) seeds on reproductive complications of nicotinamide-streptozotocin induced type-2 diabetes in male mice. World J Men’s Health. (2014) 32:151–8. doi: 10.5534/wjmh.2014.32.3.151
40. Ahangarpour A, Oroojan AA, Heidari H, Ghaedi E, and Taherkhani R. Effects of hydro-alcoholic extract from arctium lappa L. (Burdock) root on gonadotropins, testosterone, and sperm count and viability in male mice with nicotinamide/streptozotocin-induced type 2 diabetes. Malaysian J Med Sci. (2015) 22:25–32.
41. Abbasihormozi SH, Babapour V, Kouhkan A, Naslji AN, Afraz K, Zolfaghary Z, et al. Stress hormone and oxidative stress biomarkers link obesity and diabetes with reduced fertility potential. Cell J. (2019) 21:307–13. doi: 10.22074/cellj.2019.6339
42. Rahimiyan-Heravan M, Roshangar L, Karimi P, Sefidgari-Abrasi S, Morshedi M, Saghafi-Asl M, et al. The potential therapeutic effects of Lactobacillus plantarum and inulin on serum and testicular reproductive markers in diabetic male rats. Diabetol Metab Syndrome. (2020) 12:53. doi: 10.1186/s13098-020-00560-0
43. Al-Shaeli SJJ, Hussen TJ, and Ethaeb AM. Effect of honey bee venom on the histological changes of testes and hormonal disturbance in diabetic mice. Veterinary World. (2022) 15:2357–64. doi: 10.14202/vetworld.2022.2357-2364
44. Irgam K, Reddy BS, Hari SG, Banapuram S, and Reddy BM. The genetic susceptibility profile of type 2 diabetes and reflection of its possible role related to reproductive dysfunctions in the southern Indian population of Hyderabad. BMC Med Genomics. (2021) 14:272. doi: 10.1186/s12920-021-01129-0
45. Skurikhin EG, Pakhomova AV, Pershina OV, Krupin VA, Ermakova NN, Pan ES, et al. Role of sertoli and leydig cells in the regulation of spermatogonial stem cell and development of reproductive disorders in male C57Bl/6 mice with type 1 diabetes mellitus. Bull Exp Biol Med. (2017) 164:127–31. doi: 10.1007/s10517-017-3940-6
46. Maresch CC, Stute DC, Ludlow H, Hammes HP, Kretser DM, Hedger MP, et al. Hyperglycemia is associated with reduced testicular function and activin dysregulation in the Ins2Akitaþ/mouse model of type 1 diabetes. Mol Cell Endocrinol. (2017) 446:91–101. doi: 10.1016/j.mce.2017.02.020
47. Heeba GH and Hamza AA. Rosuvastatin ameliorates diabetes-induced reproductive damage via suppression of oxidative stress, inflammatory and apoptotic pathways in male rats. Life Sci. (2015) 141:13–9. doi: 10.1016/j.lfs.2015.09.015
48. Han XX, Jiang YP, Liu N, Wu J, Yang JM, Li YX, et al. Protective effects of Astragalin on spermatogenesis in streptozotocin-induced diabetes in male mice by improving antioxidant activity and inhibiting inflammation. Biomedicine Pharmacotherapy. (2019) 110:561–70. doi: 10.1016/j.biopha.2018.12.012
49. Khalil ASM, Giribabu N, Yelumalai S, Shahzad H, Kilari EK, and Salleh N. Myristic acid defends against testicular oxidative stress, inflammation, apoptosis: Restoration of spermatogenesis, steroidogenesis in diabetic rats. Life Sci. (2021) 278:119605. doi: 10.1016/j.lfs.2021.119605
50. Cloete L. Diabetes mellitus: an overview of the types, symptoms, complications and management. Nurs Standard. (2022) 37:61–6. doi: 10.7748/ns.2021.e11709
51. The Lancet. Diabetes: a dynamic disease. Lancet. (2017) 389:2163. doi: 10.1016/S0140-6736(17)31537-4
52. Bener A, Al-Ansari AA, Zirie M, and Al-Hamaq AOAA. Is male fertility associated with type 2 diabetes mellitus? Int Urol Nephrol. (2009) 41:777–84. doi: 10.1007/s11255-009-9565-6
53. Condorelli RA, Calogero AE, Cannarella R, Giacone F, Mongioi’ LM, Cimino L, et al. Poor efficacy of L-acetylcarnitine in the treatment of asthenozoospermia in patients with type 1 diabetes. J Clin Med. (2019) 8:585. doi: 10.3390/jcm8050585
54. Leisegang K, Sengupta P, Agarwal A, and Henkel R. Obesity and male infertility: Mechanisms and management. Andrologia. (2021) 53:e13617. doi: 10.1111/and.13617
55. Wiebe JC, Santana A, Medina-Rodríguez N, Hernández M, Nóvoa J, Mauricio D, et al. Fertility is reduced in women and in men with type 1 diabetes: results from the Type 1 Diabetes Genetics Consortium (T1DGC). Diabetologia. (2014) 57:2501–4. doi: 10.1007/s00125-014-3376-8
