Sperm DNA damage—the effect of stress and everyday life factors
M Radwan, J Jurewicz, D Merecz-Kot, W Sobala, P Radwan, M Bochenek, W Hanke. Sperm DNA damage—the effect of stress and everyday life factors. International Journal of Impotence Research. Advance online publication 14 April 2016; doi: 10.1038/ijir.2016.15.
The clinical significance of sperm DNA damage lies in its association with natural conception rates and also might have a serious consequence on developmental outcome of the newborn.
The aim of the present study is to determine whether stress and everyday life factors are associated with sperm DNA damage in adult men. The study population consisted of 286 men who attended the infertility clinic for diagnostic purposes and who had normal semen concentration of 20–300 m ml−1 or with slight oligozoospermia (semen concentration of 15–20 m ml−1) (WHO, 1999). Participants were interviewed and provided a semen sample. The sperm chromatin structure assay was assessed using flow cytometry.
In the present study, we found evidence for a relationship between sperm DNA damage parameters and everyday life factors. High and medium level of occupational stress and age increase DNA fragmentation index (P=0.03, P=0.004 and P=0.03, respectively). Other lifestyle factors that were positively associated with percentage of immature sperms (high DNA stainability index) included: obesity and cell phone use for more than 10 years (P=0.02 and P=0.04, respectively).
Our findings indicate that stress and lifestyle factor may affect sperm DNA damage. Data from the present study showed a significant effect of age, obesity, mobile phone radiation and occupational stress on sperm DNA damage. As DNA fragmentation represents an extremely important parameter indicative of infertility and potential outcome of assisted reproduction treatment, and most of the lifestyle factors are easily modifiable, the information about factors that may affect DNA damage are important.
... male sperm DNA damage measures: the percentages of DNA fragmentation index (DFI), medium DNA fragmentation index (M DFI), high DNA fragmentation index (H DFI) and high DNA stainability index (HDS—percentage of immature sperms).
Cell phone use was based on the years of usage of this equipment (0–5 years, 6–10 years, 11–25 years).
52.1% of study population used cell phone from 6 to 10 years.
Age category >40 years increased the H DFI (P=0.03). Obesity (BMI 30–40 kg m−2) and using cell phone more than 10 years was positively related to HDS (P=0.02 and P=0.04, respectively) (Table 2). Other examined lifestyle factors: smoking, alcohol consumption, coffee drinking were not related with any of the examined parameters of sperm DNA damage and high DNA stainability. The result were adjusted for potential confounders.
In our study, using a cell phone for more than 10 years increases HDS. A recent study showed that DNA fragmentation was the only parameter altered in mobile phone users, in a group of high usage (>4 h daily) that stored their phone in the trouser pocket.36 In addition, in the study performed in Poland using cell phone more than 10 years was negatively associated with the percentage of motile sperm cell.17
Although few studies have explored the association between exposure to stress and life factors, and male reproductive function, none have carefully assessed the percentage of medium DFI and the percentage of immature sperms. A detailed questionnaire information on demographics, medical, lifestyle risk factors performed among study participants allowed for control of confounding in the statistical models. The relative homogeneity of study participants (educated, white) helped reduce the chance that our findings resulted from unmeasured health, behavioral or exposure factors. This homogenicity increases the internal validity of our study, but limits the generalization of study findings to more diverse population. Additional strength arise from the fact that smoking status was verified using the level of cotinine in saliva.
In conclusion, our findings indicate that stress and lifestyle factor may affect sperm DNA damage. Data from the present study showed a significant effect of age, obesity, mobile phone radiation and occupational stress on sperm DNA damage. As DNA fragmentation represents an extremely important parameter indicative of infertility and potential outcome of assisted reproduction treatment and most of the lifestyle factors are easily modifiable, information about factors that may affect DNA damage are important.
For references regarding effects of exposure to cell phone radiation on male fertility see http://bit.ly/saferemrsperm
and on female fertility see http://bit.ly/femalefertility.
Joel M. Moskowitz, Ph.D., Director
Center for Family and Community Health
School of Public Health
University of California, Berkeley
Electromagnetic Radiation Safety
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