Public Health Commons^™

A Pilot Randomized, Controlled Trial Of An In-Home Drinking Water Intervention Among Hiv + Persons, John M. Colford, Sona R. Saha, Timothy J. Wade, Catherine C. Wright, Mai Vu, Sandra Charles, Peter Jensen, Alan Hubbard, Deborah A. Levy, Joseph N. S. Eisenberg

Journal Articles: Epidemiology

Although immunocompromised persons may be at increased risk for gastrointestinal illnesses, no trials investigating drinking water treatment and gastrointestinal illness in such patients have been published. Earlier results from San Francisco suggested an association (OR 6.76) between tap water and cryptosporidiosis among HIV + persons. The authors conducted a randomized, triple-blinded intervention trial of home water treatment in San Francisco, California, from April 2000 to May 2001. Fifty HIV-positive patients were randomized to externally identical active (N = 24) or sham (N = 26) treatment devices. The active device contained a filter and UV light; the sham provided no treatment. …

A Randomized, Controlled Trial Of In-Home Drinking Water Intervention To Reduce Gastrointestinal Illness, John M. Colford, Timothy J. Wade, Sukhminder K. Sandhu, Catherine C. Wright, Sherline Lee, Susan Shaw, Kim Fox, Susan Burns, Anne Benker, M. Alan Brookhart, Mark Van Der Laan, Deborah A. Levy

Journal Articles: Epidemiology

Trials have provided conflicting estimates of the risk of gastrointestinal illness attributable to tap water. To estimate this risk in an Iowa community with a well-run water utility with microbiologically challenged source water, the authors of this 2000-2002 study randomly assigned blinded volunteers to use externally identical devices (active device: 227 households with 646 persons; sham device: 229 households with 650 persons) for 6 months (cycle A). Each group then switched to the opposite device for 6 months (cycle B). The active device contained a 1-microm absolute ceramic filter and used ultraviolet light. Episodes of "highly credible gastrointestinal illness," a …

Blood Lead And Decision Speed In Working Age Adults, S. W. Harkins

Theses and Dissertations

Lead is a central nervous system poison. Healthy People 2010 established a target blood lead level (BLL) for children of 0 μg/dL by 2010, but is silent with regard to any changes in BLLs standards for working age adults. In this paper, the relation of BLL to performance on two neurobehavioral tests was assessed in working age adults (N = 4909; Age 20 to 59 years; 51.4% Female) employing data from the Third National Health and Nutrition Survey (NHANES 111). Multiple linear regression analyses indicated a significant effect of BLL on time taken to complete an attention demanding cognitive task …

Predictors Of Sun Protection Practices Among Adult Women In The United States, Anne Ridgely Minter

Theses and Dissertations

Background. Skin cancer is the most common form of cancer in the United States. The main modifiable risk factor for skin cancer is exposure to excessive sun and UV radiation. More than 90% of all skin cancers are known to be caused by sun exposure. However, studies on excessive sun and UV exposure are limited. The purpose of this study was to examine risk and protective factors affecting sun protection behaviors of adult women in the United States. Methods. Data on U.S. adult women (n=17,425) from the 2003 National Health Information Survey (NHIS) was analyzed. Sun protection behaviors were assessed …

Predictors Of Early Onset Of Sexual Intercourse In Male And Female Residents Of The United States, Brianna Michele Magnusson

Theses and Dissertations

Abstract Purpose: The United States has the highest rate of teen pregnancy of any industrialized nation. Adolescents who have their first sexual intercourse at a young age are at increased risk for teen pregnancies and acquiring a sexually transmitted disease. This study examines predictors of early onset sexual intercourse in male and female residents of the United States. Methods: A nationally representative sample of N=7,643 females and N=4.928 males ages 15-44 was procured from the 2002 National Survey of Family Growth (NSFG), Cycle 6. Age at first sexual intercourse was used to define early onset of sexual debut(<18 years). Socio-demographic and behavioral characteristics of the respondents, demographic and selected reproductive characteristics of the respondent's parents were examined using multiple logistic regression modeling. Results: Non-fispanic black, being raised without both parents, having a mother less than 18 years old at the age of first birth and age difference between partners were significant predictors of early onset of sexual intercourse for both males and females. Maternal education less than high school was a significant protective factor for female respondents [OR=0.72 (95%CI=0.58- 0.90)] and paternal education completed high school only [OR=1.4 (95% CI=l. 1-1.7)] was a significant risk factor for male respondents. Conclusions: Racelethnicity, age difference between partners, not being raised by both parents, having a mother who had her first birth before the age of 18 and parental education are important predictor variables. Further study should be conducted to investigate the protective effect of lack of maternal education for female respondents. Intervention programs for teen pregnancy and sexually transmitted infection prevention should target these at risk groups.

