[Lead blood levels in mothers and newborn infants covered by the Mexican Institute of Social Security]. / Niveles de plomo sanguíneo en madres y recién nacidos derechohabientes del Instituto Mexicano del Seguro Social.

OBJECTIVE: To establish the relation between maternal blood lead (MBL) and umbilical cord blood lead (CBL) levels during delivery, and to determine the major predictors for MBL in women covered by the Mexican Institute of Social Security (MISS), in Mexico City. MATERIAL AND METHODS: From 1991 to 1993, a cross-sectional study was conducted in four MISS hospitals, among normal pregnant women who volunteered to participate. Blood samples were taken from women and from the umbilical cord during delivery. Statistical analysis consisted of descriptive statistics and simple and multiple linear regression. RESULTS: A total of 1,404 mother-newborn pairs were studied. Mean maternal age was 25 years. MBL average was 10.7 +/- 6.5 micrograms/dl; no significant differences were found by hospital, age, or marital status. Mean CBL was 10.4 +/- 6.2 micrograms/dl. A log unit increase in MBL corresponded to a log increase of 0.62 in CBL (p < 0.01). Pearson's correlation was 0.61 (p < 0.01). The main predictors of MBL were: Use of lead-glazed ceramic (positively associated) and milk and orange juice intake (negatively associated). Forty-seven percent of mothers and 50 percent of the newborn babies had values higher than 10 micrograms/dl, and 578 of them had blood lead levels higher than their mothers. CONCLUSIONS: Further studies should be carried out in order to identify necessary interventions.

Validity and reproducibility of cytologic diagnosis in a sample of cervical cancer screening centers in Mexico.

OBJECTIVE: To evaluate the diagnostic precision of the cervical cytology (smear) in a sample of 16 cervical cancer screening centers (CCSCs) from the Mexican Ministry of Health and Mexican Institute for Social Security CCSCs distributed across the country. STUDY DESIGN: Each center received a batch of 90 cytologic specimens with a random positive prevalence of 1.5-36%. Positive cases were always histologically confirmed. The "gold standard" was an expert pathologist certified by the Mexican Board of Pathology. RESULTS: Our results show that cytologic diagnosis validity and reproducibility vary greatly within and between institutions. The false negative rate (FNR) varied between 10% and 54%, independent of the prevalence of positive cases. CONCLUSION: Quality control of diagnostic precision is central to the consistency of results obtained at CCSCs. In Mexico the high FNR calls for governmental regulation of cytopathology policies and methods, such as through national and international accreditation of cytotechnology programs. In order to decrease the FNR, developing countries must frame managerial development strategies to streamline the cervical cancer screening program, including continuing education, improvement of operation processes in CCSCs, internal and external quality control of cytopathology laboratories and cervical sampling procedures, and standardization of diagnostic criteria.

[Amebiasis and amebic liver abscess in Mexico: a present-day public health problem]. / La amibiasis y el absceso hepático amibiano en México, un problema de salud pública de actualidad.

BACKGROUND: Amebiasis still remains as a major public health problem in the world. It is one of the most common reasons for medical consult. There are more than half a million cases of amebiasis just at the Mexican Institute of the Social Security. There is still a lack of epidemiologic information on amebiasis in Mexico. AIM: To describe the secular trend fro amebiasis and for amebic liver abscess in the Mexican population, as well as in those covered by IMSS Solidaridad. METHOD: An ecologic trend study was carried on. Incidence rate of amebiasis in all of its forms of presentation, and of amebic liver abscess, were plotted against each year for the 1986-1994 period. RESULTS: Amebiasis incidence in all of its forms of presentation showed a stable trend in this period, as it was seen with amebic liver abscess. Amebiasis is more common in the first years of life. On the contrary, amebic liver abscess showed an inverted 'J' pattern; its occurrence is higher in the extreme years of life. Fatality rates have shown a descendent trend. CONCLUSIONS: Amebiasis reflects socioeconomic conditions in Mexico and the fact that Mexican is still an endless culture. There is a need to promote health education, better diagnostic procedures and detection of asymptomatic carriers. Health policies for mothers that are asymptomatic carriers should be reviewed, due to the high rates of amebiasis and amebic liver abscess in children under one year of age.

Amebiasis in the epidemiologic transition in Mexico: its morbidity and mortality trends in the Mexican Institute of Social Security.

Amebiasis is one of the most common parasite-related diseases and one of those with the greatest impact on health. At the Instituto Mexicano del Seguro Social (Mexican Institute of Social Security-IMSS) approximately half a million cases per year are currently treated. Of these, more than 2500 correspond to the form which invades the liver. Within the process of epidemiologic transition which Mexico is undergoing, a progressive reduction has been observed in incidence of, and mortality due to, invading amebiasis in all its clinical forms. In turn, there is a significant decrease in its fatality rate. The social and economic development and improved sanitary conditions observed in Mexico, particularly in the second half of this century, may have conditioned this process. The improvement in availability, accessibility and utilization of medical care services could also explain the reduction which has been noted in its fatality rate and mortality. The model for epidemiologic transition proposed by Omran and adapted for Mexico by Frenk, offers a plausible explanation for the changes observed in the occurrence and mortality of invading amebiasis in Mexico.

[The need, supply and demand for epidemiological research personnel in the Instituto Mexicano del Seguro Social]. / Necesidades, oferta y demanda de personal en investigación epidemiológica en el Instituto Mexicano del Seguro Social.

