Neuropathic pain in rheumatoid arthritis and its association with Afro-descendant ethnicity: a hierarchical analysis.

BACKGROUND: nociceptive pain from joint damage caused by autoimmune inflammatory disease is expected in rheumatoid arthritis. However, neuropathic pain also occurs and persists even with the disease under control. This study aimed to investigate factors associated with neuropathic pain in rheumatoid arthritis by considering sociodemographic and behavioral data as well as lifestyle and clinical aspects in a self-referenced afro-descendant ethnicity sample. METHODS: In a cross-sectional study, the Douleur Neuropathique 4, Health Assessment Questionnaire, the Hospital Anxiety and Depression Scale and sociodemographic characteristics were used. Additionally, a Bivariate analysis was performed, followed by hierarchical multiple logistic regression, with results expressed as odds ratio and 95% confidence intervals. RESULTS: the frequency of NP was at a proximal level consisting of clinical characteristics related to anxiety (p=0.03) and depression (p=0.04). When a hierarchical multiple logistic regression analysis was conducted, an independent association was identified between neuropathic pain and black race. At the third and fourth stages, when the clinical variables were adjusted by race, an association was found with moderate functionality (p=0.04) and anxiety (p=0.04). CONCLUSION: neuropathic pain in rheumatoid arthritis is related to the Afro-descendant ethnicity that affects functionality and anxiety levels.

Serum cystatin C and microalbuminuria in the detection of vascular and renal damage in early stages.

BACKGROUND: The aim of this study was to assess serum cystatin C and urinary albumin in the early detection of impairment in cardiovascular and renal function. MATERIAL ANS METHODS: Cystatin C was quantified in sera from healthy people, moreover, cystatin C was quantified in a group of patients diagnosed with chronic kidney disease for predicting a measured glomerular filtration rate <60 ml/min/1.73 m2. Finally serum cystatin C and microalbuminuria were measured in patients with increasing of risk of impairment in cardiovascular and renal function (hypertension, diabetes and hyperlipidemia). RESULTS: When the serum cystatin C was quantified in a group of risk, we observe as when being increased the cystatin C, the values of the glomerular filtration rate decreased (p <0.05), the cystatin values C were increased when increasing the age of the patients (p <0.05) and cystatin C values higher than 0.95 mg/l were not observed in patient smaller than 50 years old. In the group of risk, serum cystatin C was high regarding to the values obtained in healthy people in 27.6%, microalbuminuria in the 20.3% and both parameters were high in the 14.4% of patients with a glomerular filtration rate >90 ml/min/1.73 m2, while in patients with a glomerular filtration rate 60-90 ml/min/1.73 m2, cystatin C was high in the 51.7% and the microalbuminuria only in the 6.4%. CONCLUSIONS: Determinations of serum cystatin C associated to the quantification of urinary albumin in patients with cardiovascular risk can optimize the early detection of vascular and renal damage. Cystatin C can show vascular and renal damage in patients without urinary albumin.

Cistatina C sérica y microalbuminuria en la detección del daño vascular y renal en estadios precoces, en pacientes de riesgo sin enfermedad renal crónica / Serum cystatin C and microalbuminuria in the detection of early-stage vascular and renal damage, in at-risk patients without chronic kidney disease