Effect Of Medicaid/Schip And Wic On Oral Health Of Low-Income Children, Dahlia Naqib

Theses and Dissertations

Oral caries is the most prevalent chronic disease among US children, and disproportionately impacts those of low socioeconomic status. Studies have shown that the Special Supplemental Nutrition Program for Women Infants and Children (WIC) improves access to dental care among Medicaid children. This study investigated the impact of WIC, Medicaid, and the State Children's Health Insurance Program (SCHIP) on the prevalence of dental caries among low-income children. The 1999-2000 and 2001-2002 NHANES data were utilized for this analysis. Children 2-4 years old who participated in WIC, Medicaid, or SCHIP, or who were uninsured, and for whom both interview and complete …

Analysis Of The Impact Of A Social Norms Campaign On The Alcohol Use Of Undergraduate Students At A Public, Urban University, Amanda B. Wattenmaker

Theses and Dissertations

Purpose: To conduct a secondary analysis of survey data collected at a large, urban university assessing for change in students' alcohol use perceptions and behaviors between 2002 and 2004. After the baseline data collection in 2002, the campus launched an intensive media intervention to normalize low-risk drinking. Simultaneously, the campus shifted from being a primarily commuter to primarily residential. Methods: This cross-sectional analysis used data collected from students in randomly selected undergraduate classes in February 2002 (n= 662) and 2004 (n=1334). The survey instrument used was the National College Health Assessment. Variables were categorized as demographic, alcohol perception, and alcohol …

Long-Term Consequences Of West Nile Virus In Virginia., Diana Cruz Ocampo

Theses and Dissertations

Objective: The purpose of this investigation was to describe the long-term effects and functional outcomes of patients in Virginia who were reported to the Virginia Department of Health with West Nile virus (WNV) non-neuroinvasive and neuroinvasive disease. The study identified the duration of symptoms after initial illness, the number of persons who fully recovered versus the number who continue to be symptomatic and how patients' quality of life differed after illness.Methods: The study population was drawn from 60 human cases that met the surveillance case definition for non-neuroinvasive and neuroinvasive WNV illness in Virginia between 2002-2004. Information was collected during …

Age At Sexual Assault And Posttraumatic Stress Disorder In Females Residents Of Virginia, Ahmed Gasmelseed Babiker

Theses and Dissertations

Background Post Traumatic Stress Disorder (PTSD) is a psychiatric debilitating condition that can occur in individuals who experience extremely stressful or traumatic life events. Sexual assault is considered as one of the most traumatic stressor in life. Although few studies investigated the association between history of sexual assault and PTSD, no studies have examined the impact of age at sexual assault on PTSD.Method A cross-sectional telephone survey was conducted among adult female residents of Virginia from November 2002 to February 2003. A total of 1,769 women aged 18 and older were interviewed using a random digit dialing method. Detailed screening …

The Prevalence Of Comorbid Chronic Disease In Virginia's Adult Patient Population During The Years 2001 And 2004, Joseph D. Schwartz

Theses and Dissertations

Objective: Chronic disease comorbidities, on the rise in the U.S. and Virginia, represent a new challenge to the way medicine is practiced and prescribed. This descriptive study uses Virginia hospital discharge data to describe the prevalence and trends of chronic disease comorbidities present in the state's over-45 population during the years 2001 and 2004.Methods: Data collected by Virginia Health Information was utilized. Adults over the age of 45 years and who selected for race and location were included in this analysis, with an aggregate sample size of 813,336 (N=458,593 [2001]; N=364,743 [2004]). Pearson chi-square analyses determined significant sample population differences …

Trends In Canine Lyme Disease On The Eastern Shore Of Virginia, 2000-2005, Ellen Garrett Hillyer

Theses and Dissertations

Introduction: Lyme disease is caused by the tick-borne spirochete Borrelia burgdorferi. Research has shown that dogs can be used as sentinels for human infection of Lyme disease. The purpose of this 5-year, retrospective study was to determine if there was any evidence that the incidence of canine Lyme disease has increased between 2000 and 2005 in Accomack and Northampton counties. An increased incidence in Lyme disease in dogs may indicate an increased present or future risk of Lyme disease in humans.Methods: Cases of canine Lyme disease were identified via practice invoicing systems and dogs that received doxycycline were entered into …

The Association Between Eating Habits And Hypertension Among African American Women Compared To Other Women, Anike N. Clark

