Environmental Health is my specialty with a focus on Air pollution, climate change, and heavy metals. I do health studies, exposure models, and epidemiology.
Background— As part of the Worcester Heart Attack Study, a community-wide study examining changes... more Background— As part of the Worcester Heart Attack Study, a community-wide study examining changes over time in the incidence and long-term case-fatality rates of greater Worcester, Mass, residents hospitalized with confirmed acute myocardial infarction (AMI), we investigated the hypothesis that census tract–level socioeconomic position is an important predictor of survival after hospital discharge for AMI, after adjusting for demographic and clinical characteristics. Methods and Results— Data were available for 3423 confirmed cases of AMI among metropolitan Worcester residents during the 4 study years of 1995, 1997, 1999, and 2001 who were followed up through the end of 2002. The mean age among patients was 69 years, and 58% were men. Using a multilevel Cox proportional hazards regression model, we estimated a 30% higher death rate after AMI for patients living in census tracts with the most residents living below the poverty line compared with patients living in the wealthiest cens...
The Science of the total environment, Jan 15, 2018
Particulate matter < 2.5 μm in diameter (PM) and heat are strong predictors of morbidity, yet ... more Particulate matter < 2.5 μm in diameter (PM) and heat are strong predictors of morbidity, yet few studies have examined the effects of long-term exposures on non-fatal events, or assessed the short and long-term effect on health simultaneously. We jointly investigated the association of short and long-term exposures to PM and temperature with hospital admissions, and explored the modification of the associations with the short-term exposures by one another and by temperature variability. Daily ZIP code counts of respiratory, cardiac and stroke admissions of adults ≥65 (N = 2,015,660) were constructed across New-England (2001-2011). Daily PM and temperature exposure estimates were obtained from satellite-based spatio-temporally resolved models. For each admission cause, a Poisson regression was fit on short and long-term exposures, with a random intercept for ZIP code. Modifications of the short-term effects were tested by adding interaction terms with temperature, PM and temperat...
Time-series studies reporting associations between daily air pollution and health use pollution d... more Time-series studies reporting associations between daily air pollution and health use pollution data from monitoring stations that vary in the frequency of recording. Within the Air Pollution and Health: A European and North American Approach (APHENA) project, we evaluated the impact of systematically missing daily measurements on the estimated effects of PM10 and ozone on daily mortality. For four cities with complete time-series data, we created patterns of systematically missing exposure measurements by deleting observations. Poisson regression-derived city-specific estimates were combined to produce overall effect estimates. Analyses based on incomplete time series gave considerably lower pooled PM10 and ozone health effects compared to those from complete data. City-specific estimates were generally lower although more variable. Systematically missing exposure data for air pollutants appears to lead to underestimation of associated health effects. Our findings indicate that the use of evidence from studies with incomplete exposure data may underestimate the impact of air pollution and highlight the advantage of having complete daily data in time-series studies.
Environmental health : a global access science source, Jan 25, 2008
Air pollution and social characteristics have been shown to affect indicators of health. While us... more Air pollution and social characteristics have been shown to affect indicators of health. While use of spatial methods to estimate exposure to air pollution has increased the power to detect effects, questions have been raised about potential for confounding by social factors. A study of singleton births in Eastern Massachusetts was conducted between 1996 and 2002 to examine the association between indicators of traffic, land use, individual and area-based socioeconomic measures (SEM), and birth outcomes (birth weight, small for gestational age and preterm births), in a two-level hierarchical model. We found effects of both individual (education, race, prenatal care index) and area-based (median household income) SEM with all birth outcomes. The associations for traffic and land use variables were mainly seen with birth weight, with an exception for an effect of cumulative traffic density on small for gestational age. Race/ethnicity of mother was an important predictor of birth outco...
An important topic when estimating the effect of air pollutants on human health is choosing the b... more An important topic when estimating the effect of air pollutants on human health is choosing the best method to control for seasonal patterns and time varying confounders, such as temperature and humidity. Semi-parametric Poisson time-series models include smooth functions of calendar time and weather effects to control for potential confounders. Case-crossover (CC) approaches are considered efficient alternatives that control seasonal confounding by design and allow inclusion of smooth functions of weather confounders through their equivalent Poisson representations. We evaluate both methodological designs with respect to seasonal control and compare spline-based approaches, using natural splines and penalized splines, and two time-stratified CC approaches. For the spline-based methods, we consider fixed degrees of freedom, minimization of the partial autocorrelation function, and general cross-validation as smoothing criteria. Issues of model misspecification with respect to weathe...
