Allergy and acute leukaemia in children with Down syndrome: a population study. Report from the Mexican inter-institutional group for the identification of the causes of childhood leukaemia

Background:

Allergies have been described as protective factors against the development of childhood acute leukaemia (AL). Our objective was to investigate the associations between allergy history and the development of AL and acute lymphoblastic leukaemia (ALL) in children with Down syndrome (DS).

Methods:

A case–control study was performed in Mexico City. The cases (n=97) were diagnosed at nine public hospitals, and the controls (n=222) were recruited at institutions for children with DS. Odds ratios (OR) were calculated.

Results:

Asthma was positively associated with AL development (OR=4.18; 95% confidence interval (CI): 1.47–11.87), whereas skin allergies were negatively associated (OR=0.42; 95% CI: 0.20–0.91).

Conclusion:

Our findings suggest that allergies and AL in children with DS share biological and immune mechanisms. To our knowledge, this is the first study reporting associations between allergies and AL in children with DS.

Epidemiology of cancer in children under one year of age in Mexico City

In this work, the epidemiology of cancer in children under one year of age in Mexico City is described. A survey (observational, descriptive and prolective study) from 1 January 1996 to 31 December 1999 was conducted at two paediatric hospitals of the Instituto Mexicano de Seguro Social in Mexico City (IMSS-MC). To calculate both the general and the by sex incidence (rates are given per 10) all new cases recorded for children under one year of age (numerator) and Mexico City population served by the IMSS (denominator) were used. When the total of 34 cases that fulfilled the requirements was analysed, an incidence of 194.5 was obtained. Leukaemia occupied first place with a rate of 68.6 and hepatic and germinal cells tumours occupied second place with an incidence of 28.6, whereas peripheral nervous system tumours (neuroblastoma) showed a very low rate (11.4). Overall, the male/female ratio for tumours was 1.4:1, with the ratio varying with different types of tumours. Cancer incidence in this population was shown to be close to that in developed countries, but differed in the distribution of the type of tumour: leukaemia had a very high incidence and that for neuroblastoma was very low.

[Factors that influence non-donation of blood in relatives of patients at a pediatric hospital]

OBJECTIVE

To identify factors that influence refusing to donating blood.

MATERIAL AND METHODS

Prospective case and control study. Hospitalized patients' relatives were interviewed with a questionnaire to evaluate their knowledge of blood and personal attitudes toward blood donation. Cases were all relatives who did not donate blood and controls who did.

RESULTS

A total of 121 individuals was studied, 30 cases and 91 controls. Age of the cases was 32.3 +/- 8.1 years and controls was 28.8 +/- 7.9 years (p = 0.04). Risk factors were female sex (OR = 6.3; 95%CI 2.4 to 17.1), being married (OR = 3.7 95%CI 1.3 to 10.5). No differences were present between the two groups in level of knowledge concerning blood. The average of positive attitudes toward blood donation was greater among relatives who donated blood (cases 5.9 +/- 1.6; controls 6.4 +/- 1.2; P = 0.049). Among the attitudes that influence refusing to donate blood were fear of getting dizzy at the sight of blood (OR = 5.2, 95%CI 1.3-21.4), fear of donating blood (OR = 2.2, 95%C, 0.8-6.0), and getting nervous at the sight of blood (OR = 4.1, 95%CI% 1.5-10.9).

CONCLUSIONS

Among patient's relatives who donate blood positive personal attitudes toward blood donation have more weight than knowledge on the subject.

[Cryptosporidium parvum infection in malnourished and non malnourished children without diarrhea in a Mexican rural population]

Cryptosporidium parvum is associated with diarrheic disease and mainly affects children and immunocompromised hosts. In most of the cases, cryptosporidiosis infection is asymptomatic in immunocompetent subjects. The objectives of the study were to determine the frequency of asymptomatic infection caused by the parasite in children with and without malnutrition and to determine the risk factors associated to infection.

METHODS

Children from one to fifteen years old without diarrhea were included, somatometry were performed. The socioeconomic and sanitary conditions were investigated for each family and community. The Faust method and Kinyoun stain were employed identify parasites and Cryptosporidium parvum in feces. Odds ratio (OR), 95% confidence intervals (75% CI), chi 2 Mantel-Haenszel, Fisher exact test and chi 2 trends were calculated.

