Do seasonal variations in ambient temperature, humidity and daylight duration affect semen parameters? A retrospective analysis over eight years

Abstract

Natural life depends on biological rhythms that enable living creatures to thrive and survive. Biological rhythms or clocks allow species to adapt their physiological functions to external environmental changes. The environmental changes, creating a complex circadian (day) and circannual (year) rhythmicity, affect the whole organism, particularly the endocrine glands and the gonads. The hypothalamic-pituitary-gonadal axis is extremely susceptible to circannual rhythmicity, regulating the hormone levels (Santi et al., 2020). One of the most critical functions of annual hormone changes in nature is the optimisation of reproduction timing, thereby ensuring the highest survival chances of the offspring (Henkel et al., 2006; Roenneberg & Aschoff, 1990). Unlike other animal species, humans do not necessitate to set a season of fertility and can reproduce throughout the entire year. Although the human is not normally considered a seasonal breeder, many reports demonstrated the seasonal changes in gonadotropins, gonadal hormones and melatonin

Sperm Quality and Environment: A Retrospective, Cohort Study among 21,715 Semen Samples in a Southern Province of China

“…In terms of insolation duration, animal model studies suggested that seasonal variations may be mediated by endogenous mechanisms related to daylight length [28]. Our data showed that insolation duration had no significant effect on any of the parameters of semen analysis, which is similar to the results of a study in Turkey [29]. It is possible that the effects of sunlight on the change of human semen parameters may be relatively slow, which requires long-term observation and comparison, such as decades or even hundreds of years, or the data of regions with different insolation duration.…”

Effects of seasonal variations and meteorological factors on IVF pregnancy outcomes: a cohort study from Henan Province, China

“…Additionally, indoor heating is common in some areas of Henan Province, which may have affected the study results; nevertheless, all patients were inevitably affected by the external environment. Temperature has been shown to be associated with male fertility [30][31][32][33]. In this study, we have excluded men with severe oligozoospermia or teratozoospermia, but still cannot completely rule out the effects of seasonal variation and ambient temperature on semen quality.…”

Effects of the air pollution dynamics on semen quality and sperm DNA methylation in men living in urban industrial agglomeration

“…Similar but non-significant trend was observed regarding sperm concentration and normal morphology rates. This finding can be explained by a natural seasonal fluctuation in the semen quality from the superior winter and spring parameters to lower summer and autumn values (Kabukçu et al, 2020;Levitas et al, 2013;Mao et al, 2017;Wang et al, 2020). Comparing semen parameters throughout the year, Kabukçu et al (2020) Regarding sperm DNA methylation, air pollution was previously reported in association with global sperm DNA hypomethylation (Consales et al, 2016).…”

“…This finding can be explained by a natural seasonal fluctuation in the semen quality from the superior winter and spring parameters to lower summer and autumn values (Kabukçu et al, 2020;Levitas et al, 2013;Mao et al, 2017;Wang et al, 2020). Comparing semen parameters throughout the year, Kabukçu et al (2020) Regarding sperm DNA methylation, air pollution was previously reported in association with global sperm DNA hypomethylation (Consales et al, 2016). As for gene-specific changes, exposure to polycyclic aromatic hydrocarbons was found associated with H19 hypomethylation in sperm (Ma et al, 2019).…”