56. Hao YN, Feng YN, Yan XW, Chen L, Zhong RQ, Tang XF, et al. Gut microbiota-testis axis: FMT improves systemic and testicular micro-environment to increase semen quality in type 1 diabetes. Mol Med. (2022) 28:45. doi: 10.1186/s10020-022-00473-w
57. Yan XW, Feng YN, Hao YN, Zhong RQ, Jiang Y, Tang XF, et al. Gut-testis axis: microbiota prime metabolome to increase sperm quality in young type 2 diabetes. Microbiol Spectr. (2022) 10:e0142322. doi: 10.1128/spectrum.01423-22
58. Athyros AG, Doumas M, Imprialos KP, Stavropoulos K, Georgianou E, Katsimardou A, et al. Diabetes and lipid metabolism. Hormones. (2018) 17:61–7. doi: 10.1007/s42000-018-0014-8
59. Singh A, Shadangi S, Gupta PK, and Rana S. Type 2 diabetes mellitus: A comprehensive review of pathophysiology, comorbidities, and emerging therapies. Compr Physiol. (2025) 15:e70003. doi: 10.1002/cph4.70003
60. Kim N, Nakamura H, Masaki H, Kumasawa K, Hirano K, and Kimura T. Effect of lipid metabolism on male fertility. Biochem Biophys Res Commun. (2017) 485:686–92. doi: 10.1016/j.bbrc.2017.02.103
61. Guo WC, Song YC, Sun Y, Du HS, Cai Y, You QQ, et al. Systemic immune-inflammation index is associated with diabetic kidney disease in Type 2 diabetes mellitus patients: Evidence from NHANES 2011-2018. Front Endocrinol. (2022) 13:1071465. doi: 10.3389/fendo.2022.1071465
62. Lontchi-Yimagou E, Sobngwi E, Matsha TE, and Kengne AP. Diabetes mellitus and inflammation. Curr Diabetes Rep. (2013) 13:435–44. doi: 10.1007/s11892-013-0375-y
63. Muriach M, Flores-Bellver M, Romero FJ, and Barcia JM. Diabetes and the brain: oxidative stress, inflammation, and autophagy. Oxid Med Cell Longevity. (2014) 2014:102158. doi: 10.1155/2014/102158
64. Chen Y, Zheng Y, Gao Y, Lin Z, Yang S, Wang T, et al. Single-cell RNA-seq uncovers dynamic processes and critical regulators in mouse spermatogenesis. Cell Res. (2018) 28:879–96. doi: 10.1038/s41422-018-0074-y
65. Johnson L, Staub C, Neaves WB, and Yanagimachi R. Live human germ cells in the context of their spermatogenic stages. Hum Reprod. (2001) 16:1575–82. doi: 10.1093/humrep/16.8.1575
66. Berndtson WE. Replication needed to distinguish alterations in cell ratios, the frequency of individual stages of the cycle of the seminiferous epithelium, or the appearance of abnormalities in the testes of rodents, rabbits, or humans. J Andrology. (2010) 31:593–606. doi: 10.2164/jandrol.109.008920
67. Hira K and Begum AS. Methods for evaluation of TNF-α Inhibition effect. Methods Mol Biol. (2021) 2248:271–9. doi: 10.1007/978-1-0716-1130-2_21
68. Bailey CJ, Flatt PR, and Conlon JM. An update on peptide-based therapies for type 2 diabetes and obesity. Peptides. (2023) 161:170939. doi: 10.1016/j.peptides.2023.170939
69. Böni-Schnetzler M and Meier DT. Islet inflammation in type 2 diabetes. Semin Immunopathology. (2019) 41:501–13. doi: 10.1007/s00281-019-00745-4
70. Oppong A, Leung YH, Ghosh A, Peyot M, Paquet M, Morales C, et al. Essential role of germ cell glycerol-3-phosphate phosphatase for sperm health, oxidative stress control and male fertility in mice. Mol Metab. (2024) 90:102063. doi: 10.1016/j.molmet.2024.102063
71. The International Diabetes Federation. Diabetes now affects one in 10 adults worldwide. (2021) Available online at: https://idf.org/news/diabetes-now-affects-one-in-10-adults-worldwide/
Keywords: type 1 diabetes, type 2 diabetes, inflammation, male infertility, meta-analysis
Citation: Hao Y, Yang Z, Feng Y, Zhao Y and Ren Y (2025) Inflammation-mediated effects of diabetes mellitus on male fertility: a systematic review and meta-analysis. Front. Endocrinol. 16:1600565. doi: 10.3389/fendo.2025.1600565
Received: 31 March 2025; Accepted: 27 October 2025;
Published: 17 November 2025.
Edited by:
Chencheng Xue, National University of Singapore, SingaporeReviewed by:
Julia Jarosławska, Polish Academy of Sciences, PolandHimanshu Pawankumar Gupta, Columbia University, United States
Copyright © 2025 Hao, Yang, Feng, Zhao and Ren. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
*Correspondence: Yanan Hao, aHluMTgzNTQyNTUwOThAMTYzLmNvbQ==
Zheng Yang2