Humoral immunity in tuberculin skin test anergy and its role in high-risk persons exposed to active tuberculosis.

The most common test to identify latent tuberculosis is the tuberculin skin test that detects T cell responses of delayed type hypersensitivity type IV. Since it produces false negative reactions in active tuberculosis or in high-risk persons exposed to tuberculosis patients as shown in this report, we studied antibody profiles to explain the anergy of such responses in high-risk individuals without active infection. Our results showed that humoral immunity against tuberculin, regardless of the result of the tuberculin skin test is important for protection from active tuberculosis and that the presence of high antibody titers is a more reliable indicator of infection latency suggesting that latency can be based on the levels of antibodies together with in vitro proliferation of peripheral blood mononuclear cells in the presence of the purified protein derivative. Importantly, anti-tuberculin IgG antibody levels mediate the anergy described herein, which could also prevent reactivation of disease in high-risk individuals with high antibody titers. Such anti-tuberculin IgG antibodies were also found associated with blocking and/or stimulation of in vitro cultures of PBMC with tuberculin. In this regard, future studies need to establish if immune responses to Mycobacterium tuberculosis can generate a broad spectrum of reactions either toward Th1 responses favoring stimulation by cytokines or by antibodies and those toward diminished responses by Th2 cytokines or blocking by antibodies; possibly involving mechanisms of antibody dependent protection from Mtb by different subclasses of IgG.

Community participation in health services

This study critically analyzes and synthesizes community participation (CP) theory across disciplines, defining and beginning to map out the elements of CP according to a preliminary framework of structure, process, intermediate outcomes, and ultimate outcomes. The first study component sought to determine the impact of Sight N' Soul, a CP project utilizing neighborhood health workers (NHWs), on appointment missing in an indigent urban African-American population. It found that persons entering the vision care system through contact with an NEW were about a third less likely to miss an appointment than those persons entering the system through some other avenue. While theory in this area remains too poorly developed to hypothesize causal relationships between structure, process, and outcomes, a summary of the elements of Sight N' Soul's structure and process both developed the preliminary framework and serves as a first step to mapping these relationships. The second component of the study uncovered the elements of structure and process that may contribute to a sustained egalitarian partnership between community people and professionals, a CP program called Project HEAL. Elements of Project HEAL's structure and process included a shared belief in the program; spirituality; contribution, ownership, and reciprocation; a feeling of family; making it together; honesty, trust, and openness about conflict; the inevitability of uncertainty and change; and the guiding interactional principles of respect; love, care, and compassion; and personal responsibility. The third component analyzed the existing literature, identifying and addressing gaps and inconsistencies and highlighting areas needing more highly developed ethical analysis. Focal issues include the political, economic, and historical context of CP; the power of naming; the issue of purpose; the nature of community; the power to muster and allocate resources; and the need to move to a systems view of health and well-being, expanding our understanding of the universe of potential outcomes of CP, including iatrogenic outcomes. Intermediate outcomes might include change in community, program, and individual capacity, as well as improved health care delivery. Ultimate outcomes include increased positive interdependencies and opportunities for contribution; improved mental, physical, and spiritual health; increased social justice; and decreased exploitation. ^

A STUDY OF THE ATTITUDES OF ELDERLY CONSUMERS TOWARD DENTAL CARE AND ORAL HEALTH

This paper describes a study of the attitudes of elderly consumers toward dental care and oral health. Four hundred and two respondents ages 60-97 were interviewed with a 62 item questionnaire. Attitudes were measured regarding: quality of care, sufficient utilization of care, priority of oral health, patient-provider interaction, individual control over health, powerful others control of health, and chance as the locus of control over health. Analysis of variance was performed on the sample of males and females separately. Fifty-four hypotheses were tested on each sex. Race and self-concept were excellent predictors of attitude for both sexes and SES (socioeconomic status) and self-reported health were good predictors for females. There was no statistically significant relationship between the frequency with which the elderly utilize dental care and their attitudes toward the quality of care they receive. Foremost reason for non-utilization was that of no felt need. Those selecting this reason were likely to be Anglo females, wearers of dentures, in good health. Those selecting cost as the foremost reason for non-utilization were Black, in fair health, of either sex, missing some teeth, but with no dentures. Overall attitudes toward quality of dental care were positive, despite the fact that this group was exposed to dental care in its infancy. This may suggest that the elderly recognize the importance of technological advances in dentistry. Women with low income and education levels were more likely to have positive attitudes about quality of care than other females. Attitudes about interaction between patient and provider were overall negative. The sample scored high on individual control over health, and scored lower, but nonetheless positively, on feelings that persons other than themselves are most essential to maintaining health. Overall these elderly persons did not agree that they relied on chance in matters of health. Those who did choose this locus were female, with lower SES and health status. Though males scored high on internal control of health, those with lowest scores were Mexican-American or had never been married. Sex and ethnicity were the best predictors of attitude across all measures in the study.^