In 1991 the Directorate of Public Health was created at the Mexican Institute for Social Security, with its epidemiologic activities oriented towards surveillance and research. This new vision, as well as the epidemiologic transition in Mexico, have raised the need for researchers training. In 1988 the Specialization Course in Public Health was developed as a response to the detected needs. This course was reformed three years later in duration, depth and name (Epidemiology instead of Public Health). The requirement of a thesis has led to the development of epidemiologic and health services research. Two diplomates in epidemiology and immunology and microbiology were also developed as a response to the need of actualization due to the advances in epidemiologic methodology in the past decades. A demand for actualization and continuous education has been expressed by the epidemiologists through a survey. The Directorate has also proposed priority themes for research in order to guide the requirements of research raised by the epidemiologist already trained at the Institute.

[The prevalence of non-insulin-dependent diabetes mellitus and the associated risk factors in a population of Mexico, D. F]. / Prevalencia de diabetes mellitus no insulinodependiente y factores de riesgo asociados en una población de México, D.F.

Non-insulin-dependent diabetes mellitus (NIDDM) is a chronic disabling disease, that shortens length of life and implies a high burden for a community. Its prevalence goes from 0 per cent in Papua, New Guinea to 34 per cent in Pima Indians. There are very few prevalence studies in Mexico, and the strength of association of the known risk factors with the occurrence of the disease is not established. A prevalence cross sectional study was carried out with users of a first level medical care unit, with a meter measure of capillary glucose levels. Those with a previous diagnosis of diabetes or whose capillary glucose level were 200 mg or over were considered diabetics. Hyperglycemia was when the levels were recorded between 121 and 199 mg. The crude prevalence of NIDDM was 5.6 per cent (CI 95% 4.5-6.8), With almost no sex difference. Hyperglycemia prevalence was 2.9 per cent (CI 95% 2.0-3.7). Age was the main risk factor for the development of NIDDM. Those between 40 and 59 years showed a high risk (OR 10.8; CI 95% 5.4-22.0; p < 0.0001), and it was greater for the 60 years or elder (OR 20.6; CI 95% 9.8-44.1; p < 0.0001). Weight was also an important risk factor, with a 2.7 fold greater risk for obese persons (CI 95% 1.6-4.6; p < 0.0001). Other, risk factors were familiar history of diabetes (OR 1.5; CI 95% 0.9-2.3; p = 0.096), and overcrowding (OR 1.9; CI 95% 1.0-3.4; p = 0.03). In order to analyze independently each variable, a logistic regression model was applied, and a similar strength of association was observed for the crude model, but for obesity whose effect was modified by age. When only new cases were analyzed in the former model, the association with obesity was maintained. There is a need to develop prevalence studies of NIDDM in Mexico and to measure the strength of association with the known and the not jet well known risk factors of this disease in order to establish health policies according to the Mexican reality.

[Main causes of non-compliance with pulmonary tuberculosis treatment]. / Principales causas de abandono del tratamiento contra la tuberculosis pulmonar.

One hundred rural patient with pulmonary tuberculosis and 74 urban patients were included in the study in order to study the main causes of non-compliance. Crude cumulative incidencia was 42% (73/164). Those factors with the strongest association with non-compliance, independently of its association with other factors, were to live in rural areas (OR 0 10.4; p < 0.001), had not gone to school (analfabet) (OR = 4.5; p < 0.001), and last more than an hour to reach the medical care unit (protector) (OR = 0.40; p = 0.07). No association was found with socioeconomic factors, neither with the patient's knowledge of the disease. Identifying those factors related to non-compliance is important, since non-compliance occurs in the very firsts days of treatment, when the shortage of treatment or giving fewer pills do not work at all. To get a better medial control may be a good way to reach the expected control of the disease.

[Epidemiology of cervical cancer at the Mexican Institute of Social Security]. / Epidemiología del cáncer cervicouterino en el Instituto Mexicano del Seguro Social.

In order to study the secular trend and age and geographic distribution of cervical cancer at the Mexican Institute for Social Security, an ecologic study was carried on. During the last 10 years cervical cancer has been the second most common neoplasia, being the leading one in women. For those between 30 and 44 years old it is the third cause of death, and one of the first ten in all age groups until 64. Mortality has shown a stable trend for the last 15 years, in a range from 3.3 to 4.5 deaths per 100,000 inhabitants. Mortality rates increase with age. There is a fine-fold increase in the risk of death for women 40 to 49 years old (CI 95% 4.2-6.4%) and a tenfold increase for those over 80, (CI 95% 7.3-12.6) when taking those under 40 years old as a reference group. In 1989, the cervical cancer incidence was 9.7 cases for each 100,000 person-years. Morbidity and mortality are unequally distributed along the country. There is a need for the development of research in order to know better the occurrence of this disease as well as how known risk factors affect it.

[Strategy for controlling poliomyelitis in Mexico: greater vaccination coverage of children less than 1 year of age]. / Una estrategia para el control de la poliomielitis en México: mayor cobertura de vacunación en menores de un año.

In spite of the widespread use of oral poliovirus vaccine, some countries have not achieved an optimal control of poliomyelitis. According to Sabin, this fact is due to a lack of immunization coverage of children under one year of age. In this study, the relationship between the general morbidity rate for polio and vaccination coverage of children under one year of age, in people protected by the Mexican Institute of Social Security, is analyzed. There is a negative correlation between these two variables: the lesser the coverage, the greater the rates. There is also a correlation between the rate of polio and the rate of polio for the year prior to each of the years of the study period. In a multiple regression model, both the coverage and the rate for the previous year were significantly correlated with the rate of polio. In order to get an optimum control of this disease, it is advantageous to consider that it is not enough to increase the coverage but that this coverage must be opportune, i.e., in the first year of life.