Analysis of Mycobacterium tuberculosis in the state of Texas for rifampin resistance using molecular beacons

Mycobacterium tuberculosis, a bacillus known to cause disease in humans since ancient times, is the etiological agent of tuberculosis (TB). The infection is primarily pulmonary, although other organs may also be affected. The prevalence of pulmonary TB disease in the US is highest along the US-Mexico border, and of the four US states bordering Mexico, Texas had the second highest percentage of cases of TB disease among Mexico-born individuals in 1999 (CDC, 2001). Between the years of 1993 and 1998, the prevalence of drug-resistant (DR) TB was 9.1% among Mexican-born individuals and 4.4% among US-born individuals (CDC, 2001). In the same time period, the prevalence of multi-drug resistant (MDR) TB was 1.4% among Mexican-born individuals and 0.6% among US-born individuals (CDC, 2001). There is a renewed urgency in the quest for faster and more effective screening, diagnosis, and treatment methods for TB due to the resurgence of tuberculosis in the US during the mid-1980s and early 1990s (CDC, 2007a), and the emergence of drug-resistant, multidrug-resistant, and extremely drug-resistant tuberculosis worldwide. Failure to identify DR and MDR-TB quickly leads to poorer treatment outcomes (CDC, 2007b). The recent rise in TB/HIV comorbidity further complicates TB control efforts. The gold standard for identification of DR-TB requires mycobacterial growth in culture, a technique taking up to three weeks, during which time DR/MDR-TB individuals harboring resistant organisms may be receiving inappropriate treatment. The goal of this study was to determine the sensitivity and specificity of real-time quantitative polymerase chain reaction (qPCR) using molecular beacons in the Texas population. qPCR using molecular beacons is a novel approach to detect mycobacterial mutations conferring drug resistance. This technique is time-efficient and has been shown to have high sensitivity and specificity in several populations worldwide. Rifampin (RIF) susceptibility was chosen as the test parameter because strains of M. tuberculosis which are resistant to RIF are likely to also be MDR. Due to its status as a point of entry for many immigrants into the US, control efforts against TB and drug-resistant TB in Texas is a vital component of prevention efforts in the US as a whole. We show that qPCR using molecular beacons has high sensitivity and specificity when compared with culture (94% and 87%, respectively) and DNA sequencing (90% and 96%, respectively). We also used receiver operator curve analysis to calculate cutoff values for the objective determination of results obtained by qPCR using molecular beacons. ^

Assessment of markers of medication literacy in a US-Mexico border community

Each year an estimated 180,000 people in the United States (U.S.) die as a result of medication errors, now considered a major public health problem. If a patient cannot correctly act on information related to medication use or "Medication Literacy" there is an increased potential for error. Medication use issues are unique on the US-Mexico border because they include high rates of herbal products and medication products from Mexico as well as issues related to the preferred language (English or Spanish) of the patient. To evaluate the medication literacy in a US-Mexico border community, this retrospective study evaluates 180 subjects representing four diverse economic segments of a metropolitan US-Mexico Border community who have taken a Medication Literacy Assessment. The assessment tool has been created to understand how patients interpret medication information for prescription, over-the-counter, herbal, and Mexican medication product use, and how they problem-solve medication questions. The Medication Literacy Assessment tool specifically assesses document literacy (e.g., prescription labels), prose literacy (e.g., patient leaflets), numeracy (e.g., calculations and measurements) as well as qualitative data related to medication use practices. The main hypothesis of this study is that the ability to interpret and use medications will vary based on education, language (Spanish or English), and recruitment sites (economically diverse communities). The results will provide information to better characterize medication use in a primarily Hispanic population on the US-Mexico border and may be used to influence policy decisions regarding prescription and over-the-counter product information.^

Validating the dietary intake questions from the Tu Salud, ¡Si Cuenta! questionnaire