Objetivo: Evaluar la cistatina C sérica y la microalbuminuria en la detección precoz de las alteraciones vasculares y renales. Material y método: La cistatina C sérica fue cuantificada en suero de un grupo de personas sanas y en un grupo de pacientes con enfermedad renal crónica para establecer un valor de cistatina C a partir del cual se pueda predecir un filtrado glomerular <60 ml/min/1.73 m2. Finalmente, la cistatina C sérica y la microalbuminuria fueron cuantificadas en pacientes con un incremento del riesgo de daño vascular y renal (hipertensión, diabetes e hiperlipemia). Resultados: Cuando la cistatina C sérica fue cuantificada en un grupo de riesgo, observamos cómo al aumentar los valores de cistatina C disminuían los valores del filtrado glomerular (p <0,05), que los valores de cistatina C se incrementaban al aumentar la edad de los pacientes (p <0,05) y cómo valores de cistatina C superiores a 0,95 mg/l no se observaron en pacientes con edad inferior a 50 años. En los pacientes del grupo de riesgo con un filtrado glomerular >90 ml/min/1,73 m2, la cistatina C sérica estaba elevada en un 27,6% con respecto a los valores obtenidos en personas sanas; existía microalbuminuria en un 20,3% y elevación de ambos parámetros en un 14,4%. Con valores de filtrado glomerular 60-90 ml/min/1,73 m2, la cistatina C estaba elevada en un 51,7%, la microalbuminuria en un 6,4% y ambos parámetros en un 23,8%. Conclusiones: Determinaciones de cistatina C sérica asociadas a la cuantificación de microalbuminuria en pacientes con riesgo pueden mejorar la detección del daño vascular y renal en estadios precoces. La cistatina C puede poner de manifiesto el daño vascular y renal precoz incluso en pacientes sin microalbuminuria (AU)

Background: The aim of this study was to assess serum cystatin C and urinary albumin in the early detection of impairment in cardiovascular and renal function. Material ans methods: Cystatin C was quantified in sera from healthy people, moreover, cystatin C was quantified in a group of patients diagnosed with chronic kidney disease for predicting a measured glomerular filtration rate <60 ml/min/1.73 m2. Finally serum cystatin C and microalbuminuria were measured in patients with increasing of risk of impairment in cardiovascular and renal function (hypertension, diabetes and hyperlipidemia). Results: When the serum cystatin C was quantified in a group of risk, we observe as when being increased the cystatin C, the values of the glomerular filtration rate decreased (p <0.05), the cistatina values C were increased when increasing the age of the patients (p <0.05) and cystatin C values higher than 0.95 mg/l were not observed in patient smaller than 50 years old. In the group of risk, serum cystatin C was high regarding to the values obtained in healthy people in 27.6%, microalbuminuria in the 20.3% and both parameters were high in the 14.4% of patients with a glomerular filtration rate >90 ml/min/1.73 m2, while in patients with a glomerular filtration rate 60-90 ml/min/1.73 m2, cystatin C was high in the 51.7% and the microalbuminuria only in the 6.4%. Conclusions: Determinations of serum cystatin C associated to the quantification of urinary albumin in patients with cardiovascular risk can optimize the early detection of vascular and renal damage. Cystatin C can show vascular and renal damage in patients without urinary albumin (AU)

Vertebral heart scale in the beagle dog.

OBJECTIVE: To determine if Buchanan's vertebral heart scale can be applied to beagle dogs to establish reference values for this breed and to determine the possible influence of optimal lung inflation on the cardiac measurements. METHODS: The cardiac health of 19 beagle dogs was examined by echocardiography, electrocardiogram, non-invasive blood pressure measurement, complete blood count and serum chemistry profile. Right and left lateral recumbent radiographs of the thorax were obtained while the dogs were conscious and while under general anaesthesia with optimal lung inflation. The vertebral heart scale was measured in all radiographs. RESULTS: The mean (sd) vertebral heart scale in the beagle dogs was 10.3 (0.4) v, showing a significant difference from the mean vertebral heart scale of 9.7 (0.5) v in Buchanan's original study with dogs of different breeds. Degree of inspiration had no significant effect on the vertebral heart scale. CLINICAL SIGNIFICANCE: The vertebral heart scale provides the veterinarian with a possible way of objectively evaluating canine heart size without having to rely on echocardiography. However, the results should be interpreted critically and breed-specific differences should be taken into account, especially with values slightly above the reference range.

Retrospective study on the diagnostic value of full-thickness biopsies from the stomach and intestines of dogs with chronic gastrointestinal disease symptoms.