Theses and Dissertations

Background: Hypertension is a major public health concern for African American women. Many studies have shown a greater prevalence of hypertension, as well as physical inactivity, excess weight, and diabetes, in African Americans. Objective: To determine if differences in eating patterns, as measured by Healthy Eating Index (HEI) scores, between African American women and other women in the United States are associated with hypertension. Methods: Data were extracted from the Third National Health and Nutrition Examination Survey (NHANESIII). The sample included 31,189,534 women aged 45 years or greater after survey weights were applied. The majority was White (86.1 %); minority …

The Incidence And Prevalance Of Cervical Cancer In Vietnamese Women (1993-1995): A Analysis Of Seer Reported Cases, Thuy Do

Theses and Dissertations

Background: Cervical cancer is the third most common reproductive cancer in the U.S. To date, one report concluded that U.S. Vietnamese women had the highest incidence rate (43.0/100,000). The current study examines whether U.S. Vietnamese women are more likely to have cervical cancer in comparison to Whites, Blacks, Hispanics, American Indians, and other Asian subgroups. Methods: SEER data of cervical cancers diagnosed from 1993-1995 (n = 37,790) was utilized. Using SPSS, chi-square statistics assessed whether Vietnamese women were older and more likely to be married or diagnosed at a later stage. Logistic regression assessed the amount of risk race/ethnicity contributes …

Assessing The Relationship Between Socioeconomic Variables And Risk Of Overweight Among Children 6 Years Of Age, Marilyn Cochon Batan

Theses and Dissertations

Background: The percentage of overweight children has tripled in the last thirty years. Inconsistent findings are published regarding the relationship between socioeconomic variables and being overweight in childhood.Objective: To determine whether socioeconomic variables are associated with risk of being overweight among six year olds. Methods: Six year olds with BMI data were selected from the National Survey of Children's Health (n=4,362). Variables were coded and a low socioeconomic index was created. Using population weights, descriptive statistics were generated and regression was utilized to assess the relationship between socioeconomic variables and being 'at risk' for overweight. Socioeconomic variables were also compared …

Predictors Of Induced Abortion Among Female Youth Center Users In Port-Au-Prince, Haiti, Rachel Barker

Theses and Dissertations

Objective: Induced abortions occur in every country in the world. However sixty percent of the world's women live in countries where abortion is illegal. 19 million pregnancies end in unsafe and/or illegal abortions. Annually, 68,000 women die from unsafe abortions. Legal or not, unsafe abortion is one of the great neglected problems of health care in developing countries like Haiti and is a serious concern to women during their reproductive lives. Methods: The data for this study was collected from youth centers (ages 15-24) and used to estimate percentage distributions of abortion ratios by selected characteristics of women, particularly age …

The Relationship Between Breastfeeding And The Development Of Asthma In Early Childhood, River Anne Pugsley

Theses and Dissertations

Purpose: Asthma can have significant adverse effects on the health and quality of life of children, and the prevalence of this condition continues to rise. Breastfeeding may protect against asthma, but some uncertainty remains. The purpose of this study was to further examine the relationship between breastfeeding and the risk of developing asthma in early childhood. Methods: Data were collected from the State and Local Area Integrated Telephone Survey: National Survey of Children's Health, 2003. The study population consisted of 33,315 children ages 0 to 5 years. Prevalence rates of asthma and breastfeeding ,were calculated, as were crude and Mantel-Haenszel …

Estimating Percentile-Specific Causal Effects: A Case Study Of Micronutrient Supplementation, Birth Weight, And Infant Mortality, Francesca Dominici, Scott L. Zeger, Giovanni Parmigiani, Joanne Katz, Parul Christian

Johns Hopkins University, Dept. of Biostatistics Working Papers

In developing countries, higher infant mortality is partially caused by poor maternal and fetal nutrition. Clinical trials of micronutrient supplementation are aimed at reducing the risk of infant mortality by increasing birth weight. Because infant mortality is greatest among the low birth weight infants (LBW) (• 2500 grams), an effective intervention may need to increase the birth weight among the smallest babies. Although it has been demonstrated that supplementation increases the birth weight in a trial conducted in Nepal, there is inconclusive evidence that the supplementation improves their survival. It has been hypothesized that a potential benefit of the treatment …

A Hybrid Newton-Type Method For The Linear Regression In Case-Cohort Studies, Menggang Yu, Bin Nan

