Science for the People
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June/July 2000
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Features
Cleaner Air Coming to Detroit
Henry Ford Hospital to Close Incinerator
by Mary Beth Doyle
Selling Their Future Short?
Engler Panel Ignores Doctors' Advice
by Dave Dempsey
Recycling Land
Brownfield Redevelopment is a Balancing Act of Priorities
by Mike Tolinski
Dumbing Down the Children
Michigan, Other States Ignore Federal Lead Testing Law
by Peter Montague
Columns
Tiny Township Turns Down GM
Rural Milan Residents Reject Rail-Car Yard, by Aretta Schills
Diet, Health, and the Environment
An Interview with John Robbins, by Rachel Shaw
Healthy Home and Garden
Energy Star Products Save Cash and Power, by Kristi Jacques
Huron Valley News
Webster Township Holds Sprawl Forum, by Ernie Becker
Science for the People
Pesticides Linked to Decreased Fertility, by Mary Beth Doyle
By Mary Beth Doyle
Pesticides Linked to Decreased Fertility
A Dutch study found that paternal exposure to pesticides may inhibit the ability of their sperm to fertilize a woman's eggs. Researchers examined 836 couples who sought in-vitro fertilization (IVF) treatment between 1991 and 1998. Those men who reported occupational exposure to pesticides were asked additional questions about the nature of their exposure. These data were then compared with data on rates of successful fertilization.
The researchers showed that rates of successful fertilization in IVF treatment were significantly decreased for couples with male partners who were occupationally exposed to pesticides. Those men with the highest exposure to pesticides had only 22% of the fertilization success of a comparison group. The researchers comment that "our results are the first to suggest that paternal pesticide exposure decreases the sperm fertilizing ability in vitro", but they caution that since most men in their study were exposed to many types of pesticides, it is difficult to ascertain which chemical affects fertilization ability.
Source: "Pesticide Exposure and Decreased Fertilisation [sic] Rates In Vitro," Tielemans, E, et al., The Lancet, Vol 354, No. 9177, August 7, 1999.
Hormone therapy may increase breast cancer risk
A new study found that a commonly prescribed combination of hormones after menopause may increase a woman's risk of breast cancer. Taking estrogen in conjunction with progesterone significantly increased a women's breast cancer risk by 8% a year. The study found women prescribed estrogen alone had a only a1% a year increased risk of breast cancer. Hormone replacement therapy is often prescribed to reduce menopausal symptoms and to reduce the risk of osteoporosis and heart disease.
The risk subsides after women stop taking the hormones, and after 4 years, no significant increase is seen in women who took hormone-replacement therapy as compared to those who did not. "I think these results should not discourage a woman from using hormones on a short-term basis for treatment of menopausal symptoms," Catherine Schairer of the NCI, the study's principal author told the Washington Post. "Long-term use is more questionable."
Source: "Menopausal Estrogen and Estrogen-Progestin Replacement Therapy and Breast Cancer Risk." Schairer, Catherine, et al. JAMA. 2000; 283:485-491
DDT in breast milk
A study of DDT and its break-down products in the breast milk of mothers living in Mexico City found that 6% of the babies studied were receiving DDT intake at greater than the allowable daily intake levels set by the World Health Organization. Children receiving the highest levels of DDT were ingesting more than 13 times the 'safe' limit set by the WHO. DDT use is banned in many countries, including the U.S., but is still used in Mexico and other countries. Age, place of residence, consumption of meat and fish, and total time breastfeeding are all factors that contributed to the amount of DDT and metabolites found in the breast milk.
Source: Laura Torres-Arreola et al., "Levels of Dichloro-Dyphenyl-Trichloroethane (DDT) Metabolites in Maternal Milk and Their Determinant Factors," Archives of Environmental Health 54(2), March/April 1999, p. 124-129.
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