Adverse effects of circadian desynchrony on the male reproductive system: an epidemiological and experimental study

Abstract STUDY QUESTION Is circadian desynchrony a risk factor of male reproductive damage in semen parameters and/or reproductive hormones? SUMMARY ANSWER Circadian desynchrony correlates with decrease of sperm count, which was improved when circadian desynchrony was attenuated. WHAT IS KNOWN ALREADY Circadian desynchrony caused by work (shift work) and non-work-related reasons is prevalent worldwide and has been found to be associated with decreased female fertility, but whether it harms male reproductive health is unclear. STUDY DESIGN, SIZE, DURATION A hybrid research was conducted. (i) A cross-sectional study of 1346 Chinese men in 2007 was used to analyze the association between semen/hormone biomarkers and work-related circadian desynchrony, which was divided into rotating shift work and permanent shift work against non-shift work. (ii) A cohort of 796 Chinese undergraduates from 2013 to 2014 was used to analyzed the association between semen/hormone biomarkers and non-work-related circadian desynchrony (between school days and days off). (iii) The biomarker identified simultaneously in both populations was further validated in male C57BL/6J mice housed under conditions simulating circadian desynchrony. PARTICIPANTS/MATERIALS, SETTING, METHODS A total of 17 semen/hormone biomarkers were compared among rotating shift workers and permanent shift workers against non-shift workers in the 1346 reproductive-age Chinese men. A total of 14 semen/hormone biomarker was analyzed in the undergraduate cohort for correlation with non-work-related circadian desynchrony (measured by Munich Chronotype Questionnaire) in 2013 and 2014 and compared between the 2 years. Photoperiod-shifting method was used to establish the mouse model, in which the biomarker was examined and molecular mechanism was explored by apoptosis analysis, DNA content analysis, transcriptome sequencing, real-time PCR and western blotting. MAIN RESULTS AND THE ROLE OF CHANCE Among the semen/hormone biomarkers, sperm count was found to be lower in rotating shift workers, who had a higher risk of low sperm count defined by Chinese Ministry of Health (total sperm/ejaculate < 120 × 106) than non-shift workers (odds ratio = 1.26, 95% CI 1.05–1.52). This biomarker was replicated in the undergraduate cohort, where each hour of circadian desynchrony was associated with 1.16 (95% CI 1.02–1.31) fold odds of low sperm count, and sperm count increased during 2014 in men who reduced circadian desynchrony after 2013. A decrease of sperm count with circadian desynchrony and its recovery after removal of circadian desynchrony was also observed in the mouse model. During asynchrony, increased apoptosis was found in seminiferous tubules and the marker genes of post-spermatocyte stage cells were down-regulated. The most enriched functional pathway was homologous recombination, which happened during meiosis. LIMITATIONS, REASONS FOR CAUTION The study of human beings was observational while the animal study has potential difference in circadian desynchrony exposure and species susceptibility. Further researches are needed to clarify the causal relationship in men. WIDER IMPLICATIONS OF THE FINDINGS These findings provide novel insight to the effect of circadian desynchrony on male reproductive health and a potential strategy for prevention of reproductive damage. STUDY FUNDING/COMPETING INTEREST(S) This study was supported by the National Key R&D Program of China [2017YFC1002001] and National Natural Science Foundation of China [81871208]. There are no conflicts of interest to declare. TRIAL REGISTRATION NUMBER NA.

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296 Sex differences in sleep and wakefulness of police officers working shifts: evidence from a field study

SLEEP ◽

10.1093/sleep/zsab072.295 ◽

2021 ◽

Vol 44 (Supplement_2) ◽

pp. A118-A118

Author(s):

Gabriela Caetano ◽

Laura Kervezee ◽

Fernando Gonzales-Aste ◽

Philippe Boudreau ◽

Diane Boivin

Keyword(s):