An evaluation of histologic findings in full-thickness biopsies from the gastrointestinal tract (GIT) from 64 dogs with chronic GIT disease symptoms was performed. In the majority of cases (38/64; 59%), intestinal lymphangiectasia and mucosal edema of unknown etiology were present. In 10 dogs (16%) an eosinophilic colitis, either alone or together with gastritis and/or enteritis, was found. In 5 dogs (8%) lymphocytic-plasmacytic enteritis or enterocolitis was diagnosed. Five dogs (8%) had an intestinal T-cell lymphoma. Samples from the remaining cases were histologically normal or did not allow for a final diagnosis. In contrast to reports about findings in endoscopic biopsies (which often are of varying quality or inadequate for diagnosis), in the majority of cases of this study, examination of full-thickness biopsies from the GIT allowed us to make a definitive histopathologic diagnosis. Furthermore, the study revealed that transmural biopsies are very helpful for diagnosing lymphoma.

Eosinophilic granulomatous gastroenterocolitis and hepatitis in a 1-year-old male Siberian Husky.

A case of eosinophilic granulomatous gastroenterocolitis and hepatitis in a 1-year-old male Siberian Husky is described. The dog presented with a history of diarrhea, weakness, lethargy, and anorexia of several months' duration. Hematologic and biochemical examinations, abdominal ultrasonography, computer tomography, and exploratory laparotomy were performed. Histopathologic examination of full-thickness biopsies from the gastrointestinal tract and liver revealed the presence of eosinophilic granulomatous lesions in the submucosa and tunica muscularis of stomach, jejunum, ileum, colon, and liver. Infectious agents were not detected by light microscopic and electron microscopic examination or by immunohistochemistry. On the basis of the findings, it is concluded that the disease in this dog represents an unusual manifestation of chronic idiopathic inflammatory bowel disease.

Filtration, haze and foam characteristics of fermented wort mediated by yeast strain.

AIMS: To investigate the influence of the choice of yeast strain on the haze, shelf life, filterability and foam quality characteristics of fermented products. METHODS AND RESULTS: Twelve strains were used to ferment a chemically defined wort and hopped ale or stout wort. Fermented products were assessed for foam using the Rudin apparatus, and filterability and haze characteristics using the European Brewing Convention methods, to reveal differences in these parameters as a consequence of the choice of yeast strain and growth medium. CONCLUSIONS: Under the conditions used, the choice of strain of Saccharomyces cerevisiae effecting the primary fermentation has an impact on all of the parameters investigated, most notably when the fermentation medium is devoid of macromolecular material. SIGNIFICANCE AND IMPACT OF THE STUDY: The filtration of fermented products has a large cost implication for many brewers and wine makers, and the haze of the resulting filtrate is a key quality criterion. Also of importance to the quality of beer and some wines is the foaming and head retention of these beverages. The foam characteristics, filterability and potential for haze formation in a fermented product have long been known to be dependant on the raw materials used, as well as other production parameters. The choice of Saccharomyces cerevisiae strain used to ferment has itself been shown here to influence these parameters.

[Chronic-idiopathic enteropathy in cats--a case control study]. / Die chronisch-idiopathische Enteropathie bei der Katze--Eine Fall-Kontroll-Studie.

Aim of this study is to clinically, microbiologically and histopathologically characterize inflammatory bowel disease (IBD) in the cat. Nine cats with chronic persistent or intermitent vomitus and diarrhea were examined between 1998 and 2001. All cats had a thuorough diagnostic workup performed. Full thickness biopsies from stomach, duodenum, jejunum, ileum and colon were surgically obtained for histopathological examination. Duodenal juice was obtained by direct aspiration for microbiologic qualitative and semiquantitative examination. Seven cats euthanized for other medical reasons were used as controls. Six cats had a lymphoplasmacytic IBD and three an eosinophilic IBD. Four cats with IBD had additional diseases diagnosed. Three cats with IBD had elevated bacterial counts. Retrospectively no correlation could be found between clinical symptoms and histopathological results. Serum TLI was not able to differentiate chronic pancreatitis and IBD. Serum folic acid and cobalamin did not correlate with the distribution of lesions in the gastrointestinal tract. Finally, no correlation was found between bacterial counts in the proximal duodenum and IBD.