Background. Poor nutrition is an important factor in the onset of obesity which is a growing problem in the United States that disproportionately affects Mexican-Americans. In order to form recommendations and effectively target nutrition in interventions it is necessary to have valid epidemiological tools to better understand dietary trends. Purpose. The purpose of this study is to evaluate the validity of the nutritional intake questions from the Tu Salud, ¡Sí Cuenta! Questionnaire in an adult Mexican-American population. Methods. Fifty participants in the Cameron County Hispanic Cohort were recruited into the validity study, which consisted of completing the Tu Salud, ¡Sí Cuenta! questionnaire and the 24-hour recall with a 2 hour time period between administrations. Responses were analyzed to determine the percent agreement, kappa statistic and Spearman rank order correlation. Results: Five items had good validity (>0.6), three items had fair validity (>0.4), and three items had poor validity (<0.4). In general, items that had low validity were those that were reported in low frequencies by study subjects. Overall, the Tu Salud, ¡Sí Cuenta! questionnaire showed good validity, making this questionnaire a valuable tool to assess the dietary intake patterns of this Mexican-American adult population. ^

Environmental tobacco smoke exposure, respiratory and cardiovascular health in restaurant and bar workers in Mexico

Environmental tobacco smoke (ETS) is a well established health hazard, being causally associated to lung cancer and cardiovascular disease. ETS regulations have been developed worldwide to reduce or eliminate exposure in most public places. Restaurants and bars constitute an exception. Restaurants and bar workers experience the highest ETS exposure levels across several occupations, with correspondingly increased health risks. In Mexico, previous exposure assessment in restaurants and bars showed concentrations in bars and restaurants to be the highest across different public and workplaces. Recently, Mexico developed at the federal level the General Law for Tobacco Control restricting indoors smoking to separated areas. AT the local level Mexico City developed the Law for the Protection of Non-smokers Health, completely banning smoking in restaurants and bars. Studies to assess ETS exposure in restaurants and bars, along with potential health effects were required to evaluate the impact of these legislative changes and to set a baseline measurement for future evaluations.^ A large cross-sectional study conducted in restaurants and bars from four Mexican cities was conducted from July to October 2008, to evaluate the following aims: Aim 1) Explore the potential impact of the Mexico City ban on ETS concentrations through comparison of Mexico City with other cities. Aim 2). Explore the association between ETS exposure, respiratory function indicators and respiratory symptoms. Aim 3). Explore the association between ETS exposure and blood pressure and heart rate.^ Three cities with no smoking ban were selected: Colima (11.5% smoking prevalence), Cuernavaca (21.5% smoking prevalence) and Toluca (27.8% smoking prevalence). Mexico City (27.9% smoking prevalence), the only city with a ban at the time of the study, was also selected. Restaurants and bars were randomly selected from municipal records. A goal of 26 restaurants and 26 bars per city was set, 50% of them under 100 m2. Each establishment was visited during the highest occupancy shift, and managers and workers answered to a questionnaire. Vapor-phase nicotine was measured using passive monitors, that were activated at the beginning and deactivated at the end of the shift. Also, workers participated at the beginning and end of the shift in a short physical evaluation, comprising the measurement of Forced Expiratory Volume in the first second (FEV1) and Peak Expiratory Flow (PEF), as well as blood pressure and heart rate.^ A total of 371 establishments were invited, 219 agreed to participate for a 60.1% participation rate. In them, 828 workers were invited, 633 agreed to participate for a 76% participation rate. Mexico City had at least 4 times less nicotine compared to any of the other cities. Differences between Mexico City and other cities were not explained by establishment characteristics, such as ventilation or air extraction. However, differences between cities disappeared when ban mechanisms, such as policy towards costumer's smoking, were considered in the models. An association between ETS exposure and respiratory symptoms (cough OR=1.27, 95%CI=1.04, 1.55) and respiratory illness (asthma OR=1.97, 95%CI=1.20, 3.24; respiratory illness OR=1.79, 95%CI=1.10, 2.94) was observed. No association between ETS and phlegm, wheezing or respiratory infections was observed. No association between ETS and any of the spirometric indicators was observed. An association between ETS exposure and increased systolic and diastolic blood pressure at the end of the shift was observed among non-smokers (systolic blood pressure beta=1.51, 95%CI=0.44, 2.58; diastolic blood pressure beta=1.50, 95%CI=0.72, 2.28). The opposite effect was observed in heavy smokers, were increased ETS exposure was associated with lower blood pressure at the end of the shift (systolic blood pressure beta=1.90, 95%CI=-3.57, -0.23; diastolic blood pressure beta=-1.46, 95%CI=-2.72, -0.02). No association in light smokers was observed. No association for heart rate was observed. ^ Results from this dissertation suggest Mexico City's smoking ban has had a larger impact on ETS exposure. Ventilation or air extraction, mechanisms of ETS control suggested frequently by tobacco companies to avoid smoking bans were not associated with ETS exposure. This dissertation suggests ETS exposure could be linked to changes in blood pressure and to increased respiratory symptoms. Evidence derived from this dissertation points to the potential negative health effects of ETS exposure in restaurants and bars, and provides support for the development of total smoking bans in this economic sector. ^

