Synergy of Biostatistics and Epidemiology in Air Pollution Health Effects Studies

The extraordinary advances in quantifying the health effects of ambient air pollution over the last five decades have led to dramatic improvement in air quality in the United States. This work has been possible through innovative epidemiologic study designs coupled with advanced statistical analytic methods. This paper presents a historical perspective on the coordinated developments of epidemiologic designs and statistical methods for air pollution health effects studies at the Harvard School of Public Health.

Antenatal depressive symptoms and adverse perinatal outcomes

Background

The association of antenatal depression with adverse pregnancy, birth, and postnatal outcomes has been an item of scientific interest over the last decades. However, the evidence that exists is controversial or limited. We previously found that one in five women in Kuwait experience antenatal depressive symptoms. Therefore, the aim of this study was to examine whether antenatal depressive symptoms are associated with preterm birth (PTB), small for gestational age (SGA), or large for gestational age (LGA) babies in this population.

Methods

This was a secondary analysis based on data collected in the Transgenerational Assessment of Children’s Environmental Risk (TRACER) Study that was conducted in Kuwait. Logistic regression analysis was used to examine whether antenatal depressive symptoms assessed using the Edinburgh Depression Scale (EDS) were associated with preterm birth, small for gestational age, and large for gestational age babies.

Results

A total of 1694 women had complete information about the outcomes of interest. Women with depressive symptoms in pregnancy had increased, albeit non-significant, odds of having PTB (OR = 1.41; 95%CI: 0.81, 2.45), SGA babies (OR = 1.26; 0.80, 1.98), or LGA babies (OR = 1.27; 0.90, 1.79). Antenatal depressive symptoms had similar increased odds for the three outcomes even after adjusting for several covariates though none of these reached statistical significance.

Conclusions

In the present study, the depressive symptoms in pregnancy did not predict adverse birth outcomes, such as PTB, SGA, and LGA, which adds to the currently non-conclusive literature. However, further research is needed to examine these associations, as the available evidence is quite limited.

Mortality Benefits and Control Costs of Improving Air Quality in Mexico City: The Case of Heavy Duty Diesel Vehicles

Diesel vehicles are significant contributors to air pollution in Mexico City. We estimate the costs and mortality benefits of retrofitting heavy-duty vehicles with particulate filters and oxidation catalysts. The feasibility and cost-effectiveness of controls differ by vehicle model-year and type. We evaluate 1985 to 2014 model-year vehicles from 10 vehicle classes and five model-year groups. Our analysis shows that retrofitting all vehicles with the control that maximizes expected net benefits for that vehicle type and model-year group has the potential to reduce emissions of primary fine particles (PM_2.5 ) by 950 metric tons/year; cut the population-weighted annual mean concentration of PM_2.5 in Mexico City by 0.90 µg/m³ ; reduce the annual number of deaths attributable to air pollution by over 80; and generate expected annual health benefits of close to 250 million US$. These benefits outweigh expected costs of 92 million US$ per year. Diesel retrofits are but one step that should viewed in the context of other efforts--such as development of an integrated public transportation system, promotion of the rational use of cars, reduction of emissions from industrial sources and fires, and redesign of the Mexico City Metropolitan Area to reduce urban sprawl--that must be analyzed and implemented to substantially control air pollution and protect public health. Even if considering other potential public health interventions, which would offer greater benefits at the same or lower costs, only by conducting, promoting, and publishing this sort of analyses, we can make strides to improve public health cost-effectively.

Guidance to Reduce the Cardiovascular Burden of Ambient Air Pollutants: A Policy Statement From the American Heart Association

In 2010, the American Heart Association published a statement concluding that the existing scientific evidence was consistent with a causal relationship between exposure to fine particulate matter and cardiovascular morbidity and mortality, and that fine particulate matter exposure is a modifiable cardiovascular risk factor. Since the publication of that statement, evidence linking air pollution exposure to cardiovascular health has continued to accumulate and the biological processes underlying these effects have become better understood. This increasingly persuasive evidence necessitates policies to reduce harmful exposures and the need to act even as the scientific evidence base continues to evolve. Policy options to mitigate the adverse health impacts of air pollutants must include the reduction of emissions through action on air quality, vehicle emissions, and renewable portfolio standards, taking into account racial, ethnic, and economic inequality in air pollutant exposure. Policy interventions to improve air quality can also be in alignment with policies that benefit community and transportation infrastructure, sustainable food systems, reduction in climate forcing agents, and reduction in wildfires. The health care sector has a leadership role in adopting policies to contribute to improved environmental air quality as well. There is also potentially significant private sector leadership and industry innovation occurring in the absence of and in addition to public policy action, demonstrating the important role of public-private partnerships. In addition to supporting education and research in this area, the American Heart Association has an important leadership role to encourage and support public policies, private sector innovation, and public-private partnerships to reduce the adverse impact of air pollution on current and future cardiovascular health in the United States.

Exposure to Air Pollution and Particle Radioactivity With the Risk of Ventricular Arrhythmias

BACKGROUND

Individuals are exposed to air pollution and ionizing radiation from natural sources through inhalation of particles. This study investigates the association between cardiac arrhythmias and short-term exposures to fine particulate matter (particulate matter ≤2.5 µm aerodynamic diameter; PM2.5) and particle radioactivity.

METHODS

Ventricular arrhythmic events were identified among 176 patients with dual-chamber implanted cardioverter-defibrillators in Boston, Massachusetts between September 2006 and June 2010. Patients were assigned exposures based on residential addresses. Daily PM2.5 levels were estimated at 1-km×1-km grid cells from a previously validated prediction model. Particle gross β activity was used as a surrogate for particle radioactivity and was measured from several monitoring sites by the US Environmental Protection Agency's monitoring network. The association of the onset of ventricular arrhythmias (VA) with 0- to 21-day moving averages of PM2.5 and particle radioactivity (2 single-pollutant models and a 2-pollutant model) before the event was examined using time-stratified case-crossover analyses, adjusted for dew point and air temperatures.

RESULTS

A total of 1,050 VA were recorded among 91 patients, including 123 sustained VA among 25 of these patients. In the single-pollutant model of PM2.5, each interquartile range increase in daily PM2.5 levels for a 21-day moving average was associated with 39% higher odds of a VA event (95% CI, 12%-72%). In the single-pollutant model of particle radioactivity, each interquartile range increase in particle radioactivity for a 2-day moving average was associated with 13% higher odds of a VA event (95% CI, 1%-26%). In the 2-pollutant model, for the same averaging window of 21 days, each interquartile range increase in daily PM2.5 was associated with an 48% higher odds of a VA event (95% CI, 15%-90%), and each interquartile range increase of particle radioactivity with a 10% lower odds of a VA event (95% CI, -29% to 14%). We found that with higher levels of particle radioactivity, the effect of PM2.5 on VAs is reduced.

CONCLUSIONS

In this high-risk population, intermediate (21-day) PM2.5 exposure was associated with higher odds of a VA event onset among patients with known cardiac disease and indication for implanted cardioverter-defibrillator implantation independently of particle radioactivity.

