Geographic information systems (GIS) and community health: some statistical issues.
Explore the source record for details and available documents.
Community Health Planning↗
Biomedical subjects
M Kulldorff
Publications and source records attributed to M Kulldorff.
Fried, well-done red meat and risk of lung cancer in women (United States).
OBJECTIVE: Some epidemiological studies suggest that diets high in fat, saturated fat, or cholesterol are associated with increased risk of lung cancer. Since meat consumption is correlated with the intake of saturated fat and cholesterol, we investigated the role of meat intake and cooking practices in relation to lung cancer risk. METHODS: A population-based case-control study of both non-smoking and smoking women was conducted in Missouri. A 100-item food frequency questionnaire (FFQ) with detailed questions on meat consumption was completed by 593 cases and 623 frequency matched controls. We estimated quantity of meat eaten (grams/day) according to cooking method, and doneness level. Odds ratios (ORs) and 95% confidence intervals (C.I.s) were calculated using logistic regression. Multivariate models included age, packyears of smoking, body mass index (BMI, kg/m2), education, and intake of calories, fat, fruit/fruit juices, and vegetables. RESULTS: When comparing 90th and 10th percentiles, lung cancer risk increased for total meat consumption (OR = 1.6, C.I. 1.1-2.4), red meat (OR = 1.8, C.I., 1.2-2.7), well-done red meat (OR = 1.5, C.I.s, 1.1-2.1) and fried red meat (OR = 1.5, C.I., 1.1-2.0). The odds ratios for 5th vs. 1st quintiles using the categorical variable for well-done red meat and fried red meat were essentially the same as reported above; however, the increase in risk was associated mainly with the 5th quintile. The ORs for a 10-gram increase in consumption were, 1.04 for total meat, 1.06 for red meat, 1.08 for well done red meat, and 1.09 for fried red meat. CONCLUSIONS: Consumption of red meat, especially fried and/or well-done red meat, was associated with increased risk of lung cancer.
Adult↗
Evaluating cluster alarms: a space-time scan statistic and brain cancer in Los Alamos, New Mexico.
OBJECTIVES: This article presents a space-time scan statistic, useful for evaluating space-time cluster alarms, and illustrates the method on a recent brain cancer cluster alarms in Los Alamos, NM. METHODS: The space-time scan statistic accounts for the preselection bias and multiple testing inherent in a cluster alarm. Confounders and time trends can be adjusted for. RESULTS: The observed excess of brain cancer in Los Alamos was not statistically significant. CONCLUSIONS: The space-time scan statistic is useful as a screening tool for evaluating which cluster alarms merit further investigation and which clusters are probably chance occurrences.
Brain Neoplasms↗
An evaluation of rectal mucosal proliferation measure variability sources in the polyp prevention trial: can we detect informative differences among individuals' proliferation measures amid the noise?
We assessed components of total variability of bromodeoxyuridine (BrdUrd) and proliferating cell nuclear antigen (PCNA) assays of rectal mucosal proliferation in a subset of 390 participants from the U. S. National Cancer Institute's multicenter Polyp Prevention Trial. Biopsies were blindly double-scored by two technicians. For those participants for whom at least one evaluable biopsy was obtained, a mean of 2.0 and 2.6 biopsies, and 6.2 and 8.7 crypts/biopsy were evaluated, respectively, with the BrdUrd and PCNA assays. Factors such as clinical center, scorer, and month of biopsy collection significantly affected the observed values of the labeling index (LI) and proliferative height (PH). Therefore, it is essential to control or adjust for these variables in proliferation studies. Sources of random variation for LI and PH measures remaining after the aforementioned factors include between-participant variation and several sources of within-participant variation, including variation over time, between biopsies, and between multiple measurements on the same biopsy. Both LI and PH measurements exhibited substantial variability over time, between biopsies, and from reading-to-reading of the same biopsy. When other sources of variability have been accounted for, the PCNA LI seems to have little between-participant variation. This brings into question its utility as a marker in colorectal cancer studies. The PCNA PH showed significant between-participant variability and may hold some promise as a useful marker in colorectal cancer studies. Results for BrdUrd were less conclusive. The BrdUrd LI showed marginally significant between-participant variation, whereas the corresponding variation for PH was nonsignificant.
Adult↗
Breast cancer clusters in the northeast United States: a geographic analysis.
High breast cancer mortality rates have been reported in the northeastern part of the United States, with recent attention focused on Long Island, New York. In this study, the authors investigate whether the high breast cancer mortality is evenly spread over the Northeast, in the sense that any observed clusters of deaths can be explained by chance alone, or whether there are clusters of statistical significance. Demographic data and age-specific breast cancer mortality rates for women were obtained for all 244 counties in 11 northeastern states and for the District of Columbia for 1988-1992. A recently developed spatial scan statistic is used, which searches for clusters of cases without specifying their size or location ahead of time, and which tests for their statistical significance while adjusting for the multiple testing inherent in such a procedure. The basic analysis is adjusted for age, with further analyses examining how the results are affected by incorporating race, urbanicity, and parity as confounding variables. There is a statistically significant and geographically broad cluster of breast cancer deaths in the New York City-Philadelphia, Pennsylvania, metropolitan area (p = 0.0001), which has a 7.4% higher mortality rate than the rest of the Northeast. The cluster remains significant when race, urbanicity, and/or parity are included as confounding variables. Four smaller subclusters within this area are also significant on their own strength: Philadelphia with suburbs (p = 0.0001), Long Island (p = 0.0001), central New Jersey (p = 0.0001), and northeastern New Jersey (p = 0.0001). The elevated breast cancer mortality on Long Island might be viewed less as a unique local phenomenon and more as part of a more general situation involving large parts of the New York City-Philadelphia metropolitan area. The several known and hypothesized risk factors for which we could not adjust and that may explain the detected cluster are most notably age at first birth, age at menarche, age at menopause, breastfeeding, genetic mutations, and environmental factors.
