Criterios de retorno al trabajo y determinación del valor de vulnerabilidad por Covid-19 / Criteria for returning to work and determination of the vulnerability value for Covid-19

Resumen: Objetivo: Establecer criterios médicos de retorno al trabajo en personal con riesgo de complicaciones por Covid-19. Material y métodos. Se realizó una revisión sistemática para identificar las condiciones y las características clínicas que influyen en el riesgo de desarrollar Covid-19 grave. Resultados: Se ha demostrado incremento del riesgo en obesidad, edad >60 años, diabetes mellitus, hipertensión arterial, enfermedad pulmonar obstructiva crónica, enfermedad cardiovascular, enfermedad renal crónica y cáncer. Solamente en diabetes se ha estudiado si el control previo influye. Se proponen condiciones específicas y el nivel de riesgo epidemiológico para el retorno al trabajo. Conclusiones: El retorno laboral de estos grupos debe priorizarse buscando favorecer el control de la enfermedad, identificando el estado de salud que incrementa el riesgo y protegiendo el derecho al trabajo. Se presentan recomendaciones para guiar la reincorporación al trabajo.

Abstract: Objective: To establish medical criteria for return to work to people with increased risk of severe illness from Covid-19. Materials and methods. We performed a systematic review to identify the conditions and clinical characteristics that influence the risk of developing severe Covid-19. Results: Increased risk has been shown in obesity, age >60 years old, diabetes mellitus, arterial hypertension, chronic obstructive pulmonary disease, cardiovascular disease, chronic kidney disease and cancer. Only in diabetes it has been studied whether prior control influences. Specific medical conditions and epidemiological risk level for return to work are proposed. Conclusions: Return to work of vulnerable groups should be prioritized, seeking to promote disease control, identifying health conditions that increase risk, and protecting the right to work. We present recommendations to guide the return to work.

Criterios de retorno al trabajo y determinación del valor de vulnerabilidad por Covid-19.

Objetivo. Establecer criterios médicos de retorno al trabajo en personal con riesgo de complicaciones por Covid-19. Material y métodos. Se realizó una revisión sistemática para identificar las condiciones y las características clínicas que influyen en el riesgo de desarrollar Covid-19 grave. Resultados. Se ha demostrado incremento del riesgo en obesidad, edad >60 años, diabetes mellitus, hipertensión arterial, enfermedad pulmonar obstructiva crónica, enfermedad cardiovascular, enfermedad renal crónica y cáncer. Solamente en diabetes se ha estudiado si el control previo influye. Se proponen condiciones específicas y el nivel de riesgo epidemiológico para el retorno al trabajo. Conclusiones. El retorno laboral de estos grupos debe priorizarse buscando favorecer el control de la enfermedad, identificando el estado de salud que incrementa el riesgo y protegiendo el derecho al trabajo. Se presentan recomendaciones para guiar la reincorporación al trabajo.

Childhood acute leukemias are frequent in Mexico City: descriptive epidemiology.

BACKGROUND: Worldwide, acute leukemia is the most common type of childhood cancer. It is particularly common in the Hispanic populations residing in the United States, Costa Rica, and Mexico City. The objective of this study was to determine the incidence of acute leukemia in children who were diagnosed and treated in public hospitals in Mexico City. METHODS: Included in this study were those children, under 15 years of age and residents of Mexico City, who were diagnosed in 2006 and 2007 with leukemia, as determined by using the International Classification of Childhood Cancer. The average annual incidence rates (AAIR), and the standardized average annual incidence rates (SAAIR) per million children were calculated. We calculated crude, age- and sex-specific incidence rates and adjusted for age by the direct method with the world population as standard. We determined if there were a correlation between the incidence of acute leukemias in the various boroughs of Mexico City and either the number of agricultural hectares, the average number of persons per household, or the municipal human development index for Mexico (used as a reference of socio-economic level). RESULTS: Although a total of 610 new cases of leukemia were registered during 2006-2007, only 228 fit the criteria for inclusion in this study. The overall SAAIR was 57.6 per million children (95% CI, 46.9-68.3); acute lymphoblastic leukemia (ALL) was the most frequent type of leukemia, constituting 85.1% of the cases (SAAIR: 49.5 per million), followed by acute myeloblastic leukemia at 12.3% (SAAIR: 6.9 per million), and chronic myeloid leukemia at 1.7% (SAAIR: 0.9 per million). The 1-4 years age group had the highest SAAIR for ALL (77.7 per million). For cases of ALL, 73.2% had precursor B-cell immunophenotype (SAAIR: 35.8 per million) and 12.4% had T-cell immunophenotype (SAAIR 6.3 per million). The peak ages for ALL were 2-6 years and 8-10 years. More than half the children (58.8%) were classified as high risk. There was a positive correlation between the average number of persons per household and the incidence of the pre-B immunophenotype (Pearson's r, 0.789; P = 0.02). CONCLUSIONS: The frequency of ALL in Mexico City is among the highest in the world, similar to those found for Hispanics in the United States and in Costa Rica.