Postnatal depressive symptoms in women with and without antenatal depressive symptoms: results from a prospective cohort study

Evidence exists that the risk factors for depression in the antenatal and postnatal period may differ, but only a handful of studies looked at depression longitudinally. The aims of this study were (1) to estimate the prevalence of postnatal depressive symptoms in Kuwait where data about postnatal depression are scarce and identify its determinants and (2) to compare these risk factors between women who had experienced antenatal depressive symptoms and those that did not. Data collected in the TRansgenerational Assessment of Children's Environmental Risk (TRACER) Study in Kuwait were used in this analysis. The sample was restricted to the 1348 women who answered the Edinburgh Postnatal Depression Scale (EPDS) both antenatally and postnatally. The prevalence of postnatal depressive symptoms, defined by an EPDS score ≥ 10, was 11.7%. Overall, antenatal depressive symptoms were the strongest determinant of postnatal depressive symptoms. Multivariable logistic regression analysis showed that in women with depressive symptoms in pregnancy, having a lower household income was the most significant risk factor for postnatal depressive symptoms. Among women without antenatal depressive symptoms, those who had lower income, were Kuwaitis, experienced other problems in pregnancy such as perceived stress, PTSD symptoms and social isolation, and those who delivered a boy had higher odds of postnatal depressive symptoms. Antenatal depressive symptoms and other psychosocial characteristics can predict postnatal depressive symptoms. Therefore, maternal mental health issues should be detected during the antenatal period and support should be provided in order to lower the risk of postnatal depression and its sequelae.

Depressive symptoms and comorbid problems in pregnancy - results from a population based study

OBJECTIVE

To estimate the prevalence of antenatal depressive symptoms, identify relevant risk factors, and assess comorbid mental health problems, among pregnant women enrolled in a population based study.

METHODS

This was a secondary analysis of data collected from 1916 pregnant women who participated in the TRansgenerational Assessment of Children's Environmental Risk (TRACER) study in Kuwait, and had answered the Baseline Questionnaire and completed the Edinburgh Depression Scale (EDS). Logistic regression models were used to examine the association of depressive symptoms with baseline socio-demographic characteristics and psychosocial indicators.

RESULTS

The prevalence of antenatal depressive symptoms, using a cut-off of EDS score ≥ 10, was 20.1%. Depressive symptoms were reported more by women of lower family income and had self-reported history of depression prior to pregnancy, with women in the third trimester having higher odds of antenatal depressive symptoms compared to those in the second trimester. Pregnancy-related anxiety, higher perceived stress levels, and post-traumatic stress disorder symptoms were comorbid with the presence of depressive symptoms.

CONCLUSION

The findings showed that one in five pregnant women in Kuwait experiences antenatal depressive symptoms and that these symptoms are comorbid with other mental health problems. Screening for antenatal depression and providing support to pregnant women should be considered.

Coupling external with internal exposure metrics of trihalomethanes in young females from Kuwait and Cyprus

The Eastern Mediterranean and the Middle Eastern regions are both understudied in terms of possible environmental health risks for their populations. Water scarcity and desalination treatment provide the general population of countries from these regions (e.g., Kuwait and Cyprus) with unique tap water characteristics. This study investigated the association between external (tap water and 24 h personal air samples) and internal (urine) THM exposure metrics that reflected information about THM-related habits and activities collected using questionnaires and time activity diaries. The study population comprised of young females residing in either Kuwait (n=13) or Cyprus (n=22). First morning urine voids were collected on 2 consecutive days. Urinary creatinine-adjusted total THM (TTHM) levels were higher in Kuwait (median (interquartile range): 1044 (814, 1270) ng/g) than in Cyprus (691 (510, 919) ng/g, P<0.05). Median personal air TTHM levels in Kuwait (1.4 (0.7, 1.7) μg/m³) were higher than those in Cyprus (0.9 (0.5, 1.4) μg/m³), but did not reach statistical significance (P=0.17). Median tap water TTHM in Kuwait (6.7 (5.4, 11.6) μg/l) did not correlate with urinary or air THM and they were lower than those in Cyprus (29.5 (20.1, 48.0) μg/l; P<0.01). Despite that tap water did not contain chloroform (TCM), TCM was detected in both air and urine samples in Kuwait, suggesting other TCM exposure sources, such as household cleaning activities. Total duration of activities and mopping were significantly correlated with air and urine THM in Kuwait, as reported in the time activity diary. Personal air and urine exposure metrics were correlated in Kuwait (TTHM ρ=0.62, P<0.05), but not in Cyprus (TTHM ρ=-0.32, P>0.05). Time-activity diaries and urinary THM seemed to be useful measures of THM exposures in Kuwait. Coupling both external with internal exposure metrics could find use in population health studies towards further refining the association between environmental exposures and health outcomes.

Particulate Air Pollution, Exceptional Aging, and Rates of Centenarians: A Nationwide Analysis of the United States, 1980-2010

BACKGROUND

Exceptional aging, defined as reaching age 85 years, shows geographic inequalities that may depend on local environmental conditions. Links between particulate pollution-a well-recognized environmental risk factor-and exceptional aging have not been investigated.

OBJECTIVES

We conducted a nationwide analysis of ~28 million adults in 3,034 United States counties to determine whether local PM2.5 levels (particulate matter < 2.5 μm in aerodynamic diameter) affected the probability of becoming 85- to 94-year-olds or centenarians (100- to 104-year-olds) in 2010 for individuals who were 55-64 or 70-74 years old, respectively, in 1980.

METHODS

We used population-weighted regression models including county-level PM2.5 from hybrid land-use regression and geostatistical interpolation, smoking, obesity, sociodemographic, and age-specific migration variables.

RESULTS

On average, 2,295 and 71.4 per 10,000 of the 55- to 64- and 70- to 74-year-olds in 1980, respectively, remained in the 85- to 94- and 100- to 104-year-old population in 2010. An interquartile range (4.19 μg/m3) increase in PM2.5 was associated with 93.7 fewer 85- to 94-year-olds (p < 0.001) and 3.5 fewer centenarians (p < 0.05). These associations were nearly linear, were stable to model specification, and were detectable below the annual PM2.5 national standard. Exceptional aging was strongly associated with smoking, with an interquartile range (4.77%) increase in population who smoked associated with 181.9 fewer 85- to 94-year-olds (p < 0.001) and 6.4 fewer centenarians (p < 0.001). Exceptional aging was also associated with obesity rates and median income.

CONCLUSIONS

Communities with the most exceptional aging have low ambient air pollution and low rates of smoking, poverty, and obesity. Improvements in these determinants may contribute to increasing exceptional aging. Citation: Baccarelli AA, Hales N, Burnett RT, Jerrett M, Mix C, Dockery DW, Pope CA III. 2016. Particulate air pollution, exceptional aging, and rates of centenarians: a nationwide analysis of the United States, 1980-2010. Environ Health Perspect 124:1744-1750; http://dx.doi.org/10.1289/EHP197.

Countervailing effects of income, air pollution, smoking, and obesity on aging and life expectancy: population-based study of U.S. Counties

BACKGROUND

Income, air pollution, obesity, and smoking are primary factors associated with human health and longevity in population-based studies. These four factors may have countervailing impacts on longevity. This analysis investigates longevity trade-offs between air pollution and income, and explores how relative effects of income and air pollution on human longevity are potentially influenced by accounting for smoking and obesity.

METHODS

County-level data from 2,996 U.S. counties were analyzed in a cross-sectional analysis to investigate relationships between longevity and the four factors of interest: air pollution (mean 1999-2008 PM2.5), median income, smoking, and obesity. Two longevity measures were used: life expectancy (LE) and an exceptional aging (EA) index. Linear regression, generalized additive regression models, and bivariate thin-plate smoothing splines were used to estimate the benefits of living in counties with higher incomes or lower PM2.5. Models were estimated with and without controls for smoking, obesity, and other factors.

