Yvonne N. Flores

Comparison of HPV-based assays with Papanicolaou smears for cervical cancer screening in Morelos State, Mexico

Objective: To compare the performance of human papillomavirus (HPV) assays with conventional Pap cytology for cervical cancer (CC) screening in Mexico. Methods: Pap smears, self-collected vaginal specimens (SS) for HPV testing, and clinician-collected cervical specimens (CS) for HPV testing were obtained from 7868 women, aged 15–85 years old, attending CC screening at the Mexican Institute of Social Security (IMSS) between May and October, 1999. SS and CS specimens were screened for oncogenic HPV DNA by Hybrid Capture 2. Women who received cytological interpretations of atypical squamous cells of undetermined significance (ASCUS), and/or a positive HPV test were referred for colposcopy and histologic studies. The relative estimates for sensitivity, specificity and predictive values of each test were calculated using histological diagnoses of cervical intraepithelial neoplasia (CIN) grades 2 or 3, or CC histological diagnosis. Results: Oncogenic HPV detection rate was 11.6% for SS, and 9.3% for CS. Pap smear abnormalities were observed in 2.4% of the women. Of 1147 women who had at least one abnormal test result, 88.5% underwent colposcopy, and 101 biopsy-confirmed CIN2/3 or cancer cases were identified. The relative sensitivity estimates for the Pap test, SS and CS were 59.4% (95% CI: 49.2–68.9), 71.3% (95% CI: 61.3–79.6), and 93.1% (95% CI: 85.8–96.9), respectively, while the specificities were 98.3% (95% CI: 98.0–98.6), 89.2% (95% CI: 88.5–89.9), and 91.8% (95% CI: 91.2–92.4), respectively. The positive predictive values of Pap, SS and CS were 36.1, 9.1 and 14.9, the colposcopy referrals needed to detect a case of CIN2/3 or cancer were 2.8, 11.0 and 6.7, respectively. Discussion: Both HPV assays detected more cases of CIN2/3 or CC than Pap cytology alone. However, the HPV assays increased the number of colposcopy referrals. Our study suggests that HPV testing could be an effective way to improve the performance of CC screening.

Risk Factors for Chronic Liver Disease in Blacks, Mexican Americans, and Whites in the United States: Results From NHANES IV, 1999–2004

OBJECTIVES:Morbidity and mortality due to liver disease and cirrhosis vary significantly by race/ethnicity in the United States. We examined the prevalence of liver disease risk factors among blacks, Mexican Americans, and whites, including elevated aspartate aminotransferase and alanine aminotransferase activity, infection with viral hepatitis B or hepatitis C, alcohol intake, obesity, diabetes, and metabolic syndrome.METHODS:Data were obtained from the Fourth National Health and Nutrition Examination Survey (NHANES IV). A logistic regression was used to examine the association of race/ethnicity to liver disease risk factors, controlling for the demographic and socioeconomic variables.RESULTS:Mexican-American men and women are the most likely to have elevated aminotransferase activity. Among men, Mexican Americans are more likely than whites to be heavy/binge drinkers, and blacks are more likely to have hepatitis B or hepatitis C. Among women, Mexican Americans are more likely than whites to be obese and diabetic, and less likely to be heavy/binge drinkers; blacks are more likely than whites to have hepatitis B or hepatitis C, be obese or diabetic, and less likely to be heavy/binge drinkers.CONCLUSIONS:In this national sample, the prevalence of risk factors for liver disease varies by race/ethnicity. Mexican Americans and blacks have a greater risk of developing liver disease than their white counterparts. These findings are consistent with the observed racial/ethnic disparities in morbidity and mortality due to chronic liver disease and contribute to the efforts to identify the causes of these disparities. This information can be used by health professionals to tailor screening and intervention programs.

Improving cervical cancer screening in Mexico: results from the Morelos HPV Study

OBJECTIVE The purpose of this paper is to describe some of the results of the Morelos HPV Study. The main objective of the Morelos HPV Study is to evaluate the use of human papillomavirus (HPV) DNA testing, as compared to the Papanicolaou (Pap) test, for cervical cancer (CC) screening. MATERIAL AND METHODS The Morelos HPV Study is currently being conducted in Mexico, to examine the possibility of using HPV testing for CC screening. The HPV testing of self-collected vaginal and clinician-collected cervical specimens was evaluated as part of this study. The acceptability of the HPV testing of self-collected specimens was compared to that of the Pap test. A cost-effectiveness analysis (CEA) and cost-benefit analysis (CBA) was also performed. RESULTS The Morelos HPV Study results indicate that HPV testing has a greater sensitivity to detect cervical intraepithelial neoplasia (CIN) 2/3 and CC than the Pap test. Our results also indicate an over-all lower acceptability of the Pap test as compared to the self-collected procedure. The results of the CEA and CBA indicate that screening women between the ages of 20-80 for CC using some type of HPV testing is always more cost-effective than screening for CC using the Pap test. CONCLUSIONS Our results suggest that self- and clinician-collected HPV testing could be used in CC prevention programs, as an effective complement or substitute for the Pap test. This paper is available too at: http://www.insp.mx/salud.index.html.

