Medicine and Health Sciences Commons^™

Screening At Worksite Applying The Framingham Heart Study Score., Paulo A. Lotufo

Paulo A Lotufo

The first evaluation of class of occupation and cardiovascular risk factors in a Brazilian sample of civil servants. 1) context: Cardiovascular diseases are the main causes of death in Brazil. The high-risk approach to cardiovascular risk factors by screening test at worksite is one possible strategy of prevention. 2) objective: to verify the impact of a risk factors screening according to occupational levels. 3) type of study: cross-sectional 4) setting: occupational division of University of Sao Paulo 5) participants: 6,587 employees aged 20 to 69 years-old classified according three occupational grades (non-skilled, both manual and non-manual jobs; technical; faculty). 6) …

Analysis Of Longitudinal Marginal Structural Models , Jennifer F. Bryan, Zhuo Yu, Mark J. Van Der Laan

U.C. Berkeley Division of Biostatistics Working Paper Series

In this article we construct and study estimators of the causal effect of a time-dependent treatment on survival in longitudinal studies. We employ a particular marginal structural model (MSM), and follow a general methodology for constructing estimating functions in censored data models. The inverse probability of treatment weighted (IPTW) estimator is used as an initial estimator and the corresponding treatment-orthogonalized, one-step estimator is consistent and asymptotically linear when the treatment mechanism is consistently estimated. We extend these methods to handle informative censoring. A simulation study demonstrates that the the treatment-orthogonalized, one-step estimator is superior to the IPTW estimator in terms …

An Empirical Study Of Marginal Structural Models For Time-Independent Treatment, Tanya A. Henneman, Mark J. Van Der Laan

U.C. Berkeley Division of Biostatistics Working Paper Series

In non-randomized treatment studies a significant problem for statisticians is determining how best to adjust for confounders. Marginal structural models (MSMs) and inverse probability of treatment weighted (IPTW) estimators are useful in analyzing the causal effect of treatment in observational studies. Given an IPTW estimator a doubly robust augmented IPTW (AIPTW) estimator orthogonalizes it resulting in a more e±cient estimator than the IPTW estimator. One purpose of this paper is to make a practical comparison between the IPTW estimator and the doubly robust AIPTW estimator via a series of Monte- Carlo simulations. We also consider the selection of the optimal …

Chronic Obstructive Pulmonary Disease Surveillance --- United States, 1971--2000, David M. Mannino, David M. Homa, Lara J. Akinbami, Earl S. Ford, Stephen C. Redd

David M. Mannino

PROBLEM/CONDITION:

Chronic obstructive pulmonary disease (COPD) includes chronic bronchitis and emphysema but has been defined recently as the physiologic finding of nonreversible pulmonary function impairment. This surveillance summary reports trends in different measures of COPD during 1971-2000.

REPORTING PERIOD COVERED:

This report presents national data regarding objectively determined COPD (1971-1994); COPD-associated activity and functional limitations (1980-1996); self-reported COPD prevalence, COPD physician office and hospital outpatient department visits, COPD hospitalizations, and COPD deaths (1980-2000); and COPD emergency department visits (1992-2000).

DESCRIPTION OF SYSTEMS:

The Centers for Disease Control's National Center for Health Statistics conducts the National Health Interview Survey annually, which …

The Analysis Of Placement Values For Evaluating Discriminatory Measures, Margaret S. Pepe, Tianxi Cai

UW Biostatistics Working Paper Series

The idea of using measurements such as biomarkers, clinical data, or molecular biology assays for classification and prediction is popular in modern medicine. The scientific evaluation of such measures includes assessing the accuracy with which they predict the outcome of interest. Receiver operating characteristic curves are commonly used for evaluating the accuracy of diagnostic tests. They can be applied more broadly, indeed to any problem involving classification to two states or populations (D = 0 or D = 1). We show that the ROC curve can be interpreted as a cumulative distribution function for the discriminatory measure Y in the …