Predictors of diagnostic delay among tuberculosis patients in a U.S.-Mexico border community

Delays in diagnosis of pulmonary tuberculosis have detrimental effects on the health of the ailing patient as well as the people around him or her. These effects are magnified in highly-travelled parts of the world. Identifying factors predictive of diagnostic delay is challenging, as these vary widely by culture and geography. Predictors of delay for tuberculosis patients living in the Northeastern Mexican city of Matamoros, a binationally-transited area, have yet to be described. Using secondary analysis of a retrospective survey, this study sought to identify predictors of diagnostic delay in a sample of culture-positive tuberculosis patients in Matamoros. Sociodemographic, behavioral, and health-related factors were measured and compared. Using bivariate and step-wise regression analyses at an alpha level of 0.05, the author found the following to be statically significant predictors for this sample (R 2=0.171): prior treatment of diabetes, recurrence of tuberculosis, and having ever used cocaine. A question assessing knowledge of immunocompromised subgroups was also identified as a predictor, although its implications are unclear. Notably, the instrument did not distinguish between patient and health system delay. In summary, more research should be conducted in the Matamoros area in order to fully understand the dynamics of delayed diagnosis and its application to public health practice.^

Factors influencing hurricane evacuation among Hispanic population

The recent hurricanes of Katrina, Rita, and Dolly have brought to light the precarious situation populations place themselves in when they are unprepared to face a storm, or do not follow official orders to evacuate when a destructive hurricane is poised to hit the area. Three counties in southern Texas lie within 60 miles of the Gulf of Mexico, and along the Mexican border. Determining the barriers to hurricane evacuation in this distinct and highly impoverished area of the United States would help aid local, state, and federal agencies to respond more effectively to persons living here.^ The aim of this study was to examine intention to comply with mandatory hurricane evacuation orders among persons living in three counties in South Texas by gender, income, education, acculturation and county of residence. A questionnaire was administered to 3,088 households across the three counties using a two-stage cluster sampling strategy, stratified by all three counties. The door-to-door survey was a 73-item instrument that included demographics, reasons for and against evacuation, and preparedness for a hurricane. Weighted data were used for the analyses.^ Chi-square tests were run to determine whether differences between observed and expected frequencies were statistically significant. A logistic regression model was developed based on that univariate analysis. Results from the logistic regression estimated odds ratios and their 95 percent confidence intervals for the independent variables.^ Logistic regression results indicate that females were less likely than men to follow an evacuation order. Having a higher education meant more likelihood of evacuating. Those respondents with a higher affiliation with Spanish than English were more likely to follow the evacuation orders. Hidalgo County residents were less likely to evacuate than Cameron or Willacy Counties' residents. Local officials need to implement communication efforts specifically tailored for females, residents with less of an affiliation with Spanish, and Hidalgo County residents to ensure their successful evacuation prior to a strong hurricane's landfall.^

A systematic review of literature on socioeconomic disparities in the prevalence of dental caries

