Gustavo Olaiz-Fernández

Seroprevalencia de la hepatitis C en adultos de México: ¿un problema de salud pública emergente?

Objective. Hepatitis C Virus (HCV) infection is becoming a chronic disease in 60-85% of individuals and is a cause of hepatic cirrhosis and hepatocellular carcinoma. The objective of this study was to report the seroprevalence of HCV infection in a probabilistic sample of the Mexican population. Material and Methods. This study is based on information obtained from the National Health Survey conducted in 2000. A total of 21 271 sera randomly selected for anti-HCV and RNA of HCV was studied. It was performed at the National Institute of Public Health in 2005. Results. Seroprevalence of HCV antibodies was 1.4% (IC95% 1.1%-1.6%), of which 35.7% had active infection. Risk factors for infection were using heroine (RM= 9.8, IC: 2.1-41.4), being separated from his/her spouse (RM= 2.6, IC: 1.1-5.9), being a widower (RM= 2.2, IC: 1.1-4.3) and living in the northern states in the country (RM= 1.9, IC: 1.1-3.2). Conclusion. Results from this study indicate that HCV is an emerging public health problem in Mexico. Risk factors indicate that the main route of transmission is through transfusion of blood products (previous to 1996) and the second route is through usage of intravenous drugs and sexual practices.

Diabetes mellitus en adultos mexicanos: resultados de la Encuesta Nacional de Salud 2000

Objective. To show the prevalence of diabetes mellitus (DM) and its associated factors in adults, using data derived from the 2000 National Health Survey (NHS). Material and Methods. The 2000 NHS was conducted between November 1999 and June 2000. An adult questionnaire was administered to 45 294 subjects 20 years of age and older. Capillary glucose levels, weight, height and blood pressure were obtained. Individual weighted factors were considered in the statistical analysis, as was the survey’s complex sampling design to obtain variances using SUDAAN 7.5.6. Results. The national prevalence of DM in adults ages 20 years and older was 7.5% (95% CI: 7.1-7.9). The prevalence was 7.8% in women and 7.2% in men. It was higher according to age: 2.3% in adults 40 years or younger and 21.2% in those older than 60 years of age. In the urban population, prevalence was 8.1% and in the rural population it was 6.5%. The disease was more frequent in the northern region of the country (8.4%) and in the Mexico City metropolitan area (8.1%). DM was more frequent in the population with the least amount of schooling (9.9%), the lowest income (8.1%), high blood pressure (13.7%), hypercholesterolemia (23.3%) microalbuminuria (15.5%) and renal disease (12.3%). Using multivariate logistic regression, stratified by gender, variables associated with DM were identified: age, little schooling, family history of DM, high blood pressure, renal disease or hypercholesterolemia in both genders. Abdominal obesity was associated with DM in women only and living in an urban area was associated with DM only in men. The highest associations were observed

Perfil del comportamiento sexual en adolescentes mexicanos de 12 a 19 años de edad: resultados de la ENSA 2000

Objective. To describe traits associated with sexual behaviors in Mexican adolescents, their knowledge about contraception, and factors associated with pregnancy and utilization of contraceptives during first sexual intercourse. Material and Methods. Data from the Mexican National Health Survey 2000 (ENSA 2000) were analyzed. This study, conducted between September 1999 and March 2000, was a complex survey with a probabilistic, stratified, and cluster sampling design. The sample population included 15 241 adolescents 12 to 19 years of age. Data analysis included descriptive statistics and a chi-squared test for differences of proportions; also, logistic regression was used to obtain odds ratios. Results. A total of 69.2% adolescents reported knowledge of at least one contraception method; 16.4% of subjects reported having had sexual intercourse. Males initiated sexual intercourse earlier than females and only 37% of all adolescents utilized contraceptives during their first sexual intercourse. Logistic regression analysis showed that being male, having a higher education, having knowledge of at least one contraception method, and having initiated sexual intercourse at an older age, were factors associated with utilization of a contraception method in their first sexual intercourse. A total of 55.7% of sexually active female adolescents had been pregnant. Pregnancy among adolescents was associated with low educational level, sexual activity at early age, and to have sometime lived in free union. Conclusions. The majority of sexually active adolescents did not use contraception during their first sexual intercourse, rendering them at risk of unwanted pregnancies.