Infection and death from influenza A H1N1 virus in Mexico: a retrospective analysis.

BACKGROUND: In April, 2009, the first cases of influenza A H1N1 were registered in Mexico and associated with an unexpected number of deaths. We report the timing and spread of H1N1 in cases, and explore protective and risk factors for infection, severe disease, and death. METHODS: We analysed information gathered by the influenza surveillance system from April 28 to July 31, 2009, for patients with influenza-like illness who attended clinics that were part of the Mexican Institute for Social Security network. We calculated odds ratios (ORs) to compare risks of testing positive for H1N1 in those with influenza-like illness at clinic visits, the risk of admission for laboratory-confirmed cases of H1N1, and of death for inpatients according to demographic characteristics, clinical symptoms, seasonal influenza vaccine status, and elapsed time from symptom onset to admission. FINDINGS: By July 31, 63 479 cases of influenza-like illness were reported; 6945 (11%) cases of H1N1 were confirmed, 6407 (92%) were outpatients, 475 (7%) were admitted and survived, and 63 (<1%) died. Those aged 10-39 years were most affected (3922 [56%]). Mortality rates showed a J-shaped curve, with greatest risk in those aged 70 years and older (10.3%). Risk of infection was lowered in those who had been vaccinated for seasonal influenza (OR 0.65 [95% CI 0.55-0.77]). Delayed admission (1.19 [1.11-1.28] per day) and presence of chronic diseases (6.1 [2.37-15.99]) were associated with increased risk of dying. INTERPRETATION: Risk communication and hospital preparedness are key factors to reduce mortality from H1N1 infection. Protective effects of seasonal influenza vaccination for the virus need to be investigated. FUNDING: None.

Father's occupational exposure to carcinogenic agents and childhood acute leukemia: a new method to assess exposure (a case-control study).

BACKGROUND: Medical research has not been able to establish whether a father's occupational exposures are associated with the development of acute leukemia (AL) in their offspring. The studies conducted have weaknesses that have generated a misclassification of such exposure. Occupations and exposures to substances associated with childhood cancer are not very frequently encountered in the general population; thus, the reported risks are both inconsistent and inaccurate. In this study, to assess exposure we used a new method, an exposure index, which took into consideration the industrial branch, specific position, use of protective equipment, substances at work, degree of contact with such substances, and time of exposure. This index allowed us to obtain a grade, which permitted the identification of individuals according to their level of exposure to known or potentially carcinogenic agents that are not necessarily specifically identified as risk factors for leukemia. The aim of this study was to determine the association between a father's occupational exposure to carcinogenic agents and the presence of AL in their offspring. METHODS: From 1999 to 2000, a case-control study was performed with 193 children who reside in Mexico City and had been diagnosed with AL. The initial sample-size calculation was 150 children per group, assessed with an expected odds ratio (OR) of three and a minimum exposure frequency of 15.8%. These children were matched by age, sex, and institution with 193 pediatric surgical patients at secondary-care hospitals. A questionnaire was used to determine each child's background and the characteristics of the father's occupation(s). In order to determine the level of exposure to carcinogenic agents, a previously validated exposure index (occupational exposure index, OEI) was used. The consistency and validity of the index were assessed by a questionnaire comparison, the sensory recognition of the work area, and an expert's opinion. RESULTS: The adjusted ORs and 95% confidence intervals (CI) were 1.69 (0.98, 2.92) during the preconception period; 1.98 (1.13, 3.45) during the index pregnancy; 2.11 (1.17, 3.78) during breastfeeding period; 2.17 (1.28, 3.66) after birth; and 2.06 (1.24, 3.42) for global exposure. CONCLUSION: This is the first study in which an OEI was used to assess a father's occupational exposure to carcinogenic agents as a risk factor for the development of childhood AL in his offspring. From our results, we conclude that children whose fathers have been exposed to a high level of carcinogenic agents seem to have a greater risk of developing acute leukemia. However, confounding factors cannot be disregarded due to an incomplete control for confounding.

Incidence of cancer in children residing in ten jurisdictions of the Mexican Republic: importance of the Cancer registry (a population-based study).

