Consumption of Toxic Oil in Spain Continues to Cause Neurologic Symptoms 18 Years Later.

Business Editors/Environment Writers

RESEARCH TRIANGLE PARK, N.C.--(BUSINESS WIRE)--Aug. 5, 2003

Study Published Today in Environmental Health Perspectives

Correlates Exposure in the Early 1980s with Effects Today

People who consumed toxic oil in their food during a 1981 epidemic in Spain have a greater chance of having adverse neurobehavioral effects years later when compared with a control group, according to a study published today in the August issue of the peer-reviewed journal Environmental Health Perspectives (EHP).

Toxic oil syndrome, or TOS, appeared as a new disease in Spain in 1981 when thousands of people consumed denatured rapeseed oil sold illicitly as pure olive oil. High temperatures and extreme vacuum conditions during the refining of the oil led to a reaction that caused the creation of two new families of compounds. More than 100 different compounds from these two families have been found in the oils, and their toxicologic mechanism are still little known.

In May of 1981, more than 10,000 people became ill with respiratory distress, headaches, abdominal pain, fever, muscle cramps, and other symptoms. By the time the outbreak was quelled, more than 20,000 persons were diagnosed with TOS. About 59% of those progressed to a chronic stage of the disease, with symptoms including neurologic deficiencies, carpal tunnel syndrome, and muscle cramps.

In a study of 80 TOS patients and 76 control subjects conducted from 1998 to 1999, researchers administered neurobehavioral and neurophysiologic tests. Those with TOS were significantly more associated with decreased grip strength in both hands, slower reaction times, and poorer performance on cognitive tests. These effects were not documented by standard clinical examination and were found more frequently in women.

"Here we have a situation where the food supply was tampered with and unintended, untested compounds were consumed by thousands of people. We can see from this study that now, decades later, these people are still feeling the impacts of this exposure," says Dr. Jim Burkhart, science editor for EHP. "For those who suffer from TOS, this study should provide some emotional release, as the nature of the symptoms makes them difficult to assess."

Study participants completed questionnaires and were analyzed by neurologists and were given a battery of tests. Tests included hand strength, steadiness during standing, heart rate variability, attention span, short-term memory, and many others. Once the researchers stratified the results by gender, they found that the overall results were driven primarily by the effects in women, who tended to have poorer prognosis than men in regards to TOS.

Doctors may need to heed the results in providing greater sensitivity to this syndrome. "This is the first quantitative evidence of the existence of a neurologic deficit from TOS that has persisted for 18 years after the intoxication," the study authors wrote. "We found that TOS-affected participants consistently reported more symptoms than a referent group matched by gender. Although the frequencies of neurologic symptoms in the TOS group were very high, no clinically relevant abnormalities were observed in the physical neurologic examination performed by either of the two neurologists who examined the study participants."

The study team was led by Manuel Posada de la Paz of Instituto de Salud Carlos III, in Madrid, Spain. Other team members included Rossanne M. Philen, Fredric Gerr, Richard Letz, Maria Jose Ferrari Arroyo, Lydia Vela, Maravillas Izquierdo, Concepcion Martin Arribas, Ignacio Abaitua Borda, Alejandro Ramos, Cristina Mora, Gloria Matesanz, Maria Teresa Roldan, and Juan Pareja.

EHP is the journal of the National Institute of Environmental Health Sciences, part of the U.S. Department of Health and Human Services. More information is available online at http://www.ehponline.org/.

Editor's note: A full copy of the report is available by fax or e-mail (PDF format) to media at no charge. Go to http://www.ehponline.org/press/, call 919-653-2585, or e-mail [e-mail].