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R Tapia-Conyer

Publications and source records attributed to R Tapia-Conyer.

At least 19 recordsLinked to original sources
PubMed2007

Mexican anthropometric percentiles for ages 10-18.

OBJECTIVE: To elaborate Mexican growth charts based on international methodology. DESIGN: Data were obtained from the Mexican National Health Survey. The survey was stratified and probabilistic representative of all the country. SETTING: Nationwide open population living in urban and rural areas. SUBJECTS: Boys (8545) and girls (9983) from 10 to 18 years participating in the survey. METHODS: Age, weight and height were recorded. Empirical percentiles were calculated and smoothed. Smoothed curves were approximated using least-mean square estimation. RESULTS: Tables and figures for percentile values of weight, height and body mass index (BMI) for age, as well as percentile values of weight and BMI for height for both genders are presented. Regarding 50th BMI for age percentiles, Mexicans had higher levels than the Americans in the Centers for Disease Control and Prevention growth charts; Mexicans were lower but had similar weights than the Americans. Owing to the high BMI, the percentile corresponding to an overweight level (25 kg/m(2)) at 18 years was 74.5 in boys and 72.5 in girls, whereas obesity level (30 kg/m(2)) at 18 years was 97.3 and 97.4 in boys and girls, respectively. CONCLUSIONS: The present growth charts are snapshots of a Mexican population. Because of the high median BMI compared to US and World Health Organization standards, we must be cautious in establishing an upper normal cutoff for clinical normality, not merely selecting the 85th and 95th percentiles as equivalents of overweight and obesity, respectively. Therefore, we proposed percentiles 74.5 in boys and 72.5 in girls as the action points of overweight as they are the percentiles corresponding to BMI 25 kg/m(2) at 18 years. SPONSORSHIP: The survey was supported by the Mexican Minister of Health. Statistical analyses were sponsored by Dr Del-Rio-Navarro.

Adolescent↗
PubMed2004

The body mass index is a less-sensitive tool for detecting cases with obesity-associated co-morbidities in short stature subjects.

OBJECTIVE: To assess the ability of the body mass index (BMI) to detect obesity-associated morbidity in subjects with a normal or short stature. METHODS: Information was obtained on 119 975 subjects from a cardiovascular risk factors detection program. Standardized questionnaires were used. Capillary glucose and cholesterol concentrations were measured. Diabetes, arterial hypertension and hypercholesterolemia were selected as end points. Sensitivity, specificity and the likelihood ratio for several BMI thresholds were calculated. ROC curves were constructed to identify the BMI cutoff points with best diagnostic performance. The area under the curve (AUC) was used to assess the proficiency of BMI. RESULTS: Short stature (height </=150 cm for women or </=160 cm for men) was found in 24 854 subjects (20.7%). These cases had a higher prevalence of type II diabetes and arterial hypertension even after adjusting for confounding variables. In addition, the frequency of the abnormalities was higher even at the lowest BMI values; the prevalence increased in direct proportion with the BMI, but at a lower rate compared to cases with normal stature. The AUC for every co-morbidity was smaller in short stature subjects. The likelihood ratio for detecting co-morbidities increased at the same BMI value in subjects with or without short stature. CONCLUSIONS: The prevalence of obesity-associated co-morbidities is higher in subjects with short stature compared to those without it. The proficiency of BMI as a diagnostic tool is poor in short stature subjects. This problem is not resolved by decreasing BMI thresholds used to define overweight.

Adult↗
PubMed2001

Evaluation and reform of Mexican National Epidemiological Surveillance System.

To generate timely and reliable information for decision making in local health centers, Mexico's National Epidemiological Surveillance System (SINAVE) was evaluated and reformed. The reform was achieved by consensus through national meetings of epidemiologists, using a conceptual model of requirements, leadership, participation, and motivation. The new SINAVE is run by committees that use data from 16 468 local health centers that generate homogeneous information from all health institutions. Indicators, flowcharts, and standardized instruments were created. The reforms modernized SINAVE and strengthened epidemiologists' leadership, consolidated local decision making, and assessed control actions needed to improve the health of the Mexican population.

Community Health Centers↗
PubMed2000

Survey of drug resistance of Mycobacterium tuberculosis in 3 Mexican states, 1997.