Sex Differences ◽

Circadian Rhythms ◽

Shift Work ◽

Police Officers ◽

Field Studies ◽

Time Of Day ◽

Cycle Phase ◽

Shift Workers ◽

Work Related ◽

Time Awake

Abstract Introduction National reports of work-related injuries found the excess risk of work injury attributed to shift work to be significantly higher among women. The Working Time Society (WTS) concluded that male sex is one of the few factors that is “consistently associated with perceived or actual shift work tolerance”. However, it is unclear if physiological parameters are involved. Laboratory-controlled studies report sex differences in circadian rhythms (body temperature, melatonin). In sleep deprivation protocols, alertness and cognitive performances were affected by sex, menstrual cycle phase and hormonal contraceptives [HC] use. Nevertheless, field studies that compare male and female shift workers are scarce. Methods An observational study including 76 police officers working on patrol: 56 males and 20 females (11 using [HC], 6 not using [non-HC] and 3 with unknown use of hormonal contraception) aged 32.0 ± 5.3 years. Participants were followed throughout a month-long work cycle (1,457 morning, evening, night, or other shifts, plus rest days). They filled out time-stamped questionnaires (Samn-Perelli, KSS, Visual Analogue Scales, ~5/day; sleep and work-related information, ~1–2/day), completed 5-min Psychomotor Vigilance Tasks (PVT, ~2/day), and wore an actigraph to collect activity data. Linear mixed-effects models were used to analyze the effects of group, time awake and time-of-day on fatigue, sleepiness, alertness, mood and PVT measures. Results Self-reported measures and psychomotor performance significantly varied with time awake and time-of-day. Fatigue and sleepiness levels were significantly higher among female compared to male police officers, both with time awake and across the 24-h day. These variations were similar between non-HC females and the other groups. Compared to males, HC females were more fatigued and less alert, both with time awake and across the 24-h day, and sleepier with time awake. Having children at home did not explain these differences. Conclusion The results of this study expand our knowledge on the sex differences in the sleep and circadian physiology and demonstrate a critical effect of HC on women fatigue, sleepiness and alertness when working shifts. Sex and hormonal parameters must be considered in occupational medicine as well as in future laboratory and field studies on shift workers and circadian rhythms. Support (if any) IRSST, FRQS.

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Relationship of work-related stress with obesity among Brazilian female shift workers

Public Health Nutrition ◽

10.1017/s1368980020004243 ◽

2020 ◽

pp. 1-7

Author(s):

Janaína Cristina da Silva ◽

Anderson Garcez ◽

Gabriela Herrmann Cibeira ◽

Heloísa Theodoro ◽

Maria Teresa Anselmo Olinto

Keyword(s):

Shift Work ◽

Night Shift ◽

Cross Sectional Study ◽

Cross Sectional ◽

Work Related Stress ◽

Shift Workers ◽

Night Shift Work ◽

Work Related ◽

Prevalence Of Obesity ◽

Related Stress

Abstract Objectives: To explore the relationship between work-related stress and obesity among female shift workers. Additionally, we also aimed to test the interaction between shift work and work-related stress in this association. Design: A cross-sectional study was conducted among Brazilian female shift workers. Work-related stress was assessed through a demand–control questionnaire (Job Stress Scale). Work-related stress was defined by the presence of high psychological demands and low control at work. The obesity cases were defined as those with a BMI of 30 kg/m2 or more. Multivariate Poisson regression with robust variance was used to obtain the prevalence ratios (PR) and their respective 95 % CI. Setting: A group of industries located in southern Brazil in 2017. Participants: Four hundred and twenty female workers aged 18–59 years. Results: The overall prevalence of obesity was 30 % (95 % CI: 25·6, 34·4), and the presence of work-related stress was identified in 24 % (95 % CI: 19·9, 28·1) of the sample. We found an indication of interaction between work-related stress and night shift work on obesity (P = 0·026). After adjusting for confounding factors, work-related stress was associated with a 71 % greater probability of obesity (PR = 1·71; 95 % CI: 1·02, 2·87; P = 0·042) among female night shift workers. Conclusions: In this study, we revealed that exposure to work-related stress and night shift work were associated with obesity among female shift workers. Furthermore, the prevalence of obesity was high among female shift workers.