La enfermedad meningocócica: un problema de salud para los ancianos? / The invasive meningococcal disease: a health problem among elderly?

Se presenta el comportamiento de la enfermedad meningocócica (EM) en las personas mayores de 60 años en Cuba desde 1988 hasta 1997 e incluyó un total de 150 casos reportados. Se calcularon las tasas de incidencia y mortalidad espacíficas, la letalidad, el porcentaje de formas clínicas y el tiempo (en días) transcurrido entre los primeros síntomas y el comienzo de la enfermedad en 4 grupos de edad (60-64, 65-74, 75-84 y >84). Resultaron más afectados los ancianos con edad entre 65-74 años (68 casos: 45.33 porciento) y entre 75-84 años (34 casos: 22.66 porciento). Las mayores tasas de incidencia y los mayores números de casos se observaron entre 19898 y 1990. Todos los grupos de edad disminuyen marcadamente su incidencia a final del período con relación al inicio. Fallecieron 76 casos en el período analizado, de los cuales más del 50 porciento ocurrienron entre 1988 y 1990. La letalidad de todo el período fue alta (51.3 porciento), incrementándose ostensiblemente a partir de 75 años. Predominó el número de meningoenfalitis sobre la meningococcemia en todos los grupos de edad. El 52.6 porciento de los fallecidos según el tiempo transcurrido desde el comienzo de la enfermedad ocurrieron precozmente (³ día ). Concluimos que la EM en ancianos constituye actualmente en Cuba un problema de salud por afectar mayormente las edades más activas de este grupo de edad y tener una alta letalidad. La inmunización de dicho grupo de edad puede ser recomendada como para la prevención de esta infección (AU)

A survey of personal exposures to benzene in Mexico City.

Benzene is a widely distributed environmental contaminant that causes leukemia. It is an important component in gasoline, it is used frequently as a solvent or chemical feedstock in industry, and it is emitted as a product of incomplete combustion. In Mexico City, investigators suspect that benzene exposure might be elevated and may pose a risk to the population; however, no published data are available to confirm or disconfirm this suspicion. We, therefore, conducted a survey in 3 occupational groups in Mexico City. Forty-five volunteers who used portable passive monitors measured their personal exposure to benzene during a workshift. None of the participants smoked during the monitoring period. Benzene exposure was significantly higher among service-station attendants (mean = 359.5 microg/m3 [standard deviation = 170.4 microg/m3]) than among the street vendors (83.7 microg/m3 and 45.0 microg/m3, respectively) and office workers (45.2 microg/m3 and 13.3 microg/m3, respectively). However, the benzene exposure levels observed among office workers were substantially higher than levels reported elsewhere for general populations. Our results highlight the need for more complete studies by investigators who should assess the potential benefits of setting environmental standards for benzene in Mexico.

Environmental exposure to volatile organic compounds among workers in Mexico City as assessed by personal monitors and blood concentrations.

Benzene, an important component in gasoline, is a widely distributed environmental contaminant that has been linked to known health effects in animals and humans, including leukemia. In Mexico City, environmental benzene levels, which may be elevated because of the heavy traffic and the poor emission control devices of older vehicles, may pose a health risk to the population. To assess the potential risk, portable passive monitors and blood concentrations were used to survey three different occupational groups in Mexico City. Passive monitors measured the personal exposure of 45 workers to benzene, ethylbenzene, toluene, o-xylene and m-/p-xylene during a work shift. Blood concentrations of the above volatile organic compounds (VOCs), methyl tert-butyl ether, and styrene were measured at the beginning and the end of a work shift. Passive monitors showed significantly higher (p > 0.0001) benzene exposure levels among service station attendants (median = 330 microg/m3; range 130-770) as compared to street vendors (median = 62 microg/m3; range 49-180) and office workers (median = 44 microg/m3, range 32-67). Baseline blood benzene levels (BBLs) for these groups were higher than those reported for similar populations from Western countries (median = 0.63 microg/L, n = 24 for service station attendants; median = 0.30 microg/L, n = 6 for street vendors; and median = 0.17 microgr;g/L, n = 7 for office workers). Nonsmoking office workers who were nonoccupationally exposed to VOCs had BBLs that were more than five times higher than those observed in a nonsmoking U.S. population. BBLs of participants did not increase during the work shift, suggesting that because the participants were chronically exposed to benzene, complex pharmacokinetic mechanisms were involved. Our results highlight the need for more complete studies to assess the potential benefits of setting environmental standards for benzene and other VOCs in Mexico.