Dental caries, also known as tooth decay, are a disease of the oral cavity that affects the tooth structure and leads to the occurrence of cavities in teeth. Dental caries are one of the leading chronic diseases in the population and are very common in childhood. If not treated appropriately, dental caries have debilitating effect on the oral and general health of individuals. ^ Objectives. The aims of this review are to (1) analyze and elucidate the relationship between the social and economic determinants of health like income, education and race/ethnicity and the prevalence of dental caries and (2) identify and understand the pathways/underlying causes through which these factors affect the occurrence of dental caries. This review will provide a foundation for formulation of better oral health policies in future by identifying the key socio-economic factors and pathways affecting the prevalence of dental caries. Knowledge about these socioeconomic factors could be incorporated in the design of future policies and interventions to achieve greater benefits.^ Methods. This review includes information from all pertinent articles, reviews, surveys, reports, peer reviewed literature and web sources that were published after 2000. The selection criterion includes literature focusing on individuals between the ages of 1 to 65 years, and individuals from different subgroups of community based on income, education and race/ethnicity. The analyses of literature include identifying if a relationship between income/education/race and the prevalence of dental caries exists by comparing the prevalence of dental caries in different socio-economic groups. Also included in this review are articles that are relevant to the mechanisms/pathways through which income/education/race affect the prevalence of dental caries.^ Results. Analyses of available literature suggests that disparities in the prevalence of dental caries may be attributed to differences in income, education and race/ethnicity. Higher prevalence of dental caries was observed in African-American and Mexican-American individuals, and in people with low income and low education. The leading pathways through which the socioeconomic factors affect the prevalence of dental caries are the lack of access to dental care, lack of awareness about good oral hygiene beliefs and habits, oral health, inability to afford dental care, lack of social support to maintain oral health and lack of dental insurance.^ Conclusion. Disparities in the prevalence of dental caries exist in various socio-economic groups. The relationship between socio-economic factors and dental caries prevalence should be considered in the development of future policies and interventions that are aimed at reducing the prevalence of dental caries and enhancing oral health status.^

Stages of change and carotene intake in the Paso del Norte region: Que Sabrosa Vida

Understanding a population's dietary behavior is important to promote behaviors which have the most beneficial impact on health. The most recent Dietary Guidelines for Americans (2005) identifies carotenoids as a key nutrient to be consumed through increased intake of fruits and vegetables (FV). While some studies have included or focused on the Hispanic population, few have focused only on Mexican-American populations and staged its intake of FV. Stage of change behavior theory has been used to understand the adoption and promotion of healthy behaviors such as increased intake of FV. It has been shown to effectively aid interventionists' understanding of dietary behavior. Intake patterns of FV of older women, rural residents, and adolescents of Mexican American descent have been conducted but not by stages of change. This study aimed to determine the relationship between stages of change for fruits and vegetables (SOC-FV) and total carotene intake to assess the quality of SOC-FV as a surrogate measure of total carotene. ^ Data from the 2000 Qué Sabrosa Vida Community Nutrition Survey (QSV-CNS) were analyzed to identify the SOC-FV and sources of carotenes in a Mexican American population 18-60 yrs. of the Paso del Norte region. A 107 item interviewer administered food frequency questionnaire (FFQ) specifically calibrated for a Mexican American population was used to collect usual intake of total carotene. The QSV survey study population included 963 participants, 590 (61.3%) women and 373 (38.7%) men. A statistically significant mean difference in caloric intake between men and women was found (p-value = <0.01). When total carotene intake was adjusted for energy, there were significant differences between men and women (p-value = <0.0001) with women consuming a higher amount of total carotene (406 RE/kcal 1,000) than men (332 RE/kcal 1000). The food sources of total carotene for both genders included many items found in a traditional Mexican American diet. Chile, after carrots, was the highest contributor of dietary carotene. Total carotene intake was not associated with stages of change among women or men and their distributions were not linear. Mean differences of total carotene by stages of change were significant for women for pre-contemplation/contemplation (p-value = 0.04) and preparation (p-value = 0.0004) but not for men. ^ SOC-FV may serve as a surrogate measure for dietary carotene intake. This study's Mexican American population had a high carotene quality diet derived from traditional food items irrespective of their stage of change for fruits and vegetables. To better understand this population's dietary intake a measure for acculturation should be included. Interventions aimed at Mexican American populations should aim to promote traditional diets consistent with cultural practices.^ ^

A Su Salud Injury Prevention expansion: Analysis of injury prevention perceptions in a Hispanic community