BACKGROUND: Drug resistance threatens global tuberculosis (TB) control efforts. Population-based estimates of drug resistance are needed to develop strategies for controlling drug-resistant TB in Mexico. OBJECTIVE: To obtain population-based data on Mycobacterium tuberculosis drug resistance in Mexico. METHODS: To obtain drug resistance data, we conducted a population-based study of TB cases in the states of Baja California, Sinaloa, and Oaxaca, Mexico. We performed cultures and drug susceptibility testing on M tuberculosis isolates from patients with newly diagnosed, smear-positive TB from April 1 to October 31, 1997. RESULTS: Mycobacterium tuberculosis was isolated from 460 (75%) of the 614 patients. Levels of resistance in new and retreatment TB cases to 1 or more of the 3 current first-line drugs used in Mexico (isoniazid, rifampin, and pyrazinamide) were 12.9% and 50.5%, respectively; the corresponding levels of multi-drug-resistant TB were 2.4% and 22.4%. Retreatment cases were significantly more likely than new cases to have isolates resistant to 1 or more of the 3 first-line drugs (relative risk [RR], 3.9; 95% confidence interval [CI], 2.8-5.5), to have isoniazid resistance (RR, 3.6; 95% CI, 2.5-5.2), and to have multi-drug-resistant TB (RR, 9.4; 95% CI, 4.3-20.2). CONCLUSIONS: This population-based study of M tuberculosis demonstrates moderately high levels of drug resistance. Important issues to consider in the national strategy to prevent M tuberculosis resistance in Mexico include consideration of the most appropriate initial therapy in patients with TB, the treatment of patients with multiple drug resistance, and surveillance or periodic surveys of resistance among new TB patients to monitor drug resistance trends.

Adult↗
PubMed2000

Prevalence of pre-obesity and obesity in urban adult Mexicans in comparison with other large surveys.

OBJECTIVE: 1. To estimate the prevalence of pre-obesity and obesity in a 1992 to 1993 national survey of the Mexican urban adult population. 2. To compare our findings with other national surveys and with data for Mexican Americans. RESEARCH METHODS AND PROCEDURES: The national representative sample of the Mexican urban adult population included 8462 women and 5929 men aged 20 to 69 years from 417 towns of >2500 people. Body mass index (BMI), calculated from measured weight and height, was classified using the World Health Organization categories of underweight (BMI < 18.5 kg/m2), normal weight (BMI 18.5 to 24.9 kg/m2), pre-obesity (PreOB = BMI 25 to 29.9 kg/m2) and obesity (OB = BMI 30+ kg/m2). Estimates for Mexican Americans were calculated from U.S. survey data. RESULTS: Overall, 38% of the Mexican urban adult population were classified as pre-obese and 21% as obese. Men had a higher prevalence of pre-obesity than women did at all ages, but women had higher values of obesity. Both pre-obesity and obesity increased with age up to the age range brackets of 40 to 49 or 50 to 59 years for both men and women. Both pre-obesity and obesity prevalence estimates were remarkably similar to data for Mexican Americans from 1982 through 1984. Comparison with other large surveys showed that countries differed more in the prevalence of obesity than of pre-obesity, leading to differences in the PreOB/OB ratio, and that countries also differed in the gender ratio (female/male) for both pre-obesity and obesity. DISCUSSION: Pre-obesity and obesity were high in our population and increased with age. Our approach of characterizing large surveys by PreOB/OB and gender ratios appeared promising.

Adult↗
PubMed1999

Hypertension in urban Mexico: the 1992-93 national survey of chronic diseases.

The purpose of this work is to estimate the prevalence of hypertension in the urban population of Mexico. We studied a multistage national sample representative of the urban population in 417 cities of over 2500 people. The blood pressure of 14 657 individuals (6053 men and 8604 women) aged 20-69 years was measured after a 5-min rest using a standard mercury sphygmomanometer. The survey personnel had been previously trained and standardised. The main results show a crude prevalence of hypertension, as defined by the JNC VI, of 28.1% in women and 37.5% in men (27.2% and 37.1% age-adjusted). Both genders exhibited a trend of increasing hypertension with age. In individuals under 50 years of age, women had lower rates than men, but the difference disappeared in the older groups. The awareness of hypertension (28%) as well as the success of treatment (22%) were low in our sample. Our results had more similarities than differences with respect to those observed in other national surveys. It is concluded that hypertension in Mexico is an important public health problem similar to that seen in developing and developed nations. Efforts should be aimed at strengthening measures to prevent and control hypertension in Mexico. More information is needed of the sort obtained from longitudinal studies.

Adult↗
PubMed1999

Serologic IgG response to urease in Helicobacter pylori-infected persons from Mexico.

Helicobacter pylori urease is required to counteract acidity during colonization of the stomach, and has been suggested as a major immunodominant antigen. The aim of this study was to determine the anti-urease response in a representative national serologic survey in Mexico. The population surveyed included persons 1-90 years of age from all socioeconomic levels and geographic zones of the country. Helicobacter pylori status was determined by ELISA serology. The IgG anti-urease was studied by ELISA using a recombinant apoenzyme. We found that 2,930 of the 7,720 infected patients (38%) were seropositive for IgG urease. The rate of IgG anti-urease positivity increased with age; in children < 10 years old it was < 20% and in persons > 40 years old it was > 50%. Age and a region with a high level of development were risk factors for seropositivity, whereas gender, educational level, crowding, and socioeconomic level were not associated with seropositivity. In conclusion, in natural infection with H. pylori, the response to urease is poor, mainly during the first years of infection. This inconsistent immune response to the enzyme may favor persistence of infection. A vaccine eliciting a consistent anti-urease response might overcome immune evasion and enhance clearance of bacteria after exposure.