[VA-MENGOC-BC vaccine: its impact on meningococcal disease in children 1-4 years old]. / Vacuna VA-MENGOC-BC: su repercusión sobre la enfermedad meningocócica en niños de 1 a 4 años.

VA-MENGOC-BC vaccine has been administered to Cuban infants since 1991 through the National Immunization Program (NIP) so it was necessary to evaluate its effects on 1-4 years-old children included in the highest risk group. To this end, a descriptive study of the morbidity and mortality from meningococal disease was carried out taking the vaccine histories of 145 cases occurred from 1991 to 1996 into account. The decreasing trend of the incidence density (ID) of meningococcal disease in all the age groups in the studied period was among the most important results, the highest decline was observed in one-year old infants with an ID of. 10.8 per 100,000 children/years at the end of the period. The percent distribution of occurrence showed a predominance of one-year old group at the beginning of the program. Implementation, and a change to 3-4 years old group at the end of the period. A high of percent of vaccinated sick children had been immunized against MD over one year ago (697.5 days as average). 35 children died during the period and the highest mortality density decline (1 per 100,000 children a year) was observed as of 1993; 2 years-old children were at highest risk of death. Seventy three percent (73.1%) of those vaccinated had been immunized for over once year. The general lethality was 24.1%, the lowest was 14.3% in one year old children. The changes occurred in meningococcal disease behaviour within this high risk group, which are attributed to the administration of vaccine as part of the NIP fully justifies the continuation of the application of this vaccine.

The application of single cell gel electrophoresis or Comet assay to human monitoring studies.

OBJECTIVE: In the search of new human genotoxic biomarkers, the single cell gel electrophoresis assay has been proposed as a sensible alternative. MATERIAL AND METHODS: This technique detects principally single strand breaks as well as alkali-labile and repair-retarded sites. RESULTS: Herein we present our experience using the single cell gel electrophoresis assay in human population studies, both occupationally and environmentally exposed. CONCLUSIONS: We discuss the assay feasibility as a genotoxic biomarker.

The influence of bone and blood lead on plasma lead levels in environmentally exposed adults.

There is concern that previously accumulated bone lead stores may constitute an internal source of exposure, particularly during periods of increased bone mineral loss (e.g., pregnancy, lactation, and menopause). Furthermore, the contribution of lead mobilized from bone to plasma may not be adequately reflected by whole-blood lead levels. This possibility is especially alarming because plasma is the main circulatory compartment of lead that is available to cross cell membranes and deposit in soft tissues. We studied 26 residents of Mexico City who had no history of occupational lead exposure. Two samples of venous blood were collected from each individual. One sample was analyzed by inductively coupled plasma-magnetic sector mass spectrometry for whole-blood lead levels. The other sample was centrifuged to separate plasma, which was then isolated and analyzed for lead content by the same analytical technique. Bone lead levels in the tibia and patella were determined with a spot-source 109Cd K-X-ray fluorescence instrument. Mean lead concentrations were 0.54 microg/l in plasma, 119 microg/l in whole blood, and 23.27 and 11.71 microg/g bone mineral in the patella and tibia, respectively. The plasma-to-whole-blood lead concentration ratios ranged from 0.27% to 0.70%. Whole-blood lead level was highly correlated with plasma lead level and accounted for 95% of the variability of plasma lead concentrations. Patella and tibia lead levels were also highly correlated with plasma lead levels. The bivariate regression coefficients of patella and tibia on plasma lead were 0.034 (p<0. 001) and 0.053 (p<0.001), respectively. In a multivariate regression model of plasma lead levels that included whole-blood lead, patella lead level remained an independent predictor of plasma lead level (ss = 0.007, p<0.001). Our data suggest that although whole-blood lead levels are highly correlated with plasma lead levels, lead levels in bone (particularly trabecular bone) exert an additional independent influence on plasma lead levels. It will be important to determine whether the degree of this influence increases during times of heightened bone turnover (e.g., pregnancy and lactation).