Case-Control Current Status Data, Nicholas P. Jewell, Mark J. Van Der Laan

U.C. Berkeley Division of Biostatistics Working Paper Series

Current status observation on survival times has recently been widely studied. An extreme form of interval censoring, this data structure refers to situations where the only available information on a survival random variable, T, is whether or not T exceeds a random independent monitoring time C, a binary random variable, Y. To date, nonparametric analyses of current status data have assumed the availability of i.i.d. random samples of the random variable (Y, C), or a similar random sample at each of a set of fixed monitoring times. In many situations, it is useful to consider a case-control sampling scheme. Here, …

Current Status Data: Review, Recent Developments And Open Problems, Nicholas P. Jewell, Mark J. Van Der Laan

U.C. Berkeley Division of Biostatistics Working Paper Series

Researchers working with survival data are by now adept at handling issues associated with incomplete data, particular those associated with various forms of censoring. An extreme form of interval censoring, known as current status observation, refers to situations where the only available information on a survival random variable T is whether or not T exceeds a random independent monitoring time C. This article contains a brief review of the extensive literature on the analysis of current status data, discussing the implications of response-based sampling on these methods. The majority of the paper introduces some recent extensions of these ideas to …

Are Differences In Exposure To A Multicomponent School-Based Intervention Associated With Varying Dietary Outcomes In Adolescents?, Amanda S. Birnbaum, Leslie A. Lytle, Mary Story, Cheryl L. Perry, David M. Murray

Department of Public Health Scholarship and Creative Works

Multicomponent interventions are recommended for health behavior change among adolescents. However, it is difficult to disentangle the effects of multiple intervention components. This article reports outcomes associated with varying levels of exposure to a school-based nutrition intervention, Teens Eating for Energy and Nutrition at School (TEENS). Four incremental exposureswere possible: (1) control group, (2) school environment interventions only, (3) classroom plus environment interventions, and (4) peer leaders plus classroom plus environment interventions. Patterns suggesting dose response were observed, with peer leaders reporting the largest increases in fruit, vegetable, and lower fat food consumption. Students exposed to classroom plus environment interventions …

Production Of A Monoclonal Antibody Against Benzo[Α]Pyrene Diol Epoxide Dna Adducts, Brian Peden Austin

Chemistry & Biochemistry Theses & Dissertations

Benzo[α]pyrene is a ubiquitous pollutant produced from the incomplete combustion of organic material such as fossil fuels. It is found in the workplace, urban air, drinking water, and the food supply. Recently, it has been proposed that benzo[α]pyrene may be the causative agent in the formation of lung adenocarcinomas among some Taiwanese women exposed to cooking oil fumes without adequate ventilation. In this study, calf thymus DNA was modified in vitro with benzo[α]pyrene-diol epoxide (BPDE) to a level consistent with that found in biological samples. This DNA of low modification was used as an immunogen in the production of a …

Surveillance For Asthma - United States, 1980-1999, David M. Mannino, David M. Homa, Lara J. Akinbami, Jeanne E. Moorman, Charon Gwynn, Stephen C. Redd

David M. Mannino

Problem/Condition: Asthma, a chronic disease occurring among both children and adults, has been the focus of clinical and public health interventions during recent years. In addition, CDC has outlined a strategy to improve the timeliness and geographic specificity of asthma surveillance as part of a comprehensive public health approach to asthma surveillance.

Reporting Period Covered: This report presents national data regarding self-reported asthma prevalence, school and work days lost because of asthma, and asthma-associated activity limitations (1980--1996); asthma-associated outpatient visits, asthma-associated hospitalizations, and asthma-associated deaths (1980--1999); asthma-associated emergency department visits (1992--1999); and self-reported asthma episodes or attacks (1997--1999).

