jueves, 17 de julio de 2014

CDC - NIOSH Science Blog – Workplace Exposures and the National Action Plan for Infertility

CDC - NIOSH Science Blog – Workplace Exposures and the National Action Plan for Infertility

Workplace Exposures and the National Action Plan for Infertility

Categories: Reproductive Health
Infertility is a significant health issue in the U.S. as well as globally.  In addition to the large health and fiscal impacts of infertility, the inability to conceive can be devastating to individuals or couples. Research suggest that between 12% and 18% of couples struggle with infertility,[1] which may be caused by a wide variety of factors including genetic abnormalities, aging, acute and chronic diseases, treatments for certain conditions, behavioral factors, and exposure to environmental, occupational, and infectious hazards. However, many questions about infertility remain unanswered.
Today, the Centers for Disease Control and Prevention (CDC) released the National Public Health Action Plan for the Detection, Prevention and Management of Infertility.This plan was created in consultation with many governmental and nongovernmental partners.  NIOSH contributed to this Action Plan, specifically related to reducing exposures to occupational agents that can harm reproductive health and fertility in women and men.
Environmental and occupational hazards account for an unknown proportion of infertility cases, but are known to affect reproductive health and fertility in women and men, and suspected of causing declining human sperm quality in industrialized countries.[2], [3], [4]An evaluation conducted in developed countries in the 1980s by the World Health Organization (WHO) found that 37% of infertility cases were attributable to female factors, 8% were attributable to male factors, 35% of infertility cases were linked to both male and female factors, and 5% were due to unknown cause(s).  The remaining 15% of women in this infertile population became pregnant.[5] Another evaluation conducted in 1988-1989 estimated that male factors account for the infertility in approximately 20% of the couples, with another 30-40% of cases attributable to reproductive abnormalities that were present in both partners.[6]
Although some occupational exposures have been shown to impair fertility (e.g., lead, some pesticides, and some solvents), the overall contribution of occupational exposures to male and female infertility is unknown.  Less than 5% of all chemicals used in the U.S. have been tested, even in laboratory animals, to determine if they are toxic to reproductive health.
The CDC National Public Health Action Plan recommends that surveillance of possible risk factors for infertility should include data on:
  • sociodemographic characteristics (e.g., age, race/ethnicity, education, place of residence, socioeconomic status),
  • health behaviors (e.g., use of alcohol, tobacco, caffeine, illicit drugs, anabolic steroids), body weight and related factors, adherence to screening and treatment recommendations related to risk factors,
  • physical and mental health conditions (e.g., genetic disorders, STDs, obesity, depression, cancer),
  • environmental exposures (e.g., household chemicals),
  • occupational exposures (e.g., physical work practices , several solvents, several pesticides, some metals like lead, phthalates, bisphenol A) and
  • prenatal and intergenerational exposures (e.g., diethylstilbestrol and sleep).
The report also emphasizes that actions taken to protect the reproductive health of workers and the general health of their families from harmful exposures should be based on sound, scientific measurements of (1) the hazardous exposures, (2) reproductive health parameters, and (3) the efficacy of the intervention methods being considered. Adopting a science-based approach should lead to a better understanding and prevention of workplace hazards that reduce reproductive health.
NIOSH has a long history of addressing reproductive issues.  Today, NIOSH researchers use state-of-the-art research methods – including biomonitoring techniques – to determine whether exposure to specific occupational hazards affect the reproductive health of working women and men and the health of their families.  Populations that NIOSH has studied include factory, foundry and agriculture workers, military personnel, miners, police officers, flight attendants, nurses, cosmetologists, and others.  More information can be found on the NIOSH topic page on Reproductive Health.
If you have concerns that your fertility may be affected by workplace exposures you can find an occupational clinic in your area by using the directory on the Association of Occupational and Environmental Clinics (AOEC) websiteExternal Web Site Icon.  Additionally, those who work in a setting with exposure to toxic chemicals that might affect fertility may consider requesting a Health Hazard Evaluation by NIOSH.  Experts from NIOSH will evaluate your request and decide how best to respond.
NIOSH is always looking for collaborations with outside researchers.  Please contact us via the blog below or at nioshblog@cdc.gov if there may be opportunities for a partnership.
NIOSH recognizes the importance and power of feedback from people on the front lines.  We want to hear from employees, employers, health professionals, researchers and others with concerns and thoughts about the effects of occupational hazards on infertility.
Steven M. Schrader, PhD, and James S. Kesner, PhD
Dr. Schrader leads the Reproductive Health Assessment Team within the Biomonitoring and Health Assessment Branch in the NIOSH Division of Applied Research Technology.
Dr. Kesner is a research biologist in the NIOSH Reproductive Health Assessment Team in the Division of Applied Research and Technology.

[1] Thoma ME, McLain AC, Louis JF, King RB, Trumble AC, Sundaram R, Buck Louis GM. The prevalence of infertility in the United States as estimated by the current duration approach and a traditional constructed approach. Fertil Steril 2013;99:1324–31.
[2] Hauser R. The environment and male fertility: recent research on emerging chemicals and semen quality. Semin Reprod Med. 2006;24:156-167.
[3] Swan SH, Elkin EP, Fenster L. The question of declining sperm density revisited: an analysis of 101 studies published 1934–1996. Environ Health Perspect. 2000;108:961-966.
[4] Rolland M, Le Moal J, Wagner V, Royère D, De Mouzon J. Decline in semen concentration and morphology in a sample of 26,609 men close to general population between 1989 and 2005 in France. Hum Reprod. 2013;28:462-470.
[5] World Health Organization. Recent advances in medically assisted conception. Report of a WHO Scientific Group. World Health Organ Tech Rep Ser. 1992;820:1-111.

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