Biomedical subjects

Janice Weinberg

Publications and source records attributed to Janice Weinberg.

7 recordsLinked to original sources

PubMed2006

Method for mapping population-based case-control studies: an application using generalized additive models.

BACKGROUND: Mapping spatial distributions of disease occurrence and risk can serve as a useful tool for identifying exposures of public health concern. Disease registry data are often mapped by town or county of diagnosis and contain limited data on covariates. These maps often possess poor spatial resolution, the potential for spatial confounding, and the inability to consider latency. Population-based case-control studies can provide detailed information on residential history and covariates. RESULTS: Generalized additive models (GAMs) provide a useful framework for mapping point-based epidemiologic data. Smoothing on location while controlling for covariates produces adjusted maps. We generate maps of odds ratios using the entire study area as a reference. We smooth using a locally weighted regression smoother (loess), a method that combines the advantages of nearest neighbor and kernel methods. We choose an optimal degree of smoothing by minimizing Akaike's Information Criterion. We use a deviance-based test to assess the overall importance of location in the model and pointwise permutation tests to locate regions of significantly increased or decreased risk. The method is illustrated with synthetic data and data from a population-based case-control study, using S-Plus and ArcView software. CONCLUSION: Our goal is to develop practical methods for mapping population-based case-control and cohort studies. The method described here performs well for our synthetic data, reproducing important features of the data and adequately controlling the covariate. When applied to the population-based case-control data set, the method suggests spatial confounding and identifies statistically significant areas of increased and decreased odds ratios.

Case-Control Studies↗

PubMed2006

Comparison of the effects of a new conjugated oral estrogen, estradiol-3beta-glucoside, with oral micronized 17beta-estradiol in postmenopausal women.

The objective of this article is to evaluate the pharmacokinetics of serum estrone and estradiol levels in women who were taking either 17beta-estradiol-3beta-glucoside (E(2)-3beta-glucoside) or 17beta-estradiol (E(2)) daily and to examine the effects of E(2)-3beta-glucoside and E(2) on postmenopausal symptoms, gonadotropins, hepatic metabolism, and coagulation factors. Healthy postmenopausal women on estrogen who had undergone a hysterectomy were recruited. Subjects were randomly assigned to receive equivalent doses of either E(2)-3beta-glucoside or micronized E(2) for 28 days. Pharmacokinetic studies of estrone and estradiol were performed on days 1, 2, 28, and 29. Gonadotropin levels and Kupperman Index (KI) scores were determined at baseline and on treatment day 28. Mean serum estradiol and estrone concentrations in those taking E(2)-3beta-glucoside were comparable with those taking E(2). Mean baseline follicle stimulating hormone (FSH) levels were 84 +/- 27 mIU/mL and 71 +/- 24 mIU/mL in the E(2)-3beta-glucoside and E(2) groups, respectively, with significant decreases (P < 0.01) of 54 +/- 21 mIU/mL and 38 +/-18 mIU/mL, respectively, by treatment day 28. Baseline KI scores in the E(2)-3beta-glucoside group were 10 +/- 6 compared with 5 +/- 4 on treatment day 28, which is equivalent to a 50% reduction in menopausal symptoms (P = 0.003). The change in KI scores in the E(2) group was not statistically significant. Total serum estradiol and estrone levels in women taking E(2)-3beta-glucoside are comparable with those in women taking E(2). E(2)-3beta-glucoside reduces serum gonadotropin levels to the premenopausal range and is effective at reducing postmenopausal symptoms. E(2)-3beta-glucoside is a novel synthetic estrogen that is well tolerated and has promise as a hormone replacement therapy.

Administration, Oral↗

PubMed2005

Cluster detection methods applied to the Upper Cape Cod cancer data.

BACKGROUND: A variety of statistical methods have been suggested to assess the degree and/or the location of spatial clustering of disease cases. However, there is relatively little in the literature devoted to comparison and critique of different methods. Most of the available comparative studies rely on simulated data rather than real data sets. METHODS: We have chosen three methods currently used for examining spatial disease patterns: the M-statistic of Bonetti and Pagano; the Generalized Additive Model (GAM) method as applied by Webster; and Kulldorff's spatial scan statistic. We apply these statistics to analyze breast cancer data from the Upper Cape Cancer Incidence Study using three different latency assumptions. RESULTS: The three different latency assumptions produced three different spatial patterns of cases and controls. For 20 year latency, all three methods generally concur. However, for 15 year latency and no latency assumptions, the methods produce different results when testing for global clustering. CONCLUSION: The comparative analyses of real data sets by different statistical methods provides insight into directions for further research. We suggest a research program designed around examining real data sets to guide focused investigation of relevant features using simulated data, for the purpose of understanding how to interpret statistical methods applied to epidemiological data with a spatial component.

Adult↗

PubMed2005

Spatial analysis of lung, colorectal, and breast cancer on Cape Cod: an application of generalized additive models to case-control data.

