Exposición prenatal a ftalatos. Anemia materna, duración de la gestación y somatometría del recién nacido / Prenatal exposure to phthalates. Maternal anemia, pregnancy duration and neonatal somatometry

Los ésteres del ácido ftálico conocidos comúnmente como ftalatos son contaminantes ubicuos existentes en alimentos, aire, suelo, sedimentos, productos de belleza y materiales de construcción a los que las mujeres embarazadas se encuentran expuestas. Exposiciones previas de ftalatos durante la fecundación pueden producir mayor riesgo de efectos adversos por contacto de la madre con estos. Muchas sustancias químicas pueden atravesar la placenta y llegar al embrión en el periodo de mayor diferenciación, pueden acumularse en los tejidos corporales y liberarse al torrente sanguíneo, para de esta manera producir un daño en el proceso de gestación. El objeto del presente estudio fue identificar la asociación de la presencia de metabolitos de ftalatos con efectos adversos en el embarazo. El promedio del grupo de edad fue de 21,3±4,4 años, los recién nacidos tuvieron un peso de 2.927±490g, la presencia del metabolito monobenzil ftalato predominó en el 53,13% de las muestras, las fuentes de exposición a ftalatos son: jabón y crema en 93,7% y desodorante en 90,6%. El dimetil ftalato (DMP) se asoció con anemia con una p<0,01; el DMP se asoció a la disminución de la edad gestacional con p<0,04, el monobutil ftalato (MBP) se asoció a recién nacidos del sexo femenino con p<0,01, la presencia de monobutil ftalato se asocia a la disminución del perímetro cefálico, torácico y abdominal así como al peso de los recién nacidos con diferencias estadísticamente significativas (AU)

Phthalic acid esters, commonly known as phthalates, are ubiquitous pollutants in foods, air, ground, sediments, beauty products and construction materials to which pregnant women are exposed. Previous phthalate exposure during fertilization can increase the risk of undesired effects through maternal contact with these esters. Many chemical substances can cross the placenta and reach the embryo in the period of greatest differentiation. These substances accumulate in body tissues and are then released into the bloodstream, thus producing harmful effects in the pregnancy. The aim of the present study was to identify the association between the presence of phthalate metabolites and adverse effects in pregnancy. The mean maternal age was 21.3±4.4 years. The mean birthweight was 2927±490 grams. Monobenzyl phthalate metabolite predominated in 53.13% of the samples. Sources of phthalate exposure were soap and cream in 93.7% and deodorant in 90.6%. Dimethyl phthalate was associated with anemia (P<0.01) and decreased gestational age (P<0.04). Mono butyl phthalate was associated with female sex in the neonate (P<0.01), decreased head, chest and abdominal circumference and lower birthweight, with statistically significant differences (AU)

[Difficulties of the methods for studying environmental exposure and neural tube defects]. / Dificultades en los métodos de estudio de exposiciones ambientales y defectos del tubo neural.

OBJECTIVE: To discuss the attitudes in the assessment of environmental exposures as risk factors associated with neural tube defects, and to present the main risk factors studied to date. RESULTS: Environmental exposures have been suggested to have a roll in the genesis of birth defects. However, studies conducted in human populations have found difficulties in the design and conduction to show such an association for neural tube defects (anencephaly, espina bifida and encephalocele) because of problems raised from: a) the frequency measures used to compare time trends and communities, b) the classification of heterogeneous malformations, c) the inclusion of maternal, paternal and fetal factors as an integrated process and, d) the assessment of environmental exposures. CONCLUSIONS: Hypothetically both maternal and paternal environmental exposures can produce damage before and after conception by direct action on the embryo and the fetus-placenta complex. Therefore, in the assessment of environmental exposures we need to take into account: a) both paternal and maternal exposures; b) the critical exposure period, three months before conception for paternal exposures and one month around the conceptional period for maternal exposures; c) quantitatively evaluate environmental exposures when possible, avoiding a dichotomous classification; d) the use of biological markers of exposure is highly recommended as well as markers of genetic susceptibility.

[The case-control design in medical research]. / El diseño de casos y controles en la investigación médica.

The aim of this paper is to present a conceptual and practical framework of the case-control design in medical research. To illustrate this method, practical examples directed to clinicians and other health professionals interested in medical research are presented. The case-control method is very versatile and allows for multiple applications. Guidelines for the selection of cases and controls, and some considerations on sample size are presented. In the statistical analysis we use concrete examples of how to estimate odds ratios, confidence intervals, and methods to control for potential confounders, from stratified analysis to logistic regression.

[Does clinical depression increase the risk of death from non-violent causes?]. / Aumenta la depresión clínica el riesgo de muerte por causas no violentas?