Description of …

Bse: Risk, Uncertainty, And Policy Change, Enda Cummins, Pat Grace, Kevin Mcdonnell, Shane Ward

RISK: Health, Safety & Environment (1990-2002)

The authors discuss how, in our "risk society," a range of potential risks and uncertainties are associated with new technologies and new diseases, such as BSE. These risks bring with them worries about human health, while the ability to assess and manage new health scares is an essential skill for government and related industries.

Migraine And Coronary Heart Disease In Women And Men, Paulo A. Lotufo

Paulo A Lotufo

Objective.—We evaluated migraine as an independent risk factor for subsequent coronary heart disease (CHD) events among women in the Women’s Health Study (WHS) and men in the Physicians’ Health Study (PHS). Background.—Although several studies have suggested that migraine is associated with increased risk of stroke, there are few and conflicting data on whether migraine predicts risk of future CHD events. Methods.—The WHS is an ongoing randomized, double-blind, placebo-controlled trial of low-dose aspirin and vitamin E in the primary prevention of cardiovascular disease and cancer in 39,876 women health professionals aged 45 years in 1993, and the PHS is a completed …

Epidemologia Das Doenças Cardiovasculares No Brasil [Portuguese], Paulo A. Lotufo

Paulo A Lotufo

No abstract provided.

Estimating Causal Parameters In Marginal Structural Models With Unmeasured Confounders Using Instrumental Variables, Tanya A. Henneman, Mark Johannes Van Der Laan, Alan E. Hubbard

U.C. Berkeley Division of Biostatistics Working Paper Series

For statisticians analyzing medical data, a significant problem in determining the causal effect of a treatment on a particular outcome of interest, is how to control for unmeasured confounders. Techniques using instrumental variables (IV) have been developed to estimate causal parameters in the presence of unmeasured confounders. In this paper we apply IV methods to both linear and non-linear marginal structural models. We study a specific class of generalized estimating equations that is appropriate to these data, and compare the performance of the resulting estimator to the standard IV method, a two-stage least squares procedure. Our results are applied to …

Surveillance For Waterborne-Disease Outbreaks--United States, 1999-2000, Sherline H. Lee, Deborah A. Levy, Gunther F. Craun, Michael J. Beach, Rebecca L. Calderon

Journal Articles: Epidemiology

PROBLEM/CONDITION: Since 1971, CDC, the U.S. Environmental Protection Agency (EPA), and the Council of State and Territorial Epidemiologists (CSTE) have maintained a collaborative surveillance system for the occurrences and causes of waterborne-disease outbreaks (WBDOs).This surveillance system is the primary source of data concerning the scope and effects of waterborne diseases on persons in the United States.

REPORTING PERIOD COVERED: This summary includes data regarding outbreaks occurring during January 1999-December 2000 and previously unreported outbreaks occurring in 1995 and 1997.

DESCRIPTION OF THE SYSTEM: The surveillance system includes data for outbreaks associated with drinking water and recreational water. State, territorial, and …

Associations Between Water-Treatment Methods And Diarrhoea In Hiv-Positive Individuals, J. N. S. Eisenberg, T. J. Wade, A. Hubbard, D. I. Abrams, R. J. Leiser, S. Charles, M. Vu, S. Saha, C. C. Wright, Deborah A. Levy, P. Jensen, J. M. Colford

Journal Articles: Epidemiology

This manuscript extends our previously published work (based on data from one clinic) on the association between three drinking water-treatment modalities (boiling, filtering, and bottling) and diarrhoeal disease in HIV-positive persons by incorporating data from two additional clinics collected in the following year. We conducted a cross-sectional survey of drinking water patterns, medication usage, and episodes of diarrhoea among HIV-positive persons attending clinics associated with the San Francisco Community Consortium. We present combined results from our previously published work in one clinic (n = 226) with data from these two additional clinics (n = 458). In this combined analysis we …