RESULTS

Models which account for smoking and obesity result in substantially smaller estimates of the effects of income and pollution on longevity. Linear regression models without these two variables estimate that a $1,000 increase in median income (1 μg/m(3) decrease in PM2.5) corresponds to a 27.39 (33.68) increase in EA and a 0.14 (0.12) increase in LE, whereas models that control for smoking and obesity estimate only a 12.32 (20.22) increase in EA and a 0.07 (0.05) increase in LE. Nonlinear models and thin-plate smoothing splines also illustrate that, at higher levels of income, the relative benefits of the income-pollution tradeoff changed-the benefit of higher incomes diminished relative to the benefit of lower air pollution exposure.

CONCLUSIONS

Higher incomes and lower levels of air pollution both correspond with increased human longevity. Adjusting for smoking and obesity reduces estimates of the benefits of higher income and lower air pollution exposure. This adjustment also alters the tradeoff between income and pollution: increases in income become less beneficial relative to a fixed reduction in air pollution-especially at higher levels of income.

Birth Outcomes in a Prospective Pregnancy-Birth Cohort Study of Environmental Risk Factors in Kuwait: The TRACER Study

BACKGROUND

Rapid development and westernisation in Kuwait and other Gulf states have been accompanied by rising rates of obesity, diabetes, asthma, and other chronic conditions. Prenatal experiences and exposures may be important targets for intervention. We undertook a prospective pregnancy-birth cohort study in Kuwait, the TRansgenerational Assessment of Children's Environmental Risk (TRACER) Study, to examine prenatal risk factors for early childhood obesity. This article describes the methodology and results of follow-up through birth.

METHODS

Women were recruited at antenatal clinical visits. Interviewers administered questionnaires during the pregnancy and collected and banked biological samples. Children are being followed up with quarterly maternal interviews, annual anthropometric measurements, and periodic collection of biosamples. Frequencies of birth outcomes (i.e. stillbirth, preterm birth, small and large for gestational age, and macrosomia) were calculated as a function of maternal characteristics and behaviours.

RESULTS

Two thousand four hundred seventy-eight women were enrolled, and 2254 women were followed to delivery. Overall, frequencies of stillbirth (0.6%), preterm birth (9.3%), and small for gestational age (7.4%) were comparable to other developed countries, but not strongly associated with maternal characteristics or behaviours. Macrosomia (6.1%) and large for gestational age (23.0%) were higher than expected and positively associated with pre-pregnancy maternal overweight/obesity.

CONCLUSIONS

A large birth cohort has been established in Kuwait. The collected risk factors and banked biosamples will allow examination of the effects of prenatal exposures on the development of chronic disease in children. Initial results suggest that maternal overweight/obesity before pregnancy should be targeted to prevent macrosomia and its associated sequelae of childhood overweight/obesity.

Occupational vehicle-related particulate exposure and inflammatory markers in trucking industry workers

BACKGROUND

Previous studies have suggested an association between particulate air pollution and cardiovascular disease, but the mechanism is still unclear.

OBJECTIVE

We examined the association between workplace exposure to vehicle-related particles and cardiovascular disease related systemic inflammatory markers, C-reactive protein (hs-CRP), soluble intercellular adhesion molecule-1 (sICAM-1), and interleukin-6 (IL-6) in 137 trucking terminal workers (non-drivers) in the U.S. trucking industry.

METHODS

We visited two large trucking terminals in 2009 and measured vehicle-related elemental carbon (EC), organic carbon (OC), and particulate matter with aerodynamic diameter ≤2.5µm (PM2.5), for 5 days consecutively at the main work areas. Each participant provided a blood sample and completed a health questionnaire during the sampling period. Individual workplace exposure level was calculated by 12-h time weighted moving averages based on work shift. The association between each blood marker and exposure to each pollutant during 0-12, 12-24, 24-36, and 36-48h before the blood draw was examined by multivariable regression analyses.

RESULTS

In general, OC and EC had a positive association with sICAM-1, especially for exposure periods 12-24 (lag12-24) and 24-36 (lag24-36)h prior to blood draw [β=54.9 (95%CI: 12.3-97.5) for lag12-24 and β=46.5 (95%CI: 21.2-71.8) for lag12-24; change in sICAM-1 (in ng/mL) corresponding to an IQR increase in OC]. A similar pattern was found for EC and PM2.5. We did not find an association between measured pollutants up to 48h before blood draw and hs-CRP or IL-6.

CONCLUSION

In this group of healthy workers, short-term exposure to vehicle-related air pollutants may be associated with sICAM-1. Our findings may be dependent on the exposure period studied.

"What We Breathe Impacts Our Health: Improving Understanding of the Link between Air Pollution and Health"

Air pollution contributes to the premature deaths of millions of people each year around the world, and air quality problems are growing in many developing nations. While past policy efforts have succeeded in reducing particulate matter and trace gases in North America and Europe, adverse health effects are found at even these lower levels of air pollution. Future policy actions will benefit from improved understanding of the interactions and health effects of different chemical species and source categories. Achieving this new understanding requires air pollution scientists and engineers to work increasingly closely with health scientists. In particular, research is needed to better understand the chemical and physical properties of complex air pollutant mixtures, and to use new observations provided by satellites, advanced in situ measurement techniques, and distributed micro monitoring networks, coupled with models, to better characterize air pollution exposure for epidemiological and toxicological research, and to better quantify the effects of specific source sectors and mitigation strategies.

Daily indoor-to-outdoor temperature and humidity relationships: a sample across seasons and diverse climatic regions

The health consequences of heat and cold are usually evaluated based on associations with outdoor measurements collected at a nearby weather reporting station. However, people in the developed world spend little time outdoors, especially during extreme temperature events. We examined the association between indoor and outdoor temperature and humidity in a range of climates. We measured indoor temperature, apparent temperature, relative humidity, dew point, and specific humidity (a measure of moisture content in air) for one calendar year (2012) in a convenience sample of eight diverse locations ranging from the equatorial region (10 °N) to the Arctic (64 °N). We then compared the indoor conditions to outdoor values recorded at the nearest airport weather station. We found that the shape of the indoor-to-outdoor temperature and humidity relationships varied across seasons and locations. Indoor temperatures showed little variation across season and location. There was large variation in indoor relative humidity between seasons and between locations which was independent of outdoor airport measurements. On the other hand, indoor specific humidity, and to a lesser extent dew point, tracked with outdoor, airport measurements both seasonally and between climates, across a wide range of outdoor temperatures. These results suggest that, in general, outdoor measures of actual moisture content in air better capture indoor conditions than outdoor temperature and relative humidity. Therefore, in studies where water vapor is among the parameters of interest for examining weather-related health effects, outdoor measurements of actual moisture content can be more reliably used as a proxy for indoor exposure than the more commonly examined variables of temperature and relative humidity.

Tradeoffs between income, air pollution and life expectancy: Brief report on the US experience, 1980-2000

During the period of 1980-2000, the US obtained substantial reductions in air pollution and improvements in life expectancy (LE). Multiple factors contributed to improved health. This report explores and illustrates trade-offs between income, air pollution, and LE. Both improved air quality and income growth contributed to LE gains - without evidence of substantial negative tradeoffs between air pollution and income. Cleaner air may be considered an "economic good" with contributions to health, wellbeing, and human capital.

Chemical Composition of Fine Particulate Matter and Life Expectancy: In 95 US Counties Between 2002 and 2007

BACKGROUND

In a previous study, we provided evidence that a decline in fine particulate matter (PM2.5) air pollution during the period between 2000 and 2007 was associated with increased life expectancy in 545 counties in the United States. In this article, we investigated which chemical constituents of PM2.5 were the main drivers of the observed association.