Studies of the effect of depression on life expectancy have found controversial results. In the past, an excess mortality was attributed to conditions seen at psychiatric institutions. More recently, in addition to an excess mortality due to violent causes of death, some studies also found excess mortality due to non-violent and all-cause mortality. Hospital studies that evaluated this relationship are generally flawed and lack of control for potential confounders. Underlying physical illnesses could explain the excess mortality reported. On the other hand, community-based studies have studied small number of depressed subjects, and have used diverse measurements of depression which hamper comparability. This paper critically reviews recent published studies and discusses possible mechanisms for this association.

[Malnutrition as a multiple cause of death]. / El análisis de la desnutrición como causa múltiple de muerte.

With the purpose of describing the role of malnutrition at death time, an analysis of multiple causes of death in children under five years-old was performed on deaths which occurred during April and May 1985 in Mexico City. A proportional mortality analysis was done taking in consideration all the causes listed on the death certificate, not only the underlying causes. The number of deaths associated to malnutrition was greater by multiple cause than by underlying cause (OR = 7.9, 95% CI 5.0-12.7, p = 0.00000). The importance of considering multiple causes of death, mainly when there are frequent diseases which are some times recorded as underlying cause of death, is also discussed.

[Therapeutic effectiveness of anticoagulation in acute myocardial infarction: a case-control study]. / Efectividad terapéutica de la anticoagulación en el infarto agudo del miocardio: un estudio de casos y controles.

The main aim was to assess the role of anticoagulant therapy (AT) in reducing the mortality for patients with acute myocardial infarction (AMI). A pair-matched case-control study was designed according to three confounding factors: gender, age (+/- 5 years), and hospitalization date (+/- 13 months). Cases were defined as patients with AMI who died during hospitalization and controls were those patients with AMI who survived. Excluded from the study were patients with strong indications or contraindications for use of AT, and also those with early death (less than 12 hr). The study undertaken at the National Institute of Cardiology "Ignacio Chávez" of Mexico City and all necessary information was obtained from clinical charts of patients discharged between the period from January 1, 1975 to December 31, 1985. Complete information was accomplished for 212 pairs of cases and controls. A protective odds ratio (favoring use of AT) = 12.1 (p less than 0.0001, 95% CI 4.2-34.9) was obtained by means of a multiple logistic regression analysis by conditional method. Other variables that entered into the logistic model were: antithrombotic therapy, severity measured by Killip scale and by Norris index. Such findings support the favorable therapeutic role of AT in patients with AMI.

[Ionizing radiation at low doses and cancer: epidemiological controversy]. / Radiación ionizante a dosis bajas y cáncer: controversia epidemiológica.

The carcinogenic effects of ionizing radiation at high doses are un questionable. On the other hand, the deleterious exposure effects to low doses have not been totally proven, mainly due to methodological problems and difficulty in measuring reliable dose exposure. In this paper, some recent studies examining the effects of ionizing radiation in some occupational groups are reviewed and discussed. Also, the main areas of epidemiologic controversy are stressed. For future experiences, prospective, longitudinal studies with occupational cohorts, measuring radiation exposure with adequate registry and follow-up, are suggested.

[Analysis of multiple-cause mortality: a new approach]. / El análisis de la mortalidad por causa múltiple: un nuevo enfoque.

Due to changes in mortality patterns, cronic and degenerative diseases have become a major problem in Mexico. Description and explanation of this kind of deaths is difficult by means of a single cause of death. In order to have a better understanding of this fenomenum an analysis of 4021 deaths occurred in Mexico city during april and may in 1985 using multiple cause of death was performed, this analysis take count of all causes reported in death certificates. With the method of multiple cause we found that the number of associated deaths, for example with hypertension and nutritional deficiencies, was considerably greater that when reported as underlying cause.

[Years of potential life lost in Mexico. Applications in the planning of health services]. / Años de vida potencial perdidos en México. Aplicaciones en la planeación de servicios de salud.

During health care services planning, rational and coherent information is required in order to allocate resources in accordance with local relative need. In an attempt to recognize the national condition, Stone's method was used. This is a semi-quantitative method for analysing the relationship between health care resources and need. Years of potential life lost index was used for need assessment among the states, and confronted to its Federal Public Health Investment. The optimum resource/need ratio is regarded as that pertaining to the reference population, the nation as a whole. Deviation from the optimum ratio in the states is interpreted as a manifestation of inequitable resource distribution. The results show striking differences in needs and resources. Resource/need ratio varied from 0.21 in Oaxaca to 3.79 in Distrito Federal. The states least favoured in resource sharing were Oaxaca, Puebla, Hidalgo and México. On the other hand, Tamaulipas, Baja California Sur, Quintana Roo and Distrito Federal exceeded the optimum. These indexes permit a quantitative expression of the relationship between need and resources in order to reach geographical equity.