RESULTS

One hundred thirty two children were included. In 10/132 (7.5%) cysts of Cryptosporidium were found, 7/71 in children with malnutrition (9.8%) and 3/61 without malnutrition (4.9%) p = 0.23. 69.7% of the children had parasitosis. According to the presence of C. parvum in feces, the different factors calculated were: Diarrhea in family OR = 5.82 (95%IC 0.86-39.18), not hand washing OR = 5.08 (95%IC 0.62-110.49), age less than 5 years old OR = 4.90 (95%IC 0.60-106.9), drinking non-potable water OR = 3.34 (95%IC 0.40-73.01) and malnutrition 2.11 (95%IC 0.46-10.89). Association was found between the number of people in the same house and the risk of infection (p = 0.005). The presence of diarrhea in the family (OR = 4.15, 95%IC 0.47-36.91) and drinking non-potable water (OR = 4.19, 95%IC 0.48-36.32) were the significant factors in the regression logistic model.

CONCLUSIONS

The frequency of Cryptosporidium infection were 7.5%. Diarrhea in the family, overcrowding and drinking non-potable water were associated with C. parvum infection, malnutrition was not a significant risk factor.

[Incidence of acute leukemia in children in Mexico City, from 1982 to 1991]

OBJECTIVE

To measure the incidence rate and trend of acute leukemia (AL) in political districts of Mexico City.

MATERIAL AND METHODS

Descriptive longitudinal study conducted at six hospitals that care for nearly 97.5% of all cancer cases among children in Mexico City. Study data were collected in 1995 and 1996, and were analyzed in 1999, at the National Medical Center "Siglo XXI" Children's Hospital, of the Mexican Institute for Social Security. Calculations of acute leukemia annual incidence rates, standardized rates, and standardized morbidity rates (SMR) with 95% confidence intervals, were obtained for each district. Morbidity trends were assessed through average change rates.

RESULTS

In this study we observed an increasing trend of acute lymphoblastic leukemia (ALL) incidence in five districts: Alvaro Obregon, Cuauhtemoc, Gustavo A. Madero, Iztacalco, and Venustiano Carranza. Acute myeloblastic leukemia (AML) showed no significantly statistic increase of incidence in any district. AML did show a significant SMR in Alvaro Obregon district (SMR = 2.91, 95% CI 1.63-4.80). Higher SMRs were found in the south and southwest areas of the city.

CONCLUSIONS

Increasing incidence of ALL was observed in five districts of Mexico City. AML incidence was the highest in Alvaro Obregon district.

Validation of a prognostic index in the critically ill newborn

OBJECTIVE

Elaborate and assess the degree of validity of a prognostic model for evaluating patients admitted to the Neonatal Intensive Care Unit (NICU).

DESIGN

Cases and controls nested in a cohort.

SETTING

NICU of two tertiary hospitals and another second level hospital.

PATIENTS

The study was carried out in two phases. During the first phase (elaboration of a model), 336 newborns were studied; 112 belonged to the case group (dead patients) and 224 to the control group (live patients discharged). For the second phase (model validation), 300 patients were included that did not participate in the first phase, 100 cases and 200 controls.

MEASUREMENTS

For each patient admitted to the study, clinical, paraclinical, perinatal and comorbidity factors were determined within the first 12 hours. Variables of statistical significance in the bivariate analysis were included in a logistic regression model with the objective of identifying a prognostic model.

RESULTS

The variables that constituted the prognostic index were gestational age x birth weight, the paO2/FiO2 ratio x O2 saturation, arrest cardiac, major congenital malformations, septicemia and base excess. The model showed to have a sensitivity of 70% and a specificity of 91% during the elaboration cohort. In the validation cohort, sensitivity was 68% and specificity was 92%, a positive predictive value of 80%, negative predictive value of 85% and a correct classification rate was 84%.

CONCLUSIONS

The Neonatal Mortality Prognostic Index (NMPI) developed in this study showed to be useful for the evaluation of hospital mortality for severely ill newborns admitted to NICU.

