Paul J. Mills, PhD
Izabela Kania-Korwel, PhD John Fagan, PhD
Linda K. McEvoy, PhD
Gail A. Laughlin, PhD Elizabeth Barrett-Connor, MD
The herbicide Roundup is sprayed onto genetically modified crops and applied as a desiccant to most small non–genetically modified grains. Use of this herbicide has increased since 1994 when genetically modified crops were introduced in the United States. Glyphosate, the primary ingredient in the herbicide, is found in these crops at harvest. Environmental exposure through dietary intake of these crops has potential adverse health effects and can be assessed by measuring urinary excretion. We measured excretion levels of glyphosate and its metabolite aminomethylphosphonic acid (AMPA) in participants from the Rancho Bernardo Study (RBS) of Healthy Aging.