The University of Michigan Department of Biostatistics Working Paper Series

Case-cohort designs are increasingly commonly used in large epidemiological cohort studies. Nan, Yu, and Kalbeisch (2004) provided the asymptotic results for censored linear regression models in case-cohort studies. In this article, we consider computational aspects of their proposed rank based estimating methods. We show that the rank based discontinuous estimating functions for case-cohort studies are monotone, a property established for cohort data in the literature, when generalized Gehan type of weights are used. Though the estimating problem can be formulated to a linear programming problem as that for cohort data, due to its easily uncontrollable large scale even for a …

Referent Selection Strategies In Case-Crossover Analyses Of Air Pollution Exposure Data: Implications For Bias, Holly Janes, Lianne Sheppard, Thomas Lumley

UW Biostatistics Working Paper Series

The case-crossover design has been widely used to study the association between short term air pollution exposure and the risk of an acute adverse health event. The design uses cases only, and, for each individual, compares exposure just prior to the event with exposure at other control, or “referent” times. By making within-subject comparisons, time invariant confounders are controlled by design. Even more important in the air pollution setting is that, by matching referents to the index time, time varying confounders can also be controlled by design. Yet, the referent selection strategy is important for reasons other than control of …

Bayesian Hierarchical Distributed Lag Models For Summer Ozone Exposure And Cardio-Respiratory Mortality, Yi Huang, Francesca Dominici, Michelle L. Bell

Johns Hopkins University, Dept. of Biostatistics Working Papers

In this paper, we develop Bayesian hierarchical distributed lag models for estimating associations between daily variations in summer ozone levels and daily variations in cardiovascular and respiratory (CVDRESP) mortality counts for 19 U.S. large cities included in the National Morbidity Mortality Air Pollution Study (NMMAPS) for the period 1987 - 1994.

At the first stage, we define a semi-parametric distributed lag Poisson regression model to estimate city-specific relative rates of CVDRESP associated with short-term exposure to summer ozone. At the second stage, we specify a class of distributions for the true city-specific relative rates to estimate an overall effect by …

Dynamical Epidemic Suppression Using Stochastic Prediction And Control, Ira Schwartz, Lora Billings, Erik Bollt

Department of Mathematics Faculty Scholarship and Creative Works

We consider the effects of noise on a model of epidemic outbreaks, where the outbreaks appear randomly. Using a constructive transition approach that predicts large outbreaks prior to their occurrence, we derive an adaptive control scheme that prevents large outbreaks from occurring. The theory is applicable to a wide range of stochastic processes with underlying deterministic structure.

Data Adaptive Estimation Of The Treatment Specific Mean, Yue Wang, Oliver Bembom, Mark J. Van Der Laan

U.C. Berkeley Division of Biostatistics Working Paper Series

An important problem in epidemiology and medical research is the estimation of the causal effect of a treatment action at a single point in time on the mean of an outcome, possibly within strata of the target population defined by a subset of the baseline covariates. Current approaches to this problem are based on marginal structural models, i.e., parametric models for the marginal distribution of counterfactural outcomes as a function of treatment and effect modifiers. The various estimators developed in this context furthermore each depend on a high-dimensional nuisance parameter whose estimation currently also relies on parametric models. Since misspecification …

Indigenous Healing Practices And Their Effect On Tb And Hiv/Tb Patients’ Utilization And Compliance With Anti-Tb Medication, Josephine Thinwa

Independent Study Project (ISP) Collection

A sample of 27 Tuberculosis patients attending New Brighton Clinic in small urban community for treatment were surveyed and interviewed on their use of alternative treatments and interpretation of TB. This study specifically focused on TB patients’ use of traditional medicine in treating TB and whether this use had an effect on the patients’ willingness to utilize and adherence to anti-TB treatment from the clinic. Investigations were also done to characterize if an HIV positive status influenced TB patients’ inclination to utilize traditional medicine. Through a focus group discussion with three traditional healers, information was provided on traditional medicine and …

Descriptive And Comparative Study Of The Nutritional Knowledge And Behavior Of Mothers Of Young Children Who Have Received Targeted Nutritional Education And Those Who Have Not As A Method To Ascertain The Effectiveness Of The Little Tree Nutritional And Educational Centre In Combating Malnutrition In The Pienaarsig Township Of Nieu Bethesda, Eastern Cape Province, South Africa, Amelia Peterson

Independent Study Project (ISP) Collection

No abstract provided.

