La nueva oleada de la investigación en salud pública: de la evidencia a la política

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Breast cancer in Mexican women: an epidemiological study with cervical cancer control

OBJETIVO: O câncer de mama (CM) é uma das principais causas de morte por câncer em mulheres, no México, com aumento da incidência e da mortalidade nos últimos anos. O estudo realizado objetivou identificar possíveis fatores de risco relacionados ao CM. MÉTODOS: Realizou-se um estudo epidemiológico de casos hospitalares de CM e de controles hospitalares com câncer cérvico-uterino (CACU) em oito hospitais de terceiro nível, na Cidade do México. Foram estudados 353 casos incidentes de CM e 630 controles com CACU, identificados entre mulheres com menos de 75 anos de idade, residentes na área metropolitana da Cidade do México pelo menos há um ano. O diagnóstico foi confirmado histologicamente em ambos os grupos. As variáveis foram analisadas de acordo com critérios aprovados biológica e estatisticamente. Foram efetuadas análises univariadas, bivariadas e multivariadas. Os casos e controles foram estratificados de acordo com o estado hormonal menopáusico (pré e pós-menopausa). Foi usado o odds ratio (OR) como método de associação com intervalos de confiança (IC) acima de 95%. RESULTADOS: Os fatores associados com o CM foram: nível socioeconômico alto (OR=2,77 IC 95% 1,77 -- 4,35); menarca prematura (OR=1,32 IC 95% 0,88 -- 2,00); idade acima de 31 anos quando da primeira gravidez (OR=5,49 IC 95% 21,16 -- 13,98) e um histórico familiar de CM (OR=4,76 IC 95% 2,10 -- 10,79). Por outro lado, um aumento na duração da amamentação foi um fator protetor (>; 25 meses OR=0,38 IC 95% 0,20 -- 0,77). CONCLUSÕES: Os resultados contribuíram para a identificação de fatores de risco para o CM descritos na literatura internacional na população de mulheres mexicanas. A amamentação parece exercer importante papel na proteção do CM. Em virtude das mudanças no estilo de vida das mulheres, as mulheres jovens tendem a diminuir seu período de amamentação.INTRODUCTION: In Mexico, breast cancer (BC) is one of the main causes of cancer deaths in women, with increasing incidence and mortality in recent years. Therefore, the aim of the study is identify possible risk factors related to BC. METHODS: An epidemiological study of hospital cases of BC and controls with cervical uterine cancer (CUCA) was carried out at eight third level concentration hospitals in Mexico City. The total of 353 incident cases of BC and 630 controls with CUCA were identified among women younger than 75 years who had been residents of the metropolitan area of Mexico City for at least one year. Diagnosis was confirmed histologically in both groups. Variables were analyzed according to biological and statistical plausibility criteria. Univariate, bivariate and multivariate analyses were carried out. Cases and controls were stratified according to the menopausal hormonal status (pre and post menopause). RESULTS: The factors associated with BC were: higher socioeconomic level (OR= 2.77; 95%CI = 1.77 - 4.35); early menarche (OR= 1.32; 95%CI= 0.88 - 2.00); old age at first pregnancy (>;31 years: OR= 5.49; 95%CI= 2.16 - 13.98) and a family history of BC (OR= 4.76; 95% CI= 2.10 - 10.79). In contrast, an increase in the duration of the breastfeeding period was a protective factor (>;25 months: OR= 0.38; 95%CI= 0.20 - 0.70). CONCLUSIONS: This study contributes to the identification of risk factors for BC described in the international literature, in the population of Mexican women. Breastfeeding appears to play an important role in protecting women from BC. Because of changes in women`s lifestyles, lactation is decreasing in Mexico, and young women tend not to breastfeed or to shorten the duration of lactation

Susceptibility to Smoking among Adolescents and Its Implications for Mexico’s Tobacco Control Programs. Analysis of the Global Youth Tobacco Survey 2003–2004 and 2006–2007

Smoking prevention efforts should either prevent target groups from becoming susceptible to smoking or prevent susceptible adolescents from progressing to becoming regular smokers. To describe the prevalence of susceptibility to smoking among never smoker students from cities that applied the GYTS in 2003 and 2006. The GYTS uses a two-stage cluster sample survey design that produces representative samples of students aged 12–15 years enrolled in public, private, and technical schools. The survey was undertaken at 399 schools in 9 cities. The GYTS surveyed 33,297 students during the academic years 2003–04 and 2006–07. Among never smokers, about 25% are likely to initiate smoking in the next 12 months. There are no differences in susceptibility to smoking by gender. When comparing results from 2003 and 2006, the susceptibility index has not changed, but for one city. The GYTS results are useful for monitoring susceptibility to smoking among adolescents and provide evidence for strengthening the efforts of tobacco control programs in Mexico