Multiple imputation for missing continuous and dichotomous data: The effects of patterns of missingness and variable correlations on type I error with small samples

The purpose of this study is to investigate the effects of predictor variable correlations and patterns of missingness with dichotomous and/or continuous data in small samples when missing data is multiply imputed. Missing data of predictor variables is multiply imputed under three different multivariate models: the multivariate normal model for continuous data, the multinomial model for dichotomous data and the general location model for mixed dichotomous and continuous data. Subsequent to the multiple imputation process, Type I error rates of the regression coefficients obtained with logistic regression analysis are estimated under various conditions of correlation structure, sample size, type of data and patterns of missing data. The distributional properties of average mean, variance and correlations among the predictor variables are assessed after the multiple imputation process. ^ For continuous predictor data under the multivariate normal model, Type I error rates are generally within the nominal values with samples of size n = 100. Smaller samples of size n = 50 resulted in more conservative estimates (i.e., lower than the nominal value). Correlation and variance estimates of the original data are retained after multiple imputation with less than 50% missing continuous predictor data. For dichotomous predictor data under the multinomial model, Type I error rates are generally conservative, which in part is due to the sparseness of the data. The correlation structure for the predictor variables is not well retained on multiply-imputed data from small samples with more than 50% missing data with this model. For mixed continuous and dichotomous predictor data, the results are similar to those found under the multivariate normal model for continuous data and under the multinomial model for dichotomous data. With all data types, a fully-observed variable included with variables subject to missingness in the multiple imputation process and subsequent statistical analysis provided liberal (larger than nominal values) Type I error rates under a specific pattern of missing data. It is suggested that future studies focus on the effects of multiple imputation in multivariate settings with more realistic data characteristics and a variety of multivariate analyses, assessing both Type I error and power. ^

The impact of a brief foot care intervention for persons with diabetes

Purpose of the study. The purpose of this randomized controlled clinical trial was to determine if a brief intervention would improve foot self-care behaviors in adult patients with Type 2 diabetes who presented to the emergency department for non-emergent care in a predominantly Hispanic southwestern border community. ^ Methods. A pre-post-test, three-group design was used to compare the foot self-care behaviors of patients who received usual care to those who received lower extremity amputation (LEA) risk assessment and to those who received LEA risk assessment plus a brief foot self-care intervention. After being randomized into 3 groups (N = 167), baseline assessments of demographics, diabetes history, acculturation, and the Summary of Diabetes Self Care Activities (SDSCA) questionnaire and Modified Insulin Management Diabetes Self Efficacy Scale (MIMDSES) were completed in English or Spanish. At one-month, 144 (84%) participants were available for follow-up by the research assistant masked to group assignment. ^ Results. At baseline, significant differences in foot self-care behaviors and self monitoring blood glucose were noted based on ethnicity and gender. Men had significantly lower confidence in their ability to manage their diabetes overall. There was a significant difference between baseline and follow up self reported foot self-care behaviors within the intervention group (t (47) = −4.32, p < .01) and the control group (t (46) = −2.06, p < .05). There were no significant differences between groups for self-reported foot self-care behaviors. There was a significant difference in observed foot self-care behaviors between groups (F(2,135) = 2.99, p < .05). Self-efficacy scores were positively correlated with self-reported self-care behaviors. ^ Conclusions. This predominantly Hispanic population with type 2 diabetes reported performing diabetes self-care behaviors less than five days a week. There were within group changes, but no significant between group changes in reported self-care behaviors. However, at the one month follow up, there were significant differences between groups in observed foot self-care behaviors with the intervention group demonstrating the most accurate behaviors. Differences based on gender and ethnicity emphasize the need to individualize diabetes education. Priorities for culturally competent diabetes education, approaches to increasing self-efficacy and future research directions are suggested. ^

Estimating parameters in Markov models for longitudinal studies with missing data or surrogate outcomes