History-Adjusted Marginal Structural Models And Statically-Optimal Dynamic Treatment Regimes, Mark J. Van Der Laan, Maya L. Petersen

U.C. Berkeley Division of Biostatistics Working Paper Series

Marginal structural models (MSM) provide a powerful tool for estimating the causal effect of a treatment. These models, introduced by Robins, model the marginal distributions of treatment-specific counterfactual outcomes, possibly conditional on a subset of the baseline covariates. Marginal structural models are particularly useful in the context of longitudinal data structures, in which each subject's treatment and covariate history are measured over time, and an outcome is recorded at a final time point. However, the utility of these models for some applications has been limited by their inability to incorporate modification of the causal effect of treatment by time-varying covariates. …

Estimation Of Treatment Effects In Randomized Trials With Noncompliance And A Dichotomous Outcome , Mark J. Van Der Laan, Alan E. Hubbard, Nicholas P. Jewell

U.C. Berkeley Division of Biostatistics Working Paper Series

We propose a class of estimators of the treatment effect on a dichotomous outcome among the treated subjects within covariate and treatment arm strata in randomized trials with non-compliance. Recent articles by Vansteelandt and Goethebeur (2003) and Robins and Rotnitzky (2004) have presented consistent and asymptotically linear estimators of a causal odds ratio, which rely, beyond correct specification of a model for the causal odds ratio, on a correctly specified model for a potentially high dimensional nuisance parameter. In this article we propose consistent, asymptotically linear and locally efficient estimators of a causal relative risk and a new parameter -- …

Estimation Of Direct And Indirect Causal Effects In Longitudinal Studies, Mark J. Van Der Laan, Maya L. Petersen

U.C. Berkeley Division of Biostatistics Working Paper Series

The causal effect of a treatment on an outcome is generally mediated by several intermediate variables. Estimation of the component of the causal effect of a treatment that is mediated by a given intermediate variable (the indirect effect of the treatment), and the component that is not mediated by that intermediate variable (the direct effect of the treatment) is often relevant to mechanistic understanding and to the design of clinical and public health interventions. Under the assumption of no-unmeasured confounders, Robins & Greenland (1992) and Pearl (2000), develop two identifiability results for direct and indirect causal effects. They define an …

Cancer Esophagus Karachi 1995-2002:Epidemiology, Risk Factors And Trends, Y. Bhurgri, N. Faridi, L. A.G. Kazi, S. K. Ali, H. Bhurgri, A. Usman, J. Malik, A. Bhurgri, R. Ahmed, S. Muzaffar, N. Kayani, Shahid Pervez, S. H. Hasan

Department of Pathology and Laboratory Medicine

Objective: To study the trends of cancer esophagus in Karachi South during 1995-2002 and identify risk factors.

Methods: Incident esophageal cancer cases recorded at the Karachi Cancer Registry for Karachi South, during 1st January 1995 to 31st December 2003 were reviewed. For maximum completion of data, incident cases registered from 1st January 1995 to 31st December 2002 were included for final analyses.

Results: The Age Standardized Incidence Rates (ASIRs) of cancer esophagus in Karachi South for males were 6.5/100,000 (1995-1997) and 6.4/100,000 (1998-2002). In females the observed rates were 7.0/100,000 (1995-1997) and 8.6/100,000 (1998-2002).

Conclusion: In the moderately high incidence, …

Multiple Testing Methods For Chip-Chip High Density Oligonucleotide Array Data, Sunduz Keles, Mark J. Van Der Laan, Sandrine Dudoit, Simon E. Cawley

U.C. Berkeley Division of Biostatistics Working Paper Series

Cawley et al. (2004) have recently mapped the locations of binding sites for three transcription factors along human chromosomes 21 and 22 using ChIP-Chip experiments. ChIP-Chip experiments are a new approach to the genome-wide identification of transcription factor binding sites and consist of chromatin (Ch) immunoprecipitation (IP) of transcription factor-bound genomic DNA followed by high density oligonucleotide hybridization (Chip) of the IP-enriched DNA. We investigate the ChIP-Chip data structure and propose methods for inferring the location of transcription factor binding sites from these data. The proposed methods involve testing for each probe whether it is part of a bound sequence …

Combining Predictors For Classification Using The Area Under The Roc Curve, Margaret S. Pepe, Tianxi Cai, Zheng Zhang

UW Biostatistics Working Paper Series

We compare simple logistic regression with an alternative robust procedure for constructing linear predictors to be used for the two state classification task. Theoritical advantages of the robust procedure over logistic regression are: (i) although it assumes a generalized linear model for the dichotomous outcome variable, it does not require specification of the link function; (ii) it accommodates case-control designs even when the model is not logistic; and (iii) it yields sensible results even when the generalized linear model assumption fails to hold. Surprisingly, we find that the linear predictor derived from the logistic regression likelihood is very robust in …