[Descriptive epidemiology of malignant tumors in children]

The object of this study is to present the descriptive epidemiology of cancer in children at the world and national levels. The international and national literature published on cancer in children was comprehensively reviewed, with emphasis on reports treating epidemiological aspects of time, place and person. For practical reasons and with the aim of integrating the information, only the more relevant publications were included. Incidence and child mortality were analyzed. Overall incidence is between 100 and 150 (annual rates = cases x 10(6) children). Specific incidence varies according to the type of cancer, the region and the country. The Latin American pattern of neoplasms is constituted by leukemias, lymphomas, and central nervous system tumors (CNST); in the Northamerican/European pattern the CNST appear in second place and in the African pattern, lymphomas show predominance. Incidence is higher among the younger than 5 year olds, from urban environments, and there is a 1% annual increase of cancer in Northamerican children. Child mortality has diminished remarkably, mainly in developed countries, whereas in developing or underdeveloped countries, incidence remains stable or shows a slight fall. The incidence of cancer in children is greater in developed countries, but in underdeveloped countries it may be underestimated. These countries have not managed to reduce the incidence of child mortality caused by cancer, as have the United States or Great Britain. Further studies on the epidemiology of cancer in children are necessary, since many data remain unknown.

Malnutrition in childhood lymphoblastic leukemia: a predictor of early mortality during the induction-to-remission phase of the treatment

BACKGROUND

Previous reports have shown that undernourished children with acute lymphoblastic leukemia (ALL) have a poorer long-term survival as compared with children with normal nourishment status. It has been shown that both the relapse and mortality rates of undernourished children with ALL are higher during the continuation phase of the chemotherapy and are apparently related to a poor tolerance of ablative chemotherapy. No previous articles have analyzed the early mortality rate of these patients.

METHODS

We carried out a case-control study, and have studied the effect of severe malnutrition on the mortality of 17 children with ALL during the initial induction-to-remission phase of the treatment. These 17 cases were compared with 76 controls who had survived at least the phases of induction and consolidation.

RESULTS

It was found that the chance of dying during the initial phase of the treatment was 2.6 times higher (confidence interval 95%: 0.55-11.89) in undernourished children with ALL than in those children with normal nourishment status. The risk of death increased with the severity of undernourishment (p = 0.04).

CONCLUSIONS

These data confirm the prognostic value of malnutrition in children with ALL and suggest that undernourishment may also influence early mortality during the induction-to-remission phase of the treatment.

[Risk factors for the development of germ cell tumors in children]

The search for risk factors for development of germ cell tumors (GCT) in children who lived in Mexico City (MC). A protective, observational, case-control study was conducted in children under 15 years of age resident in MC, insurer by the Mexican Institute of Social Security. The study population was selected between January 1st, 1990 and December 31st, 1994. Parents of the children were interviewed with a 230-items precoded questionnaire, validated previously with a pilot study. For analysis were obtained simple frequencies and odds ratios (OR) and 95% confidence interval (95%CI). There were 21 cases and 105 controls. The most significant risk factors were winter conception (OR = 7.6, 95% CI 1.5-39.3; P = 0.007); low parental education level (OR = 2.9, 95% CI 1.1-7.5; P = 0.026); and parental combined dust and electricity exposure before pregnancy (OR = 26, 95% CI 2.28-1291.86; P = 0.0007). during (OR8.58, 95% CI 0.89-106.55; P = 0.041) and after pregnancy (OR = 9.66, 95% CI 0.99-120.22; P = 0.027). There was a protective effect with repetitive infections during infancy. In conclusion, Winter conception is in accordance with infectious etiology theory of GCT development. The low parental education level and the combined exposure to dust and electricity are very important. The protective effect of repetitive infections and other factors make necessary more epidemiologic studies in this field.

Epidemiology of lymphomas in children residing in Mexico City

BACKGROUND

The aim of this paper is to present the epidemiological characteristics of time, subject and place of lymphomas in children residing in Mexico City, Mexico (MC).

METHODS

The type of study was a retrospective hospital survey. All records of children with lymphomas registered between 1982 and 1991 at the main hospitals that treat children with cancer in MC were reviewed. Neoplasms were classified into Hodgkin's disease (HD) and non-Hodgkin's lymphomas (NonHL). Trend and incidence by sex, age and area of residence in MC were evaluated. Time of diagnosis, as well as parental occupation and educational level, were registered.

