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www.scientificamerican.com 2015 0000311.txt

#Common Chemicals Linked to Early Menopause Fifteen chemicals that disrupt our endocrine hormonal systems have been linked to earlier menopause among US women. Amber Cooper from Washington University in St louis, US, and colleagues found women aged 45 to 55 exposed to the organic compounds were up to six times more likely to be unexposed menopausal than peers. The substances include long-banned but persistent polychlorinated biphenyls (PCBS) and pesticide residues. However, two derive from a shorter-lived phthalate plasticiser, which makes polymer products more pliable and is still in use. igher everyday exposure levels were associated with menopause coming, on average, two to four years earlier, says Cooper. moking is thought to be associated with menopause coming one to one and a half years earlier, so it a pretty significant associationut this is not a study that can prove causation. The researchers exploited data collected by the National Health and Nutrition Examination Survey (NHANES) from people across the US from 1999-2008, including women age at their last menstrual cycle. Cooper team could therefore consider hundreds of menopausal women in whom NHANES scientists had measured at least one potential endocrine disruptor chemical (EDC) by gas or liquid chromatography-mass spectroscopy. Cooper team focused on 28 long-lived chemicals and 12 phthalates thought to harm reproduction. They first hunted for differences between average menopausal age among women whose blood or urine had concentrations in the highest 10%recorded and those with lower concentrations. Two further ose-responseanalyses tracked EDC concentration effect on menopausal age across the whole group. Fifteen EDCS had a statistically significant effect in at least one of these three measures. Finally, comparing all women aged 45-55 with exposure dataracketing the average US woman menopausal age at 51ave odds of being menopausal as EDC levels increased. Mono-(2-ethyl-5-hydroxyhexyl) phthalate and mono-(2-ethyl-5-oxohexyl) phthalate registered the strongest associations. These compounds are both biomarkers for human exposure to the plasticiser di-(2-ethylhexyl) phthalate (DEHP set to be banned under EU Reach regulations this month. Several PCBS, the pesticide Mirex and ß-hexachlorocyclohexane, a by-product of the pesticide Lindane, were linked also strongly to earlier menopause. Jessica Tyrrell from the University of Exeter, UK, who previously found an income-chemical exposure link in NHANES data, notes that the many similar associations support the study validity. t is definitely interesting, but would certainly need replicating, she adds. Cooper agrees. he most important thing this study can do is promote future research to tease out true causative effects, she says c

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