Risk Factors In Hiv-Associated Diarrhoeal Disease: The Role Of Drinking Water, Medication And Immune Status, J. N. S. Eisenberg, T. J. Wade, S. Charles, M. Vu, A. Hubbard, C. C. Wright, Deborah A. Levy, P. Jensen, J. M. Colford

Journal Articles: Epidemiology

In a cross-sectional survey of 226 HIV-infected men, we examined the occurrence of diarrhoea and its relationship to drinking water consumption patterns, risk behaviours, immune status and medication use. Diarrhoea was reported by 47% of the respondents. Neither drinking boiled nor filtered water was significantly associated with diarrhoea (OR = 0.5 [0.2, 1.6], 1.2 [0.6, 2.5] respectively), whereas those that drank bottled water were at risk for diarrhoea (OR = 3.0 [1.1, 7.8]). Overall, 47% always or often used at least one water treatment. Of the 37% who were very concerned about drinking water, 62% had diarrhoea, 70% always or …

Participant Blinding And Gastrointestinal Illness In A Randomized, Controlled Trial Of An In-Home Drinking Water Intervention, John M. Colford, Judy R. Rees, Timothy J. Wade, Asheena Khalakdina, Joan F. Hilton, Isaac J. Ergas, Susan Burns, Anne Benker, Catherine Ma, Cliff Bowen, Daniel C. Mills, Duc J. Vugia, Dennis D. Juranek, Deborah A. Levy

Journal Articles: Epidemiology

We conducted a randomized, triple-blinded home drinking water intervention trial to determine if a large study could be undertaken while successfully blinding participants. Households were randomized 50:50 to use externally identical active or sham treatment devices. We measured the effectiveness of blinding of participants by using a published blinding index in which values >0.5 indicate successful blinding. The principal health outcome measured was "highly credible gastrointestinal illness" (HCGI). Participants (n=236) from 77 households were successfully blinded to their treatment assignment. At the end of the study, the blinding index was 0.64 (95% confidence interval 0.51-0.78). There were 103 episodes of …

The Role Of Diet And Physical Activity For Ovarian Cancer Results From The Adventist Health Study, Fatemeh Kiani

Loma Linda University Electronic Theses, Dissertations & Projects

A few aspects of the epidemiology of ovarian cancer are well understood, such as the inverse relationship with parity and oral contraceptive (OC) use. The role of other factors such as the potential influence of diet or physical activity is far from being established. A few studies, however, have been able to identify dietary risk factors for ovarian cancer. In this dissertation, I have conducted two studies that investigate the relationship between dietary factors and physical activity and the three endpoints: 1) nonfatal ovarian cancer (1976-1982; time to diagnosis), 2) fatal ovarian cancer (1976-1988; time to death), and 3) total …

Why More Is Required To Address Maine’S Childhood Lead-Poisoning Problem, David Littell

Maine Policy Review

Although largely hidden from the public eye, childhood lead poisoning has been identified as one of Maine’s leading environmental health problems. Recent data show not only that lead-poisoning levels are unacceptably high among Maine’s children, but also that screening rates are lower than recommended by national health organizations and lower than in other New England states. David Littell discusses why childhood lead poisoning is such a problem in Maine and what can be done to remedy the situation, providing a thorough examination of how children are exposed to lead and the magnitude of the problem. He reviews the state’s existing …

Changes In The Transmission Of Tuberculosis In New York City From 1990 To 1999, Elvin H. Geng

Elvin H Geng

Background: Over the past decade, there has been a reduction in the incidence of tuberculosis in New York City and in the United States. However, the reduction has been confined mainly to U.S.-born persons. Understanding the reasons for the lack of reduction among non–U.S.-born persons may lead to new strategies for tuberculosis control. Methods: We performed DNA fingerprinting with the IS6110 insertion sequence of the organisms isolated from patients with culture-positive tuberculosis in northern Manhattan from 1990 to 1999. The goal was to identify the strains responsible for multiple infections, presumably through recent transmission (clusters of cases), as well as …