Public health informatics: improving and transforming public health in the information age.

Development of effective public health information systems requires understanding public health informatics (PHI), the systematic application of information and computer science and technology to public health practice, research, and learning. PHI is distinguished from other informatics specialties by its focus on prevention in populations, use of a wide range of interventions to achieve its goals, and the constraints of operating in a governmental context. The current need for PHI arises from dramatic improvements in information technology, new pressures on the public health system, and changes in medical care delivery. Application of PHI principles provides unprecedented opportunities to build healthier communities.

Epidemiologic evidence for a new class of compounds associated with toxic oil syndrome.

Toxic oil syndrome appeared in epidemic form in Spain in 1981. Epidemiologic studies have demonstrated that illness was caused by consumption of rapeseed oil that had been denatured with aniline. Chemical analyses of oil specimens conducted in conjunction with epidemiologic studies have established that consumption of specific oils containing fatty acid anilide contaminants was associated with increased risk for disease. New chemical analytic methods identified a family of compounds, the di-fatty acid esters of phenylamino propane-diol, and one of these compounds, the 1,2-di-oleyl ester of 3-(N-phenylamino)-1,2-propanediol (DPAP), has been found to be more strongly associated with disease status than the fatty acid anilides. We found the odds ratio for exposure to DPAP (OR = 26.4, 95% CI = 6.4-76.3) is much higher than the odds ratio for exposure to oleyl anilide (OR = 4.1, 95% CI = 2.2-7.8), implying that exposure to DPAP was a more relevant risk factor for development of toxic oil syndrome than exposure to oleyl anilide. In this paper, we review and present analyses of data from multiple studies of the possible etiologic role of DPAP in toxic oil syndrome. The presence of DPAP in oil collected from affected and unaffected households was a more specific correlate of case relatedness than was the presence of fatty acid anilides, and it was equally sensitive. Moreover, DPAP was found in oil from the only refinery whose oil was clearly associated with illness.

Toxic oil syndrome mortality: the first 13 years.

BACKGROUND: The toxic oil syndrome (TOS) epidemic that occurred in Spain in the spring of 1981 caused approximately 20000 cases of a new illness. Overall mortality and mortality by cause in this cohort through 1994 are described for the first time in this report. METHODS: We contacted, via mail or telephone, almost every living member of the cohort and family members of those who were known to have died in order to identify all deaths from 1 May 1981 through 31 December 1994. Cause of death data were collected from death certificates and underlying causes of death were coded using the International Classification of Diseases, 9th Revision. RESULTS: We identified 1663 deaths between 1 May 1981 and 31 December 1994 among 19 754 TOS cohort members, for a crude mortality rate of 8.4%. Mortality was highest during 1981, with a standardized mortality ratio (SMR) of 4.92 (95% confidence interval [CI]: 4.39-5.50) compared with the Spanish population as a whole. The highest SMR, (20.41, 95% CI: 15.97-25.71) was seen among women aged 20-39 years during the period from 1 May 1981 through 31 December 1982. Women <40 years old, who were affected by TOS , were at greater risk for death in most time periods than their unaffected peers, while older women and men were not. Over the follow-up period, mortality of the cohort was less than expected when compared with mortality of the general Spanish population, or with mortality of the population of the 14 provinces where the epidemic occurred. We also found that, except for deaths attributed to external causes including TOS and deaths due to pulmonary hypertension, all causes of death were decreased in TOS patients compared to the Spanish population. The most frequent underlying causes of death were TOS, 350 (21.1%); circulatory disorders, 536 (32.3%); and malignancies, 310 (18.7%). CONCLUSIONS: We conclude that while on average people affected by toxic oil syndrome are not at greater risk for death over the 13-year study period than any of the comparison groups, women <40 years old were at greater risk of death.

Tryptophan produced by Showa Denko and epidemic eosinophilia-myalgia syndrome.