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Male reproductive health at risk due to exposure to perfluoroalkyl substances: Recent research highlights

10.25259/jrhm_18_2020 ◽

2021 ◽

Vol 2 ◽

pp. 13

Author(s):

Shilpi Singh ◽

Shio Kumar Singh

Keyword(s):

Reproductive Health ◽

Reproductive Toxicity ◽

Reproductive Hormones ◽

Consumer Products ◽

Perfluoroalkyl Substances ◽

Seminiferous Tubules ◽

Environmental Matrices ◽

The Past ◽

Sperm Counts ◽

Male Reproductive Health

Perfluoroalkyl substances (PFASs) are a group of synthetic organic chemicals that are persistent in the environment as well as in wildlife and human body. Further, PFASs are considered as persistent organic pollutants. PFASs have been extensively used in many industrial and consumer products over the past several decades and, therefore, they are found in various environmental matrices. A large number of studies during the past decades have reported the toxic effects of these compounds on the male reproductive health including damage to the seminiferous tubules, changes in reproductive hormones level, and low sperm counts and the molecular mechanism(s) involved in such effects. In the present review, we have summarized the reproductive toxicity of some PFASs, namely, perfluorooctanoic acid, perfluorooctane sulfonate, perfluorododecanoic acid, and perfluorononanoic acid in the male. This article briefly describes the findings on PFASs which may attract the attention of the reproductive toxicologists to examine the potential risk to the male reproductive health because of the continued contamination of the environment by these compounds.

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The relationship between diet, energy balance and fertility in men

International Journal for Vitamin and Nutrition Research ◽

10.1024/0300-9831/a000577 ◽

2020 ◽

Vol 90 (5-6) ◽

pp. 514-526 ◽

Cited By ~ 2

Author(s):

Edyta Suliga ◽

Stanisław Głuszek

Keyword(s):

Energy Balance ◽

Male Fertility ◽

Sperm Count ◽

Direct Analysis ◽

Reproductive Hormones ◽

Semen Parameters ◽

The Right ◽

Meta Analyses ◽

The Impact ◽

The Relationship

Abstract. Research conducted in recent years provides more and more evidence that diet can have a significant impact on male fertility. The aim of the study was to analyze the relationship between diet, energy balance and fertility in men. A comprehensive literature search of published studies in various languages, was carried out in electronic databases. The direct analysis included 96 works published between 2008 and 2018, including 12 randomized controlled trials and 23 systematic reviews and meta-analyses. A strong adherence to a healthy dietary pattern is positively correlated with total sperm count, progressive motility and total motile sperm count (all p < 0.05). However, attention is drawn to the fact that foods that are considered “healthy” can sometimes contain a significant amount of pollution, which negatively affect the semen parameters. An adequate intake of antioxidants or their supplementation have been quite effective in the prevention and treatment of male infertility. The improvement of pregnancy rate after antioxidant therapy ranged in various studies from 11% to 41%. An important problem, however, may be choosing the right dose of the supplement or finding an appropriate combination of antioxidants that may be more effective than any single antioxidant. The normalization of men’s body weight is beneficial for the quality of sperm and the concentration of male reproductive hormones. Further, long-term studies require the assessment of the impact of drastic weight loss after bariatric surgery on male fertility.

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Investigation of the effect of body mass index (BMI) on semen parameters and male reproductive system hormones

Archivio Italiano di Urologia e Andrologia ◽

10.4081/aiua.2017.3.219 ◽

2017 ◽

Vol 89 (3) ◽

pp. 219 ◽

Cited By ~ 4

Author(s):

Mehmet Zeynel Keskin ◽

Salih Budak ◽

Evrim Emre Aksoy ◽

Cem Yücel ◽

Serkan Karamazak ◽

...

Keyword(s):

Body Mass Index ◽

Body Mass ◽

Sperm Count ◽

Reproductive Hormones ◽

Semen Parameters ◽

Total Testosterone ◽

Significant Difference ◽

Group 3 ◽

Group 2 ◽

Group 1

Aim: To evaluate the effects of body mass index (BMI) ratio on semen parameters and serum reproductive hormones. Materials and methods: The data of 454 patients who prsented to male infertility clinics in our hospital between 2014 and 2015 were analyzed retrospectively. Weight, height, serum hormone levels and semen analysis results of the patients were obtained. BMI values were calculated by using the weight and height values of the patients and they were classified as group 1 for BMI values ≤ 25 kg/m2, as group 2 for BMI values 25-30 kg/m2 and as group 3 for BMI values ≥ 30 kg/m2. Results: The mean values of BMI, semen volume, concentration, total motility, progressive motility, total progressive motile sperm count (TPMSC), normal morphology according to Kruger, head abnormality, neck abnormality, tail abnormality, FSH, LH, prolactin, T/E2, total testosterone and estradiol parameters of the patients were considered. Patients were divided according to BMI values in Group 1 (n = 165), Group 2 (n = 222) and Group 3 (n = 56). There was no statistically significant difference in terms of all variables between the groups. Conclusions: We analyzed the relationship between BMI level and semen parameters and reproductive hormones, demonstrating no relationship between BMI and semen parameters. In our study, BMI does not affect semen parameters although it shows negative correlation with prolactin and testosterone levels.