RESULTS

A trend was only observed for HD in the total group (r:0.62; P = 0.05). In 1991, incidence for HD was 6.12 (rates x 10(6)) and 3.87 for NonHL. The highest average incidence was found in children 5-9 years of age (5.40) for HD, and in the age groups of 1-4 and 5-9 (3.10 and 3.33, respectively), for NonHL. Incidence was higher among boys for both lymphoma categories, but the male-to-female ratio was much higher in HD. Time of diagnosis, incidence in terms of place of residence, and parental educational level and occupation also differed from one lymphoma category to the other.

CONCLUSION

The epidemiology of HD is different from that of NonHL, both showing a pattern similar to that of Latin American children.

[Classification by levels of clinico-epidemiological research designs]

The objective was to identify the characteristics of epidemiologic designs enabling their classification. A critical review of the literature in the clinical epidemiologic area was done to establish the main differences between designs. A meeting with experts to discuss this controversial topic and obtain criteria by consensus was organized. We propose an integral classification based on levels with two fundamental shafts: intervention and explanatory reasoning.

Incidence of malignant neoplasms in children attending Social Security Hospitals in Mexico City

An increase in neoplasms in Mexican children has been reported. In 1991, the incidence in children from Mexico City (MC) was 70 (x 10(6) child/year), although this rate might be underestimated. The aim of the present study was to estimate the incidence of malignant neoplasms in children resident in MC attending Social Security (SS) hospitals. This study was a retrospective hospital survey. All records of childhood malignant neoplasms diagnosed between 1992 and 1993 in the two SS hospitals which attend childhood neoplasms in MC were reviewed. Histopathological diagnoses were reevaluated and incidence rates (x 10(6) child/ year) in terms of age, sex, and place of residence were estimated. A total of 667 cases were found for the period of study, of which 199 corresponded to residents of MC. The neoplasms with highest prevalence were leukemias (39.2%), lymphomas (17.6%), and central nervous system tumors (12.6%). A general incidence of 94.3 was found, which was highest in children under 5 years of age. Leukemias had an incidence of 36.4, lymphomas of 15.2, and central nervous system tumors of 12.0. Prevalence was higher in boys (male/female ratio of 1.6). As for the place of residence, the highest incidence corresponded to children living in the southern areas of MC. Eighty percent of the leukemias were acute lymphoblastic, while 54% of solid neoplasms were classified as stages III and IV. In conclusion, the incidence of malignant neoplasms in children resident in MC treated at SS hospitals is consistent with that found worldwide, and also with the Latin American pattern.

[Psychosocial adaptation in children and adolescents with craniofacial malformations]

To determine children's perception of their own psychosocial functioning, to compare it with their parents' perception, and determine the type and rate of their psychopathological syndromes and family functioning, and to investigate correlation among these data. Nineteen children with craniofacial deformities and their parents responded to the Columbia Impairment Scale, the Child Behavior Checklist and the McMaster General Functioning Subscale. Psychosocial impairment is a trend in children with craniofacial deformities. There is a correlation between children's and parents' perception of the patient's psychosocial adaptation, global psychopathology and externalizing and aggressive syndromes. A less strong correlation was found with internalizing, somatization and attention deficit syndromes, and with family functioning. Craniofacial deformities in childhood pose special risks for psychosocial adjustment due to type of illness and environmental and family factors.

[The utility of joint sensitivity and specificity curves applied to a diagnostic test]

The aim of this study was to obtain the cut point to determine an individual's seronegativity with respect to measles using commercial reagents. To determine the test sensitivity, the serum of 22 individuals 21 years of age or older, and a positive history of measles (positive control group) was studied. For specificity, the serum of 22 children 15 to 24 months old, and no measles vaccination record nor positive history of measles (negative control group), was analyzed. The antibodies titer determination for both groups was done using the ELISA technique and the Brunell method, subsequently, as well as a ROC curve (Received Operating Curve). When the Brunell method was used, the cut points were 0.4090 (sensitivity 1.0 and specificity 0.95) and 0.5042 (sensitivity 0.95 and specificity 1.0). When a ROC curve was done the cut point was 0.4500, with a sensitivity and specificity of 100 per cent. It was also concluded that the latter is the best method to obtain this cut point, because it does not establish arbitrary values when the data distribution does not follow a normal pattern.