Evidence from an array of scientific studies strongly supports the conclusion that ingestion of products containing L-tryptophan (LT) produced by Showa Denko KK caused the 1989 epidemic of eosinophilia-myalgia syndrome (EMS) in the United State. In case-control studies of EMS, LT exposure was essentially universal among cases but rare among controls. Of 6 manufacturers of LT, only LT manufactured by Showa Denko KK was clearly associated with illness. The data meet other Hill criteria for inferring a causal relationship. Consistent findings were found in multiple independently conducted studies. There was a dose-response effect, with risk of illness increasing as a function of the amount of tryptophan consumed. The extremely small p values observed in the multiple independently conducted studies effectively rule out the possibility that the tryptophan-EMS association was the result of chance. Moreover, no potential confounding factor or bias explains the association. The incidence of EMS in the United States diminished abruptly once LT containing products were recalled.

Toxic oil syndrome: traceback of the toxic oil and evidence for a point source epidemic.

Rapeseed oil denatured with aniline was the vehicle of the causal agent of the toxic oil syndrome (TOS) epidemic that occurred in Spain in 1981. Although the precise aetiologic agent remains unknown, researchers established that increasing concentrations of oleyl anilide and other fatty acid anilides were associated with an increased risk for disease. To examine the hypothesis that 5-litre plastic containers of rapeseed oil associated with TOS, and which contained oleyl anilide had a characteristic shape, we measured fatty acid, sterol and fatty acid anilide levels in oil from containers of different shapes. We identified 1673 bottles of oil that had been collected during the Spanish Government's oil exchange programme and linked these bottles to people with TOS as reported in the official government census of patients with TOS. Although rapeseed oil (identified by the presence of brassicasterol) was found in 798 (47.7%) of the 1673 bottles examined, contamination with fatty acid anilide occurred in only 329 (19.6%) of the 1673 bottles and 319 (97%) of the 329 were oil containers of the shape sold by RAELCA, an oil company in Madrid. The first aniline-denatured oil that RAELCA had purchased to be refined specifically for distribution was refined at the ITH refinery of Seville, and this oil has been most directly associated with the epidemic. Previous work has shown that the only toxic oil linked to a specific refinery was that associated with rapeseed oil from the ITH refinery in Seville, and the epidemic began shortly after this oil was delivered to RAELCA for retail sale. On the basis of these findings, we conclude that oil refined by ITH and distributed by RAELCA was the principal, and probably the only, oil responsible for the TOS epidemic. Information about the history and treatment of this oil may yield important clues towards identifying the aetiologic agent of TOS.

Possible etiologic agents for toxic oil syndrome: fatty acid esters of 3-(N-phenylamino)-1,2-propanediol.

The etiologic agent(s) that was responsible for the 1981 toxic oil syndrome [TOS] epidemic in Spain has not been identified. Liquid chromatography combined with atmospheric pressure ionization tandem mass spectrometry was used for the analysis of oils associated with TOS. Analyses focused on measuring 3-(N-phenylamino)-1,2-propanediol [PAP], the 3-oleyl ester of PAP [MEPAP], and the 1,2-di-oleyl ester of PAP [DEPAP]. DEPAP and MEPAP were found more frequently and at higher concentrations in TOS case-associated oils than in control oils with odds ratios of 13.7 (95% CI 5.0-38) and 21.9 (95% 6.1-78), respectively. Other fatty acid esters of PAP are also likely to be present in the TOS case-associated oils. More significantly, DEPAP and MEPAP were found in aniline-denatured rapeseed oil refined at ITH, the oil refining company with the clearest link to TOS cases, yet these PAP esters were not detected in unrefined aniline-denatured samples of rapeseed oil delivered to ITH. These results show that the esters of PAP were products of the ITH refining process and were not formed spontaneously during storage. PAP esters were not detected in samples of other aniline-denatured rapeseed oils that were refined elsewhere, and which were not associated with illness. These findings provide strong support for the hypothesis that one or more of the fatty acid esters of PAP were the etiologic agents for TOS.

Mortality among people affected by toxic oil syndrome.

The authors conducted a mailed questionnaire survey of a 5% sample of the cohort of 20,643 people officially recognized by the Spanish government as having had toxic oil syndrome, a previously undescribed illness that was epidemic in Spain in 1981. After three mailings of a letter and questionnaire, responses for only 66% of the sample had been received. Nevertheless, responses were obtained from virtually all remaining patients (or surrogates for them in the cases of patients that had died) when they were sought by telephone. In 1981, there was clear-cut excess mortality in the cohort (standardized mortality ratio [SMR] 6.51; 95% confidence interval [CI]: 3.92-10.17). During the period January 1982 through 7 March 1988, there was no statistically significant overall mortality excess except during the period 1982-1983 among people aged < 65 years (SMR 2.26; 95% CI: 1.03-4.29). Toxic oil syndrome substantially altered the patterns of mortality among affected people. Analysis of deaths by cause among the TOS cohort will be useful for further evaluation of the long-term impact of the TOS epidemic.