Physical activity and risk of Metabolic Syndrome in an urban Mexican cohort

BackgroundIn the Mexican population metabolic syndrome (MS) is highly prevalent. It is well documented that regular physical activity (PA) prevents coronary diseases, type 2 diabetes and MS. Most studies of PA have focused on moderate-vigorous leisure-time activity, because it involves higher energy expenditures, increase physical fitness, and decrease the risk of MS. However, for most people it is difficult to get a significant amount of PA from only moderately-vigorous leisure activity, so workplace activity may be an option for working populations, because, although may not be as vigorous in terms of cardio-respiratory efforts, it comprises a considerable proportion of the total daily activity with important energy expenditure. Since studies have also documented that different types and intensity of daily PA, including low-intensity, seem to confer important health benefits such as prevent MS, we sought to assess the impact of different amounts of leisure-time and workplace activities, including low-intensity level on MS prevention, in a sample of urban Mexican adults.MethodsThe study population consisted of 5118 employees and their relatives, aged 20 to 70 years, who were enrolled in the baseline evaluation of a cohort study. MS was assessed according to the criteria of the National Cholesterol Education Program, ATP III and physical activity with a validated self-administered questionnaire. Associations between physical activity and MS risk were assessed with multivariate logistic regression models.ResultsThe prevalence of the components of MS in the study population were: high glucose levels 14.2%, high triglycerides 40.9%, high blood pressure 20.4%, greater than healthful waist circumference 43.2% and low-high density lipoprotein 76.9%. The prevalence of MS was 24.4%; 25.3% in men and 21.8% in women. MS risk was reduced among men (OR 0.72; 95%CI 0.57–0.95) and women (OR 0.78; 95%CI 0.64–0.94) who reported an amount of ≥30 minutes/day of leisure-time activity, and among women who reported an amount of ≥3 hours/day of workplace activity (OR 0.75; 95%CI 0.59–0.96).ConclusionOur results indicate that both leisure-time and workplace activity at different intensity levels, including low-intensity significantly reduce the risk of MS. This finding highlights the need for more recommendations regarding the specific amount and intensity of leisure-time and workplace activity needed to prevent MS.

An integrated method for evaluating community-based safe water programmes and an application in rural Mexico

The burden of diarrhoeal disease remains high in the developing world. Community-based safe drinking water programmes are being promoted as cost-effective interventions that will help reduce this illness burden. However, the effectiveness of these programmes remains under-investigated. The primary argument of this paper is that the biological exposure reductions underlying safe water interventions vary tremendously over space and time, and studies that only report results of intent-to-treat analyses cannot reveal why such programmes succeed or fail. The paper develops a stepwise evaluation framework to characterize, and so analyse, the technical, financial, social and behavioural factors that underlie exposure and mediate the impact of safe water investments. Relevant factors include physical performance of the water system, community capacity to maintain and manage the systems, and the time and budget constraints of households participating in the programme. The approach draws on the public health, community-based resource management, and household choice literatures to identify modifiable points of failure along the causal pathway to programme impact. The evaluation framework is used to assess the performance and impact of UVWaterworks, a community-based water purification system in rural Mexico, 5 years after the programme began. No impact on diarrhoea incidence was found in this case. The assessment method revealed that (a) household priorities and preferences were a key factor in maintaining exposure to safe drinking water sources, and therefore (b) user convenience was a primary leverage point for programme improvement. The findings indicate that a comprehensive examination of the many factors that influence the performance and impact of safe water programmes is necessary to elucidate why these programmes fail or succeed.

HPV testing for cervical cancer screening appears more cost-effective than Papanicolau cytology in Mexico

ObjectiveTo determine the incremental costs and effects of different HPV testing strategies, when compared to Papanicolau cytology (Pap), for cervical cancer screening in Mexico.MethodsA cost-effectiveness analysis (CEA) examined the specific costs and health outcomes associated with (1) no screening; (2) only the Pap test; (3) only self-administered HPV; (4) only clinician administered HPV; and (5) clinician administered HPV plus the Pap test. The costs of self- and clinician-HPV testing, as well as with the Pap test, were identified and quantified. Costs were reported in 2008 US dollars. The health outcome associated with these screening strategies was defined as the number of high-grade cervical intraepithelial neoplasia or cervical cancer cases detected. This CEA was performed using the perspective of the Mexican Institute of Social Security (IMSS) in Morelos, Mexico.ResultsScreening women between the ages of 30–80 for cervical cancer using clinical-HPV testing or the combination of clinical-HPV testing, and the Pap is always more cost-effective than using the Pap test alone.ConclusionsThis CEA indicates that HPV testing could be a cost-effective screening alternative for a large health delivery organization such as IMSS. These results may help policy-makers implement HPV testing as part of the IMSS cervical cancer screening program.

