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Search Results: 1 - 10 of 36621 matches for " Maritsa; Hernández-Avila "
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Presentación
Hernández-Avila Mauricio
Salud Pública de México , 2003,
Abstract:
Abstract
HERNáNDEZ-AVILA MAURICIO
Salud Pública de México , 1997,
Abstract:
Abstract
HERNáNDEZ-AVILA MAURICIO
Salud Pública de México , 1997,
Abstract:
EDITORIAL
HERNáNDEZ-AVILA MAURICIO
Salud Pública de México , 1998,
Abstract:
Exposición al plomo y su relación con el tiempo requerido para embarazo
Guerra-Tamayo,Juan Luis; Hernández-Cadena,Leticia; Téllez-Rojo,Martha María; Mercado-García,Adriana del S; Solano-González,Maritsa; Hernández-Avila,Mauricio; Hu,Howard;
Salud Pública de México , 2003, DOI: 10.1590/S0036-36342003000800004
Abstract: objective: to determine the effects of lead exposure on the time elapsed to become pregnant. material and methods: the study population consisted of 142 women residing in mexico city between 1997 and 2001, who were already participating in a study to evaluate effects of lead exposure on reproductive health. measurements of lead in bone were performed when women were first admitted to the program. information on lead exposure and other variables of interest was obtained through a questionnaire. participants were followed up to assess the relationship between the time required to become pregnant and lead exposure. statistical analysis consisted of kaplan-meier estimates and cox proportional hazards models. results: of the total number of women in the program, 42 got pregnant: 34 before the first year of follow-up, and 8 at a later date. the mean value for lead concentration in blood was 9.3 μg/dl. the mean values for lead concentration in patella and tibia were 16.0 y 11.0 μg pb/g of bone, respectively. survival analysis was performed and no differences were detected in blood lead levels and time to pregnancy in the first year. nevertheless, in women with blood lead levels above 10.0 μg/dl, the likelihood of not achieving pregnancy was five times higher (95% confidence interval [ci] 0.05-0.56) after one year of follow-up compared with women with blood lead levels below 10.0 μg/dl. conclusions: exposure to high lead concentrations may be an important risk factor influencing the time period for a woman to get pregnant, especially in fertile women who have tried to get pregnant for more than a year.
Association between the plasma/whole blood lead ratio and history of spontaneous abortion: a nested cross-sectional study
Héctor Lamadrid-Figueroa, Martha M Téllez-Rojo, Mauricio Hernández-Avila, Belem Trejo-Valdivia, Maritsa Solano-González, Adriana Mercado-Garcia, Donald Smith, Howard Hu, Robert O Wright
BMC Pregnancy and Childbirth , 2007, DOI: 10.1186/1471-2393-7-22
Abstract: We studied 207 pregnant Mexico City residents during the 1st trimester of pregnancy, originally recruited for two cohorts between 1997 and 2004. Criteria for inclusion in this study were having had at least one previous pregnancy, and having valid plasma and blood Pb measurements. Pb was measured in whole blood and plasma by inductively coupled plasma mass spectrometry using ultra-clean techniques. History of miscarriage in previous pregnancies was obtained by interview. The incidence rate of spontaneous abortion was defined as the proportion of previous pregnancies that resulted in miscarriage. Data were analyzed by means of Poisson regression models featuring the incidence rate of spontaneous abortion as the outcome and continuous or categorized plasma/blood Pb ratios as predictor variables. All models were adjusted for age and schooling. Additionally, logistic regression models featuring inclusion in the study sample as the outcome were fitted to assess potential selection bias.The mean number of miscarriages was 0.42 (range 0 to 4); mean Pb concentrations were 62.4 and 0.14 μg/L in whole blood and plasma respectively. Mean plasma/blood Pb ratio was 0.22%. We estimated that a 0.1% increment in the plasma/blood Pb ratio lead was associated to a 12% greater incidence of spontaneous abortion (p = 0.02). Women in the upper tertile of the plasma/blood Pb ratio had twice the incidence rate of those in the lower tertile (p = 0.02). Conditional on recruitment cohort, inclusion in the study sample was unrelated to observable characteristics such as number of abortions, number of pregnancies, blood Pb levels, age schooling, weight and height.Women with a large plasma/whole blood Pb ratio may be at higher risk of miscarriage, which could be due to a greater availability of placental barrier-crossing Pb.Several studies have reported a positive association between maternal blood lead concentration and the risk of spontaneous abortion [1-3]. This is of concern since one of the
Validity and reproducibility of a food frequency questionnaire to assess dietary intake of women living in Mexico City
HERNáNDEZ-AVILA MAURICIO,ROMIEU ISABELLE,PARRA SOCORRO,HERNáNDEZ-AVILA JUAN
Salud Pública de México , 1998,
Abstract: Objective. To assess the reproducibility and validity of a 116 item semi-quantitative food frequency questionnaire (FFQ), designed to assess the relation between dietary intake and chronic diseases. Material and methods. To test the reproducibility of the FFQ questionnaire, the FFQ was administered twice to 134 women residing in Mexico City at an interval of approximately one year; to assess the validity we compared results obtained by the FFQs with those obtained by four 4-day 24-hour recalls at three month intervals. Validity and reproducibility were evaluated using regression analysis and Pearson and intraclass correlation coefficients of log-e and calorie-adjusted nutrient scores. Results. Mean values for intake of most nutrients assessed by the two food frequency questionnaires were similar. However, means for the 24-hr recall were significantly lower. Intraclass correlation coefficients for nutrient intakes, assessed by questionnaires, administered one year apart, ranged from 0.38 for cholesterol to 0.54 for crude fiber. Correlation coefficients between energy-adjusted nutrient intakes, measured by diet recalls, and the first FFQ ranged from 0.12 for polyunsaturated fatty acids to 0.67 for saturated fatty acids. Regression coefficients between 24-hr recall and FFQ,s were all significant were significant for all nutrients, except for polyunsaturated fat, folic acid, vitamin E and Zinc. Conclusions. These data indicate that this semi-quantitative FFQ is reproducible and provides a useful estimate by which to categorize individuals by level of past nutrient intake. However, its application outside Mexico City or in different age and gender populations will require additional modifications and validation efforts.