Dyslipidemias and obesity in Mexico

Objective. To describe in a national sample 1) the mean total cholesterol (TC), HDL-cholesterol (HDLc) and triglyceride (TG) concentrations, 2) the prevalence of the most common lipid abnormalities and 3) the association between obesity and these conditions. Material and Methods. We analyzed the nationally representative, cross-sectional Mexican Health Survey (2000). The final analytic sample used consisted of 2 351 individuals at fasting state. TC, HDLc and TG were determined. BMI was classified according to the WHO cutoff points. Sex-specific means and 95% confidence intervals (95%CI) were calculated by age group for TC, HDLc and TG. The prevalence of: a) hypercholesterolemia (HC), b) hypoalphalipoproteinemia (HA), c) hypertriglyceridemia (HT), d) HT with HA and e) HC with HT was calculated adjusting for age. Multivariate logistic regression models were estimated to analyze the association of obesity to the prevalence of dyslipidemias. Results. The mean TC, HDLc, and TG concentrations were: 197.5 mg/dl (95% CI= 194.0, 201.1), 38.4 mg/dl (95% CI= 37.2, 39.5) and 181.7 mg/dl (95% CI= 172.7, 190.6), respectively. HC was present in 40.5% of the adult females (95% CI=35.5, 45.4) and 44.6 of the adult males (95% CI=37.7, 51.4); HA was the most prevalent form of dyslipidemia, present in 64.7% (95% CI=58.7, 70.8) and 61.4% (95% CI=54.4, 68.3) of females and males, respectively. Obesity increased ~1.4 times the probability ratio (PR) of having HC among women and 1.9 among men. Conclusion. TC concentrations from our study in Mexico were similar to those found for Mexican-Americans and the prevalence of HC was slightly lower than the one reported in the US;

Prevalencia en México de la infección y el estado de portador de la hepatitis B en adultos

Objective. To estimate the prevalence of chronic hepatitis B infection and carrier status in Mexico; to analyze the frequency and distribution of hepatitis B markers in relation to the demographic and geographic variables and to identify risk factors. Materials and Methods. A total of 12 014 sera samples from the 2000 National Health Survey that were randomly selected for Anti-HB c and HBsAg were studied. The sera were collected between November 1999 and June 2000 on a national level. Results. Seroprevalence for anti-HB c and HBsAg were 3.3% (CI 95%: 2.8-3.9) and 0.21% (0.11-0.37), respectively. Odds ratios adjusted by age for anti-HB c were: 15.3 for subjects 50 to 59 years old as compared with adults less than 29 years of age; 2.6 for residents in the southern region of the country as compared with residents in the central region; 4.6 for laborers as compared with business owners; 2.1 for women having had stillbirths; and 1.7 for adults having initiated sexual relations before 25 years of age. Conclusion. The epidemiological pattern for hepatitis B in Mexico is lower than the data worldwide. Nevertheless, it is of concern that 1.7 million Mexicans have suffered from the infection caused by this virus and 107 000 suffer from a chronic carrier status.

Los efectos agudos de la contaminación del aire en la salud de la población: evidencias de estudios epidemiológicos

Rosales-Castillo JA, Torres-Meza VM, Olaiz-Fernandez G, Borja-Aburto VH. Acute effects of air pollution on health: Evidence from epidemiological studies. Salud Publica Mex 2001;43:544-555. The English version of this paper is available at: http://www.insp.mx/salud/index.html Abstract Objective. To summarize the evidence of acute health ef- fects from exposure to particulate matter and ozone. Ma- terial and Methods. A meta-analysis was performed using random effect models, to summarize the health effects of pollution, published in major international and Mexican jour- nals up to June 2000. Results. Results were given as per- cent increase in ten units of PM10 (µg/m3) and ozone (ppb). PM10 was found to have an effect on mortality (0.96%), hospital admissions (1.39%), emergency room visits (3.11%), respiratory symptoms (7.72%), pulmonary forced vital ca- pacity (1.42%), and restricted activity days (7.74%). Ozone effects were equally significant. Conclusions. These find- ings show the great impact that air pollutants may have on the health of populations living in large metropolis. The Eng- lish version of this paper is available at: http://www.insp.mx/ salud/index.html

Body mass index associated with hyperglycemia and alterations of components of metabolic syndrome in Mexican adolescents

Objective. This research aims to describe the epidemiology of obesity and its association with alterations in some components of metabolic syndrome, such as serum concentrations of glucose, insulin, and some lipids in a sub-sample of the Mexican Health Survey (MHS) of youth ages 10 to 19 years. Material and Methods. This analysis is based on a randomly selected sub-sample of the MHS of 20% of the youth ages 10 to19 years (n=1977), carried-out in Mexico in the year 2000 and distinguishes differences between national, rural and urban areas as well as four geographical country regions. Serum concentrations of glucose, insulin, triglycerides (TG), total cholesterol (TC) and HDL-cholesterol (HDLc) were measured. The protocol was approved by the Ethics Committee of the Mexican National Institute of Public Health. Results. Overall, 14.8% of the individuals were overweight, 6.7% were obese and 37.5% had a family history of type 2 diabetes mellitus (DM2). The overall mean concentrations of glucose, insulin, total cholesterol, and triglycerides were significantly higher and those of HDLc were significantly lower in obese subjects than in individuals with normal Body Mass Index (BMI) (p< 0.05-0.001). The probability ratio (PR) of being in quintile 5 for glucose distribution was significantly higher for obese males and females (RP=2.1, p<0.001) than for their non-obese counterparts. It was also higher for females with a history of DM2 (RP=1.12, p<0.02), but not for males. The PR of being in quintile 5 for insulin distribution was significantly higher for obese males (RP=3.51, p<0.001) and females (RP=3.3, p<0.001) than for non-obese counterparts. It was

Surveillance of acute health effects of air pollution in Mexico City.