Antioxidant supplementation and respiratory functions among workers exposed to high levels of ozone.

Ozone exposure has been related to adverse respiratory effects, in particular to lung function decrements. Antioxidant vitamins are free-radical scavengers and could have a protective effect against photo-oxidant exposure. To evaluate whether acute effects of ozone on lung functions could be attenuated by antioxidant vitamin supplementation, we conducted a randomized trial using a double-blind crossover design. Street workers (n = 47) of Mexico City were randomly assigned to take daily a supplement (75 mg vitamin E, 650 mg vitamin C, 15 mg beta carotene) or a placebo and were followed from March to August 1996. Pulmonary function tests were done twice a week at the end of the workday. During the follow-up, the mean 1-h maximum ozone level was 123 ppb (SD = 40). During the first phase, ozone levels were inversely associated with FVC (beta = -1.60 ml/ppb), FEV1 (beta = -2.11 ml/ppb), and FEF25-75 (beta = -4.92 ml/ppb) (p < 0.05) in the placebo group but not in the supplement group. The difference between the two groups was significant for FVC, FEV1, and FEF25-75 (p < 0.01). During the second phase, similar results were observed, but the lung function decrements in the placebo group were smaller, suggesting that the supplementation may have had a residual protective effect on the lung. These results need to be confirmed in larger supplementation studies.

[Giant fusiform aneurysm of the middle cerebral artery. Surgical treatment with multiple clipping: a case report]. / Aneurisma gigante fusiforme de la arteria cerebral media. Tratamiento quirúrgico con clipaje múltiple: presentación de un caso.

INTRODUCTION: Giant cerebral aneurysms (GCA) are defined by sizes above 2.5 cm. GCA clinically appear by the mass effect exerted on adjacent structures, and in other cases, by embolismal action of the mural thrombo or as a post rupture subarachnoid hemorrhage. THERAPEUTICAL OPTIONS INCLUDE: inducting mural thrombosis, inserting an intraneurysmatic balloon, setting a bypass and surgical clipping. The major characteristics of giant fusiform aneurysm (GFA), the lack of neck and the inclusion of main vessels, give surgical treatment a great complexity. CLINICAL CASE: 25 year old woman diagnosed of GFA of the middle cerebral artery, treated with direct surgical access with clipping and reconstruction of the vascular wall with fenestrated clips arranged in tandem. CONCLUSIONS: The lack of an accessible neck for clipping and exclusion of giant and fusiform intracranial aneurysms, forced practising bypass as a compulsory surgical alternative. Multiple clipping was a viable choice because of its simplicity and less surgical risk. This technique is not applicable to giant serpentine aneurysms as it is only feasible in cases of fusiform aneurysms with no intraluminal thrombosis. A satisfactory evolution of this case, keeping asintomatic after 18 months of the intervention guarantees its application in young patients with giant thrombosed aneurysms of low clinical repercussion.

Effects of intermittent ozone exposure on peak expiratory flow and respiratory symptoms among asthmatic children in Mexico City.