[Usefulness of residuals in clinical research]

The simple linear regression analysis, multiple linear regression and logistic regression constitute powerful statistical analysis tools widely used in clinical research. These kinds of analyses are based upon mathematical models which at the same time are established on certain basic assumptions. The regression analysis assumptions are basically: a) that the model is really linear, b) that the distribution of data is normal (from a statistical point of view), c) that the variances of the employed data are homogeneous (homocedastics) and that the included data are independent. The regression diagnostic has become popular as a form to evaluate if the assumptions have been accomplished, one of its most important techniques is the residual analysis. A residual can be defined as the value which measures the distance between the regression line and the corresponding value of the variable "y". Among these kinds of residuals used to evaluate the assumptions of regression are: the crude residual, the standardized, of student and the jackknife. The most useful among them is the jackknife residual. The usefulness and limitations of the residuals in the evaluation of the regression analysis assumptions are described, basically referring to the identification and handling of extreme values (outliers).

[Risk factors associated with the development of leukemia in children]

INTRODUCTION

Leukemia is the most frequent neoplasia in children; in our country it is the main cause of medical attention in children with cancer. The are different risk factors associated with the development of this kind of cancer.

OBJECTIVE

To identify which of the already known factors described in the literature associated with the development of leukemia are most frequent in the pediatric population of Mexico City.

MATERIAL AND METHODS

A protective case-control study was carried out using prevalent and incident cases. In two third level hospitals of Mexico City, a total of 81 children who had been diagnosed as suffering from different kind of leukemia, confirmed by biopsy of bone marrow, were select and studied. The control were 154 children from two different sources: 77 of them came from the same hospital where the cases received medical care, the selection criteria was not to have any kind of neoplasia; and 77 came from the same community where those diagnosed children cases lived, the selection criteria for this group was that they were healthy children. Both cases and community controls were visited at home and interview to complete precoded questionnaire with the different variables of the study. The information from the hospital controls was obtained during the time they stayed in the hospital. Odds ratio (OR's) for the different associations were calculated, as well as its confidence intervals at 95% (IC) accord to Cornfield and unconditioned logistic regression was carried out to control confounding variables.

RESULTS

OR greater than 1 was found in those with familiar cancer background 1.93 (1.2-3.63); the mother being exposed to X-ray during pregnancy 1.89 (0.84-4.22); previous abortions before the child with leukemia was born 2.44 (1-06-5.68); being born from full term birth 2.42 (0.47-16.65); being born with weight greater that 3500 g 2.21 (1.04-4.33); being exposed to fertilizers 4.73 (1.04-24.14) and insecticides 1.93 (1.05-3.56). OR smaller than 1 was found in those who have been in a hospital because of an infectious disease during the first year of life 0.57 (0.17-1.74); to have suffered from chicken pox 0.59 (0.32-1.08). No association to parent's age or job was found. Multivariated analysis shows that the exposure to insecticide is the most important risk factor associated with the development of leukemia in children.

CONCLUSIONS

We obtained positive associations to different risk factors described in the literature, having found that exposure to fertilizers is the most important risk factor and finding no association with the parent's occupation. This leads to the need of carrying out further studies to investigate, in more detail, the occupation of the father to confirm whether or not this is a risk factor.

[The use of thoracic radiography in a third-level-care pediatric hospital]

OBJECTIVES

1. To describe the frequency in which the thorax radiography is requested in a third-level pediatric hospital, 2. To identify the frequency of detected abnormalities in such a study by the radiology service, 3. To describe the frequency and the characteristics form the information considered as useful in a clinical way, not only in the radiography application but in the radiologic report and the clinical file as well, 4. To identify the frequency in which the thorax radiography result is associated with diagnosis changes and/or therapeutic ones. DESIGN OF THE INVESTIGATION: Descriptive survey.

STUDY UNITS

371 thorax X-rays completed during December 1990 and January 1991.

PRIMARY RESULTS

The thorax radiographies were 32% of the entire radiological study during the survey; 335 of the latter ones (90%) were requested for inpatients. The hospital services which had the highest request for such a study were the Intensive Care Unit (n = 149, 40%) and Medical Pediatrics (n = 116, 31%). The most frequent diagnosis leading to the application was pneumonia (n = 55, 15%) and solid neoplasia (n = 51, 14%). Three-hundred forty eight of the applications had diagnostic impression given by the physician in charge(94%); whereas only 127 (34%) mentioned clinical data. The radiology report was attached to the file in 162 (44%) of the cases. It was found that form the patients who had a radiology report and the thorax radiography as an initial study (n = 95), 48 (50%) suffered from abnormalities. The results of the study were transcribed in the file in 58 cases (16%); the physician's interpretation was written down in 229 cases (62%) and in 84 studies (23%) there was no reference to the results of the study (P < 0.0001). Changes in the therapeutic plan of 93 cases (50%) were identified from the studies with official report by the radiologist, other radiology studies were requested in 65 of the patients (35%), after the interpretation of such study.