Background: A unique, active, timely, low-cost surveillance system for the metropolitan area of Mexico City was established in the mid-1990s. Methods: The system obtained upper and lower respiratory tract symptoms and eye symptoms from daily interviews for a systematic sample of the general nonhospitalized population living within a 2-km radius of air pollution monitors during 1996-1997. Results: Ozone increments (10 ppb) were associated with upper respiratory symptoms (odds ratio [OR] = 1.003; 95% confidence interval [CI] = 1.002-1.004) and ocular symptoms indicators (OR = 1.005; CI = 1.004-1.007), and with a higher risk of lower respiratory symptoms indicator among nonsmokers (OR = 1.003; CI = 1.002-1.005). Increases in relative humidity reduced the risk of increments of sulfur dioxide on the 3 acute health indicators. Association of PM10 with health indicators varied among the 5 regions. During emergency episodes, symptoms increased sharply when ozone reached 281 ppb, a finding that resulted in a change in the ozone criteria for emergency declaration from 294 to 281 ppb. Conclusions: This system has been low cost, timely, and useful for local decision making.

Concentraciones de proteína C reactiva en adultos mexicanos: alta prevalencia de un factor de riesgo cardiovascular

OBJETIVO: Examinar la distribucion y variables relacionadas con las concentraciones de proteina C reactiva (CRP) en adultos mexicanos. MATERIAL Y METODOS: Se estudio a 2 194 adultos que participaron en la ENSA 2000. La concentracion de CRP en suero se midio por un metodo de alta sensibilidad. Se obtuvo informacion sobre caracteristicas sociodemograficas, enfermedad cronica y habitos. Se midieron glucosa en ayuno, presion arterial, peso, talla y circunferencia de cintura. RESULTADOS: Se estudio a 730 hombres y 1 464 mujeres no embarazadas. La edad promedio fue de 38.3±15.2 anos. Los limites de CRP se hallaron entre 0.19 y 255 mg/l (mediana: 2.26; rango intercuartil (RI): 0.96, 5.83 mg/l). La concentracion de CRP fue mayor en mujeres (mediana: 2.86; RI: 1.11, 6.68 mg/l) en comparacion con los hombres (mediana: 1.63; RI: 0.8, 3.87 mg/l; p 3.0-10 mg/l. En el analisis multivariado de regresion probit, la edad, el IMC, la circunferencia de cintura, la diabetes mellitus, la microalbuminuria y el uso de anticonceptivos hormonales se vincularon de forma positiva con el riesgo de concentraciones de CRP >1 mg/l. El sexo masculino y el consumo moderado de alcohol se relacionaron de modo negativo con el riesgo de concentraciones de CRP >3 mg/l (p 3.0-10 mg/l en adultos mexicanos, lo que indica una considerable proporcion de individuos con alto riesgo cardiovascular, al margen de otros factores de riesgo.

Niveles de plomo sanguíneo en madres y recién nacidos derechohabientes del Instituto Mexicano del Seguro Social

OBJETIVO: Establecer la relacion entre el nivel de plomo sanguineo materno (PSM) y el de sangre en cordon umbilical (PSC) al momento del parto, asi como determinar los principales predictores del PSM en derechohabientes del Instituto Mexicano del Seguro Social (IMSS), en el Distrito Federal (D.F.). MATERIAL Y METODOS: Se realizo un estudio transversal en el que se reclutaron voluntarias con embarazo normoevolutivo y se les tomaron muestras de sangre al momento del parto, en cuatro hospitales del IMSS en el D.F., de 1991 a 1993. Se tomo, ademas, muestra de sangre de cordon umbilical. Los datos fueron analizados mediante regresion lineal simple y multiple. RESULTADOS: Se estudiaron un total de 1 404 binomios madre-hijo; el promedio de edad de las madres fue de 25 anos. La media de PSM fue 10.7 ± 6.5 µg/dl; no se encontraron variaciones significativas por hospital, edad o estado civil. Para el PSC la media fue de 10.4 ± 6.2 µg/dl. Por cada aumento en una unidad logaritmica de PSM, el PSC aumenta 0.62 (p<0.01) unidades logaritmicas. La correlacion entre ambos fue de 0.61 (p<0.01). Los principales predictores de PSM fueron el uso de loza vidriada, el consumo de leche y jugo de naranja, estos ultimos se asociaron inversamente con el PSM. Un 47% de las madres y 50% de los ninos tuvieron valores superiores a 10 µg/dl. En 578 recien nacidos se registraron niveles de plomo superiores a los de la madre. CONCLUSIONES: Se sugiere continuar la linea de investigacion para proponer tipos de intervencion.