Unintentional injury is the leading cause of death for American ages one to 44 and is ranked in the top ten causes of death for all age groups (CDC, 2006a). A Su Salud Injury Prevention was developed to address injury prevention awareness and education. The program is a mass media education campaign that uses role models, mass media, and community outreach to prevent injury. In 2009, University Health System (UHS) expanded the program. Baseline data were collected from 426 residents in targeted neighborhoods northwest of downtown San Antonio to support the expansion. The purpose of this study was to explore injury perceptions, knowledge, and behaviors of adults living in the expansion area, and define the predominant factors associated with these perceptions. A secondary aim was to assess community awareness and willingness to participate in the program.^ Survey results showed motor vehicle crashes (MVC), falls, drinking and driving, and guns and assaults were considered the most serious injures for adults. The most serious child injuries were MVC, abuse and neglect, falls, and head injuries. Residents were knowledgeable of state seatbelt policy, and over 90% responded as compliant for seatbelt and child car seat use. Most were knowledgeable about drinking and driving state policy and negative outcomes. However, 70% of those reporting driving under the influence of alcohol within the last year engaged in repeat high risk behavior. Men and residents under the age of 55 were more likely to engage in repeat drinking and driving (OR= 3.6, 7.0 respectively). Residents consider injury prevention an important issue, and have interest in a local injury prevention program. Younger women are the most likely to participate in a local program as potential role models and volunteers.^ Results from the study are summarized into an injury prevention and demographic profile of the community that will be used to develop tailored injury prevention messages to create a more effective program, and support program coordinators in effective community engagement. Results will also be used as a comparative basis for future evaluation of a behavioral injury prevention program focused on a predominantly Mexican-American community.^

The influence of social connectedness and self-esteem on participant retention in a bi-ethnic longitudinal study

In prospective studies it is essential that the study sample accurately represents the target population for meaningful inferences to be drawn. Understanding why some individuals do not participate, or fail to continue to participate, in longitudinal studies can provide an empirical basis for the development of effective recruitment and retention strategies to improve response rates. This study examined the influence of social connectedness and self-esteem on long-term retention of participants, using secondary data from the “San Antonio Longitudinal Study of Aging” (SALSA), a population-based study of Mexican Americans (MAs) and European Americans (EAs) aged over 65 years residing in San Antonio, Texas. We tested the effect of social connectedness, self-esteem and socioeconomic status on participant retention in both ethnic groups. In MAs only, we analyzed whether acculturation and assimilation moderated these associations and/or had a direct effect on participant retention. ^ Low income, low frequency of social contacts and length of recruitment interval were significant predictors of non-completer status. Participants with low levels of social contacts were almost twice as likely as those with high levels of social contacts to be non-completers, even after adjustment for age, sex, ethnic group, education, household income, and recruitment interval (OR = 1.95, 95% CI: 1.26–3.01, p = 0.003). Recruitment interval consistently and strongly predicted non-completer status in all the models tested. Depending on the model, for each year beyond baseline there was a 25–33% greater likelihood of non-completion. The only significant interaction, or moderating, effect observed was between social contacts and cultural values among MAs. Specifically, MAs with both low social contacts and low acculturation on cultural values (i.e., placed high value on preserving Mexican cultural origins) were three and half times more likely to be non-completers compared with MAs in other subgroups comprised of the combination of these variables, even after adjustment for covariates. ^ Long term studies with older and minority participants are challenging for participant retention. Strategies can be designed to enhance retention by paying special attention to participants with low social contacts and, in MAs, participants with both low social contacts and low acculturation on cultural values. Minimizing the time interval between baseline and follow-up recruitment, and maintaining frequent contact with participants during this interval should also be is integral to the study design.^

The contribution of change in ethnic composition to prevalence of obesity and overweight

Objective. The prevalence of overweight and obesity differs substantially among children of different ethnic origin in the United States. The objective of this project is to estimate to what extent changes in ethnic composition since 1980 have contributed to the current general “obesity epidemic” in the childhood population of the United States.^ Methods. Populations by single year of age, 0 to 19, male and female, for Hispanics, non-Hispanic whites, and non-Hispanic blacks, from the US Census’ July estimates for 1985, 1990, 1995, 2000 and 2005 were taken and compared to the population and percentage of those groups from 1980. Age, sex, and ethnicity specific prevalence rates for overweight in 1980 were then applied to the populations by age for the specified year and differences in expected and actual overweight populations were assessed.^ Result. The results from this investigation provide estimates of the contribution that different ethnic groups have made to the overall prevalence of overweight and obesity in the childhood population of the United States. Assuming that the 1976-1980 prevalence rates had remained unchanged, and then comparing the population had there been no change in ethnic composition with the population given the actual change in ethnicity, the percentage increase was 1.06% in 1985, 1.72% in 1990, 2.57% in 1995, 3.95% in 2000, and 4.39% in 2005.^ Conclusion. The changes in ethnic composition of the population, independent of changes in ethnicity-specific prevalence, have contributed substantially to the current overall prevalence of obesity in the United States childhood population. There are a number of factors that may be responsible for the apparent susceptibility of Mexican-Americans and non-Hispanic blacks to overweight and obesity. Further research is needed on specific characteristics of those populations.^

