Effect of Environmental Factors on Human Fertility

1. Effect of Environmental FactorsonHuman Fertility By: Siamak Bashar PhD student in Public Health ( Epidemiology) Department of Health Sciences Walden University

2. Secondary infertility 30% Primary infertility 70% Primary and Secondary Infertility Despite having unprotected intercourse for at least 12 months: Total Infertility Cases Female: Has never conceived Male: Has never impregnated a female Female: Has previously conceived but is subsequently unable to do so Male: Has previously impregnated a female but is subsequently unable to do so Hatcher RA, Trussell J, Stewart F, et al. 1994 Stewart GK. 1998

3. Fertility Facts Frequency: 1 out of 6 couples in the US Responsibility: 35% female infertility 35% male 20% both 10% unknown Maternal Age USA 20-24 4.1% 30-34 9.4% 25-29 5.5% 35-39 19.7% Healy et al, 1994

4. Male Factors Female Factors 40% 40% 20% Unknown/Both Among couples with identifiable causes of infertility Nelson, A.L, Marshall, J.R. 2004.

5. What can cause infertility?Unexplained-18%Female Male • Ovulation disorders • Tube/uterus blockage • Cervix • Endometriosis • Other • Sperm count and defects • Erectile or ejaculation deficiency Intrinsic vs. Extrinsic, Environmental

6. Decrease Human Fertility & Reproductive Health Level • Increase percentage of US Women with impaired Fecundity by age • ( 1982-2002) • Declining Male Testosterone (Travison et al. J Clin Endocrinol Metab, 2006) • Increasing Testicular Cancers in the United States ( Shah et al. Journal of Andrology, 2007) • Decreasing Age of Puberty ( Euling , et al. Paediatrics ,2000)

7. What Is Changing?

8. Environmental Influenceson Human Reproduction • Environmental Chemical • Nutrition • Life style • Emerging old and starting New Sexual Transmitted Diseases • Behavioural Factors • Interaction Among the Factors

9. Infertility From Public Health Point of View The WHO estimates that there are 60 million to 80 million infertile couples worldwide • Core infertility: a certain percentage of couples who would be infertile as a result of conditions that we cannot prevent, treat, or even know • Acquired Infertility: which generally indicates that there are causes in the community responsible for the excess of infertile couples FATHALLA, M,(1990). Fertility Overview

10. Acquired Infertility or Infertility Caused by Environmental Factors 1.Lifestyle factors including: age, weight, smoking, diet, exercise, psychological stress, caffeine consumption, and alcohol consumption • 2. Occupational &Environmental Factors: • Physical: such as Light, Temperature, Altitude, and Radiation • Chemical: Such as Natural or man-made • Biological: Such as Viruses, Microorganisms 3.Behavioral Factors: Such as Stress and Drug addiction Homan, et al 2007 http://humupd.oxfordjournals.org/cgi/content/abstract/13/3/209

11. Environmental Factors Related to Infertility • Toxic agents • Tobacco use • Alcohol Use • Radiation • Sexual Transmitted Diseases Sharpe, R.M., & Franks, S., (2002).Environment, lifestyle and infertility — an inter- generational issue, Nature Cell Biology & Nature Medicine8(S1), S33- S40 http://www.nature.com/fertility/content/full/ncb-nm-fertilitys33.html

12. Female Male • Lead poisoning reduces conception rates, associated with fetal wastage • Lead reduces sex drive, sperm count • Pesticides reduce sperm count Toxic Agents & Infertility Stewart GK. 1998.

13. Chemicals&Their Adverse Reproductive Health Effects • DDT/DDE (a): Reduced parity, impaired lactation, decreased semen quality, impaired fertility, and small-for-gestational-age babies • Dibromochloropropane : Decreased sperm counts & infertility • Pesticides in general :No apparent effects alone but decreased semen quality • and fecundity, spontaneous abortion, pre-term birth, and small for gestational age in mixtures • PCB(b): Impaired response to ovulation induction, reduced parity, impaired lactation, and potential reduced fecundability (a)=DDT/DDE = dichlorodiphenyltrichloroethane/dichlorobischlorophenylethylene (b)=PCB = polychlorinated biphenyls Younglai et al, 2006 & Hruska et al., 2000. http://humupd.oxfordjournals.org/cgi/content/abstract/11/1/43

14. Tobacco Use & Infertility • Decreased rates of conception • Increased rates of miscarriage • Increased risk of ectopic pregnancy • Increased risk of placenta previa • Negative effects on fetus • Sperm production • Motility • Morphology • Fertilization capacity Stewart GK. 1998. Bouyer J, et al. Am J Epidemiology. 2003.

15. Cigarette Smoking and Its Adverse Effects on Infertility • Male: • Negatively affects sperm production, motility and morphology • Increased risk of DNA damage • Female: • Negatively affect the follicular microenvironment and alter hormone levels in the luteal phase • Early Menopause • Increased thickness of Zona Pellucida Homan, G.F. et al, 2007 http://humupd.oxfordjournals.org/cgi/content/abstract/13/3/209

16. Alcohol Use & Infertility • Decreased rates of conception • Increased rates of miscarriage • Ovulatory infertility • Negative effects on fetus • Lower testosterone levels • Decreased sperm production • Impotence Stewart GK. 1998.

17. Female Male Ovarian failure Fetal wastage Fetal damage Testicular damage or cancer Chromosomal aberrations Radiation & Infertility Stewart GK. 1998.

18. Physical Exertion / Heat & Infertility Men Women Athletes may experience reversible amenorrhea without long-term effects Frequent heat exposure can temporarily reduce sperm production, such as welders, fire fighters, and ceramic workers. Stewart GK. 1998. Hruska et al., 2000

19. 2.3 million infertile couples 15–30% Unable to conceive Sexually Transmitted Diseases & Infertility Chlamydia: Pelvic inflammatory Disease Gonorrhea : Pelvic Inflammatory Disease Human papillomavirus Donovan P. 1993.