CONCLUSIONS

Abnormalities in 50% were identified from the total thorax radiographies requested as the patient entered. The study application mentioned as a whole (94%) the diagnostic impression which led to the application, but only in 127 cases (34%) were supporting clinical data written down. The radiology report was attached to the file in less than half the cases (44%). In 63% of the cases the supporting reason of the study was written down whereas in 23% there was no reference to the result at all.

[Residence close to high-tension electric power lines and its association with leukemia in children]

INTRODUCTION

There are different risk factors which have been related to the presence of leukemia in children. In the past years one of these factors has become relevant, the risk of living in an area near to high electric voltage lines, generators of electromagnetic fields of low frequency (EMF), which can cause development of leukemia in children.

OBJECTIVE

To learn whether living in an area close to EMF generator sources, electric transformers, high electric voltage distribution or transmission lines and electric substations, is a risk factor in the development of leukemia in children living in Mexico City.

MATERIAL AND METHODS

A projective study of case-control was accomplished. The cases were obtained from hospitals of the third level. The diagnosis of leukemia in its different varieties was confirmed through biopsy of bone marrow. The controls were selected in the same hospital from inpatients and outpatients with different problems, except neoplasia. A total sample of 81 cases and 77 controls was analyzed. The residence of the controls and cases were visited using a questionnaire coded with the different study variables. To diminish the memory bias in relation to EMF, the subjects were shown different pictures pointing out the different sources of exposures, which were asked. Having obtained the information, different odds ratios (OR) were calculated for the different associations, as well as the confidence intervals at 95% and an unconditioned logistic regression was accomplished to know the adjusted OR.

RESULTS

There were no differences between the cases and controls according to the relative who gave the information, the current age of children, the parents's age, the social class and the parent's occupation. It was found that all the generating sources of EMF, which were involved in the study, had and OR above 1. Being the highest, the ones living near the distribution or transmission wires of high voltage with an OR of 2.63 (1.26-5.36) and 2.5 (0.97-6.67) respectively. When the distance of exposure was controlled, the highest OR was for distribution lines (OR 2.12; 0.79-5.85). When the analysis was applied to persons who have moved from the residence, it was found that the OR was above 1 in all the associations, the highest being the distribution wires and with the distance the highest was the electric substations. Furthermore, the multivariate analysis showed that the risk continued only for the distribution wires.

CONCLUSIONS

The EMF exposure was found positive, however this is not very precise, that is why it is necessary to carry out other studies to confirm the existence of the association and correct possible biases which could appear during the research.

[Diagnostic performance of immunologic tests in amebic liver abscess using receiver operating characteristic curves]

Objectives. 1) To identify the tests of immunological diagnosis with a high diagnostic efficiency in amebic liver abscess. 2) To determine the ideal cutoff point for such tests. 3) To identify the influence degree of the antigen used over the test efficiency. Design. Comparative survey. Study units. Analysis of 24 articles identified in the medical literature about tests of immunological diagnosis in amebic liver abscess. Measurements. Starting from the articles, operating characteristics curves (ROC) were established derived from the test application to patients with amebic liver abscess. Results. A great variability in the diagnostic efficiency was identified between the various tests, even when the analysis was focused on the investigations of a specific test. It was not possible to conclude which test had a major degree of efficiency due to such variability. The cutoff level considered as relevant was higher than the one traditionally used for indirect hemagglutination and it had concordance with the one presently accepted for the fluorescence antibodies test. By maintaining steady the spectrum of the study patients and the type of test, variability among the tests persisted. This was due to the use of different antigens. Conclusions. A great variation in the diagnostic efficiency of the analyzed tests was identified. The variation source was the type of test, the antigen used and probably the illness spectrum.