Prevalence of gastro esophageal reflux disease following the Montreal Consensus and its association with Helicobacter pylori infection and obesity in a random sample of adults of Ciudad Juarez, Mexico, 2004.

Gastroesophageal reflux disease is a common condition affecting 25 to 40% of the population and causes significant morbidity in the U.S., accounting for at least 9 million office visits to physicians with estimated annual costs of $10 billion. Previous research has not clearly established whether infection with Helicobacter pylori, a known cause of peptic ulcer, atrophic gastritis and non cardia adenocarcinoma of the stomach, is associated with gastroesophageal reflux disease. This study is a secondary analysis of data collected in a cross-sectional study of a random sample of adult residents of Ciudad Juarez, Mexico, that was conducted in 2004 (Prevalence and Determinants of Chronic Atrophic Gastritis Study or CAG study, Dr. Victor M. Cardenas, Principal Investigator). In this study, the presence of gastroesophageal reflux disease was based on responses to the previously validated Spanish Language Dyspepsia Questionnaire. Responses to this questionnaire indicating the presence of gastroesophageal reflux symptoms and disease were compared with the presence of H. pylori infection as measured by culture, histology and rapid urease test, and with findings of upper endoscopy (i.e., hiatus hernia and erosive and atrophic esophagitis). The prevalence ratio was calculated using bivariate, stratified and multivariate negative binomial logistic regression analyses in order to assess the relation between active H. pylori infection and the prevalence of gastroesophageal reflux typical syndrome and disease, while controlling for known risk factors of gastroesophageal reflux disease such as obesity. In a random sample of 174 adults 48 (27.6%) of the study participants had typical reflux syndrome and only 5% (or 9/174) had gastroesophageal reflux disease per se according to the Montreal consensus, which defines reflux syndromes and disease based on whether the symptoms are perceived as troublesome by the subject. There was no association between H. pylori infection and typical reflux syndrome or gastroesophageal reflux disease. However, we found that in this Northern Mexican population, there was a moderate association (Prevalence Ratio=2.5; 95% CI=1.3, 4.7) between obesity (≥30 kg/m2) and typical reflux syndrome. Management and prevention of obesity will significantly curb the growing numbers of persons affected by gastroesophageal reflux symptoms and disease in Northern Mexico. ^

Process evaluation of intervention program for prevention of early sexual activity and alcohol use among Hispanic teenagers

Hispanic teens are a high-risk population for initiation of early sexual activity and alcohol use which in turn has numerous social and health consequences. One strategy to address prevention of these behaviors is to implement a capacity building intervention that promotes parent child communication, encompasses their cultural values and community participation. This study describes the process evaluation of a pilot intervention program amongst Hispanic teens and their families living along the Texas-Mexico border. “Girls Lets Talk” is a small group intervention with 10-14 year old teens and their female adult family members that involves education regarding effects of alcohol use and sexual activity as well as activities for monitoring and refusal skills to prevent risky behaviors. Two waves of the program each consisting of at least seven mother daughter dyads were conducted. During the designing process, community advisory board meetings and focus groups were held to review course materials and ensure they were appropriate to the Mexican American culture. Parent and adolescent surveys were administered at the beginning and end of the intervention to assess for psychosocial outcome variables. All sessions received high mean satisfactory scores (mean of 4.00 or better on a five point scale) for both adult and adolescent participants. Qualitative feedback was obtained via debriefing sessions to evaluate experience as well as alter recruitment strategies. A Wilcoxon Sign Rank analysis of the pre and post intervention surveys was done that showed significant changes in some outcome variables such as intentions and confidence for monitoring behaviors for adults and beliefs regarding sexual activity. “Girls Lets Talk” is a promising example of how a process evaluation plan can help develop a theory based health promotion program using the community based participatory research approach. The intervention may also be effective in altering intentions and enhancing self-efficacy among parents and teens in order to decrease risky behaviors such as early sexual activity and alcohol use.^

