Eosinophilia-myalgia syndrome associated with exposure to tryptophan from a single manufacturer
L. Slutsker, F. C. Hoesly, L. Miller, L. P. Williams, J. C. Watson and D. W. Fleming
Division of Field Services, Epidemiology Program Office, Centers for Disease Control, Atlanta, Ga. 30333.
Although eosinophilia-myalgia syndrome has been linked to use of
tryptophan, it has been unclear whether tryptophan itself or a contaminant
causes illness. In Oregon, we compared the brand and source of tryptophan
used by 58 patients with eosinophilia-myalgia syndrome with the brand and
source of tryptophan used by 30 asymptomatic controls identified through a
random telephone survey and 63 asymptomatic controls who contacted the
Oregon Health Division voluntarily. Although a single brand/retail lot of
tryptophan was statistically associated with the development of
eosinophilia-myalgia syndrome, there was no common importer, wholesaler,
tablet maker, encapsulator, or distributor. However, 45 (98%) of 46 cases
had taken a product made by one manufacturer, compared with three (30%) of
10 telephone survey controls and 15 (48%) of 31 volunteer controls. Retail
lots of tryptophan from this manufacturer that were associated with cases
were significantly more likely to have been produced from January through
June 1989 than lots from this manufacturer that were taken by controls.
These findings indicate that the recent epidemic of eosinophilia-myalgia
syndrome was caused by a contaminant or an alteration in a subset of
tryptophan manufactured by a single company in Japan shortly before the
outbreak began.
