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Objectives: To study the incidence of eosinophilia-myalgia syndrome, the risk factors associated with the syndrome, and the clinical spectrum of illness associated with L-tryptophan use in an exposed population., Design: Retrospective cohort and nested case-control studies of risk factors for eosinophilia-myalgia syndrome using inpatient and outpatient chart reviews, telephone interviews, and in-person patient interviews. Descriptive study of clinical course of L-tryptophan users., Setting: Office practice of one psychiatrist based in a small city (population 43,467) in South Carolina., Patients: Eligible subjects were all patients from the practice who used L-tryptophan during the 1989 study interval. Of these, 418 (87%) were interviewed., Main Outcome Measures: Clinical spectrum of illness associated with L-tryptophan use, including definite and possible cases of eosinophilia-myalgia syndrome., Results: Among the 418 interviewed L-tryptophan users, we identified 47 definite cases (11%) and 68 possible cases (16%) of eosinophilia-myalgia syndrome, most of which involved patients who were using one retail brand of L-tryptophan (brand A). Among the 157 brand A users, we identified 45 definite cases (29%) and 36 possible cases (23%) of eosinophilia-myalgia syndrome, and the risk for the syndrome increased as the brand A dose increased. Fifty percent (19 of 38) of those using more than 4000 mg/day developed definite eosinophilia-myalgia syndrome, and 84% (32 of 38) developed either definite or possible eosinophilia-myalgia syndrome. On multivariate analysis, risk for definite eosinophilia-myalgia syndrome was associated with brand A dose and age of the patient; however, gender, race, and use of other medications were not associated with the syndrome., Conclusions: These results suggest that many people exposed to the agent causing eosinophilia-myalgia syndrome may develop illness, and dose of presumably contaminated L-tryptophan is the single most important predictor of eosinophilia-myalgia syndrome. The broad range of signs and symptoms reported by patients using L-tryptophan illustrates that a strict case definition may identify only about half of those affected.

Eosinophilia-myalgia syndrome, a newly recognized disorder that occurred in epidemic proportions during 1989, is associated with ingestion of manufactured tryptophan. A case is defined by debilitating myalgias and absolute eosinophilia greater than or equal to 1.0 x 10(9) cells/L. As of July 10, 1990, a total of 1531 cases had been reported nationwide, including 27 deaths. The highest rates of reported illness are concentrated in the western states, 68% are non-Hispanic white women aged 35 years and older, and data on associated clinical findings suggest a multisystemic disorder. The most frequent features include arthralgia (73%), rash (60%), cough or dyspnea (59%), peripheral edema (59%), elevated aldolase level (46%), and elevations in the results of liver function tests (43%). Neuropathy or neuritis, resulting in paralysis and death in some patients, was seen in 27%, and chest roentgenogram abnormalities were noted in 21% of those tested. Ninety-one percent reported onset of symptoms during or after May 1989, and 97% reported having taken tryptophan before the onset of symptoms. Since the recall of over-the-counter preparations of tryptophan in November 1989, the number of new cases of this potentially fatal disorder has fallen dramatically.

The morbidity and mortality associated with the 1980 heat wave in St Louis and Kansas City, Mo, were assessed retrospectively. Heat-related illness and deaths were identified by review of death certificates and hospital, emergency room, and medical examiners' records in the two cities. Data from the July 1980 heat wave were compared with data from July 1978 and 1979, when there were no heat waves. Deaths from all causes in July 1980 increased by 57% and 64% in St Louis and Kansas City, respectively, but only 10% in the predominantly rural areas of Missouri. About one of every 1,000 residents of the two cities was hospitalized for or died of heat-related illness. Incidence rates (per 100,000) of heatstroke, defined as severe heat illness with documented hyperthermia, were 26.5 and 17.6 for St Louis and Kansas City, respectively. No heatstroke cases occurred in July 1979. Heatstroke rates were ten to 12 times higher for persons aged 65 years or older than for those younger than 65 years. The ratios of age-adjusted heatstroke rates were approximately 3:1 for nonwhite v white persons and about 6:1 for low v high socioeconomic status. Public health preventive measures in future heat waves should be directed toward the urban poor, the elderly, and persons of other-than-white races.

Mapping is a useful tool for initiating data analysis of relatively infrequent injury events and can lead to interesting hypotheses that can then be tested in further epidemiologic studies. From national death certificate data for the years 1979 through 1985, we made dot maps of fatalities due to excessive heat (International Classification of Diseases code E900) among persons 65 years or older. The maps show clusterings of deaths, particularly in the central, south central, and southeastern sections of the United States, to an extent not fully explained by the population density or temperature extremes. The counties principally affected were highly urbanized and, for races other than white, were relatively poor. Our maps identify counties in which heat-related health problems in the elderly are particularly severe. Public health officials in high-risk areas should undertake heat-wave contingency planning and physicians practicing in such areas should familiarize themselves with the treatment of the spectrum of heat-related illnesses.

To identify risk factors associated with heatstroke, a case-control study in St Louis and Kansas City, Mo, was conducted during July and August 1980. Questionnaire data were gathered for 156 persons with heatstroke (severe heat illness with documented hyperthermia) and 462 control subjects matched by age, sex, and neighborhood of residence. A stepwise linear logistic regression procedure was used to identify factors significantly associated with heatstroke. Alcoholism, living on the higher floors of multistory buildings, and using major tranquilizers (phenothiazines, butyrophenones, or thioxanthenes) were factors associated with increased risk. Factors associated with decreased risk were using home air conditioning, spending more time in air-conditioned places, and living in a residence well shaded by trees and shrubs. Being able to care for oneself, characteristically undertaking vigorous physical activity, but reducing such activity during the heat, and taking extra liquid were also associated with decreased risk. Our findings also suggest effective preventive measures. During a heat wave, the greatest attention should be directed toward high-risk groups, and relief efforts should include measures shown to be associated with reduced risk.