Lifetime changes in body mass index and risk of breast cancer in minority women

Introduction: Obesity is an epidemic in the United States, especially among Hispanics and African-Americans. Studies of obesity and breast cancer risk and subtype have been conducted primarily in non-Hispanic whites. Obesity is inversely associated with premenopausal breast cancer, but both obesity and weight gain increase the risk of postmenopausal disease. Obesity has been associated with breast cancer subtype in many studies. Methods: To assess the association between changes in body mass index (BMI) over the lifetime, weight gain, and breast cancer in Mexican-American women, we conducted a case-control study using 149 cases and 330 age-matched controls. In a second study, we identified 212 African-American and 167 Mexican-American women with breast cancer in the ongoing ELLA Bi-National Breast Cancer Study, abstracted medical charts to classify tumors as ER+/PR+, HER2+, or ER-/PR-/HER2-, and assessed the association between lifetime changes in body mass index, weight gain, and breast cancer subtype. In both studies, growth mixture modeling was use to identify trajectories of change in BMI over the lifetime, and these trajectories were used as exposures in a logistic regression model to calculate odds ratios (OR). Results: There was no association between trajectories of change in BMI and breast cancer risk in Mexican-American women. In addition, BMI at ages 15 and 30 and at diagnosis was not associated with breast cancer. However, adult weight gain was inversely associated with breast cancer risk (per 5kg, OR=0.92, 95% CI: 0.85-0.99). The case-only analysis found no association between obesity at ages 15 and 30 and at diagnosis and breast cancer subtype. Further, there was no association between adult weight gain (defined as weight change from age 15 to time of diagnosis) and breast cancer subtype. Conclusions: Obesity was not associated with breast cancer risk in Mexican-American women, while adult weight gain reduced the risk independently of menopausal status. These results are contradictory of those in non-Hispanic white women and suggest that the etiology of breast cancer may differ by race/ethnicity. Further, obesity was not associated with breast cancer subtype in African-American and Mexican-American women, contrary to results in non-Hispanic white women. ^

An examination of the cross-cultural reliability and construct validity of a measure of loneliness

Loneliness is a pervasive, rather common experience in American culture, particularly notable among adolescents. However, the phenomenon is not well documented in the cross-cultural psychiatric literature. For psychiatric epidemiology to encompass a wide array of psychopathologic phenomena, it is important to develop useful measures to characterize and classify both non-clinical and clinical dysfunction in diverse subgroups and cultures.^ The goal of this research was to examine the cross-cultural reliability and construct validity of a scale designed to measure loneliness. The Roberts Loneliness Scale (RLS-8) was administered to 4,060 adolescents ages 10-19 years enrolled in high schools along either side of the Texas-Tamaulipas border region between the U.S. and Mexico. Data collected in 1988 from a study focusing on substance use and psychological distress among adolescents in these regions were used to examine the operating characteristics of the RLS-8. A sample stratified by nationality and language, age, gender, and grade was used for analysis.^ Results indicated that in general the RLS-8 has moderate reliability in the U.S. sample, but not in the Mexican sample. Validity analyses demonstrated that there was evidence for convergent validity of the RLS-8 in the U.S. sample, but none in the Mexican sample. Discriminant validity of the measures in neither sample could be established. Based on the factor structure of the RLS-8, two subscales were created and analyzed for construct validity. Evidence for convergent validity was established for both subscales in both national samples. However, the discriminant validity of the measure remains unsubstantiated in both national samples. Also, the dimensionality of the scale is unresolved.^ One primary goal for future cross-cultural research would be to develop and test better defined culture-specific models of loneliness within the two cultures. From such scientific endeavor, measures of loneliness can be developed or reconstructed to classify the phenomenon in the same manner across cultures. Since estimates of prevalence and incidence are contingent upon reliable and valid screening or diagnostic measures, this objective would serve as an important foundation for future psychiatric epidemiologic inquiry into loneliness. ^