Pathogenicity island cag, vacA and IS605 genotypes in Mexican strains of Helicobacter pylori associated with peptic ulcers

<p>Abstract</p> <p>Background</p> <p><it>Helicobacter pylori </it>is associated with chronic gastritis, peptic ulcers, and gastric cancer. Two major virulence factors of <it>H. pylori </it>have been described: the pathogenicity island <it>cag </it>(<it>cag </it>PAI) and the vacuolating cytotoxin gene (<it>vacA</it>). Virtually all strains have a copy of <it>vacA</it>, but its genotype varies. The <it>cag </it>PAI is a region of 32 genes in which the insertion of IS<it>605 </it>elements in its middle region has been associated with partial or total deletions of it that have generated strains with varying virulence. Accordingly, the aim of this work was to determine the <it>cag </it>PAI integrity<it>, vacA </it>genotype and IS<it>605 </it>status in groups of isolates from Mexican patients with non-peptic ulcers (NPU), non-bleeding peptic ulcers (NBPU), and bleeding peptic ulcers (BPU).</p> <p>Methods</p> <p>The <it>cag </it>PAI integrity was performed by detection of eleven targeted genes along this locus using dot blot hybridization and PCR assays. The <it>vacA </it>allelic, <it>cag </it>PAI genotype 1 and IS<it>605 </it>status were determined by PCR analysis.</p> <p>Results</p> <p>Groups of 16-17 isolates (n = 50) from two patients with NPU, NBPU, and BPU, respectively, were studied. 90% (45/50) of the isolates harbored a complete <it>cag </it>PAI. Three BPU isolates lacked the <it>cag </it>PAI, and two of the NBPU had an incomplete <it>cag </it>PAI: the first isolate was negative for three of its genes, including deletion of the <it>cagA </it>gene, whereas the second did not have the <it>cagM </it>gene. Most of the strains (76%) had the <it>vacA </it>s1b/m1 genotype; meanwhile the IS<it>605 </it>was not present within the <it>cag </it>PAI of any strain but was detected elsewhere in the genome of 8% (4/50).</p> <p>Conclusion</p> <p>The patients had highly virulent strains since the most of them possessed a complete <it>cag </it>PAI and had a <it>vacA </it>s1b/m1 genotype. All the isolates presented the <it>cag </it>PAI without any IS<it>605 </it>insertion (genotype 1). Combined <it>vacA </it>genotypes showed that 1 NPU, 2 NBPU, and 1 BPU patients (66.6%) had a mixed infection; coexistence of <it>H. pylori </it>strains with different <it>cag </it>PAI status was observed in 1 NBPU and 2 BPU (50%) of the patients, but only two of these patients (NBPU and BPU) had different <it>vacA </it>genotypes.</p

Violência física intra-familiar entre jovens mexicanos e egípcios

OBJECTIVE: To determine the prevalence of experiencing intra-familial violence among Mexican and Egyptian youth and to describe its associated risk factors. METHODS: Data from questionnaires applied to 12,862 Mexican and 5,662 Egyptian youth, aged 10 to 19, who attended public schools were analyzed. Biviarate and logistic regression analysis were used to determine the relationship between socio-demographics, the experience of intra-familial violence and violence perpetration. RESULTS: The prevalence of having experienced intra-familial violence was comparable across the Mexican and Egyptian populations (14% and 17%, respectively). In Mexico, young men were more likely to have experienced such violence (OR=2.36) than women, whereas in Egypt, young women were at slightly greater risk than young men (OR=1.25). Older age, male gender and urban residence were independent correlates of experiencing intra-familial violence among Mexican youth. For Egyptian adolescents, in contrast, younger age, female gender and having non-married parents were independent correlates of victimization. Intra-familial violence victims were also more likely than non-victims to perpetrate violence (Mexico: OR=13.13; Egypt: OR=6.58). CONCLUSIONS: Mexican and Egyptian youth experienced intra-familial violence at a relatively low prevalence when compared with youth of other countries. A strong association was found between experiencing intra-familial violence and perpetrating violence.OBJETIVO: Determinar a prevalência da violência intra-familiar sofrida por jovens mexicanos e egípcios, e descrever os fatores de risco associados. MÉTODOS: Os dados analisados foram obtidos de questionários aplicados a 12.862 mexicanos e 5.662 egípcios, jovens de 10 a 19 anos, que freqüentam escolas públicas. O relacionamento entre fatores sociodemográficos, a violência sofrida e sua perpetração foram investigados por meio de análise bivariada e regressão logística. RESULTADOS: A prevalência de violência intra-familiar foi comparável entre as populações mexicana e egípcia (14% e 17%, respectivamente). No México, essa violência foi muito mais provável entre os homens jovens do que entre mulheres (OR=2,36), enquanto que no Egito era mais provável entre as mulheres jovens do que homens (OR=1,25). Idade mais elevada, gênero masculino e residência urbana são fatores associados a violência intra-familiar entre jovens mexicanos. Entre jovens egípcios, a idade mais baixa,o gênero feminino e pais não casados foram fatores associados a essa violência. Foi mais provável a repetição da violência pelos jovens que eram vítimas da violência intra-familiar (México: OR=13,13; Egito: OR=6,58). CONCLUSÕES: A prevalência de experimentar a violência intra-familiar de jovens mexicanos e egípcios foi baixa em comparação com jovens em outros países. Houve forte associação entre vítimas de violência intra-familiar e a repetição da violência

