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Lifestyle-, environmental-, and additional health factors associated with an increased sperm DNA fragmentation: a systematic review and meta-analysis.
Szabó, A, Váncsa, S, Hegyi, P, Váradi, A, Forintos, A, Filipov, T, Ács, J, Ács, N, Szarvas, T, Nyirády, P, et al
Reproductive biology and endocrinology : RB&E. 2023;21(1):5
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The World Health Organization defines infertility as regular unprotected sexual intercourse without achieving conception within a year. In recent years, there has been a growing demand for functional, objective parameters reflecting fertility status more clearly than classical parameters. Of these, sperm DNA fragmentation (SDF) and the DNA fragmentation index – denoting the percentage of sperm with damaged DNA – seem to be of utmost importance. The aim of this study was to investigate all risk factors that may potentially be increasing SDF. This study is a systematic review and meta-analysis of one hundred and ninety articles. The earliest studies were published in 2003, and the latest in 2021. Results show that several modifiable risk factors negatively affect SDF, namely; a. health conditions: varicocele [when veins become enlarged inside the pouch of skin that holds the testicles] and impaired glucose tolerance, b. infections: Chlamydia, c. malignancies: testicular tumours, and d. lifestyle factors: smoking, alcohol consumption and body mass index. Authors conclude that several lifestyle-, environmental-, and additional health factors are associated with increased SDF.
Abstract
INTRODUCTION Infertility affects one in every six couples in developed countries, and approximately 50% is of male origin. In 2021, sperm DNA fragmentation (SDF) testing became an evidence-based test for fertility evaluations depicting fertility more clearly than standard semen parameters. Therefore, we aimed to summarize the potential prognostic factors of a higher SDF. METHODS We conducted a systematic search in three medical databases and included studies investigating any risk factors for SDF values. We calculated mean differences (MD) in SDF with 95% confidence interval (CI) for exposed and non-exposed individuals. RESULTS We included 190 studies in our analysis. In the group of associated health conditions, varicocele (MD = 13.62%, CI: 9.39-17.84) and impaired glucose tolerance (MD = 13.75%, CI: 6.99-20.51) had the most significant increase in SDF. Among malignancies, testicular tumors had the highest impact, with a maximum of MD = 11.3% (CI: 7.84-14.76). Among infections, the overall effects of both Chlamydia and HPV were negligible. Of lifestyle factors, smoking had the most disruptive effect on SDF - an increase of 9.19% (CI: 4.33-14.06). Different periods of sexual abstinence did not show significant variations in SDF values. Age seemed to have a more drastic effect on SDF from age 50 onwards, with a mean difference of 12.58% (CI: 7.31-17.86). Pollution also had a detrimental effect - 9.68% (CI: 6.85-12.52). CONCLUSION Of the above risk factors, varicocele, impaired glucose tolerance, testicular tumors, smoking, pollution, and paternal age of over 50 were associated with the highest SDF. TRIAL REGISTRATION CRD42021282533.
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The impact of diabetes mellitus type 1 on male fertility: Systematic review and meta-analysis.
Facondo, P, Di Lodovico, E, Delbarba, A, Anelli, V, Pezzaioli, LC, Filippini, E, Cappelli, C, Corona, G, Ferlin, A
Andrology. 2022;10(3):426-440
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The relationship between type 2 diabetes mellitus and male hypogonadism is well known, whereas the impact of type 1 diabetes mellitus (DM1) on male fertility and testis functions has been less studied. The aim of this study was to systematically review and discuss the available evidence evaluating paternity rate, male gonadal axis, and sperm parameters in men with DM1. This study is a systematic review and meta-analysis of fourteen studies. Results show: - reduced fertility potential in patients with DM1, as they have a lower number of children compared with unaffected population. In fact, the rate of children is statistically significantly lower among men who had been diagnosed with DM1 at an earlier age, according to a longer duration of the disease. - that men with DM1, compared with controls, have significantly lower normal sperm morphology, progressive motility and a trend toward a reduced semen volume, without difference in total sperm count and concentration. Authors conclude that DM1 might impair reproductive health at different levels, including functional sperm alterations definitively leading to reduced fertility rate in these patients.
Abstract
BACKGROUND Some evidence suggests that diabetes mellitus type 1 (DM1) could affect male fertility, gonadal axis, semen parameters, and spermatogenesis because of effects of hyperglycemia and insulin deficiency. Anyhow, the exact impact of DM1 on male fertility is unclear. OBJECTIVES To review the studies evaluating paternity rate, male gonadal axis, and semen parameters in men with DM1. MATERIALS AND METHODS A review of relevant literature from January 1980 to December 2020 was performed. Only studies published in English reporting data on fatherhood (rate of children by natural fertility), hormonal and seminal parameters were included. Out of 14 retrieved articles, the eight studies evaluating semen parameters were meta-analyzed. RESULTS The rate of children (four studies) was lower than controls among men affected by DM1, especially in men with a longer duration of disease. The data of gonadal hormonal profile in DM1 men (six studies) are very heterogeneous and a neutral effect of DM1 or a condition of subclinical hypogonadism could not be concluded. Meta-analysis showed that men with DM1 (n = 380), compared with controls (n = 434), have significantly lower normal sperm morphology [-0.36% (-0.66; -0.06), p < 0.05, six studies] and sperm progressive motility [33.62% (-39.13; -28.11), p < 0.001, two studies] and a trend toward a lower seminal volume [-0.51 (-1.03; 0.02), p = 0.06, eight studies], without difference in total sperm count and concentration. Data on scrotal ultrasound and sperm DNA fragmentation are too few. No study evaluated other factors of male infertility, such as transrectal ultrasound, semen infections, sperm auto-antibodies, and retrograde ejaculation. DISCUSSION DM1 might impair male fertility and testis functions (endocrine, spermatogenesis), but definition of its actual impact needs further studies. CONCLUSION Men with DM1 should be evaluated with a complete hormonal, seminal, and ultrasound workup to better define their fertility potential and need for follow up of testis functions.