American journal of respiratory and critical care medicine, Jan 15, 2015
Rationale: Few studies have examined associations between long-term exposure to fine particulate ... more Rationale: Few studies have examined associations between long-term exposure to fine particulate matter (PM2.5) and lung function decline in adults. Objectives: To determine if exposure to traffic and PM2.5 are associated with longitudinal changes in lung function in a population-based cohort in the Northeastern U.S., where pollution levels are relatively low. Methods: FEV1 and FVC were measured up to 2 times between 1995-2011 among 6,339 participants of the Framingham Offspring or Third Generation studies. We tested associations between residential proximity to a major roadway and PM2.5 exposure in 2001 (estimated by a land-use model using satellite measurements of aerosol optical thickness) and lung function. We examined differences in average lung function using mixed effects models and differences in lung function decline using linear regression models. Current smokers were excluded. Models were adjusted for age, sex, height, weight, pack-years, socioeconomic status indicators, ...
In vivo animal experiments demonstrate neurotoxicity of exposures to particulate matter (PM) and ... more In vivo animal experiments demonstrate neurotoxicity of exposures to particulate matter (PM) and ozone, but only one small epidemiological study had linked ambient air pollution with central nervous system (CNS) functions in children. To examine the neurobehavioral effects associated with long-term exposure to ambient PM and ozone in adults. We conducted a secondary analysis of the Neurobehavioral Evaluation System-2 (NES2) data (including a simple reaction time test [SRTT] measuring motor response speed to a visual stimulus; a symbol-digit substitution test [SDST] for coding ability; and a serial-digit learning test [SDLT] for attention and short-term memory) from 1764 adult participants (aged 37.5+/-10.9 years) of the Third National Health and Nutrition Examination Survey in 1988-1991. Based on ambient PM(10) (PM with aerodynamic diameter &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;10microm) and ozone data from the EPA Aerometric Information Retrieval System database, estimated annual exposure prior to the examination were aggregated at the centroid of each census-block group of geocoded residences, using distance-weighted averages from all monitors in the residing and adjoining counties. Generalized linear models were constructed to examine the associations, adjusting for potential confounders. In age- and sex-adjusted models, PM(10) predicted reduced CNS functions, but the association disappeared after adjustment for sociodemographic factors. There were consistent associations between ozone and reduced performance in NES2. In models adjusting for demographics, socioeconomic status, lifestyle, household and neighborhood characteristics, and cardiovascular risk factors, ozone predicted high scores in SDST and SDLT, but not in SRTT. Each 10-ppb increase in annual ozone was associated with increased SDST and SDLT scores by 0.16 (95%CI: 0.01, 0.23) and 0.56 (95%CI: 0.07, 1.05), equivalent to 3.5 and 5.3 years of aging-related decline in cognitive performance. Our study provides the first epidemiological data supporting the adverse neurobehavioral effects of ambient air pollutants in adults.
The 80,000 inhabitants of the lower part of Le Havre obtain their water supply from two karstic s... more The 80,000 inhabitants of the lower part of Le Havre obtain their water supply from two karstic springs, Radicatel and Saint-Laurent. Until 2000, the Radicatel water was settled when turbidity exceeded 3 NTU, then filtered and chlorinated, whereas the Saint-Laurent water was simply chlorinated. Our study aimed to characterize the link between water turbidity and the incidence of acute gastroenteritis (AGE). Records on drug sales used for the treatment of AGE were collected from January 1994 to June 1996 (period 1) and from March 1997 to July 2000 (period 2). Daily counts of drug sales were modeled using a Poisson Regression. We used data set 2 as a discovery set, identifying relevant (i.e. both significant and plausible) exposure covariates and lags. We then tested this model on period 1 as a replication dataset. In period 2, the daily drug sales correlated with finished water turbidity at both resources. Settling substantially modified the risk related to turbidity of both raw and ...
Wolters Kluwer Health may email you for journal alerts and information, but is committed to maint... more Wolters Kluwer Health may email you for journal alerts and information, but is committed to maintaining your privacy and will not share your personal information without your express consent. For more information, please refer to our Privacy Policy. ... Skip Navigation Links Home &gt; ...