[The prevalence of elevated arterial pressure and risk factors in adolescents in the Federal District of Mexico]

To develop studies on blood pressure (BP) of young population, such as adolescents, is important, because it is an early way to obtain information about the factors that could influence or modify the levels of BP. A group of 1,146 junior high school students from Mexico City was studied, by means of a questionnaire to identify risk factors, which were classified as: 1. inherent factors, 2. acquired risks and 3. family background. A significant association was observed related to inherent factors in scholars, mainly at monarch age with an odds ratio of 2.45; and confidence intervals of (1.05-5.63) for systolic blood pressure (SBP) and 8.81 (4.44-17.54) for diastolic blood pressure (DBP). In relation to acquired risks, there was a positive association with the use of contraceptives. As for family background there was as important association, in the following order: obesity, diabetes and hypertension. Therefore, it may be said that since early ages there are risk factors for BP; although some of them were not significantly, they can not be excluded as risk factors because there is a possibility that a longer latency period may be needed for them to act as such.

[Frequency and risk factors associated with metronidazole therapeutic noncompliance]

OBJECTIVE

to determine the frequency and risk factors of non-compliance to oral metronidazole.

STUDY DESIGN

comparative cross-sectional survey.

STUDY UNITS

111 patients who received oral metronidazole. SETTING CHARACTERISTICS: two medical units: one primary level unit and one secondary care unit of the Mexican Institute of Social Security.

MEASUREMENTS

non-compliance was assessed by home interview and pill count.

MAIN RESULTS

frequency of non-compliance was 55%. Risk factors for non-compliance were: female sex (OR = 3.0; p less than 0.05); side effects (OR = 3.1; p less than 0.05); low literacy (OR = 3.75; p less than 0.05). Stratified analysis showed no interaction between variables.

CONCLUSIONS

frequency of non-compliance to metronidazole is high, and could affect the effectiveness of medical care. Female patients with low literacy and who suffer side effects are a high risk group for non-compliance.

[Prognostic factors in a pediatric intensive care unit]

OBJECTIVES

To identify the mortality prognostic factors from a pediatric intensive care unit.

STUDY DESIGN

Retrolective cohort study with an analysis of cases and controls (ambidirectional design). PLACE OF STUDY: The intensive care unit at a Pediatric Third Level Hospital.

STUDY UNITS

All of the patients admitted into the I.C.U. for a year (August 1989 to August 1990).

MAIN MEASUREMENTS

The patients were identified when admitted into I.C.U., while evaluating their clinical course through their charts. Afterwards, they were placed into two groups, those who died while in I.C.U. (n = 49) and those in the control group which constituted the initial cohort survivors (n = 115). The prognostic factors evaluated were age, sex, diagnosis when admitted, organic failure, changes in diagnosis and treatment.

MAIN RESULTS

164 patients were studied, with a slight predominance of the male sex (53%). The patient's age fluctuated between 1 day and 17 years of age, with a mean age of 10 months. The diagnosis established when admitted were predominantly dealing with infectious problems (n = 54, 32%). The most important prognostic factors seen during the bivaried analysis were the peritoneal dialysis (RM = 12.71, IC 95% = 2.41-98.29, P less than 0.01); a Glasgow index less than or equal to 10 points (RM = 7.33, IC 95% = 1.25-47.26, P less than 0.01), respiratory organic failure (RM = 6.32, IC 95% = 2.46-16.8, P less than 0.01) and assisted mechanical ventilation (RM = 5.61, IC 95% = 2.52-12.68, P less than 0.01).

CONCLUSIONS

The mortality rate in I.C.U. was 30%. The most important prognostic factors associated to mortality after adjusting for severity were having a cardiovascular ailment, the need to administer blood products, a Glasgow index less than or equal to 10 points, heart and hematologic organic failure and when respiratory mechanical assistance was provided.

[The initial clinical probability in the diagnosis of the hospitalized pediatric patient]

OBJECTIVES

1. To determine the degree of correlation among different physicians concerning their initial diagnosis and 2. identify the degree of correlation between the probability that physicians assing an initial diagnosis and the number of days the patient is hospitalized, laboratory test and X-rays taken of the patient.

DESIGN

A comparative questionnaire.

STUDY SITE

Pediatric hospitalization Unit of a third level medical care ward of the Mexican Social Security Institute.

STUDY UNITS

All new admissions or non-programmed readmitted patients to the hospital during the months of November and December 1990.

