Aurelio Cruz

Epidemiology of HPV infection among Mexican women with normal cervical cytology.

Cervical cancer is caused by human papillomavirus (HPV) and is the most common cancer among Mexican women, but no population‐based studies have reported the prevalence and determinants of HPV infection in Mexico. A population‐based study was carried out between 1996 and 1999, based on an age‐stratified random sample of 1,340 women with normal cytologic diagnoses from 33 municipalities of Morelos State, Mexico. The prevalence of cervical HPV DNA was determined by reverse line blot strip assay to detect 17 cancer‐associated and 10 non–cancer‐associated HPV types. Two peaks of HPV DNA prevalence were observed. A first peak of 16.7% was observed in the age group under 25 years. HPV DNA prevalence declined to 3.7% in the age group 35–44 years, then increased progressively to 23% among women 65 years and older. Cancer‐associated HPV types were the most common in all age groups; non–cancer‐associated HPV types were rare in the young and became more common linearly with age. Twenty‐four types of HPV were detected; HPV 16, HPV 53, HPV 31 and HPV 18 were the most common, but none was present in more than 1.7% of subjects. The main determinant of infection with both cancer‐associated and non–cancer‐associated HPV types was the number of sexual partners in all age groups. Less‐educated women were at an increased risk of infection with cancer‐associated but not with non–cancer‐associated HPV types; low socioeconomic status was associated with detection of non–cancer‐associated HPV types. Among young women an increasing number of pregnancies was associated with lower HPV detection and among older women low socioeconomic status was related to increased HPV detection, particularly for the age group 35–54 years. Among women with cancer‐associated HPV types, there was a higher intensity of polymerase chain reaction signal in younger than in older age groups (p < 0.001). We present additional evidence for the sexually transmitted nature of HPV infection, regardless of age group and HPV type. We confirm previous findings of a second peak of high‐risk HPV infections in postmenopausal women, in this case with a clear predominance of cancer‐associated HPV types. In populations with this pattern, which can be related to reactivation of latent HPV infections or high previous exposure in older women, screening with HPV testing can have a reduced specificity among older women if proper cut‐off points for HPV positivity are not used. Longitudinal studies of immune responses to HPV infection in different age groups are warranted.

Human papillomavirus in men: comparison of different genital sites

Objective: To elucidate which anatomical sites need to be sampled to detect human papillomavirus (HPV) infection in the lower male genital tract. Method: In an HPV survey of Mexican soldiers (median age 24 years; range 16–50 years), a cell sample from 2 cm deep into the distal urethra (group 1; n = 168 men), or 0.5 cm deep into the meatus urethralis (group 2; n = 414 men) was collected, along with a sample from the external genitalia. The different samples were tested for 27 HPV types using a polymerase chain reaction based strip assay. Results: HPV DNA was detected more frequently in external genitalia samples (46.4%) than in the urethra (20.8%) or meatus samples (12.1%). Lack of samples from the urethra or meatus would have led to 5.1% and 1.5% false HPV negative results, respectively. The most frequently detected high risk HPV types (HPV 59, 52, 51, and 16) were similar in different sites, whereas low risk types were found rarely in urethra samples. Conclusions: The addition of cell samples from the meatus to those from external genitalia contributed negligibly to the evaluation of the prevalence of HPV in men. HPV detection was slightly improved by the addition of urethra samples, but the gain may not justify the discomfort of the procedure in large epidemiological studies.

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

BackgroundAlthough 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.MethodsA 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.ResultsThe 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.ConclusionsIn 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.

Specimen self-collection and HPV DNA screening in a pilot study of 100,242 women.

Since cervical cancer remains common in Mexico despite an established cytology screening program, the Ministry of Health recently introduced pilot front‐line HPV testing into the Mexican cervical cancer screening program (CCSP). Here, we present the key field performance metrics of this population‐based study. High‐risk HPV DNA (hrHPV) testing was conducted on self‐collected vaginal specimens from 100,242 women aged 25–75 years residing in Morelos State. All hrHPV positive women and a random sample of 3.2% (n = 2,864) of hrHPV negative participants were referred for colposcopic examination. The main disease endpoint of interest was cervical intraepithelial neoplasia grade 2 or higher (CIN2+). We calculated relative risk, positive predictive value and negative predictive value adjusted for screening test verification bias. The overall prevalence of hrHPV was 10.8% (95%CI 10.6–11.0). Women positive for hrHPV had a relative risk of 15.7 for histologically detectable CIN2+. The adjusted positive predictive value of the hrHPV test was 2.4% (95%CI 2.1–2.7); whereas the adjusted negative predictive value was 99.8% (95%CI 99.8–99.9). These findings suggest that large‐scale vaginal hrHPV testing in a middle‐income country can identify women at greater risk of advanced cervical abnormalities in a programmatically meaningful way but care is warranted to ensure that disease not detectable at colposcopy is kept to a minimum. PASS shows areas that need improvement and sets the stage for wider use of hrHPV screening of self‐collected vaginal specimens in Mexico.

High prevalence of antibodies to herpes simplex virus type 2 among middle-aged women in Mexico City, Mexico: a population-based study.