BACKGROUND: The availability of geographic information from cancer and birth defect registries has increased public demands for investigation of perceived disease clusters. Many neighborhood-level cluster investigations are methodologically problematic, while maps made from registry data often ignore latency and many known risk factors. Population-based case-control and cohort studies provide a stronger foundation for spatial epidemiology because potential confounders and disease latency can be addressed. METHODS: We investigated the association between residence and colorectal, lung, and breast cancer on upper Cape Cod, Massachusetts (USA) using extensive data on covariates and residential history from two case-control studies for 1983-1993. We generated maps using generalized additive models, smoothing on longitude and latitude while adjusting for covariates. The resulting continuous surface estimates disease rates relative to the whole study area. We used permutation tests to examine the overall importance of location in the model and identify areas of increased and decreased risk. RESULTS: Maps of colorectal cancer were relatively flat. Assuming 15 years of latency, lung cancer was significantly elevated just northeast of the Massachusetts Military Reservation, although the result did not hold when we restricted to residences of longest duration. Earlier non-spatial epidemiology had found a weak association between lung cancer and proximity to gun and mortar positions on the reservation. Breast cancer hot spots tended to increase in magnitude as we increased latency and adjusted for covariates, indicating that confounders were partly hiding these areas. Significant breast cancer hot spots were located near known groundwater plumes and the Massachusetts Military Reservation. DISCUSSION: Spatial epidemiology of population-based case-control studies addresses many methodological criticisms of cluster studies and generates new exposure hypotheses. Our results provide evidence for spatial clustering of breast cancer on upper Cape Cod. The analysis suggests further investigation of the potential association between breast cancer and pollution plumes based on detailed exposure modeling.

Adult↗

PubMed2003

Downsizing and health at the United States Department of Energy.

BACKGROUND: Downsizing and reorganization not only affect workers who lose their jobs, but even workers who retain their jobs are affected in negative ways. The present study measured how downsizing was accomplished at five Department of Energy facilities by evaluating communication with workers, perceived fairness of the process, and job characteristics, and how each of these were associated with worker health and well-being. METHODS: The researchers collected quantitative data using structured surveys, and captured qualitative data using interviews, focus groups, and open-ended survey responses. RESULTS: Employees, who felt that the downsizing process was fair, and that communication was open and honest, reported fewer medical symptoms, lower survivor syndrome, and more job security than their counterparts. Employees who were less immediately impacted by downsizing reported fewer medical symptoms than those who were more directly involved (e.g., delivered layoff notices, changed jobs, etc.) Thus, downsizing appears to affect the health of survivors, through the effects of the downsizing process. CONCLUSION: This examination of the effect of downsizing on the physical and mental health of surviving employees supports the conclusion that the impact of downsizing is not limited to those who lose their jobs and highlights the potential repercussions of downsizing on the emotional health of employees.

Adult↗

PubMed2002

Prevalence of allergy symptoms and associated medication use in a sample of college seniors.

The authors surveyed a random sample of college seniors at a university in Boston to determine the prevalence of allergy symptoms and the students' use of medications to relieve symptoms. Of the 400 individuals queries, 58.2% reported some symptoms during the previous year, and 63.0% of that group said their symptoms were moderate to severe. Just over 93.8% of the student respondents used medications to treat symptoms; 91.1% used over-the-counter (OTC) medications, and 55.5% used prescription medications. More than one third had used OTC antihistamines before taking an examination during the previous year. Allergy-like symptoms and associated medication use are common among college-aged students. The authors call for further research to determine whether these OTC and prescription medications affect academic performance.

Adult↗

PubMed2002

Bone mineral density assessment: comparison of dual-energy X-ray absorptiometry measurements at the calcaneus, spine, and hip.

It is widely accepted that bone mineral density (BMD) measurements obtained by dual-energy X-ray absorptiometry (DXA) at the spine, hip, and calcaneus predict fracture risk. Few published studies to date have examined the relationship between pDXA measurements at the calcaneus to those at the hip and spine. It has been demonstrated that T-score-based criteria cannot be universally applied to all skeletal sites and measurement technologies. Our goal was to define the calcaneal T-score threshold equivalent to low bone mass at the hip or spine. A total of 119 female patients between the ages of 33 and 76 yr of age were recruited at Boston University Medical Center for bone densitometry screening. Bone density measurements were obtained at the calcaneus using the portable Norland Apollo Densitometer (Norland Medical Systems, Fort Atkinson, WI) and at the hip and spine using the Norland Eclipse densitometer. By defining a pDXA T-score < or =-1 as a positive test and DXA scores < or =-1 as the presence of low bone mass, we obtained a specificity of 100% and a sensitivity of 73% (positive predictive value 100% and negative predictive value 80%) in detecting low bone mass at the femoral neck in women over age 65 yr. In women between 40 and 65 yr of age, we obtained a sensitivity of 50% and a specificity of 93% (positive predictive value 93% and negative predictive value 50%) in detecting low bone mass at the femoral neck. In women less than 40 yr of age, we obtained a sensitivity of 13% and a specificity of 100% (positive predictive value 100% and negative predictive value 75%) in detecting low bone mass at the femoral neck. From receiver operating characteristic curves, a calcaneal T-score < or =0.0 detects those with a T-score < or =-1 at the femoral neck and lumbar spine with 100% and 85% sensitivity, respectively. Peripheral DXA of the calcaneus is a sensitive and specific test to diagnose low bone mass in women over 65 yr of age. In women under 65 yr of age, this modality, though not as sensitive, is specific in detecting low bone mass. We conclude that a pDXA calcaneal T-score < or =0 is highly sensitive in predicting osteopenia and osteoporosis at the femoral neck and lumbar spine.

Absorptiometry, Photon↗