In a panel study of Mexican children (5-13 y of age) with mild asthma, the authors studied the relationship between ozone exposure and the course of childhood asthma. Decrements in peak expiratory flow rate were associated with ozone, and respiratory symptoms were associated with both ozone level and ambient particulate matter (< 10 microm) level. After the authors adjusted for minimum temperature and autocorrelation in the data, they determined that an increase of 50 ppb in a daily ozone 1-h maximum was related to an 8% increase in cough (95% confidence interval = 2, 15); a 24% increase in phlegm (95% confidence interval = 13, 35); and an 11% increase in low respiratory symptoms index (95% confidence interval = 5, 19). The authors concluded that children with mild asthma who resided in the south of Mexico City were affected adversely by the high ozone ambient levels observed in this area.

Effects of air pollution on the respiratory health of asthmatic children living in Mexico City.

The relation between air pollution and the exacerbation of childhood asthma was studied in a panel of 71 children (aged 5 to 7 yr) with mild asthma who resided in the northern part of mexico City. During the follow-up, ambient measures of particulate matter less than 10 microns (PM10, 24-h average) and ozone (1-h maximum) frequently exceeded the Mexican standards for these contaminants. The peak expiratory flow rate (PEFR) was strongly associated with PM10 levels and marginally with ozone levels. Respiratory symptoms (coughing, phlegm production, wheezing, and difficulty breathing) were associated with both PM10 and ozone levels. An increase of 20 micrograms/m3 of PM10 was related to an 8% increase in lower respiratory illness (LRI) among children on the same day (95% confidence interval [CI] = 1.04-1.15), and an increase of 10 micrograms/m3 in the weekly mean of particulate matter less than 2.5 microns (PM2.5) was related to a 21% increase in LRI (95% CI = 1.08-1.35). A 50 parts per billion (ppb) increase in ozone was associated with a 9% increase in LRI (95% CI = 1.03-1.15) on the same day. We concluded that children with mild asthma are affected by the high ambient levels of particulate matter and ozone observed in the northern part of Mexico City.

Effects of urban air pollutants on emergency visits for childhood asthma in Mexico City.

The metropolitan area of Mexico City, Mexico, has serious air pollution problems. Although air contaminants may contribute to clinical asthma, there are at present no data on the relation between air pollution exposure and childhood asthma in Mexico City. The authors reviewed data on emergency visits from January to June 1990 at one major pediatric hospital in Mexico City. They used a Poisson regression model to study the relation between the number of daily emergency visits for asthma and air pollutant levels. The levels of ozone and sulfur dioxide-exposure were significantly associated with the number of emergency visits for asthma. After adjustment for potential confounding factors, the multivariate regression model predicted that an increase of 50 ppb in the 1-hour maximum ozone level would lead to a 43% increase in the number of emergency visits for asthma on the following day. Exposure to high ozone levels (> 110 ppb) for 2 consecutive days increased the number of asthma-related emergency visits by 68 percent. The results of this study suggest that ozone exposure is positively associated with the number of children's emergency visits for asthma in Mexico City.

PIP: A retrospective analysis of records of emergency visits during January-June 1990 at the Hospital Infantil de Mexico Federico Gomez in the northern section of Mexico City was conducted to examine the association between the 395 children's (16 years) emergency visits for asthma (2.5% of all emergency visits) and daily levels of different air pollutants. Most emergency visits for asthma (67%) included children aged less than 5. The mean ozone daily one-hour maximum level was 90 ppb (range: 10-250 ppb). The ozone level exceeded the Mexican ozone standard (110 ppb) on 49 days (28%). Concentrations of ozone and sulfur dioxide exposure were linked to the number of emergency visits for asthma (p = 0.001 for 1-hour maximum with 1-day lag and p = 0.07 for 1-hour maximum on same day). When the researchers controlled for confounding factors, they found that a rise in the ozone level of 50 ppb was related to a 43% increase in the number of emergency visits for asthma with a one-day lag period. 133% of these visits were made after two consecutive days of ozone levels of at least 110 ppb. Exposure to such high ozone levels increased the number of emergency visits for asthma by 68%. These findings demonstrate a positive relationship between ozone exposure and the number of children living in Mexico City who were treated for asthma. In fact, they suggest that cumulative exposure to ozone strengthens this association.