Oil ingestion and the toxic-oil syndrome: results of a survey of residents of the Orcasur neighbourhood in Madrid, Spain.

To elucidate the aetiological role of food oil in toxic-oil syndrome (TOS), 212 families of a working class neighbourhood in Madrid were interviewed regarding the sources of food oil they consumed and whether they had become ill with TOS. Health information was later verified by review of the patients' medical records. All five case families consumed oil sold by travelling salesmen in five-litre plastic containers, but only 34% of the 207 non-case families did so (p = 0.005). Oil bought from travelling salesmen in the local weekly open-air market was associated with a particularly high risk of illness. Consumption of oil from sources other than travelling salesmen was similar in the two groups. Our results support the view that a food oil transmitted the causative agent of TOS.