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The Impact of Intense Exercise on Semen Quality

American Journal of Men s Health ◽

10.1177/1557988316669045 ◽

2016 ◽

Vol 11 (3) ◽

pp. 654-662 ◽

Cited By ~ 14

Author(s):

Paweł Jóźków ◽

Marco Rossato

Keyword(s):

Physical Activity ◽

Semen Quality ◽

Sperm Count ◽

Semen Analysis ◽

Semen Parameters ◽

Male Factor ◽

Recreational Athletes ◽

Increasing Demand ◽

Male Reproductive Health ◽

The Impact

With expanding knowledge on the health benefits of exercise, there is an increasing demand for information on the andrological consequences of participating in sports. These consequences are especially important in the context of infertility problems worldwide. The so-called “male factor” is reported in up to 50% of couples having trouble with conception. The answer to the question, “Is physical activity good for male reproductive health?” is not straightforward. A number of studies have suggested that significant changes in semen parameters may occur due to sports training of certain types, intensities, and durations. The changes to these parameters vary in scope, direction, and magnitude. Findings in recreational athletes have also differed from those in professional athletes. This review of the current literature suggests that intense physical activity may affect the semen concentration, as well as the number of motile and morphologically normal spermatozoa. Training at higher intensities and with increased loads seems to be associated with more profound changes in semen quality. In recreational athletes, exercise has either a positive or neutral effect on semen parameters. Due to many limitations (e.g., global sperm count trends, concerns about the quality control of sperm evaluations, and new standards for semen analysis), comparisons among historical data and their interpretation are difficult.

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Recovery of Prenatal Baicalein Exposure Perturbed Reproduction by Postnatal Exposure of Testosterone in Male Mice

International Journal of Endocrinology ◽

10.1155/2020/5012736 ◽

2020 ◽

Vol 2020 ◽

pp. 1-14

Author(s):

Sridevi Vaadala ◽

Naveen Ponneri ◽

Venkata Shashank Karanam ◽

Sri Bhashyam Sainath ◽

Pamanji Sreenivasuala Reddy ◽

...

Keyword(s):

Body Weight ◽

Reproductive Health ◽

Sperm Count ◽

Serum Testosterone ◽

The Body ◽

Postnatal Exposure ◽

Hypoosmotic Swelling Test ◽

Sperm Membrane ◽

Testicular Histology ◽

Male Reproductive Health

Baicalein (BC), a flavonoid, which lacks the qualities of reproductive health and shows adverse effects, is tested in this study. Inseminated mice were injected with 30, 60, and 90 mg BC/Kg body weight on gestation days 11, 13, 15, and 17. The F1 BC-exposed males of each dosage were divided into six groups. First three groups (n = 6 from each BC dosage) were used for assessment of reproductive performance, the others (n = 4 from each BC dosage) were administered with testosterone 4.16 mg/kg body weight on postnatal days 21, 31, and 41. The reproductive health of adult F1 males at the age of 55 and 60 was tested. Prenatal BC exposure showed reduced fertility after cohabitation with control females. The BC exposure significantly reduced the body weight, tissue indices, and sperm parameters (motility, count, viability, and daily sperm count) and altered the sperm membrane in a hypoosmotic swelling test. A downward trend was observed in testicular steroidogenic marker enzymes (3β- and 17β-steroid dehydrogenases) and serum testosterone, whereas increase in serum titers of FSH and LH along with altered the testicular histology. Conversely, testosterone (4.16 mg/kg body weight) partially recovered reduced male reproductive health by BC. BC impaired male reproductive health due to low levels of testosterone is reverted by external testosterone is evidenced in this study.