Adolescent↗
PubMed1999

Hepatitis A in Latin America: a changing epidemiologic pattern.

In a multicenter study, hepatitis A virus (HAV) seroprevalence was surveyed in six countries in Latin America in which in 12,000 subjects were stratified for age. The highest rates of seroprevalence were recorded in the Dominican Republic (89.0%) and Mexico (81.0%), with lower rates in Brazil (64.7%), Chile (58.1%), Venezuela (55.7%), and Argentina (55.0%). The seroprevalence of HAV in children between 1 and 5 years of age was less than 50%, except in the Dominican Republic. In the 5-10-year-old age group, seroprevalence rates have also decreased compared with previous reports. This suggests that the epidemiology is shifting from high to intermediate endemicity, with the population susceptible to HAV infection shifting from children to adolescents and adults. Furthermore, data from Brazil, Argentina, and Mexico show that HAV seroprevalence is significantly lower in people living in medium and high socioeconomic conditions. This study suggests the need for appropriate vaccination programs to be implemented targeting children, adolescents, and adults, particularly in higher socioeconomic groups.

Adolescent↗
PubMed1998

A community-based seroepidemiologic study of Helicobacter pylori infection in Mexico.

A nationwide community-based survey for Helicobacter pylori infection had not been done. This study sought to determine the seroprevalence of infection in Mexico, and the socioeconomic and demographic variables that are risk factors for infection. The survey assessed 11,605 sera from a sample population representing persons ages 1-90 years from all socioeconomic and demographic levels and from all regions of Mexico. Antibodies against H. pylori were studied by ELISA using whole cell antigen. Among the findings were that 66% of the population was infected and that age was the strongest risk factor for infection. By age 1 year, 20% were infected and by age 10 years, 50% were infected. Crowding (odds ratio [OR], 1.4), low educational level (OR, 2.42), and low socioeconomic level (OR, 1.43) were risk factors for infection. Prevalence was similar in urban and in rural communities (OR, 0.95). This study is the largest community-based seroepidemiologic study of H. pylori to date.

Adolescent↗
PubMed1997

Higher milk intake during pregnancy is associated with lower maternal and umbilical cord lead levels in postpartum women.

Lead exposure and its deleterious effects continue to be a problem in many countries. The lack of effective and safe treatments for low-level intoxication has promoted environmental interventions to control different sources of lead. In this study we evaluated the effect of milk consumption in 1849 mother-and-child pairs participating in the lead surveillance program in Mexico City. The mean lead levels were 11.2 micrograms/dL for maternal blood lead (MBL) and 10.8 micrograms/dL in umbilical cord. The correlation between blood lead and umbilical cord lead was r = 0.74. Forty-eight percent of the MBL exceeded 10 micrograms/dL and 9.5% exceeded 20 micrograms/dL. Maternal blood lead was positively related to the use of lead-glazed ceramic were and to traffic exposure and was inversely related to the consumption of milk and orange juice. Women who reported the consumption of more than 7 glasses of milk per week had a blood lead level of 8.7 micrograms/dL; in comparison, those women who reported a consumption of less than 7 glasses per week had a blood lead level of 11.1 micrograms/dL. Similar findings were observed for lead measured in umbilical cord. The association between lead levels and milk intake remained unchanged after taking in consideration other predictors of blood lead. This study suggests that a simple intervention could reduce lead burden among women and their newborns.

Animals↗
PubMed1997

First record in America of Aedes albopictus naturally infected with dengue virus during the 1995 outbreak at Reynosa, Mexico.

Mosquito collections were conducted during a dengue outbreak in Reynosa, Tamaulipas, Mexico, July-December 1995. A total of 6694 adult mosquitoes (four genera and nine species) were captured, of which 2986 (78.3% females and 21.7% males) were Aedes albopictus and 2339 (39.7% females and 60.3% males) were Ae.aegypti. These two species comprised 84.2% of the total collection. Specimens were grouped into pools, nearly 50% of them processed for detection of virus by cythopathic effect in C6-36 and VERO cell cultures and by haemagglutination test. Five pools gave positive haemagglutination reactions and were examined by immunofluorescence using monoclonal antibodies to flavivirus and to dengue virus. One pool of ten Ae.albopictus males was positive for dengue virus: serotypes 2 and 3 were identified by serotype-specific monoclonal antibodies and confirmed by RT-PCR. This is the first report of Ae.albopictus naturally infected with dengue virus in America. Also, it is the very first time Ae.albopictus males have been found infected with dengue virus in the wild.

