A study by researchers at the National Institutes of Health (NIH) and other academic research institutions, reveals that higher blood levels of cadmium in females, and higher blood levels of lead in males, delayed pregnancy in couples trying to become pregnant.
Cadmium appears naturally as a trace metal in the earth crust. Fish, plants, and animals uptake cadmium from the environment, and therefore all foods contain at least low levels
of the metal. For humans, cigarette smoke is the most significant single source of exposure to cadmium. Smokers are estimated to have
twice the levels of cadmium as do non-smokers. Exposure also occurs in
workplaces where cadmium-containing products are made, and from the air
near industrial facilities that emit cadmium. The metal is mainly used in batteries,
pigments, metal coatings and plastics. Airborne cadmium particles
can travel long distances before settling on the ground or water. Soil
levels of cadmium vary with location.
Lead, another trace metal also found in the earth's crust, is used in a
variety of products, such as ceramics, pipes, and batteries. Common
sources of lead exposure in the United States include lead-based paint
in older homes, lead-glazed pottery, contaminated soil, and contaminated
Exposure to these metals is known to have a number of negative effects on human
health, that is why these elements are also often called "toxic heavy metals". Despite their know toxicity, the effects on human fertility have not been extensively
studied, especially when studying both partners of a couple.The new study:
The study, directed by the principal
investigator Germaine M Buck Louis, director of the Division of
Epidemiology, Statistics, and Prevention Research at the NIH’s Eunice
Kennedy Shriver National Institute of Child Health and Human Development
(NICHD), was published online in Chemosphere on Saturday, February the 4th. Other authors of the study were from the NICHD, the Texas
A&M Health Science Centre School of Rural Public Health, College
Station; The Ohio State University College of Medicine, Columbus; The
EMMES Corp. in Rockville, Md.; the National Centre for Environmental
Health, Centres for Disease Control and Prevention, Atlanta; and the
Rollins School of Public Health at Emory University, Atlanta.
To conduct the study, the researchers enrolled 501 couples from four
counties in Michigan and 12 counties in Texas, from 2005 to 2009. The
women ranged from 18 to 44 years of age, and the men were over 18.
Couples provided blood samples for the analysis of cadmium, mercury and lead.
Women kept journals to record their monthly menstrual cycles and the
results of home pregnancy tests. The couples were followed until
pregnancy or for up to one year of trying.
Participants were ranked on the basis of their
blood levels of lead and cadmium, since these elements were found to be associated
with the length of time couples required to become pregnant. Nearly
every study participant had some exposure to these common metals,
although blood levels of the metals varied across participants.
Researchers calculated the probability that a couple would achieve
pregnancy by levels of blood cadmium and lead with a statistical measure
called the fecundability odds ratio. The measure estimates couples'
probability of pregnancy each cycle, by their blood concentration of
metals. A ratio less than one suggests a longer time to pregnancy, while
a ratio greater than one suggests a shorter time to pregnancy. Females'
blood cadmium concentration was associated with a ratio below 1 (0.78),
which means that the probability of pregnancy was reduced by 22 percent
with each increase in the level of cadmium. Males’ blood lead exposure
also was associated with a ratio below 1 (0.85) with increasing levels,
or about a 15 percent reduction in the probability of pregnancy for each
increase in the level of blood lead concentrations.
researchers also calculated a fecundability odds ratio based on both
partners’ combined lead, cadmium and mercury concentrations. The
researchers found a ratio of 0.82 for male lead exposure, representing
approximately a 28 percent reduction in the probability of pregnancy for
each menstrual cycle, with increasing male blood lead concentration.