METHODS

We estimated associations between temporal changes in seven major components of PM2.5 (ammonium, sulfate, nitrate, elemental carbon matter, organic carbon matter, sodium, and silicon) and temporal changes in life expectancy in 95 counties between 2002 and 2007. We included US counties that had adequate chemical components of PM2.5 mass data across all seasons. We fitted single pollutant and multiple pollutant linear models, controlling for available socioeconomic, demographic, and smoking variables and stratifying by urban and nonurban counties.

RESULTS

In multiple pollutant models, we found that: (1) a reduction in sulfate was associated with an increase in life expectancy; and (2) reductions in ammonium and sodium ion were associated with increases in life expectancy in nonurban counties only.

CONCLUSIONS

Our findings suggest that recent reductions in long-term exposure to sulfate, ammonium, and sodium ion between 2002 and 2007 are associated with improved public health.

Weather and triggering of ventricular arrhythmias in patients with implantable cardioverter-defibrillators

Outdoor ambient weather has been hypothesized to be responsible for the seasonal distribution of cardiac arrhythmias. Because people spend most of their time indoors, we hypothesized that weather-related arrhythmia risk would be better estimated using an indoor measure or an outdoor measure that correlates well with indoor conditions, such as absolute humidity. The clinical records of 203 patients in eastern Massachusetts, USA, with an implantable cardioverter-defibrillator were abstracted for arrhythmias between 1995 and 2002. We used case-crossover methods to examine the association between weather and ventricular arrhythmia (VA). Among 84 patients who experienced 787 VAs, lower estimated indoor temperature (odds ratio (OR)=1.16, 95% confidence interval (CI) 1.05-1.27 for a 1 °C decrease in the 24-h average) and lower absolute humidity (OR=1.06, 95% CI 1.03-1.08 for a 0.5 g/m(3) decrease in the 96-h average) were associated with increased risk. Lower outdoor temperature increased risk only in warmer months, likely attributable to the poor correlation between outdoor and indoor temperature during cooler months. These results suggest that lower temperature and drier air are associated with increased risk of VA onset among implantable cardioverter-defibrillator patients.

Effectiveness of the cigarette ignition propensity standard in preventing unintentional residential fires in Massachusetts

OBJECTIVES

We evaluated the Massachusetts Fire Safe Cigarette Law's (FSCL's) effectiveness in preventing residential fires.

METHODS

We examined unintentional residential fires reported to the Massachusetts Fire Incident Reporting System from 2004 to 2010. We analyzed FSCL effect on the likelihood of cigarette- versus noncigarette-caused fires and effect modification by fire scenario factors by using an interrupted time series regression model. We analyzed the effect of FSCL on monthly fire rates with Poisson regression.

RESULTS

Cigarettes caused 1629 unintentional residential fires during the study period. The FSCL was associated with a 28% (95% confidence interval = 12%, 41%) reduction in the odds of cigarette- versus noncigarette-caused fires, although not in analyses restricted to casualty fires, with smaller sample size. The largest reductions were among fires in which human factors were involved; that were first ignited on furniture, bedding, or soft goods; that occurred in living areas; or that occurred in the summer or winter.

CONCLUSIONS

The FSCL appears to have decreased the likelihood of cigarette-caused residential fires, particularly in scenarios for which the ignition propensity standard was developed. Current standards should be adopted, and the need for strengthening should be considered.

The relationship between indoor and outdoor temperature, apparent temperature, relative humidity, and absolute humidity

Many studies report an association between outdoor ambient weather and health. Outdoor conditions may be a poor indicator of personal exposure because people spend most of their time indoors. Few studies have examined how indoor conditions relate to outdoor ambient weather. The average indoor temperature, apparent temperature, relative humidity (RH), and absolute humidity (AH) measured in 16 homes in Greater Boston, Massachusetts, from May 2011 to April 2012 was compared to measurements taken at Boston Logan airport. The relationship between indoor and outdoor temperatures is nonlinear. At warmer outdoor temperatures, there is a strong correlation between indoor and outdoor temperature (Pearson correlation coefficient, r = 0.91, slope, β = 0.41), but at cooler temperatures, the association is weak (r = 0.40, β = 0.04). Results were similar for outdoor apparent temperature. The relationships were linear for RH and AH. The correlation for RH was modest (r = 0.55, β = 0.39). Absolute humidity exhibited the strongest indoor-to-outdoor correlation (r = 0.96, β = 0.69). Indoor and outdoor temperatures correlate well only at warmer outdoor temperatures. Outdoor RH is a poor indicator of indoor RH, while indoor AH has a strong correlation with outdoor AH year-round.

Traffic-related exposures and biomarkers of systemic inflammation, endothelial activation and oxidative stress: a panel study in the US trucking industry

BACKGROUND

Experimental evidence suggests that inhaled particles from vehicle exhaust have systemic effects on inflammation, endothelial activation and oxidative stress. In the present study we assess the relationships of short-term exposures with inflammatory endothelial activation and oxidative stress biomarker levels in a population of trucking industry workers.

METHODS

Blood and urine samples were collected pre and post-shift, at the beginning and end of a workweek from 67 male non-smoking US trucking industry workers. Concurrent measurements of microenvironment concentrations of elemental and organic carbon (EC & OC), and fine particulate matter (PM2.5) combined with time activity patterns allowed for calculation of individual exposures. Associations between daily and first and last-day average levels of exposures and repeated measures of intercellular and vascular cell adhesion molecule-1 (ICAM-1 & VCAM-1), interleukin 6 (IL-6) and C-reactive protein (CRP) blood levels and urinary 8-Hydroxy-2'-Deoxyguanosine (8-OHdG) were assessed using linear mixed effects models for repeated measures.

RESULTS

There was a statistically significant association between first and last-day average PM2.5 and 8-OHdG (21% increase, 95% CI: 2, 42%) and first and last-day average OC and IL-6 levels (18% increase 95% CI: 1, 37%) per IQR in exposure. There were no significant findings associated with EC or associations suggesting acute cross-shift effects.

CONCLUSION

Our findings suggest associations between weekly average exposures of PM2.5 on markers of oxidative stress and OC on IL-6 levels.