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Psycho-Social Impact of Shift Work

Business, Technology, and Knowledge Management in Asia ◽

10.4018/978-1-4666-2652-2.ch013 ◽

2013 ◽

pp. 166-174

Author(s):

Rupashree Goswami ◽

R. K. Jena ◽

B. B. Mahapatro

Keyword(s):

Job Satisfaction ◽

Shift Work ◽

Insights into leptin signaling and male reproductive health: the missing link between overweight and subfertility?

Biochemical Journal ◽

10.1042/bcj20180631 ◽

2018 ◽

Vol 475 (22) ◽

pp. 3535-3560 ◽

Cited By ~ 7

Author(s):

Bruno P. Moreira ◽

Mariana P. Monteiro ◽

Mário Sousa ◽

Pedro F. Oliveira ◽

Marco G. Alves

Keyword(s):

Reproductive Health ◽

Molecular Mechanisms ◽

Sperm Count ◽

Reproductive Function ◽

Reproductive Age ◽

Male Factor ◽

Leptin Signaling ◽

Male Reproductive Function ◽

Downward Spiral ◽

Male Reproductive Health

Obesity stands as one of the greatest healthcare challenges of the 21st century. Obesity in reproductive-age men is ever more frequent and is reaching upsetting levels. At the same time, fertility has taken an inverse direction and is decreasing, leading to an increased demand for fertility treatments. In half of infertile couples, there is a male factor alone or combined with a female factor. Furthermore, male fertility parameters such as sperm count and concentration went on a downward spiral during the last few decades and are now approaching the minimum levels established to achieve successful fertilization. Hence, the hypothesis that obesity and deleterious effects in male reproductive health, as reflected in deterioration of sperm parameters, are somehow related is tempting. Most often, overweight and obese individuals present leptin levels directly proportional to the increased fat mass. Leptin, besides the well-described central hypothalamic effects, also acts in several peripheral organs, including the testes, thus highlighting a possible regulatory role in male reproductive function. In the last years, research focusing on leptin effects in male reproductive function has unveiled additional roles and molecular mechanisms of action for this hormone at the testicular level. Herein, we summarize the novel molecular signals linking metabolism and male reproductive function with a focus on leptin signaling, mitochondria and relevant pathways for the nutritional support of spermatogenesis.

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Effect of a phytoestrogen food supplement on reproductive health in normal males

Clinical Science ◽

10.1042/cs1000613 ◽

2001 ◽

Vol 100 (6) ◽

pp. 613-618 ◽

Cited By ~ 77

Author(s):

Julie H. MITCHELL ◽

Elizabeth CAWOOD ◽

David KINNIBURGH ◽

Anne PROVAN ◽

Andrew R. COLLINS ◽

...

Keyword(s):

Reproductive Health ◽

Reproductive Tract ◽

Semen Quality ◽

Sperm Quality ◽

Sperm Count ◽

Sperm Concentration ◽

Human Sperm ◽

Food Supplement ◽

Testicular Volume ◽

Semen Parameters

Animal studies and human intervention trials have demonstrated the cancer chemopreventive properties of plant phytoestrogens, and phytoestrogen supplements are now widely available ‘over-the-counter’. However, consumption of phytoestrogen-rich diets can cause impaired fertility and reproductive tract disorders in some animals and the apparent decline in human sperm quality over recent decades may be related to increased exposure to environmental endocrine disruptors. The present study determines the effects of a short-term phytoestrogen supplement on semen quality and serum sex steroid and gonadotrophin levels in human males. Healthy volunteers took a supplement containing 40 mg of isoflavones daily for 2 months and donated blood and semen samples monthly for 2 months before and 4 months after supplementation. Semen samples were analysed for ejaculate volume, sperm concentration, total sperm count, motility and morphology. Blood samples were analysed for sex hormone and gonadotrophin levels and phytoestrogen concentrations, and testicular volume was measured using an orchidometer. The phytoestrogen supplement increased plasma genistein and daidzein concentrations to approx. 1 µM and 0.5 µM respectively; yet, there was no observable effect on endocrine measurements, testicular volume or semen parameters over the study period. This is the first study to examine the effects of a phytoestrogen supplement on reproductive health in males. We conclude that the phytoestrogen dose consumed had no effect on semen quality.

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