La epidemia de tabaquismo: Epidemiología, factores de riesgo y medidas de prevención
Lazcano-Ponce Eduardo C,Hernández-Avila Mauricio
Salud Pública de México , 2002,
Abstract:
Validity and reproducibility of a food frequency questionnaire to assess dietary intake of women living in Mexico City
HERNáNDEZ-AVILA,MAURICIO; ROMIEU,ISABELLE; PARRA,SOCORRO; HERNáNDEZ-AVILA,JUAN; MADRIGAL,HERLINDA; WILLETT,WALTER;
Salud Pública de México , 1998, DOI: 10.1590/S0036-36341998000200005
Abstract: objective. to assess the reproducibility and validity of a 116 item semi-quantitative food frequency questionnaire (ffq), designed to assess the relation between dietary intake and chronic diseases. material and methods. to test the reproducibility of the ffq questionnaire, the ffq was administered twice to 134 women residing in mexico city at an interval of approximately one year; to assess the validity we compared results obtained by the ffqs with those obtained by four 4-day 24-hour recalls at three month intervals. validity and reproducibility were evaluated using regression analysis and pearson and intraclass correlation coefficients of log-e and calorie-adjusted nutrient scores. results. mean values for intake of most nutrients assessed by the two food frequency questionnaires were similar. however, means for the 24-hr recall were significantly lower. intraclass correlation coefficients for nutrient intakes, assessed by questionnaires, administered one year apart, ranged from 0.38 for cholesterol to 0.54 for crude fiber. correlation coefficients between energy-adjusted nutrient intakes, measured by diet recalls, and the first ffq ranged from 0.12 for polyunsaturated fatty acids to 0.67 for saturated fatty acids. regression coefficients between 24-hr recall and ffq,s were all significant were significant for all nutrients, except for polyunsaturated fat, folic acid, vitamin e and zinc. conclusions. these data indicate that this semi-quantitative ffq is reproducible and provides a useful estimate by which to categorize individuals by level of past nutrient intake. however, its application outside mexico city or in different age and gender populations will require additional modifications and validation efforts.
El consumo de tabaco y alcohol en jóvenes de zonas urbanas marginadas de México: un análisis de decisiones relacionadas
Urquieta,José Edmundo; Hernández-Avila,Mauricio; Hernández,Bernardo;
Salud Pública de México , 2006, DOI: 10.1590/S0036-36342006000700005
Abstract: objectives: the purpose of this study was to: identify the economic and sociodemographic factors that influence the decisions made by youth in poor urban areas in mexico to consume tobacco and alcohol; test the hypothesis that both decisions are mutually related and; demonstrate the influence of social interactions within the household on the consumption of both substances. material and methods: this cross-sectional study analyzed information from the urban household evaluation survey (encelurb 2002, per its acronym in spanish), which constitutes the baseline measurement for a follow-up survey to evaluate the impact of a social program in urban areas of mexico. the encelurb 2002 is a multi-issue survey that collected information from 17 207 households, including data on alcohol and tobacco consumption from 15 181 youth ranging in age from 12 to 21 years old. the estimation method used was a bivariate probit model. the entire sample was analyzed as well as the subsample of youth 12 to 15 years old. results: the joint estimation of the two propensities for consumption confirmed that both decisions are closely related. the presence of older youth who smoked or consumed alcohol was positively and significantly associated with the probability of tobacco and alcohol use among youth 12 to 15 years old. the probability of consuming both addictive substances increased with age, principally among men. on the other hand, youth who lived with both parents had lower probabilities of tobacco and alcohol consumption than those living without any parent. conclusions: the results indicate that alcohol and tobacco consumption decisions are mutually related, which allows for better identification of family and individual factors associated with the propensity by youth for smoking and consuming alcohol. these results contribute to the scarce amount of information in mexico indicating the need to analyze the phenomena of addictions with regard to the consumption of various substances.
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