Evaluating the Validity of Self-Reported Smoking in Mexican Adolescents

Objectives We aimed to evaluate the validity of the self-reported smoking indicator used in the Global Youth Tobacco Survey (GYTS). Setting 43 middle and high-school classrooms from 26 schools were selected from Mexico City and Cuernavaca, Morelos. Participants A total of 1257 students provided both a questionnaire and a urine sample. Primary and secondary outcome Sensitivity and specificity of self-reported smoking compared to urinary cotinine. Validity indices were evaluated by subgroups of gender, social acceptability of smoking (ie, smoking parents or friends) and smoking frequency. Results Sensitivity and specificity for current smoking were 93.2% and 81.7%, respectively. Validity indices remained stable across gender. Parental smoking status moderated the validity of self-report, which had lower sensitivity in adolescents with non-smoking parents (86.7%) than in adolescents with smoking parents (96.6%). Sensitivity and specificity increased with smoking frequency. Conclusions This first validation study of self-reported current smoking used in the GYTS among Mexican adolescents suggests that self-reported smoking in the past 30 days is a valid and stable indicator of current smoking behaviour. This measure appears suitable for public health research and surveillance

Prevalence, concordance and determinants of human papillomavirus infection among heterosexual partners in a rural region in central Mexico

Background: Although human papillomavirus (HPV) infection in heterosexual couples has been sparsely studied, it is relevant to understand disease burden and transmission mechanisms. The present study determined the prevalence and concordance of type-specific HPV infection as well as the determinants of infection in heterosexual couples in a rural area of Mexico. Methods: A cross-sectional study was conducted in 504 clinically healthy heterosexual couples from four municipalities in the State of Mexico, Mexico. HPV testing was performed using biotinylated L1 consensus primers and reverse line blot in cervical samples from women and in genital samples from men. Thirty-seven HPV types were detected, including high-risk oncogenic types and low-risk types. Multivariate logistic regression models were utilized to evaluate factors associated with HPV. Results: The prevalence of HPV infection was 20.5% in external male genitals and 13.7% in cervical samples. In 504 sexual couples participating in the study, concordance of HPV status was 79%; 34 partners (6.7%) were concurrently infected, and 21 out of 34 partners where both were HPV positive (61.8%) showed concordance for one or more HPV types. The principal risk factor associated with HPV DNA detection in men as well as women was the presence of HPV DNA in the respective regular sexual partner (OR = 5.15, 95% CI 3.01-8.82). In men, having a history of 10 or more sexual partners over their lifetime (OR 2.5, 95% CI 1.3 - 4.8) and having had sexual relations with prostitutes (OR 1.7, 95% CI 1.01 - 2.8) increased the likelihood of detecting HPV DNA. Conclusions: In heterosexual couples in rural regions in Mexico, the prevalence of HPV infection and type-specific concordance is high. High-risk sexual behaviors are strong determinants of HPV infection in men

Population-based prevalence of cervical infection with human papillomavirus genotypes 16 and 18 and other high risk types in Tlaxcala, Mexico

This study was supported by the National Institute of Public Health of Mexico, the Coordinación de Investigación en Salud del Instituto Mexicano del Seguro Social, the Secretaría de Salud Tlaxcala, the Instituto Nacional de las Mujeres, and the Consejo Nacional de Ciencia y Tecnología [FOSISS 2013 202468]. Additional support has been provided by Roche Diagnostics, BD Diagnostics, DICIPA and Arbor Vita Corporation. The study sponsors did not played a role in designing the study, collecting, analyzing or interpreting the data, writing the report, or submitting this paper for publication. UC Berkeley Center for Global Public Health, Schoeneman Grant, Joint Medical Program Thesis Grant, and Cancer Research UK (C569/A10404)