Effect of air pollution control on mortality and hospital admissions in Ireland

During the 1980s the Republic of Ireland experienced repeated severe pollution episodes. Domestic coal burning was a major source of this pollution. In 1990 the Irish government introduced a ban on the marketing, sale, and distribution of coal in Dublin. The ban was extended to Cork in 1995 and to 10 other communities in 1998 and 2000. We previously reported decreases in particulate black smoke (BS*) and sulfur dioxide (SO2) concentrations, measured as total gaseous acidity, in Dublin after the 1990 coal ban (Clancy et al. 2002). In the current study we explored and compared the effectiveness of the sequential 1990, 1995, and 1998 bans in reducing community air pollution and in improving public health. We compiled records of daily BS, total gaseous acidity (SO2), and counts of cause-specific deaths from 1981 to 2004 for Dublin County Borough (1990 ban), county Cork (1995 ban), and counties Limerick, Louth, Wexford, and Wicklow (1998 ban). We also compiled daily counts of hospital admissions for cardiovascular, respiratory, and digestive diagnoses for Cork County Borough (1991 to 2004) and counties Limerick, Louth, Wexford, and Wicklow (1993 to 2004). We compared pre-ban and post-ban BS and SO2 concentrations for each city. Using interrupted time-series methods, we estimated the change in cause-specific, directly standardized mortality rates in each city or county after the corresponding local coal ban. We regressed weekly age- and sex-standardized mortality rates against an indicator of the post- versus pre-ban period, adjusting for influenza epidemics, weekly mean temperature, and a season smooth of the standardized mortality rates in Coastal counties presumably not affected by the bans. We compared these results with similar analyses in Midlands counties also presumably unaffected by the bans. We also estimated the change in cause-specific, directly standardized, weekly hospital admissions rates normalized for underreporting in each city or county after the 1995 and 1998 bans, adjusting for influenza epidemics, weekly mean temperature, and local admissions for digestive diagnoses. Mean BS concentrations fell in all affected population centers post-ban compared with the pre-ban period, with decreases ranging from 4 to 35 microg/m3 (corresponding to reductions of 45% to 70%, respectively), but we observed no clear pattern in SO2 measured as total gaseous acidity associated with the bans. In comparisons with the pre-ban periods, no significant reduction was found in total death rates associated with the 1990 (1% reduction), 1995 (4% reduction), or 1998 (0% reduction) bans, nor for cardiovascular mortality (0%, 4%, and 1% reductions for the 1990, 1995, and 1998 bans, respectively). Respiratory mortality was reduced in association with the bans (17%, 9%, and 3%, respectively). We found a 4% decrease in hospital admissions for cardiovascular disease associated with the 1995 ban and a 3% decrease with the 1998 ban. Admissions for respiratory disease were not consistently lower after the bans; admissions for pneumonia, chronic obstructive pulmonary disease (COPD), and asthma were reduced. However, underreporting of hospital admissions data and lack of control and comparison series tempered our confidence in these results. The successive coal bans resulted in immediate and sustained decreases in particulate concentrations in each city or town; with the largest decreases in winter and during the heating season. The bans were associated with reductions in respiratory mortality but no detectable improvement in cardiovascular mortality. The changes in hospital admissions for respiratory and cardiovascular disease were supportive of these findings but cannot be considered confirming. Detecting changes in public health indicators associated even with clear improvements in air quality, as in this case, remains difficult when there are simultaneous secular improvements in the same health indicators.

Acute exposure to air pollution triggers atrial fibrillation

OBJECTIVES

This study sought to evaluate the association of air pollution with the onset of atrial fibrillation (AF).

BACKGROUND

Air pollution in general and more specifically particulate matter has been associated with cardiovascular events. Although ventricular arrhythmias are traditionally thought to convey the increased cardiovascular risk, AF may also contribute.

METHODS

Patients with dual chamber implantable cardioverter-defibrillators (ICDs) were enrolled and followed prospectively. The association of AF onset with air quality including ambient particulate matter <2.5 μm aerodynamic diameter (PM2.5), black carbon, sulfate, particle number, NO2, SO2, and O3 in the 24 h prior to the arrhythmia was examined utilizing a case-crossover analysis. In sensitivity analyses, associations with air pollution between 2 and 48 h prior to the AF were examined.

RESULTS

Of 176 patients followed for an average of 1.9 years, 49 patients had 328 episodes of AF lasting ≥ 30 s. Positive but nonsignificant associations were found for PM2.5 in the prior 24 h, but stronger associations were found with shorter exposure windows. The odds of AF increased by 26% (95% confidence interval: 8% to 47%) for each 6.0 μg/m(3) increase in PM2.5 in the 2 h prior to the event (p = 0.004). The odds of AF were highest at the upper quartile of mean PM2.5.

CONCLUSIONS

PM was associated with increased odds of AF onset within hours following exposure in patients with known cardiac disease. Air pollution is an acute trigger of AF, likely contributing to the pollution-associated adverse cardiac outcomes observed in epidemiological studies.

Particulate matter concentrations during desert dust outbreaks and daily mortality in Nicosia, Cyprus

Ambient particulate matter (PM) has been shown to have short- and long-term effects on cardiorespiratory mortality and morbidity. Most of the risk is associated with fine PM (PM(2.5)); however, recent evidence suggests that desert dust outbreaks are major contributors to coarse PM (PM(10-2.5)) and may be associated with adverse health effects. The objective of this study was to investigate the risk of total, cardiovascular and respiratory mortality associated with PM concentrations during desert dust outbreaks. We used a time-series design to investigate the effects of PM(10) on total non-trauma, cardiovascular and respiratory daily mortality in Cyprus, between 1 January 2004 and 31 December 2007. Separate PM(10) effects for non-dust and dust days were fit in generalized additive Poisson models. We found a 2.43% (95% CI: 0.53, 4.37) increase in daily cardiovascular mortality associated with each 10-μg/m(3) increase in PM(10) concentrations on dust days. Associations for total (0.13% increase, 95% CI: -1.03, 1.30) and respiratory mortality (0.79% decrease, 95% CI: -4.69, 3.28) on dust days and all PM(10) and mortality associations on non-dust days were not significant. Although further study of the exact nature of effects across different affected regions during these events is needed, this study suggests adverse cardiovascular effects associated with desert dust events.

Ozone exposure, vitamin C intake, and genetic susceptibility of asthmatic children in Mexico City: a cohort study

Background

We previously reported that asthmatic children with GSTM1 null genotype may be more susceptible to the acute effect of ozone on the small airways and might benefit from antioxidant supplementation. This study aims to assess the acute effect of ozone on lung function (FEF_25-75) in asthmatic children according to dietary intake of vitamin C and the number of putative risk alleles in three antioxidant genes: GSTM1, GSTP1 (rs1695), and NQO1 (rs1800566).

Methods

257 asthmatic children from two cohort studies conducted in Mexico City were included. Stratified linear mixed models with random intercepts and random slopes on ozone were used. Potential confounding by ethnicity was assessed. Analyses were conducted under single gene and genotype score approaches.

Results

The change in FEF_25-75 per interquartile range (60 ppb) of ozone in persistent asthmatic children with low vitamin C intake and GSTM1 null was −91.2 ml/s (p = 0.06). Persistent asthmatic children with 4 to 6 risk alleles and low vitamin C intake showed an average decrement in FEF_25-75 of 97.2 ml/s per 60 ppb of ozone (p = 0.03). In contrast in children with 1 to 3 risk alleles, acute effects of ozone on FEF_25-75 did not differ by vitamin C intake.

Conclusions

Our results provide further evidence that asthmatic children predicted to have compromised antioxidant defense by virtue of genetic susceptibility combined with deficient antioxidant intake may be at increased risk of adverse effects of ozone on pulmonary function.

Fine particulate air pollution and life expectancies in the United States: the role of influential observations

Changes in life expectancy (LE) across metropolitan areas in the United States have been associated with substantial differential reductions in fine particulate matter (aerodynamic diameter < 2.5 microm; PM2.5) air pollution that occurred during the 1980s and 1990s. It has been suggested that a single influential observation was largely responsible for the statistically significant LE-PM2.5 associations. In this paper, the role of influential observations is further explored. Stable and statistically significant LE-PM2.5 associations are observed in analyses that control for available socioeconomic, demographic, and proxy smoking variables and that use robust regression procedures that are relatively resistant to influential observations. These associations are not dependent upon the inclusion or exclusion of any single observation.

IMPLICATIONS

These results contribute to the large and growing literature indicating that exposure to fine particulate matter air pollution has substantive adverse effects on human health. These results, however, also provide encouraging evidence that the improvements in air quality that occurred during the 1980s and 1990s contributed to measurable improvements in human health and life expectancy in the United States.

Effect of air pollution control on life expectancy in the United States: an analysis of 545 U.S. counties for the period from 2000 to 2007

BACKGROUND

In recent years (2000-2007), ambient levels of fine particulate matter (PM2.5) have continued to decline as a result of interventions, but the decline has been at a slower rate than previous years (1980-2000). Whether these more recent and slower declines of PM2.5 levels continue to improve life expectancy and whether they benefit all populations equally is unknown.