The discrete-time Markov chain is commonly used in describing changes of health states for chronic diseases in a longitudinal study. Statistical inferences on comparing treatment effects or on finding determinants of disease progression usually require estimation of transition probabilities. In many situations when the outcome data have some missing observations or the variable of interest (called a latent variable) can not be measured directly, the estimation of transition probabilities becomes more complicated. In the latter case, a surrogate variable that is easier to access and can gauge the characteristics of the latent one is usually used for data analysis. ^ This dissertation research proposes methods to analyze longitudinal data (1) that have categorical outcome with missing observations or (2) that use complete or incomplete surrogate observations to analyze the categorical latent outcome. For (1), different missing mechanisms were considered for empirical studies using methods that include EM algorithm, Monte Carlo EM and a procedure that is not a data augmentation method. For (2), the hidden Markov model with the forward-backward procedure was applied for parameter estimation. This method was also extended to cover the computation of standard errors. The proposed methods were demonstrated by the Schizophrenia example. The relevance of public health, the strength and limitations, and possible future research were also discussed. ^

The illness experience of persons with Parkinson's Disease

Background. Parkinson's disease is a chronic, progressive, age-related, neurodegenerative disorder with no known cause or promising cure. While substantial information is known about the pathophysiology of Parkinson's disease, little is known about the illness experience of persons living with the disease. The purpose of this study was to understand how persons with Parkinson's disease construct their illness experience and manage living with their illness on a daily basis. ^ Method. A qualitative study with an ethnographic approach employed the strategies of participant observations and fieldwork. Field data were generated from a two year exposure to two Parkinson's disease support groups in east Texas. Open-ended semi-structured interviews with seven men and seven women with Parkinson's disease were also conducted. These data were combined and analyzed using thematic analysis. ^ Findings. The illness experience is described through the metaphor "Sailing the Sea in The Eye of the Storm." This metaphor served as the overarching theme that covered the two interacting content themes of the voyage of Daily Negotiations in the Midst of Uncertainty and Reconstruction of the Self with Parkinson's Disease. Daily negotiations incorporated navigating daily activities with the uncertainty of both the progression and daily vicissitudes of the disease. Participants described their symptoms as progressive imprisonment that interfered with daily activities. The progressive nature of the disease required the participants to reconstruct their perceptions of themselves. Reconstructing the self involved the paradoxical balancing of preserving the self while simultaneously releasing aspects of the former self to reconstruct the self with Parkinson's disease. This process was reflected in four exemplars: I Know Me." "It's Still Me," "See Me." and "Remember Me." ^ Conclusions. This qualitative study illuminated the struggle of persons in dealing with the uncertainties and fluctuations of Parkinson's disease and the process of reconstructing their perceptions of themselves. The meaning and reconstruction of the illness experience expressed by participants will inform understanding beyond the disease itself to the illness experience that these participants must deal with on a daily basis. ^

Syndromic surveillance at a long term shelter for persons displaced by hurricanes Katrina and Rita conducted by the San Antonio Metropolitan Health District

Background. Beginning September 2, 2005, San Antonio area shelters received approximately 12,700 evacuees from Hurricane Katrina. Two weeks later, another 12,000 evacuees from Hurricane Rita arrived. By mid-October, 2005, the in-shelter population was 1,000 people. There was concern regarding the potential for spread of infectious diseases in the shelter. San Antonio Metropolitan Health District (SAMHD) established a syndromic surveillance system with Comprehensive Health Services (CHS) who provided on-site health care. CHS was in daily contact with SAMHD to report symptoms of concern until the shelter closed December 23, 2005. ^ Study type. The objective of this study was to assess the methods used and describe the practical considerations involved in establishing and managing a syndromic surveillance system, as established by the SAMHD in the long-term shelter clinic maintained by CHS for the hurricane evacuees. ^ Methods. Information and descriptive data used in this study was collected from multiple sources, primarily from the San Antonio Metropolitan Health District’s 2006 Report on Syndromic Surveillance of a Long-Term Shelter by Hausler & Rohr-Allegrini. SAMHD and CHS staff ensured that each clinic visit was recorded by date, demographic information, chief complaint and medical disposition. Logs were obtained daily and subsequently entered into a Microsoft Access database and analyzed in Excel. ^ Results. During a nine week period, 4,913 clinic visits were recorded, reviewed and later analyzed. Repeat visits comprised 93.0% of encounters. Chronic illnesses contributed to 21.7% of the visits. Approximately 54.0% were acute care encounters. Of all encounters, 17.3% had infectious disease potential as primarily gastrointestinal and respiratory syndromes. Evacuees accounted for 86% and staff 14% of all visits to the shelter clinic. There were 782 unduplicated individuals who sought services at the clinic, comprised of 63% (496) evacuees and 36% (278) staff members. Staff were more likely to frequent the clinic but for fewer visits each. ^ Conclusion. The presence of health care services and syndromic surveillance provided the opportunity to recognize, document and intervene in any disease outbreak at this long-term shelter. Constant vigilance allowed SAMHD to inform and reassure concerned people living and working in the shelter and living outside the shelter.^

