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A database of approximately 20,000 chemical exposures has been constructed in close co-operation between the School of Public Health of the University of North Carolina at Chapel Hill and the Department of Air Pollution of the Wageningen Agricultural University. A special feature of this database is that only multiple measurements of exposure from the same(More)
Epidemiological studies examining the association between exposure to tap water contaminants (such as chlorination by-products) and disease outcomes (such as cancer and adverse reproductive outcomes) have been limited by inaccurate exposure assessment. Failure to take into account the variation in beverage and tap water consumption and exposure to volatile(More)
Nonstationary behavior in occupational exposure was examined among a number of job groups from different industries. A change in the mean level of exposure between two survey periods was evaluated by applying mixed-effects models. Overall, differences between surveys were observed in slightly more than one-third of the industries analyzed and in about(More)
Exposure assessment is a critical component of epidemiologic studies, and more sophisticated approaches require that variation in exposure be considered. We examined the intra- and interindividual sources of variation in exposure to mercury vapor as measured in air, blood, and urine among four groups of workers during 1990-1997 at a Swedish chloralkali(More)
Many exposure assessment strategies rely on the occupational group as the unit of analysis in which workers are classified on the basis of job title, location, or on other characteristics related to the workplace or the job. Although statistical methods that combine exposure data collected on workers from different occupational groups are more efficient,(More)
Investigations have suggested that owing to the effects of autocorrelation and/or non-stationary behaviour exposure variability increases with the number of days between measurements. This study confirmed such increasing variability with the interval between observations in a collection of occupational data sets after controlling for factors likely to(More)
Metabolic syndrome (MetS), Type 2 diabetes (T2D), and cardiovascular disease (CVD) share an inflammatory etiology and are known to be influenced by diet. We investigated associations of hypothesized prooxidative (Fe) and antioxidative (Zn, Mg, β-carotene, vitamin C, vitamin E) micronutrients with incident MetS, T2D, and CVD in the Multi-Ethnic Study of(More)
BACKGROUND While studies indicate that the attenuating effects of imperfectly measured exposure can be substantial, they have not had the requisite data to compare methods of assessing exposure for the same individuals monitored over common time periods. METHODS We examined measurement error in multiple exposure measures collected in parallel on 32 groups(More)
Assessments of occupational exposures to chemicals are generally based upon the practice of compliance testing in which the probability of compliance is related to the exceedance [gamma, the likelihood that any measurement would exceed an occupational exposure limit (OEL)] and the number of measurements obtained. On the other hand, workers' chronic health(More)
AIMS To assess spatial fluctuations, temporal variability, and errors due to sampling and analysis in levels of disinfection by-products in routine monitoring tap water samples and in water samples collected in households within the same distribution system for an exposure assessment study. METHODS Mixed effects models were applied to quantify seasonal(More)