METHODS

We assembled a data set for 545 U.S. counties consisting of yearly county-specific average PM2.5, yearly county-specific life expectancy, and several potentially confounding variables measuring socioeconomic status, smoking prevalence, and demographic characteristics for the years 2000 and 2007. We used regression models to estimate the association between reductions in PM2.5 and changes in life expectancy for the period from 2000 to 2007.

RESULTS

A decrease of 10 μg/m in the concentration of PM2.5 was associated with an increase in mean life expectancy of 0.35 years (SD = 0.16 years, P = 0.033). This association was stronger in more urban and densely populated counties.

CONCLUSIONS

Reductions in PM2.5 were associated with improvements in life expectancy for the period from 2000 to 2007. Air pollution control in the last decade has continued to have a positive impact on public health.

Secondhand smoke exposure and inflammatory markers in nonsmokers in the trucking industry

BACKGROUND

Few studies have directly assessed the association of secondhand smoke (SHS) with cardiovascular disease-related inflammatory markers, and the findings are inconsistent.

OBJECTIVES

We assessed the association between SHS exposure and the inflammatory markers high-sensitivity C-reactive protein (hs-CRP), interleukin-6 (IL-6), and soluble intercellular adhesion molecule-1 (sICAM-1) in 199 nonsmoking U.S. trucking industry workers.

METHODS

Participants provided blood samples either by mail (blood drawn at local health care provider near home) or at the work site (blood drawn by research staff on-site) and completed a health and work history questionnaire at the time of blood draw. Exposure to SHS was measured by plasma cotinine concentrations. We used multivariate regression analyses to assess the associations between levels of cotinine and inflammatory markers.

RESULTS

The median cotinine level was 0.10 ng/mL (interquartile range, 0.04-0.23 ng/mL). The odds ratios of elevated hs-CRP (above highest CRP tertile, 1.5 mg/L) were 2.85 [95% confidence interval (CI), 1.03-7.89] for the high-cotinine group (> 0.215 ng/mL) and 2.80 (95% CI, 1.11-7.10) for the moderate-cotinine group (0.05-0.215 ng/mL), compared with the low-cotinine group (< 0.05 ng/mL), adjusting for age, sex, race, educational level, obesity, previous smoking history, job title, and medical history. Plasma cotinine levels were not associated with IL-6 or sICAM-1.

CONCLUSIONS

SHS exposure, as assessed by plasma cotinine, was positively associated with hs-CRP in this group of blue-collar workers. The strength of the association with hs-CRP depended on the cut points selected for analysis.

Long-term ambient multipollutant exposures and mortality

RATIONALE

population-based studies have demonstrated associations between ambient air pollution exposures and mortality, but few have been able to adjust for occupational exposures. Additionally, two studies have observed higher risks in individuals with occupational dust, gas, or fume exposure.

OBJECTIVES

we examined the association of ambient residential exposure to particulate matter less than 10 microm in diameter (PM(10)), particulate matter less than 2.5 microm in diameter (PM(2.5)), NO(2), SO(2), and mortality in 53,814 men in the U.S. trucking industry.

METHODS

exposures for PM(10), NO(2), and SO(2) at each residential address were assigned using models combining spatial smoothing and geographic covariates. PM(2.5) exposures in 2000 were assigned from the nearest available monitor. Single and multipollutant Cox proportional hazard models were used to examine the association of an interquartile range (IQR) change (6 microg/m(3) for PM(10), 4 microg/m(3) for PM(2.5), 4ppb for SO(2), and 8ppb for NO(2)) and the risk of all-cause and cause-specific mortality.

MEASUREMENTS AND MAIN RESULTS

an IQR change in ambient residential exposures to PM(10) was associated with a 4.3% (95% confidence interval [CI], 1.1-7.7%) increased risk of all-cause mortality. The increase for an IQR change in SO(2) was 6.9% (95% CI, 2.3-11.6%), for NO(2) was 8.2% (95% CI, 4.5-12.1%), and for PM(2.5) was 3.9% (95% CI, 1.0-6.9%). Elevated associations with cause-specific mortality (lung cancer, cardiovascular and respiratory disease) were observed for PM(2.5), SO(2), and NO(2), but not PM(10). None of the pollutants were confounded by occupational exposures. In multipollutant models, overall, the associations were attenuated, most strongly for PM(10). In sensitivity analyses excluding long-haul drivers, who spend days away from home, larger hazard ratios were observed.

CONCLUSIONS

in this population of men, residential ambient air pollution exposures were associated with mortality.

Smoke-free air laws and asthma prevalence, symptoms, and severity among nonsmoking youth

OBJECTIVE

We investigated the association between smoke-free laws and asthma prevalence, symptoms, and severity among nonsmoking youth (aged 3-15 years).

METHODS

We examined data from the 1999-2006 National Health and Nutrition Examination Survey, a cross-sectional survey designed to monitor the health and nutritional status of the US population. Survey locations were dichotomized as having or not having at least 1 smoke-free workplace, restaurant, or bar law at the county or state level that covered the entire county population. Asthma prevalence was assessed as self-reported current asthma and as ever having asthma with current symptoms. Asthmatic symptoms included persistent wheeze, chronic night cough, and wheeze-medication use. We also examined asthma severity (asthma attack or emergency-department visit for asthma) and persistent ear infection.

RESULTS

Smoke-free laws were not associated with current asthma but were significantly associated with lower odds of asthmatic symptoms (odds ratio [OR]: 0.67 [95% confidence interval (CI): 0.48-0.93]) among nonsmoking youth. The association between smoke-free laws and ever having asthma with current symptoms approached significance (OR: 0.74 [95% CI: 0.53-1.03]). Smoke-free laws were associated with lower odds of asthma attacks (OR: 0.66 [95% CI: 0.28-1.56]) and emergency-department visits for asthma (OR: 0.55 [95% CI: 0.27-1.13]), although these results were not statistically significant.

CONCLUSIONS

Our results suggest that smoke-free laws reduce asthmatic symptoms, including persistent wheeze, chronic night cough, and wheeze-medication use in nonsmoking youth.

The impact of Massachusetts' smoke-free workplace laws on acute myocardial infarction deaths

OBJECTIVES

We examined the rate of acute myocardial infarction (AMI) deaths in Massachusetts before and after the implementation of a comprehensive smoke-free workplace law in July 2004.

METHODS

We used Poisson regression models to examine the impact of the state law in cities and towns with and without previous local smoking bans and the effect of the local laws for the period of 1999 through 2006.

RESULTS

The AMI mortality rate decreased by 7.4% (95% confidence interval [CI] = 3.3%, 11.4%) after implementation of the state law. The state ban had an impact in cities and towns with no prior local smoking ban (9.2% decrease; P < .001) but not cities and towns with a prior local smoking ban. However, there was a nonsignificant 4.9% (95% CI = -5.0%, 13.9%) decrease associated with the local smoking ban that preceded the effect of the state ban. The effect of the state ban was modest (-1.6%) in the first 12 months after implementation but much larger after the first 12 months (-18.6%; P < .001).

CONCLUSIONS

Comprehensive statewide smoke-free workplace laws in Massachusetts were associated with an estimated 270 fewer AMI deaths per year. These results add to the evidence suggesting that smoke-free air laws are associated with lower rates of AMI.

Smoke-free air laws and secondhand smoke exposure among nonsmoking youth

OBJECTIVES

We investigated the association between smoke-free law coverage and cotinine among nonsmoking youth (3-19 years) with and without home secondhand smoke (SHS) exposure.