Risk factors for cervical cancer among HPV positive women in Mexico

OBJECTIVE To identify factors that are associated with an increased risk of developing high-grade cervical intraepithelial neoplasia (CIN) or cancer among human papillomavirus (HPV)-positive women in Mexico. MATERIAL AND METHODS A case-control study design was used. A total of 94 cases and 501 controls who met the study inclusion criteria were selected from the 7 732 women who participated in the Morelos HPV Study from May 1999 to June 2000. Risk factor information was obtained from interviews and from HPV viral load results. Odds ratios and 95 percent confidence intervals were estimated using unconditional multivariate regression. RESULTS Increasing age, high viral load, a young age at first sexual intercourse, and a low socio-economic status are associated with an increased risk of disease among HPV-positive women. CONCLUSIONS These results could have important implications for future screening activities in Mexico and other low resource countries.

Physical activity and reduced risk of depression: results of a longitudinal study of Mexican adults.

OBJECTIVE To evaluate the effect of physical activity (PA) on the risk of depression among Mexican adults over a 6-year follow-up period. METHOD We evaluated longitudinal data from the Health Worker Cohort Study, which follows employees of the Mexican Institute for Social Security in Morelos State, Mexico, over time. Depressive symptoms and PA were assessed at baseline and at a follow-up measurement 6 years later. The study population was free of depressive symptomatology at baseline, as assessed by the Center for Epidemiological Studies-Depression Scale (CES-D). After 6 years, the CES-D was completed once again by the participants to estimate their risk of depression based on the different PA patterns they reported during the follow-up period. PA was estimated using a questionnaire that has been applied in similar longitudinal studies and has been validated in Spanish, with metabolic equivalents (METs) as the unit of measurement. We identified three PA patterns: highly active, moderately active, and inactive. The relative risk of depression (CES-D score ≥ 16 points) was estimated using multivariate logistical regression analysis according to the PA patterns at a follow-up measurement 6 years later. RESULTS The incidence of depression after 6 years was higher among inactive participants (16.5%) than among those with an active PA pattern (10.6%). We found that more active PA patterns have an important protective effect against depression. The odds ratio (OR) for the more active PA patterns was 0.46, 95% confidence interval (CI) [0.25, 0.87], and for individuals with a moderately active PA pattern, the OR was 0.57, 95% CI [0.34, 0.93]. These ORs were obtained after adjusting for confounding variables and baseline PA levels. CONCLUSION Our results indicate that PA may reduce risk of depression in Mexican adults. These findings have potential applications for depression prevention programs in target populations with similar social and cultural contexts.

Determinantes de violencia de pareja en trabajadoras del IMSS Morelos

OBJECTIVE To study the prevalence of partner violence, and to identify the associated risk factors in a sample of female workers of IMSS (Mexican Social Security Institute), Morelos State. MATERIAL AND METHODS Cross-sectional data from 1 173 women participating in the cohort study of IMSS workers are utilized to study these associations. The study provides information on frequency of psychological, physical or sexual violence and perception of severity during the 12 months prior to the time of data collection. It was carried out in Morelos between October 1998 and March 2000. Polytomous logistic regression models were used to obtain odds ratios for different degrees of partner violence. RESULTS A high prevalence of partner violence is observed in the sample. Main factors associated with higher severity of violence are state of the relationship and alcohol intake, emotional status of the couple at home, work burden of the woman, and a history of violence in childhood. CONCLUSIONS All these factors are potentially modifiable through interventions aimed at stress reduction. These results should be considered when developing preventive programs against partner violence in Mexico.Objective. To study the prevalence of partner violence, and to identify the associated risk factors in a sample of female workers of IMSS (Mexican Social S...

Neighborhood socio-economic disadvantage and race/ethnicity as predictors of breast cancer stage at diagnosis

BackgroundThis study investigated the role of key individual- and community-level determinants to explore persisting racial/ethnic disparities in breast cancer stage at diagnosis in California during 1990 and 2000.MethodsWe examined socio-demographic determinants and changes in breast cancer stage at diagnosis in California during 1990 and 2000. In situ, local, regional, and distant diagnoses were examined by individual (age, race/ethnicity, and marital status) and community (income and education by zip code) characteristics. Community variables were constructed using the California Cancer Registry 1990-2000 and the 1990 and 2000 U.S. Census.ResultsFrom 1990 to 2000, there was an overall increase in the percent of in situ diagnoses and a significant decrease in regional and distant diagnoses. Among white and Asian/Pacific Islander women, a significant percent increase was observed for in situ diagnoses, and significant decreases in regional and distant diagnoses. Black women had a significant decrease in distant -stage diagnoses, and Hispanic women showed no significant changes in any diagnosis during this time period. The percent increase of in situ cases diagnosed between 1990 and 2000 was observed even among zip codes with low income and education levels. We also found a significant percent decrease in distant cases for the quartiles with the most poverty and least education.ConclusionsHispanic women showed the least improvement in breast cancer stage at diagnosis from 1990 to 2000. Breast cancer screening and education programs that target under-served communities, such as the rapidly growing Hispanic population, are needed in California.