Tryptophan contaminants associated with eosinophilia-myalgia syndrome. The Eosinophilia-Myalgia Studies of Oregon, New York and New Mexico.

Eosinophilia-myalgia syndrome (EMS) has been linked to ingestion of tryptophan contaminated with 1,1'-ethylidene-bis[L-tryptophan] (EBT), but other contaminants have received little study. The authors identified 101 lots of L-tryptophan that had been consumed either by persons with EMS or by asymptomatic tryptophan users and quantified the amounts of EBT and five other contaminants in each lot. After stratification of case and noncase lots by time of manufacture to adjust for the strong sequential pattern over time among case and noncase lots, higher EBT levels were still associated with a lot's case status, but the association lacked statistical significance (p = 0.120, odds ratio = 1.56, 95% confidence interval 0.758-3.23). While these findings do not rule out the possibility that EBT is the etiologic agent in EMS, they raise the possibility that other chemical contaminants in manufactured tryptophan modify the effects of EBT or that the causal agent of EMS is an entirely distinct compound.

Eosinophilia-myalgia syndrome in L-tryptophan-exposed patients.

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: coming to grips with a new illness.

In late October 1989, over 1,500 cases of an unusual illness involving severe myalgia and striking peripheral eosinophilia were reported in the United States and several other countries. Other clinical manifestations included pulmonary involvement (interstitial infiltrates and pleural effusions), skin rash and edema, axonal polyneuropathy, perimyositis, and possible adverse neurocognitive effects. Because of the primary manifestations of the illness, it was named "eosinophilia-myalgia syndrome" (EMS) by the Centers for Disease Control. Epidemiologic studies clearly linked illness to the ingestion of tryptophan produced by a single manufacturer in Japan, and the time course of the epidemic was most consistent with its being caused by a product contaminant. Epidemiologic analysis of plant operating conditions and data obtained from chemical analyses of case- and control-associated lots implicated 1,1'-ethylidene-bis(tryptophan) (EBT) as a candidate for the compound that causes EMS. However, the etiologic significance of EBT is still uncertain. Factors found to increase a person's risk for EMS included higher tryptophan dose and older age. Although cases occurred predominantly in women and patients had frequently been taking other medications concurrently with tryptophan, sex and use of several categories of other medications were not shown to influence the risk of illness. Few patients recovered rapidly and fully from the disease. Many were treated with glucocorticoid medications, and although they may have benefited from therapy in the short term, the development of chronic sequelae of EMS appears not to have been prevented. Public health practitioners currently depend on the reports of alert clinicians to detect this type of outbreak. In this case, state and federal government epidemiologists, once they were notified, were able to develop substantial basic information about the epidemic in a relatively short time. Control measures were introduced rapidly, effectively stopping the epidemic.

Manufacturing processes at two French rapeseed oil companies: possible relationships to toxic oil syndrome in Spain.

The toxic oil syndrome (TOS) epidemic that occurred in Spain in spring 1981 has been associated with the consumption of rapeseed oil that was denatured with aniline for industrial use but diverted for human consumption. The precise aetiologic agent in the oil responsible for the outbreak has not been identified. To learn more about possible contaminants and how the contamination might have occurred, we visited two French companies that process rapeseed oil and that were identified in Spanish administrative and judicial records as the ones exporting aniline-denatured rapeseed oil to Spain in 1981. With the apparently full and voluntary co-operation of personnel at both companies, we reviewed the processes involved in manufacturing, treating and transporting rapeseed oil, and we have summarized the information provided to us. Of particular importance is the finding that oil exported to Spain was taken from stock, the rest of which was sold for human consumption in the French domestic market, apparently without any adverse health effects. The differences between the oil exported to Spain and the oil sold as food in France were that aniline equivalent to 2% of the weight of the oil was added to most of the Spanish oil but not to that sold in France, and that contamination of the Spanish oil may have occurred in the tank trucks used for transportation to Spain, which had previously carried industrial chemicals. There is no assurance that the trucks were cleaned appropriately for transporting a food product before the oil was loaded for the journey to Spain. Since the clinical manifestations of TOS are not those of aniline toxicity, we conclude that the aetiological agent of TOS is likely to be one of the following: (1) a contaminant in the aniline, (2) a contaminant introduced during transportation, (3) a reaction product of normal oil components or materials used in refining with either aniline or the potential contaminants mentioned under (1) or (2) above.