Background— As part of the Worcester Heart Attack Study, a community-wide study examining changes... more Background— As part of the Worcester Heart Attack Study, a community-wide study examining changes over time in the incidence and long-term case-fatality rates of greater Worcester, Mass, residents hospitalized with confirmed acute myocardial infarction (AMI), we investigated the hypothesis that census tract–level socioeconomic position is an important predictor of survival after hospital discharge for AMI, after adjusting for demographic and clinical characteristics. Methods and Results— Data were available for 3423 confirmed cases of AMI among metropolitan Worcester residents during the 4 study years of 1995, 1997, 1999, and 2001 who were followed up through the end of 2002. The mean age among patients was 69 years, and 58% were men. Using a multilevel Cox proportional hazards regression model, we estimated a 30% higher death rate after AMI for patients living in census tracts with the most residents living below the poverty line compared with patients living in the wealthiest cens...
The Science of the total environment, Jan 15, 2018
Particulate matter < 2.5 μm in diameter (PM) and heat are strong predictors of morbidity, yet ... more Particulate matter < 2.5 μm in diameter (PM) and heat are strong predictors of morbidity, yet few studies have examined the effects of long-term exposures on non-fatal events, or assessed the short and long-term effect on health simultaneously. We jointly investigated the association of short and long-term exposures to PM and temperature with hospital admissions, and explored the modification of the associations with the short-term exposures by one another and by temperature variability. Daily ZIP code counts of respiratory, cardiac and stroke admissions of adults ≥65 (N = 2,015,660) were constructed across New-England (2001-2011). Daily PM and temperature exposure estimates were obtained from satellite-based spatio-temporally resolved models. For each admission cause, a Poisson regression was fit on short and long-term exposures, with a random intercept for ZIP code. Modifications of the short-term effects were tested by adding interaction terms with temperature, PM and temperat...
Time-series studies reporting associations between daily air pollution and health use pollution d... more Time-series studies reporting associations between daily air pollution and health use pollution data from monitoring stations that vary in the frequency of recording. Within the Air Pollution and Health: A European and North American Approach (APHENA) project, we evaluated the impact of systematically missing daily measurements on the estimated effects of PM10 and ozone on daily mortality. For four cities with complete time-series data, we created patterns of systematically missing exposure measurements by deleting observations. Poisson regression-derived city-specific estimates were combined to produce overall effect estimates. Analyses based on incomplete time series gave considerably lower pooled PM10 and ozone health effects compared to those from complete data. City-specific estimates were generally lower although more variable. Systematically missing exposure data for air pollutants appears to lead to underestimation of associated health effects. Our findings indicate that the use of evidence from studies with incomplete exposure data may underestimate the impact of air pollution and highlight the advantage of having complete daily data in time-series studies.
Environmental health : a global access science source, Jan 25, 2008
Air pollution and social characteristics have been shown to affect indicators of health. While us... more Air pollution and social characteristics have been shown to affect indicators of health. While use of spatial methods to estimate exposure to air pollution has increased the power to detect effects, questions have been raised about potential for confounding by social factors. A study of singleton births in Eastern Massachusetts was conducted between 1996 and 2002 to examine the association between indicators of traffic, land use, individual and area-based socioeconomic measures (SEM), and birth outcomes (birth weight, small for gestational age and preterm births), in a two-level hierarchical model. We found effects of both individual (education, race, prenatal care index) and area-based (median household income) SEM with all birth outcomes. The associations for traffic and land use variables were mainly seen with birth weight, with an exception for an effect of cumulative traffic density on small for gestational age. Race/ethnicity of mother was an important predictor of birth outco...
An important topic when estimating the effect of air pollutants on human health is choosing the b... more An important topic when estimating the effect of air pollutants on human health is choosing the best method to control for seasonal patterns and time varying confounders, such as temperature and humidity. Semi-parametric Poisson time-series models include smooth functions of calendar time and weather effects to control for potential confounders. Case-crossover (CC) approaches are considered efficient alternatives that control seasonal confounding by design and allow inclusion of smooth functions of weather confounders through their equivalent Poisson representations. We evaluate both methodological designs with respect to seasonal control and compare spline-based approaches, using natural splines and penalized splines, and two time-stratified CC approaches. For the spline-based methods, we consider fixed degrees of freedom, minimization of the partial autocorrelation function, and general cross-validation as smoothing criteria. Issues of model misspecification with respect to weathe...