20. Prevention Primary Prevention: A public health strategy focusing on primary prevention ;e.g., through removal of risk factors for infertility such as early detection and treatment of sexually transmitted infections and, in particular, Chlamydia infection, Smoking, Overweight, Unhealthy Life style, Occupation hazard, and Toxic chemical substances. Center for Diseases Control and Prevention, 2009 http://www.cdc.gov/std/infertility/ReportCongressInfertility.pdf

21. Prevention Secondary Prevention: Whereas primary prevention is important, infertility diagnosis and treatment are relevant to public health in their own merit. • First, infertility is an area where health care costs are borne most often by the individual, creating significant economic and racial disparities. • Second, early diagnosis and treatment of underlying medical conditions (secondary prevention) may lead to effective restoration of fertility. • Third, infertility treatment, although generally safe, is associated with adverse health outcomes for the mother and the child; epidemiologic surveillance efforts are increasingly necessary to design and implement tertiary prevention programs (i.e., the prevention of adverse outcomes of infertility treatment) Center for Diseases Control and Prevention, 2009 http://www.cdc.gov/std/infertility/ReportCongressInfertility.pdf

22. Prevention • Tertiary Prevention; the treatment of infertility, as well as some of its outcomes, contributes to increasing the cost of health care for all.

23. Public Health Policy Implications: • Research: • In the area of primary prevention, research into modifiable causes of infertility should be given high priority. Research is needed to elucidate the mechanisms through which specific medical conditions lead to infertility • In the area of secondary prevention, research is needed to evaluate the potential benefit of early detection and treatment of conditions leading to infertility, both among couples who are actively seeking a pregnancy and among individuals who may want a child in the future • In the area of clinical outcomes research and tertiary prevention, there are few and limited economic studies assessing the cost-effectiveness of infertility treatment, the financial impact of treatment options, and the effect of insurance coverage on access to treatment

24. Public Health Policy Implications • Community Action:Learning about potentially hazardous chemicals in everyday products and in the workplace and their effects on babies in utero are powerful personal motivators toward further education and activism. Safe Work: for increasing worker safety in work place , • Reduce permissible exposure levels to chemicals that harm reproduction and development so that they are more in line with environmental exposure limits • Exposure assessment and monitoring in occupational settings should be expanded • Expand occupational health researchers’ access to workers so that health consequences can be identified and corrected • Develop alliances that can improve health across different sectors. For example, making the connection between worker safety and hospital patient safety (concerning phthalates) and fostering alliances between environmental health groups and labour and worker groups Sharpe & Franks, 2002 & Woodruff et al (2008)

25. Thank You

26. References: • Bouyer, J., et al. (2003). Risk factors for ectopic pregnancy: A comprehensive analysis based on a large case-control, population-based study in France. Am J Epidemiology [serial on the Internet]; 157(3): 185-194. • Donovan ,P. (1993).Testing Positive: Sexually Transmitted Disease and the Public Health Response. New York, NY: The Alan Guttmacher Institute. • Euling, S. Y., et al. (2008). Role of environmental factors in the timing of puberty. Paediatrics; 121 Suppi 3:S167-71 • Fathalla, M.F., et al. (1991). Reproductive Health: A Global Overview. Annals of the New York Academy of Sciences, Parthenon Publishing Group. Lancs. UK & New Jersey • Fidler, A.T., & Bernstein, J. (1999). Infertility: from a personal to a public health • Hatcher RA, Trussell J, Stewart F, et al. (1994). Contraceptive Technology. 16th revised ed. New York, NY: Irvington Publishers, Inc. • Healy, D.L., Trounson ,A.O., & Andersen A.N. (1994). Female infertility: causes and treatment. Lancet, 343:1539–1544 • Homan, G.F., Davies, M., & Norman, R. (2007). The impact of lifestyle factors on reproductive performance in the general population and those undergoing infertility. Human Reproduction .13(3):209-223; doi:10.1093/humupd/dml056

27. Infertility: A Public Health Focus on Infertility Prevention, Detection, and Management. Center for Diseases Control and Prevention (CDC): Retrieved from CDC Website Jan 30, 2010: http://www.cdc.gov/std/infertility/ReportCongressInfertility.pdf • Nelson, A.L., & Marshall J.R. (2004). Impaired fertility. In Hatcher R, Trussell J, Stewart F, et al. (Eds.) Contraceptive Technology. 18th Revised Ed. New York, NY: Ardent Media, Inc. • Shah, M.N., et al. (2007). Trends in testicular germ cell tumours by ethnic groups in the United States • Int J Androl: 30:206-13; discussion 13-4. • Sharpe, R.M., & Franks, S., (2002).Environment, lifestyle and infertility — an inter- generational issue, Nature Cell Biology & Nature Medicine8(S1), S33- S40http://www.nature.com/fertility/content/full/ncb-nm-fertilitys33.html • Stewart, G.K. (1998). Impaired Fertility. In Hatcher R, Trussell J, Stewart F, et al., eds. Contraceptive Technology. 17th revised ed. New York, NY: Ardent Media, Inc. • Travison, T.G., et al. ( 2007). A population-level decline in serum testosterone levels in American men. • J Clin Endocrinol Metab; 92:196-202. • Wookruff, T.J., et al. (2008). Proceeding of the Summit on Environmental Challenges to Reproductive Health and Fertility: executive summary. Fertility and Sterility, Vol. 89, No. 2. • Younglai , E.V., et al.(2006).Environmental and occupational factors affecting fertility • and IVF success, Human Reproduction Update, Vol.11, No.1 pp. 43–57.