Toxic oil syndrome: a current clinical and epidemiologic summary, including comparisons with the eosinophilia-myalgia syndrome.

In the spring and summer of 1981, an epidemic of a new illness now referred to as the toxic oil syndrome occurred in central and northwestern Spain, resulting in some 20,000 cases, 12,000 hospital admissions and greater than 300 deaths in the 1st year of the epidemic. The initial onset of illness was usually acute, and patients presented primarily with a respiratory syndrome involving cough, fever, dyspnea, hypoxemia, pulmonary infiltrates and pleural effusions. While approximately 50% of patients recovered from this acute phase of the illness without apparent sequelae, the remaining patients developed an intermediate or chronic phase, or both, of illness involving severe myalgia, eosinophilia, peripheral nerve damage, sclerodermiform skin lesions, sicca syndrome, alopecia and joint contractures, among other findings. Epidemiologic and analytic chemical studies have clearly linked the toxic oil syndrome to the ingestion of oil mixtures containing rapeseed oil denatured with aniline. However, the precise identity of the etiologic agent within this oil has never been determined. Aniline itself did not cause the illness, but the causal agent may be a reaction product of aniline with some oil component. Although many aspects of disease activity in the involved patients have lessened with time, the ultimate consequences of their disease are not clear and are the subject of ongoing study. The recently described eosinophilia-myalgia syndrome in the United States clinically resembles the toxic oil syndrome.

Postmortem studies of the heart in three fatal cases of the eosinophilia-myalgia syndrome.

OBJECTIVE: To examine the hearts of individuals who died from the eosinophilia-myalgia syndrome associated with ingestion of L-tryptophan, with particular attention paid to the coronary arteries, the neural structures, and the conduction system of the heart because of reported terminal disturbances of cardiac rhythm and conduction. STUDY MATERIAL: Three hearts fixed in neutral formalin and well preserved with all the relevant areas of conduction system intact. METHODS: Light microscopic examination of subserial sections of the sinus node, atrioventricular node and His bundle, coronary chemoreceptor and regional nerves, ganglia, and small coronary arteries. Routine stains used were Goldner trichrome and Verhoeff-van Gieson. RESULTS: Arterial abnormalities were numerous and primarily of two types: focal fibromuscular dysplasia causing moderate to severe narrowing, as well as endarteritis and panarteritis. Extensive examples of neuritis and ganglionitis were present throughout the heart, including the conduction system, where arterial abnormalities were also abundant. In the coronary chemoreceptor there were both old and new lesions comprising focal inflammation with degeneration as well as older areas of fibrotic destruction. Within the sinus node, areas of dense fibrosis replaced all nodal tissue. These abnormalities were similar in nature and extent in all three hearts. CONCLUSIONS: The pathologic lesions present in the coronary arteries, neural structures, and conduction system of the heart in patients who died from the eosinophilia-myalgia syndrome provide a suitable anatomic substrate for substantial cardiac electrical instability, including the occurrence of sudden death. In cases of unexplained cardiac electrical instability or sudden unexpected death an inquiry should be made about previous use of L-tryptophan. In patients with the eosinophilia-myalgia syndrome, the possibility of cardiac electrical instability should be considered as part of long-range clinical management.

The eosinophilia-myalgia syndrome: the Los Alamos Conference.

On June 12 and 13, 1990 the Los Alamos National Laboratory in cooperation with the New Mexico Department of Health and Environment, the Centers for Disease Control (CDC), the Food and Drug Administration (FDA), and the National Institute of Arthritis and Musculoskeletal and Skin Diseases of the National Institutes of Health (NIH) hosted a conference on the eosinophilia-myalgia syndrome. Fifty presentations covered a variety of important issues which are summarized herein.