American journal of respiratory and critical care medicine, Jan 15, 2015
Rationale: Few studies have examined associations between long-term exposure to fine particulate ... more Rationale: Few studies have examined associations between long-term exposure to fine particulate matter (PM2.5) and lung function decline in adults. Objectives: To determine if exposure to traffic and PM2.5 are associated with longitudinal changes in lung function in a population-based cohort in the Northeastern U.S., where pollution levels are relatively low. Methods: FEV1 and FVC were measured up to 2 times between 1995-2011 among 6,339 participants of the Framingham Offspring or Third Generation studies. We tested associations between residential proximity to a major roadway and PM2.5 exposure in 2001 (estimated by a land-use model using satellite measurements of aerosol optical thickness) and lung function. We examined differences in average lung function using mixed effects models and differences in lung function decline using linear regression models. Current smokers were excluded. Models were adjusted for age, sex, height, weight, pack-years, socioeconomic status indicators, ...
In vivo animal experiments demonstrate neurotoxicity of exposures to particulate matter (PM) and ... more In vivo animal experiments demonstrate neurotoxicity of exposures to particulate matter (PM) and ozone, but only one small epidemiological study had linked ambient air pollution with central nervous system (CNS) functions in children. To examine the neurobehavioral effects associated with long-term exposure to ambient PM and ozone in adults. We conducted a secondary analysis of the Neurobehavioral Evaluation System-2 (NES2) data (including a simple reaction time test [SRTT] measuring motor response speed to a visual stimulus; a symbol-digit substitution test [SDST] for coding ability; and a serial-digit learning test [SDLT] for attention and short-term memory) from 1764 adult participants (aged 37.5+/-10.9 years) of the Third National Health and Nutrition Examination Survey in 1988-1991. Based on ambient PM(10) (PM with aerodynamic diameter &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;10microm) and ozone data from the EPA Aerometric Information Retrieval System database, estimated annual exposure prior to the examination were aggregated at the centroid of each census-block group of geocoded residences, using distance-weighted averages from all monitors in the residing and adjoining counties. Generalized linear models were constructed to examine the associations, adjusting for potential confounders. In age- and sex-adjusted models, PM(10) predicted reduced CNS functions, but the association disappeared after adjustment for sociodemographic factors. There were consistent associations between ozone and reduced performance in NES2. In models adjusting for demographics, socioeconomic status, lifestyle, household and neighborhood characteristics, and cardiovascular risk factors, ozone predicted high scores in SDST and SDLT, but not in SRTT. Each 10-ppb increase in annual ozone was associated with increased SDST and SDLT scores by 0.16 (95%CI: 0.01, 0.23) and 0.56 (95%CI: 0.07, 1.05), equivalent to 3.5 and 5.3 years of aging-related decline in cognitive performance. Our study provides the first epidemiological data supporting the adverse neurobehavioral effects of ambient air pollutants in adults.
The 80,000 inhabitants of the lower part of Le Havre obtain their water supply from two karstic s... more The 80,000 inhabitants of the lower part of Le Havre obtain their water supply from two karstic springs, Radicatel and Saint-Laurent. Until 2000, the Radicatel water was settled when turbidity exceeded 3 NTU, then filtered and chlorinated, whereas the Saint-Laurent water was simply chlorinated. Our study aimed to characterize the link between water turbidity and the incidence of acute gastroenteritis (AGE). Records on drug sales used for the treatment of AGE were collected from January 1994 to June 1996 (period 1) and from March 1997 to July 2000 (period 2). Daily counts of drug sales were modeled using a Poisson Regression. We used data set 2 as a discovery set, identifying relevant (i.e. both significant and plausible) exposure covariates and lags. We then tested this model on period 1 as a replication dataset. In period 2, the daily drug sales correlated with finished water turbidity at both resources. Settling substantially modified the risk related to turbidity of both raw and ...
Wolters Kluwer Health may email you for journal alerts and information, but is committed to maint... more Wolters Kluwer Health may email you for journal alerts and information, but is committed to maintaining your privacy and will not share your personal information without your express consent. For more information, please refer to our Privacy Policy. ... Skip Navigation Links Home &gt; ...
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Papers by Joel Schwartz