“The findings highlight the importance of assessing couples' exposure
jointly, in a single, combined measure,” Dr Buck Louis said. “Males
matter, because couples' chances of becoming pregnant each cycle were
reduced with increasing blood lead concentrations in men.” Dr. Buck Louis further summarized that "men and women planning to have children
should minimize their exposure to lead and cadmium. They can reduce cadmium exposure by avoiding cigarettes or by quitting
if they are current smokers, especially if they intend to become
pregnant in the future. Similarly, they can take steps to reduce their
exposure to lead based paints, which may occur in older housing,
including during periods of home renovation.” The just published study
Germaine M. Buck Louis, Rajeshwari Sundaram, Enrique F. Schisterman, Anne M. Sweeney, Courtney D. Lynch, Robert E. Gore-Langton, Zhen Chen, Sungduk Kim, Kathleen L. Caldwell, Dana Boyd Barr, Heavy metals and couple fecundity, the LIFE Study
, Chemosphere, Available online 4 February 2012, doi: 10.1016/j.chemosphere.2012.01.017
. Related studies
A.Z. Pollack, E.F. Schisterman, L.R. Goldman, S.L. Mumford, P.S. Albert, R.L. Jones, J. Wactawski-Wende, Cadmium, lead, and mercury in relation to reproductive hormones and anovulation in premenopausal women
, Environ. Health Perspect., 119 (2011) 1156–1161. doi: 10.1289/ehp.1003284
J.J. Wirth, R.S. Mijal, Adverse effects of low level heavy metal exposure on male reproductive function
, Syst. Biol. Reprod. Med., 56 (2010) 147–167. doi: 10.3109/19396360903582216
I. Iavicoli, L. Fontana, A. Bergamaschi, The effects of metals as endocrine disruptors
, J. Toxicol. Environ. Health B Crit. Rev., 12 (2009) 206–223. DOI: 10.1080/10937400902902062
J.D. Meeker, M.G. Rossano, B. Protas, M.P. Diamond, E. Puscheck, D. Daly, N. Paneth, J.J. Wirth, Cadmium, lead, and other metals in relation to semen quality: human evidence for molybdenum as a male reproductive toxican
t, Environ. Health Perspect., 116 (2008) 1473–1479. doi: 10.1289/ehp.11490
J. Jurasovic, P. Cvitkovic, A. Pizent, B. Colak, S. Telisman, Semen quality and reproductive endocrine function with regard to blood cadmium in Croatian male subjects
, Biometals, 17 (2004) 735–743. DOI: 10.1007/s10534-004-1689-7
C.Y. Shiau, J.D. Wang, P.C. Chen, Decreased fecundity among male lead workers
, Occup. Environ. Med., 61 (2004) 915–923. doi: 10.1136/oem.2004.014944
L. Järup, Hazards of heavy metal contamination
, Br. Med. Bullet., 68 (2003) 167–182. doi: 10.1093/bmb/ldg032
M. Joffe, L. Bisanti, P. Apostoli
, P. Kiss, A. Dale, N. Roeleveld, M.L. Lindbohm, M. Sallmén, M. Vanhoorne, J.P. Bonde, Time to pregnancy and occupational lead exposure
, Occup. Environ. Med., 60 (2003) 752–758. doi:10.1136/oem.60.10.752 M. Vahter
, M. Berglund, A. Åkesson, C. Lindén, Metals and women’s health
, Environ. Res., 88 (2002) 145–155. doi: 10.1006/enrs.2002.4338.
J.L. Pirkle, R.B. Kaufmann, D.J. Brody, T. Hickman, E.W. Gunter, D.C. Paschal, Exposure of the US population to lead, 1991–1994
, Environ. Health Perspect., 106 (1998) 745–750. doi: 10.1289/ehp.98106745
G. Assennato, C. Paci, M.E. Baser, R. Molinini, R.G. Candela, B.M. Altamura, R. Giorgino, Sperm count suppression without endocrine dysfunction in lead exposed men
, Arch. Environ. Health, 41 (1986), pp. 387–390. DOI: 10.1080/00039896.1986.9935784 Related EVISA Resources Journal Database: Journals related to "Public, Environmental and Occupational Health" Link database: Cadmium and human health Link database: Lead and human health Related EVISA News June 7, 2011: European Commission announces ban on cadmium in plastics September 8, 2009: Inorganic Mercury Level in US Women increases
last time modified: February 11, 2012