Aedes↗
PubMed1997

Alcohol consumption and pregnancy in the Mexican national addiction survey.

In 1988, the General Directorate of Epidemiology and the Mexican Institute of Psychiatry conducted the first National Addiction Survey (ENA), providing regional and national data on alcohol, tobacco, and drug use. The ENA providing a subsample of women who have been pregnant at some time in their lives. There were 5,234 affirmative responses. Women were asked if they had suffered any of three adverse outcomes during their last pregnancy: spontaneous abortion, stillbirth, and congenital abnormalities. Prevalence of spontaneous abortion was 3.8%, stillbirth 1.2%, and congenital abnormalities 1.1 %. Multiple logistic-regression models were used to analyze the effect of alcohol consumption on these problems. Consumption during pregnancy was related only with the prevalence of congenital abnormalities, with prevalence odds of 3.4. Among habitual users during the last 12 months, oniy women in the highest use category showed an important relationship with the three problems mentioned. Follow-up studies on the Mexican population are recommended in order to obtain more conclusive findings.

Journal Article↗
PubMed1997

[Molecular epidemiology in the epidemiological transition].

The epidemiological transition describes the changes in the health profile of populations where infectious diseases are substituted by chronic or non-communicable diseases. Even in industrialized countries, infectious diseases emerge as important public health problems and with a very important association with several type of neoplasm. Molecular epidemiology brings in new tools for the study of the epidemiological transition by discovering infectious agents as etiology of diseases, neither of both new. Much has been advanced in the understanding of the virulence and resistance mechanism of different strains, or improving the knowledge on transmission dynamics and dissemination pathways of infectious diseases. As to the non-communicable diseases, molecular epidemiology has enhanced the identification of endogenous risk factors link to alterations, molecular changes in genetic material, that will allow a more detail definition of risk and the identification of individual and groups at risk of several diseases. The potential impact of molecular epidemiology in other areas as environmental, lifestyles and nutritional areas are illustrated with several examples.

Chronic Disease↗
PubMed1996

Impact of oral rehydration and selected public health interventions on reduction of mortality from childhood diarrhoeal diseases in Mexico.

Reported are the results of an analysis of mortality trends from diarrhoeal diseases among under-5-year-olds in Mexico between 1978 and 1993 in relation to the impact of education, basic sanitation, and selected medical care practices. The study period was divided into three stages; the first pre-dated the widespread application of oral rehydration therapy (ORT); the second, covered the implementation of a nationwide programme promoting ORT; and the third included additional measures, such as immunization and improvements in basic sanitation. Mortality rates decreased progressively, at an average of 1.8% per year in the first stage, 6.4% in the second, and 17.8% in the third. The importance of literacy campaigns for women and the promotion of ORT was confirmed. Both of these measures reduced mortality; however, a greater reduction resulted from a massive immunization campaign against measles and improvements in sanitation (expansion of the drainage and piped water systems, improved water chlorination procedure, and effective prohibition of the use of sanitary sewage for vegetable irrigation).

Adult↗
PubMed1995

Cholesterol levels and prevalence of hypercholesterolemia in a Mexican adult population.

In Mexico, the incidence and prevalence of coronary heart disease (CHD) has increased over the past three decades and has become the leading cause of death in the country. Hypercholesterolemia is a major risk factor for coronary atherosclerosis and most developed countries currently have public health strategies that attempt to reduce the level of cholesterol. In order to determine the mean total cholesterol values and the prevalence of hypercholesterolemia, an epidemiologic survey was carried out in a representative national population sample that included men and women aged 1 to 98 years. In this report, we present the findings in all individuals older than 20 years (n = 33,558). Considering the country as a whole, the mean serum total cholesterol (TC) was 4.80 +/- 1.16 mmol/l, the prevalence of borderline hypercholesterolemia (TC between 5.17 and 6.20 mmol/l) was 22.8% and the prevalence of high risk hypercholesterolemia (TC > or = 6.20 mmol/l) was 10.6%. This cross sectional study demonstrated the existence of significant geographic differences in serum TC, with mean state values ranging from 4.43 +/- 1.05 mmol/l in the south to 5.48 +/- 1.36 mmol/l in the north. The prevalence of high risk hypercholesterolemia was as high as 24.8% in Baja California Norte and as low as 4.0% in the state of Guerrero. These large differences in mean TC values are probably diet related and reinforce the need to carry out prospective and intervention trials related to CHD and its risk factors.

Adolescent↗