Background Herpes simplex virus type 2 (HSV-2) is among the most prevalent sexually transmitted diseases worldwide. In Mexico there is a lack of population-based HSV-2 surveys. Goals To determine population-based HSV-2 seroprevalence and risk factors among women in Mexico City. Study Design A random sample of 730 women was identified among the residents of Mexico City. Women ages 25 to 85 years were selected from 3694 households. Western blot serology testing was conducted on serum samples to determine HSV-2 type-specific serostatus. A structured questionnaire was administered, and multivariate analyses were performed to identify risk factors for HSV-2 seropositivity, which were stratified into two age categories: younger than 50 years of age and 50 years of age or older. Results The HSV-2 seroprevalence among female participants was 29.8%, with a significant trend of increasing HSV-2 prevalence for each higher level of age (P < 0.001). Female participants had a median age of 46 years and were predominantly monogamous (82.6%). The overall population-based seroprevalence estimated in Mexico City among women was 35.8%. The independent risk factors for HSV-2 seropositivity included a history of two or more sexual partners (odds ratio [OR], 2.2; 95% CI, 1.4–3.4), two or more sexual partners before first pregnancy (OR, 2.3; 95% CI, 1.4–3.7), cohabitation with partner (OR, 2.5; 95% CI, 1.3–4.7), and current vaginal douching (OR, 1.7; 95% CI, 1.2–2.6). Conclusions Population-based HSV-2 seroprevalence is endemically high among middle-age women in Mexico City, and clearly is correlated with higher-risk sexual behavior. This elevated HSV-2 seroprevalence may reflect unrecognized HSV-2 transmission throughout life.

HPV in Female Partners Increases Risk of Incident HPV Infection Acquisition in Heterosexual Men in Rural Central Mexico.

Background: Knowledge about the incidence, clearance, and factors associated with human papilloma virus (HPV) infection in men is lacking, and much of what is available focuses on high-risk groups. Methods: A prospective cohort study was carried out with 504 heterosexual males from Mexico State, Mexico. Participants were monitored for 4 years at intervals of approximately 4 months, with a median total duration of follow-up of 19.8 months. The presence of cervical HPV in female sexual partners was evaluated as a risk factor. HPV DNA testing was conducted using the polymerase chain reaction technique. Risk factors associated with the incidence and clearance of HPV infection were evaluated through survival analysis. Results: The cumulative incidence of infection with any HPV type at 12 months was 15% [95% confidence interval (CI), 0.12–0.20]. About 72% of men with incident HPV cleared the infection by 12 months. The presence of cervical HPV in a mans female sex partner was the main determinant for males acquiring HPV infection of any type [adjusted HR (AHR), 2.1; 95% CI, 1.1–3.8] and oncogenic HPV infection (AHR, 4.1; 95% CI, 2.1–8.0), while having a history of anal sexual relations with women was statistically associated with acquiring nononcogenic HPV (AHR, 1.8; 95% CI, 1.1–2.9). Conclusions and Impact: The incidence of genital HPV infection in this population is relatively low, with relatively quick acquisition and clearance rates. Cervical HPV infection in mens female sexual partners was the main risk factor for genital HPV infection in men. Cancer Epidemiol Biomarkers Prev; 21(11); 1956–65. ©2012 AACR.

Análisis de productividad, calidad y costos en laboratorios del primer nivel: la biometría hemática

OBJECTIVE Assessment of productivity, quality and production costs and determination of the efficiency of top grade clinical laboratories in Mexico. METHODS Ten laboratories were selected from among the total number (52) existing in Mexico City, and the Donabedian model of structure, process and results were applied. Blood count was selected as a tracer. RESULTS The principal problems found were: inadequate distribution of trained human resources, poor glass material, inadequate analytic process and low productivity. These factors are reflected in the unit costs, which exceed reference laboratory costs by 200%. Only 50% of the laboratories analyzed generate reliable results. Only 20% of the laboratories studied operate efficiently. CONCLUSIONS To solve the problems identified requires integral strategies at different levels. A specific recomendation for the improvement of quality and productivity is an assessment of the cost/benefit of creating a central laboratory and using the remaining sites exclusively for the collection of samples.OBJETIVO: Conocer el grado de eficiencia con la que funcionan los laboratorios clinicos del primer nivel mediante una evaluacion que integre: la productividad, la calidad y los costos. METODOS: Se seleccionaron 10 laboratorios clinicos de un total de 52 existentes en la Ciudad de Mexico; se utilizo el modelo de Donabedian en sus componentes de estructura, proceso y resultado utilizando la biometria hematica como rastreador. RESULTADOS: Los principales problemas fueron: inadecuada distribucion del recurso humano calificado; malas condiciones del material de vidrio; inadecuado proceso analitico y baja productividad. Estos problemas se reflejaron en un incremento de un 200% en los costos unitarios respecto al costo ideal. Solamente son confiables los resultados de 50% de los laboratorios analizados. Veinte porciento de los laboratorios analizados son eficientes. CONCLUSIONES: La solucion a los problemas encontrados requiere de estrategias integrales que comprometen a diferentes ambitos, por lo que su solucion se plantea dificil. Se recomienda analizar el costo-beneficio de crear un laboratorio central y dejar a los demas laboratorios como sitios para la toma de muestras exclusivamente.