METHODS

We used data from the 1999-2006 National Health and Nutrition Examination Survey, a cross-sectional survey designed to monitor the health and nutritional status of the US population. Serum cotinine levels were available for 11 486 nonsmoking youth from 117 survey locations. Each location was categorized into 1 of 3 groups indicating extensive, limited, and no coverage by a smoke-free law. Cotinine was analyzed both as a dichotomous (> or =0.05 ng/mL) and as a continuous outcome.

RESULTS

Among youth without home SHS exposure, those who were living in a county with extensive coverage of a smoke-free air law had an adjusted 0.61 times (95% confidence interval: 0.48-0.78) the prevalence of detectable cotinine and 0.57 (95% confidence interval: 0.41-0.79) times lower geometric mean compared with youth without a smoke-free air law. Among youth with home SHS exposure, youth with extensive coverage of a smoke-free air law had lower geometric mean cotinine compared with youth who were living in a county without a smoke-free air law, but these differences were no longer observed after adjustment for covariates.

CONCLUSIONS

These results suggest that smoke-free laws are an effective strategy for reducing cotinine in youth without home SHS exposure; however, among youth with home SHS exposure, no benefit was detected.

Systemic inflammation, heart rate variability and air pollution in a cohort of senior adults

OBJECTIVES

Short-term elevation of ambient particulate air pollution has been associated with autonomic dysfunction and increased systemic inflammation, but the interconnections between these pathways are not well understood. We examined the association between inflammation and autonomic dysfunction and effect modification of inflammation on the association between air pollution and heart rate variability (HRV) in elderly subjects.

METHODS

25 elderly subjects in Steubenville, Ohio, were followed up to 24 times with repeated 30-min ECG Holter monitoring (545 observations). C-reactive protein (CRP), fibrinogen, interleukin-6 (IL-6), soluble inter-cellular adhesion molecule 1 (sICAM-1), and white blood cell and platelet counts were measured in peripheral blood samples collected in the first month of the study. Increased systemic inflammation was defined for subjects within the upper 20% of the distribution for each marker. A central ambient monitoring station provided daily fine particle (PM(2.5)) and sulphate (SO(4)(2-)) data. Linear mixed models were used to identify associations between inflammatory markers and HRV and to assess effect modification of the association between air pollution and HRV due to inflammatory status.

RESULTS

A 5.8 mg/l elevation in CRP was associated with decreases of between -8% and -33% for time and frequency domain HRV outcomes. A 5.1 microg/m(3) increase in SO(4)(2-) on the day before the health assessment was associated with a decrease of -6.7% in the SD of normal RR intervals (SDNN) (95% CI -11.8% to -1.3%) in subjects with elevated CRP, but not in subjects with lower CRP (p value interaction=0.04), with similar findings for PM(2.5).

CONCLUSIONS

Increased systemic inflammation is associated with autonomic dysfunction in the elderly. Air pollution effects on reduced SDNN are stronger in subjects with elevated systemic inflammation.

War-related stressors are associated with asthma risk among older Kuwaitis following the 1990 Iraqi invasion and occupation

BACKGROUND

Contemporary warfare involving civilian populations is a growing public health concern. In addition to the psychological impact, war-related trauma may result in physiological alterations and even broader health effects. Associations were examined between war-related stressors and incident asthma in elderly Kuwaiti civilians following the Iraqi invasion.

METHODS

A random sample of all Kuwaiti nationals aged 50-69 years on the day prior to the invasion were identified. Among the 7873 meeting eligibility criteria, 5567 (71%) agreed to participate and 5028 completed the questionnaire (91% of those eligible). Of these, 3759 were in Kuwait during the invasion, of whom 2294 were alive at follow-up. After exclusions for prevalent asthma or missingness on covariates, 2066 were available for analysis. War-related experiences were summarised into a continuous score using Rasch modelling. Relative Cox proportional hazard rates (HR) were calculated for asthma adjusting for covariates.

RESULTS

Over 13 years of follow-up, physician-diagnosed asthma was reported by 66/996 (6.6%) men and 104/1070 (9.7%) women. In models adjusted for gender, socioeconomic status, smoking, BMI, and air pollution related to burning oil fires, those reporting highest stress exposure were more than twice as likely to report asthma (HR 2.3, 95% CI 1.3, 3.9) compared to civilians reporting no stressors. Experiences were more salient when anchored to fear for loss of life.

CONCLUSIONS

War-related trauma is associated with increased asthma risk in these elderly civilians. Although prior research has documented the significant and persistent psychological toll of war, these findings implicate even broader health effects.

Workplace secondhand smoke exposure in the U.S. trucking industry

BACKGROUND

Although the smoking rate in the United States is declining because of an increase of smoke-free laws, among blue-collar workers it remains higher than that among many other occupational groups.

OBJECTIVES

We evaluated the factors influencing workplace secondhand smoke (SHS) exposures in the U.S. unionized trucking industry.

METHODS

From 2003 through 2005, we measured workplace SHS exposure among 203 nonsmoking and 61 smoking workers in 25 trucking terminals. Workers in several job groups wore personal vapor-phase nicotine samplers on their lapels for two consecutive work shifts and completed a workplace SHS exposure questionnaire at the end of the personal sampling.

RESULTS

Median nicotine level was 0.87 microg/m3 for nonsmokers and 5.96 microg/m3 for smokers. As expected, smokers experienced higher SHS exposure duration and intensity than did nonsmokers. For nonsmokers, multiple regression analyses indicated that self-reported exposure duration combined with intensity, lack of a smoking policy as reported by workers, having a nondriver job, and lower educational level were independently associated with elevated personal nicotine levels (model R2 = 0.52). Nondriver job and amount of active smoking were associated with elevated personal nicotine level in smokers, but self-reported exposure, lack of a smoking policy, and lower educational level were not.

CONCLUSIONS

Despite movements toward smoke-free laws, this population of blue-collar workers was still exposed to workplace SHS as recently as 2005. The perceived (reported by the workers), rather than the official (reported by the terminal managers), smoking policy was associated with measured SHS exposure levels among the nonsmokers. Job duties and educational level might also be important predictors of workplace SHS exposure.

Spatial modeling of PM10 and NO2 in the continental United States, 1985-2000

BACKGROUND

Epidemiologic studies of air pollution have demonstrated a link between long-term air pollution exposures and mortality. However, many have been limited to city-specific average pollution measures or spatial or land-use regression exposure models in small geographic areas.

OBJECTIVES

Our objective was to develop nationwide models of annual exposure to particulate matter < 10 microm in diameter (PM(10)) and nitrogen dioxide during 1985-2000.

METHODS

We used generalized additive models (GAMs) to predict annual levels of the pollutants using smooth spatial surfaces of available monitoring data and geographic information system-derived covariates. Model performance was determined using a cross-validation (CV) procedure with 10% of the data. We also compared the results of these models with a commonly used spatial interpolation, inverse distance weighting.

RESULTS

For PM(10), distance to road, elevation, proportion of low-intensity residential, high-intensity residential, and industrial, commercial, or transportation land use within 1 km were all statistically significant predictors of measured PM(10) (model R(2) = 0.49, CV R(2) = 0.55). Distance to road, population density, elevation, land use, and distance to and emissions of the nearest nitrogen oxides-emitting power plant were all statistically significant predictors of measured NO(2) (model R(2) = 0.88, CV R(2) = 0.90). The GAMs performed better overall than the inverse distance models, with higher CV R(2) and higher precision.

CONCLUSIONS

These models provide reasonably accurate and unbiased estimates of annual exposures for PM(10) and NO(2). This approach provides the spatial and temporal variability necessary to describe exposure in studies assessing the health effects of chronic air pollution.