BACKGROUND: In 1996, Mexico started to register cases of childhood cancer. Here, we describe the incidence of cancer in children, residing in ten Mexican jurisdictions, who were treated by the Instituto Mexicano del Seguro Social (IMSS). METHODS: New cases of childhood cancer, which were registered prospectively in nine principal Medical Centers of IMSS during the periods 1998-2000 (five jurisdictions) and 1996-2002 (five jurisdictions), were analyzed. Personnel were specifically trained to register, capture, and encode information. For each of these jurisdictions, the frequency, average annual age-standardized incidence (AAS) and average annual incidence per period by sex and, age, were calculated (rates per 1,000,000 children/years). RESULTS: In total 2,615 new cases of cancer were registered, with the male/female ratio generally >1, but in some tumors there were more cases in females (retinoblastoma, germ cells tumors). The principal groups of neoplasms in seven jurisdictions were leukemias, central nervous system tumors (CNS tumors), and lymphomas, and the combined frequency for these three groups was 62.6 to 77.2%. Most frequently found (five jurisdictions) was the North American-European pattern (leukemias-CNS tumors-lymphomas). Eight jurisdictions had AAS within the range reported in the world literature. The highest incidence was found for children underless than five year of age. In eight jurisdictions, leukemia had high incidence (>50). The AAS of lymphomas was between 1.9 to 28.6. Chiapas and Guerrero had the highest AAS of CNS tumors (31.9 and 30.3, respectively). The frequency and incidence of neuroblastoma was low. Chiapas had the highest incidence of retinoblastoma (21.8). Germ-cell tumors had high incidence. CONCLUSION: The North American-European pattern of cancers was the principal one found; the overall incidence was within the range reported worldwide. In general but particularly in two jurisdictions (Yucatán and Chiapas), it will be necessary to carry out studies concerning the causes of cancer in children. Due to the little that is known about the incidence of cancer in Mexican children, it will be necessary to develop a national program to establish a cancer registry for the whole of the country.

[Acute leukemias epidemiology in children. Part 1]. / Epidemiología de las leucemias agudas en niños. Parte 1.

OBJECTIVE: This paper is a revision from recent studies related to acute leukemia (AL) epidemiology in children. Cancer is the second cause of death in the pediatric population in Mexico between 1 to 15 years old. The AL are the types of cancer with more frequency in children below 15 years old and the cost of taking care of a child with cancer represents to the health institutions around 620 thousand dollars per year per case. In different places of the world the frequency of the AL has been increased and in Mexico City this is similar. Data from Instituto Mexicano del Seguro Social, in Mexico City, reports one of the highest worldwide. The environmental risk factors most consistent are the exposure in utero to X-ray, occupational exposure and pesticides. Other risk factors studied, as the exposure to electromagnetic fields, smoking and alcohol consumption in the parents, diet, and others, have had controversial results. These controversies can be explained by methodological mistakes in the studies and also because these studies did not assess the interaction between the susceptibility to AL and the environmental factors, a situation that could lead to the better understanding of the causal mechanisms of the disease. However it is recommended to have an attitude of prudent caution to accept that these factors are a cause of AL, and to have an energetic position in order to decrease the exposure to them and produce more adequate preventive strategies.

[Age of onset of different malignant tumors in childhood]. / Edad de aparición de los diferentes tumores malignos en la infancia.

OBJECTIVE: To identify the main age of onset of different malignant tumors in childhood and to describe the distribution of the different tumors in each pediatric age group. MATERIAL AND METHODS: Descriptive survey was used. We reviewed the files of six Mexico City hospitals from 1980 to 1992. We included 4595 cases divided into 13 types of cancer. Peak age was defined when in that year we encountered a frequency equal to or below 10 % of the cases. RESULTS: Peak ages for hepatic, sympathetic nervous system, germ cell tumors, retinoblastoma and rhabdomyosarcoma were between 2 and 3 years of age. Wilms' tumor appeared between the first and fourth years; central nervous system tumors between 4 and 5 years; acute lymphoblastic leukemia between 2 and 4 years; non-Hodgkin's lymphomas between 3 and 6 years; Hodgkin's disease between 4 and 8 years; bone tumors between 10 and 14 years. In acute myeloid leukemia and carcinomas no age peak was found. CONCLUSIONS: Lymphomas present an age peak different from that reported in developed countries. In neonates and infants, the most frequent tumor was retinoblastoma.

[Epidemilogy of leukemias in children. Part 2]. / Epidemiología de las leucemiacs agudas en niños. Parte 2.

The causes of most leukemias are unknown; only a few exposures have been established as risk factors. Nowadays, the AL in children is considered as the result of the interaction of different environmental factors with the genetic susceptibility to the disease. In the first part of this review, the child's environmental factors were basically covered. Now, in this second part, we are describing some factors of the child himself, as well as other proposed factors, but which have been evaluated in epidemiological research with less frequency. The most important host factor is Down's syndrome. Susceptibility aspects, such as HLA alleles, and aspects related to expositions around the home, late infections and the time in which the expositions occur, require more research. Studies that assess the interaction between the susceptibility to the acute leukemia and the environmental factors could lead to the better understanding of the causal mechanisms of the disease and to more adequate preventive strategies.