Tuberculosis in persons with concomittant diseases in Houston, Texas, 2004 to 2008

The purpose of this study is to evaluate characteristics of tuberculosis (TB) in diabetics and persons infected with HIV from 2004 to 2008 in Houston, Texas. This analysis will allow us to identify demographic trends. Previous studies have shown that in general, there is a higher risk for HIV+ persons to develop active TB, or to re-activate latent TB, as they progress in their HIV infection. In addition, similar to HIV, diabetes mellitus (DM) weakens the immune system so that persons with DM have also been shown to have a tendency to develop TB. This analysis will examine three areas of research: (a) to explore existing TB trends in Houston/Harris County and associated characteristics, (b) to ascertain the common risk factors of DM and HIV that are correlate with TB infections, and (c) from the analysis of the data, to determine if subsequent TB prevention programs are needed for specific subgroups.^

Motivational interviewing and feedback for college drinkers: Handling missing values with complete case analysis and multiple imputation

Objective: In this secondary data analysis, three statistical methodologies were implemented to handle cases with missing data in a motivational interviewing and feedback study. The aim was to evaluate the impact that these methodologies have on the data analysis. ^ Methods: We first evaluated whether the assumption of missing completely at random held for this study. We then proceeded to conduct a secondary data analysis using a mixed linear model to handle missing data with three methodologies (a) complete case analysis, (b) multiple imputation with explicit model containing outcome variables, time, and the interaction of time and treatment, and (c) multiple imputation with explicit model containing outcome variables, time, the interaction of time and treatment, and additional covariates (e.g., age, gender, smoke, years in school, marital status, housing, race/ethnicity, and if participants play on athletic team). Several comparisons were conducted including the following ones: 1) the motivation interviewing with feedback group (MIF) vs. the assessment only group (AO), the motivation interviewing group (MIO) vs. AO, and the intervention of the feedback only group (FBO) vs. AO, 2) MIF vs. FBO, and 3) MIF vs. MIO.^ Results: We first evaluated the patterns of missingness in this study, which indicated that about 13% of participants showed monotone missing patterns, and about 3.5% showed non-monotone missing patterns. Then we evaluated the assumption of missing completely at random by Little's missing completely at random (MCAR) test, in which the Chi-Square test statistic was 167.8 with 125 degrees of freedom, and its associated p-value was p=0.006, which indicated that the data could not be assumed to be missing completely at random. After that, we compared if the three different strategies reached the same results. For the comparison between MIF and AO as well as the comparison between MIF and FBO, only the multiple imputation with additional covariates by uncongenial and congenial models reached different results. For the comparison between MIF and MIO, all the methodologies for handling missing values obtained different results. ^ Discussions: The study indicated that, first, missingness was crucial in this study. Second, to understand the assumptions of the model was important since we could not identify if the data were missing at random or missing not at random. Therefore, future researches should focus on exploring more sensitivity analyses under missing not at random assumption.^

Identification of genetic variants that influence atherosclerosis in young persons

Atherosclerosis is widely accepted as a complex genetic phenotype and is the usual cause of cardiovascular disease, the world’s leading killer. Genetic factors have been proven to be important risk contributors for atherosclerosis and much work has been done to identify promising candidates that might play a role in the development of atherosclerosis. It is well known that many independent replications are needed to unequivocally establish a valid genotype-phenotype association across different populations before the findings are extended to clinical settings and to the expensive follow-up studies designed to identify causal genetic variants. Aiming to replicate the association with atherosclerosis in the Pathobiological Determinants of Atherosclerosis in Youth (PDAY) study, we assessed the relationship of 32 atherosclerosis candidate SNPs to atherosclerosis in the PDAY cohort, consisting of AA and EA young people aged 15-34 years who died of non-medical causes. Two association studies, a whole sample study and a 1:1 matched case control study were performed by use of multiple linear regression and logistic regression analyses, respectively. For the whole sample association study, 32 SNPs among 2,650 individuals (1,369 AA and 1,281 EA) were tested for the association with six early atherosclerosis phenotypes: abdominal aorta fatty streaks, abdominal aorta raised lesions, right coronary artery fatty streaks, right coronary artery raised lesions, thoracic aorta fatty streaks, and thoracic aorta raised lesions. For the matched case-control association study, 337 case-control paired samples were included; cases were chosen with the highest total raised lesion scores from the studied population, while controls were randomly selected from individuals that had no raised lesions and matched to cases by age, gender and race. Sixteen SNPs in 13 genes were found to be significantly associated with atherosclerosis in at least one of the PDAY association studies. Among these 16 findings: eight SNPs (rs9579646, rs6053733, rs3849150, rs10499903, rs2148079, rs5073691, rs10116277, and rs17228212) successfully replicated previous results, six SNPs (rs17222814, rs10811661, rs7028570, rs7291467, rs16996148 and rs10401969) were reported as new findings exclusive to our study, the last two of the 16 SNPs, rs501120 and rs6922269, showed either intriguing or conflicting result. SNP rs17222814 in ALOX5AP and SNP rs3849150 in LRRC18 were consistently associated with atherosclerosis in both prior and the two PDAY association studies. SNP rs3849150 was also identified to be highly correlated with a non-synonymous coding SNP, rs17772611, which may damage the protein (polyphen score = 0.996), suggesting that SNP rs17772611 may be the causal functional variant.^ In conclusion, our study added more support for the association of these candidate genes with atherosclerosis. SNPs rs3849150 and rs17772611 of LRRC18, as well as SNP rs17222814 of ALOX5AP, were the most significant findings from our study, and may be ranked among the best for further study.^