Breast Neoplasms↗
Dietary fats and lung cancer risk among women: the Missouri Women's Health Study (United States)
In a population-based case-control study of women in Missouri (United States), most of whom were smokers, we obtained information on adult diet to evaluate the effects of dietary fats in relation to lung cancer risk. All newly diagnosed, primary lung cancer cases among women 35 to 84 years of age reported to the Missouri Cancer Registry from 1 January 1993 to 31 January 1994 were invited to participate, as were population-based controls. The analysis focused on interviews obtained from 624 controls and 587 cases. In-person interviews were obtained from 99.0 percent of controls and 60.6 percent of cases. Age and energy-adjusted relative risks suggested a direct relation between risk of lung cancer and intake of dietary fats (e.g., total fat, saturated fat) and frequency of meat consumption. After adjusting for confounders, dietary fats were no longer associated with risk, but the adverse effect of frequent consumption of meat persisted. Risk was elevated about 90 percent (95 percent confidence interval = 1.2-3.0) among women in the highest quintile of red meat intake compared with those in the lowest quintile. Risk estimates associated with red meat consumption, however, were dependent on interview status; the effect was restricted to cases whose dietary information was provided by proxy. In summary, after adjusting for potential confounders and removing data obtained from proxy respondents, dietary fats and consumption of red meat were not associated with lung cancer risk among women in Missouri.
Adult↗
Re: Long-term survival and mortality in prostate cancer treated with noncurative intent.
Explore the source record for details and available documents.
Cohort Studies↗
Spatial disease clusters: detection and inference.
We present a new method of detection and inference for spatial clusters of a disease. To avoid ad hoc procedures to test for clustering, we have a clearly defined alternative hypothesis and our test statistic is based on the likelihood ratio. The proposed test can detect clusters of any size, located anywhere in the study region. It is not restricted to clusters that conform to predefined administrative or political borders. The test can be used for spatially aggregated data as well as when exact geographic co-ordinates are known for each individual. We illustrate the method on a data set describing the occurrence of leukaemia in Upstate New York.
Cluster Analysis↗
Risk of acute childhood leukaemia in Sweden after the Chernobyl reactor accident. Swedish Child Leukaemia Group.
OBJECTIVE: To evaluate the risk of acute childhood leukaemia in areas of Sweden contaminated after the Chernobyl reactor accident in April 1986. DESIGN: Population based study of childhood leukaemia diagnosed during 1980-92. SETTING: Coordinates for places of residence of all 1.6 million children aged 0-15 years; aerial mapped areas of Sweden heavily contaminated after the Chernobyl accident. SUBJECTS: 888 children aged 0-15 years with acute leukaemia diagnosed in Sweden during 1980-92, identified with place of birth and residence at diagnosis. MAIN OUTCOME MEASURES: Risk of leukaemia in areas contaminated after the Chernobyl accident compared with the rest of Sweden and in the same areas before the accident. RESULTS: During six and a half years of follow up after the accident the odds ratio for acute leukaemia was 0.9 (95% confidence interval 0.6 to 1.4) in highly contaminated areas (> or = 10 kBq/m2) compared with the same areas before the accident. For the subgroup acute lymphoblastic leukaemia in children aged under 5 years at diagnosis the odds ratio was 1.5 (0.8 to 2.6). For all cases diagnosed after May 1986 in highly contaminated areas compared with areas of low contamination the odds ratio was 0.9 (0.7 to 1.3). For acute lymphoblastic leukaemia in children aged under 5 years at diagnosis the odds ratio was 1.2 (0.8 to 1.9) in highly contaminated areas compared with areas of low contamination. Dose-response analysis showed no correlation between the degree of contamination and the incidence of childhood leukaemia. CONCLUSION: There has been no significant increase in the incidence of acute childhood leukaemia in areas of Sweden contaminated after the Chernobyl reactor accident.
Accidents↗
Childhood leukaemia in Sweden: using GIS and a spatial scan statistic for cluster detection.
The study of disease clustering is becoming increasingly common in the field of medical epidemiology. There is great public concern and numerous reports on perceived clusters of various diseases, and with cancers, and especially leukaemia, being the most commonly studied. We present a population based study on acute childhood leukaemia in Sweden 1973-1993, illustrating the possibility of a system for full-scale spatial epidemiological study design. The aim of the study is to test a large set of childhood leukaemia cases for the presence of geographical clusters. Necessary prerequisites, in the form of extensive population and disease data, a tool for geographical spatial analysis and a proper statistical method were fulfilled. No significant clusters were found.
Acute Disease↗
Evaluation of spatial filters to create smoothed maps of health data.
Spatial filters have been used as an easy and intuitive way to create smoothed disease maps. Birth weight data from New York State for 1994 and 1995 are used to compare the traditional filter type of fixed geographical size with a filter size of constant or nearly constant population size. The latter are more appropriate for mapping disease in geographic areas with widely varying population density, such as New York State. Issues such as the choice of population size for the filter, the scale of smoothing, the ability to detect true spatial variation and the ability to smooth over random spatial noise are evaluated and discussed.
Epidemiologic Methods↗