Health effects of particulate air pollution

In the 1980's it was generally felt that particulate air pollution concentrations in the United States were not a hazard to the public health. However, in the early 1990's the application of econometric time-series studies and prospective cohort studies suggested increased mortality associated with acute (daily) and chronic (decades) exposures to particulate air pollution commonly observed in the developed world. The epidemiologic evidence was not supported by evidence of causal associations from other disciplines. Nevertheless, the EPA moved to tighten controls on fine particulate air pollution. The debate over the science was played out in public hearings and the courts. The experience provides lessons on the use of epidemiologic data in setting public policy.

Effect of Air Pollution Controls on Black Smoke and Sulfur Dioxide Concentrations across Ireland

During the 1980s Ireland experienced severe pollution episodes, principally because of domestic coal burning. In 1990, the Irish government introduced a ban on the marketing, sale, and distribution of coal in Dublin. They extended the ban to Cork in 1995 and to ten other communities in 1998 and 2000. We previously reported declines in particulate (black smoke [BS]) and sulfur dioxide (SO₂) concentrations in Dublin following the 1990 coal ban. We now explore and compare the effectiveness of these sequential bans in 1990, 1995, 1998, and 2000. Daily BS and total gaseous acidity (SO₂) measurements were compiled between 1980 and 2004. We calculated descriptive statistics for the pre-ban (5 yr before ban) and post-ban (5 yr after ban) periods for BS and SO₂ concentrations and for season-specific periods. Mean BS levels fell in all centers post-ban compared with the pre-ban period, with decreases ranging from 4 to 35 μg∙m^-3 (-45 to -70%). These reductions were smallest in the summer and largest in the winter. These BS reductions were sustained in all centers until the end of the study period. We observed no clear pattern in SO₂ changes associated with the coal bans. The 1990, 1995, 1998, and 2000 Irish coal sale bans resulted in immediate and sustained decreases in particulate levels in centers, with the largest declines in the winter. In contrast, we did not observe consistent declines in total acidity as a measure of SO₂. It may be that coal was not the major source of SO₂. Simple legislation was very effective at improving ambient air quality in Irish cities with varying populations, geography/topography, and meteorological conditions.

Fine-particulate air pollution and life expectancy in the United States

BACKGROUND

Exposure to fine-particulate air pollution has been associated with increased morbidity and mortality, suggesting that sustained reductions in pollution exposure should result in improved life expectancy. This study directly evaluated the changes in life expectancy associated with differential changes in fine particulate air pollution that occurred in the United States during the 1980s and 1990s.

METHODS

We compiled data on life expectancy, socioeconomic status, and demographic characteristics for 211 county units in the 51 U.S. metropolitan areas with matching data on fine-particulate air pollution for the late 1970s and early 1980s and the late 1990s and early 2000s. Regression models were used to estimate the association between reductions in pollution and changes in life expectancy, with adjustment for changes in socioeconomic and demographic variables and in proxy indicators for the prevalence of cigarette smoking.

RESULTS

A decrease of 10 microg per cubic meter in the concentration of fine particulate matter was associated with an estimated increase in mean (+/-SE) life expectancy of 0.61+/-0.20 year (P=0.004). The estimated effect of reduced exposure to pollution on life expectancy was not highly sensitive to adjustment for changes in socioeconomic, demographic, or proxy variables for the prevalence of smoking or to the restriction of observations to relatively large counties. Reductions in air pollution accounted for as much as 15% of the overall increase in life expectancy in the study areas.

CONCLUSIONS

A reduction in exposure to ambient fine-particulate air pollution contributed to significant and measurable improvements in life expectancy in the United States.

A 10-year time-series analysis of respiratory and cardiovascular morbidity in Nicosia, Cyprus: the effect of short-term changes in air pollution and dust storms

BACKGROUND

To date, a substantial body of research has shown adverse health effects of short-term changes in levels of air pollution. Such associations have not been investigated in smaller size cities in the Eastern Mediterranean. A particular feature in the region is dust blown from the Sahara a few times a year resulting in extreme PM10 concentrations. It is not entirely clear whether such natural phenomena pose the same risks.

METHODS

The effect of changes in daily levels of particulate matter (PM10) and ozone (O3) on hospitalization for all, cardiovascular and respiratory causes in the two hospitals in Nicosia during 1 January 1995 and 30 December 2004 was investigated using generalized additive Poisson models after controlling for long- and short-term patterns as well as for the effect of weather. Meteorological records were reviewed to identify dust-storm days and analyses were repeated to quantify their effect on cardio-respiratory morbidity.

RESULTS

For every 10 microg/m3 increase in daily average PM10 concentrations, there was a 0.9% (95%CI: 0.6%, 1.2%) increase in all-cause and 1.2% (95%CI: -0.0%, 2.4%) increase in cardiovascular admissions. With respect to respiratory causes, an effect was observed only in the warm months. No lagged effects with levels of PM10 were observed. In contrast, positive associations with levels of ozone were only observed the two days prior to admission. These appeared stronger for cardiovascular causes and independent of the effect of PM. All-cause and cardiovascular admissions were 4.8% (95%CI: 0.7%, 9.0%) and 10.4% (95%CI: -4.7%, 27.9%) higher on dust storm days respectively. In both cases the magnitude of effect was comparable to that seen on the quartile of non-storm days with the highest levels of PM10.

CONCLUSION

We observed an increased risk of hospitalization at elevated levels of particulate matter and ozone generally consistent with the magnitude seen across several European cities. We also observed an increased risk of hospitalization on dust storm days, particularly for cardiovascular causes. While inference from these associations is limited due to the small number of dust storm days in the study period, it would appear imperative to issue health warnings for these natural events, particularly directed towards vulnerable population groups.

Low dietary nutrient intakes and respiratory health in adolescents

BACKGROUND

Epidemiologic studies have indicated that a diet rich in fruit, antioxidants, and n-3 fatty acids may contribute to optimal respiratory health. We investigated whether low dietary nutrient intakes were associated with lower pulmonary function and higher reporting of respiratory symptoms in adolescents.

METHODS

We examined the association of dietary factors (fruit, vegetables, vitamins C and E, beta-carotene, retinol, n-3 fatty acids) with respiratory health in a cohort of 2,112 twelfth-grade students in 13 communities in the United States and Canada during the 1998 to 1999 school year. We assessed the associations between dietary factors and pulmonary function with linear mixed models, and respiratory symptoms with logistic regression using a generalized estimating equation adjusted for individual and group-level covariates.

RESULTS

Low dietary fruit intake was associated with lower FEV(1) (- 1.3% of predicted; 95% confidence interval [CI], - 2.4 to - 0.2% of predicted), and increased odds of chronic bronchitic symptoms (odds ratio [OR], 1.36; 95% CI, 1.03 to 1.73) compared with higher intake. Low dietary n-3 fatty acids intake was associated with increased odds of chronic bronchitic symptoms (OR, 1.37; 95% confidence interval [CI], 1.05 to 1.81), wheeze (OR, 1.34; 95% CI, 1.06 to 1.69), and asthma (OR, 1.68; 95% CI, 1.18 to 2.39) compared with higher intake. Smokers with lower dietary vitamin C intake had higher ORs of respiratory symptoms compared with smokers who had higher intake.

CONCLUSIONS

Adolescents with the lowest dietary intakes of antioxidant and antiinflammatory micronutrients had lower pulmonary function and increased respiratory symptoms, especially among smokers, suggesting that adequate dietary intake may promote respiratory health and lessen the effects of oxidative stress.