Commercial Sexual Exploitation and Missing Children in the Coastal Region of Sao Paulo State, Brazil

The commercial sexual exploitation of children (CSEC) has emerged as one of the world’s most heinous crimes. The problem affects millions of children worldwide and no country or community is fully immune from its effects. This paper reports first generation research of the relationship that exists between CSEC and the phenomenon of missing children living in and around the coastal regions of the state of Sao Paulo, Brazil, the country’s richest State. Data are reported from interviews and case records of 64 children and adolescents, who were receiving care through a major youth serving non-governmental organization (NGO) located in the coastal city of Sao Vicente. Also, data about missing children and adolescents were collected from Police Reports – a total of 858 Police Reports. In Brazil, prostitution is not a crime itself, however, the exploitation of prostitution is a crime. Therefore, the police have no information about children or adolescents in this situation, they only have information about the clients and exploiters. Thus, this investigation sought to accomplish two objectives: 1) to establish the relationship between missing and sexual exploited children; and 2) to sensitize police and child-serving authorities in both the governmental and nongovernmental sectors to the nature, extent, and seriousness of many unrecognized cases of CSEC and missing children that come to their attention. The observed results indicated that the missing children police report are significantly underestimated. They do not represent the number of children that run away and/or are involved in commercial sexual exploitation.

Bayesian estimation of multilevel item response model with missing data

This study proposed a novel statistical method that modeled the multiple outcomes and missing data process jointly using item response theory. This method follows the "intent-to-treat" principle in clinical trials and accounts for the correlation between outcomes and missing data process. This method may provide a good solution to chronic mental disorder study. ^ The simulation study demonstrated that if the true model is the proposed model with moderate or strong correlation, ignoring the within correlation may lead to overestimate of the treatment effect and result in more type I error than specified level. Even if the within correlation is small, the performance of proposed model is as good as naïve response model. Thus, the proposed model is robust for different correlation settings if the data is generated by the proposed model.^

Application of the general linear model to assess the effect of missing data on bone marrow mononuclear cell therapy with infusion timing and follow-up MRI

With most clinical trials, missing data presents a statistical problem in evaluating a treatment's efficacy. There are many methods commonly used to assess missing data; however, these methods leave room for bias to enter the study. This thesis was a secondary analysis on data taken from TIME, a phase 2 randomized clinical trial conducted to evaluate the safety and effect of the administration timing of bone marrow mononuclear cells (BMMNC) for subjects with acute myocardial infarction (AMI).^ We evaluated the effect of missing data by comparing the variance inflation factor (VIF) of the effect of therapy between all subjects and only subjects with complete data. Through the general linear model, an unbiased solution was made for the VIF of the treatment's efficacy using the weighted least squares method to incorporate missing data. Two groups were identified from the TIME data: 1) all subjects and 2) subjects with complete data (baseline and follow-up measurements). After the general solution was found for the VIF, it was migrated Excel 2010 to evaluate data from TIME. The resulting numerical value from the two groups was compared to assess the effect of missing data.^ The VIF values from the TIME study were considerably less in the group with missing data. By design, we varied the correlation factor in order to evaluate the VIFs of both groups. As the correlation factor increased, the VIF values increased at a faster rate in the group with only complete data. Furthermore, while varying the correlation factor, the number of subjects with missing data was also varied to see how missing data affects the VIF. When subjects with only baseline data was increased, we saw a significant rate increase in VIF values in the group with only complete data while the group with missing data saw a steady and consistent increase in the VIF. The same was seen when we varied the group with follow-up only data. This essentially showed that the VIFs steadily increased when missing data is not ignored. When missing data is ignored as with our comparison group, the VIF values sharply increase as correlation increases.^