MAIN MEASUREMENTS

The treating physicians (Staff pediatricians (MB) and third (R3) and second (R2) year residents) were each asked to independently assign a probability (0 to 100) to each of the diagnosis emitted on the day the patient was admitted. When the patient was discharged, the number of days hospitalized as well as the number of laboratory tests and X-rays taken of the patient were added.

RESULTS

106 patients were evaluated, a correlation was gathered between MBs and R3s of 0.79 (P less than 0.001) and among MBs and R2s of 0.83 (P less than 0.001). The correlation between resident physicians was discretely less 0.60 (P less than 0.01). When relating the probability assigned by the physicians and the number of days the patients were hospitalized, associations were observed of 0.31 (P less than 0.05), 0.15 (P less than 0.05) and 0.19 (P = 0.04) for the MB, R3 and R2s respectively. In the case of laboratory test a correlation of 0.38, 0.06 and 0.04 (MB, R3, R2 respectively) was found. None of these correlations were statistically significant. The X-rays showed a significant correlation in cases of the MBs (0.50, P less than 0.05).

CONCLUSIONS

The probabilities assigned by the staff physician as well as the resident doctors are closely related and a lesser grade of association is seen when comparing the residents among each other. No tendencies were identified in the correlation of the probability assigned by the residents and the variables analyzed. A consistent relation was seen between the staff physician and high probabilities, longer stays, and greater number of laboratory tests and X-rays.

[The consistency and validity of a measurement in clinical pediatric research. Its definition, evaluation and interpretation]

In clinical pediatric research as in all research, one of the fundamental characteristics is the measurement of the studied features, either clinical, of laboratory or cabinet. A measurement must have two fundamental characteristics, for it to be considered as scientific: consistency and validity. The first one is centered on the variability of the measurement, which is due to the measuring instrument, to the subject or entity which is measured and to the individual or individuals who carry out the measuring, this is known as intra or interobserver variability, respectively. Validity is the fact of "actually" measuring what we want to measure. Both characteristics of measurement, are often mixed, between them and with other concepts, and this is the reason of not having a clear idea of what is the real meaning. This paper discusses the different terms that have been used for consistency and validity of a measurement. Also it points out how to assess consistency, from the validity, taking into account the measuring scale of the variables and the number of observers. Easy examples are used for the application of different formulas and for the interpretation of the results.

[Anthropometric evaluation of nutritional status in children. Procedures, standardization and significance]

A major concern for pediatrician is evaluate the infant nutritional status for clinical, epidemiological and research purposes. This paper describes different anthropometric procedures such as weight, length or height, as well as head and arm circumferences and skinfolds; give some relevant hints in order to prevent subjects, instruments and operator errors. Standardization methods are discussed and cut point to accept consistency and validity between operators are suggested. It's also discussed how to manage the raw data in order to evaluate nutritional status in terms of size, growth tendency or weight/age, length/age and weight/length indices; besides, the most important classification of the nutritional status are given. Finally, the procedures for calculating muscular and fat arm areas and corporal adiposity in order to obtain body composition are presented.

[Susceptibility to measles in the adolescent population of the Federal District]

It is well known that in developing countries, measles disease is frequently increasing among adolescents. In Mexico, it is also thought that this problem is moving in such a way; however, this can not be proven with the statistical information at hand. For this reason a serum-survey was carried out in a sample of 870 healthy teenagers drawn from public and private secondary schools in Mexico City, in order to know if they were susceptible to measles disease and in that way make the right decisions. The information background related to the vaccination and information about previously having the disease was obtained from a questionnaire that was given to the parents of the studied teenagers. In order to get de immune state of the studied group, measles antibody titles were quantified using the ELISA technique. The findings shown that the susceptibility in this group was of 21.4%, which is certainly higher than the ones that have been found in some other countries where measles epidemics in people at this age have been well documented. Accordingly, it is thought that the displacing of this illness can be found in teenagers of Mexico City. An association was found with male sex and having the illness before. Teenagers that studied in public secondary schools reported more frequently, they had had the illness than the ones who studied at private schools. It was also found that these teenagers had a higher probability of having antimeasles antibody titles which are considered non protective; that is why it is thought these students are more likely to become ill during the adolescence stage than those who already have had the illness and the consequent protection.