Association between gaseous air pollutants and inflammatory, hemostatic and lipid markers in a cohort of midlife women.

BACKGROUND: Exposures to ambient gaseous pollutants have been linked to cardiovascular diseases (CVDs), but the biological mechanisms remain uncertain. OBJECTIVES: This study examined the changes in CVD marker levels resulting from elevated exposure to ambient gaseous pollutants in midlife women. METHODS: Annual repeated measurements of several inflammatory, hemostatic and lipid makers were obtained from 2306 midlife women enrolled in the longitudinal Study of Women's Health Across the Nation (SWAN) between 1999 and 2004. Ambient carbon monoxide (CO), nitrogen dioxide (NO2), and sulfur dioxide (SO2) data were assigned to each woman based on proximity of the monitoring station to her residential address. Short- and long-term exposures were calculated, and their associations with markers were examined using linear mixed-effects regression models, adjusted for demographic, health and other factors. RESULTS: Short-term CO exposure was associated with increased fibrinogen, i.e., every interquartile increase of average prior one-week exposure to CO was associated with 1.3% (95% CI: 0.6%, 2.0%) increase in fibrinogen. Long-term exposures to NO2 and SO2 were associated with reduced high-density lipoproteins and apolipoprotein A1, e.g., 4.0% (1.7%, 6.3%) and 4.7% (2.8%, 6.6%) decrease per interquartile increment in prior one-year average NO2 concentration, respectively. Fine particle (PM2.5) exposure confounded associations between CO/NO2 and inflammatory/hemostatic markers, while associations with lipoproteins were generally robust to PM2.5 adjustment. CONCLUSIONS: Exposures to these gas pollutants at current ambient levels may increase thrombotic potential and disrupt cholesterol metabolism, contributing to greater risk of CVDs in midlife women. Caution should be exercised in evaluating the confounding by PM2.5 exposure.

Estimating the associations of apparent temperature and inflammatory, hemostatic, and lipid markers in a cohort of midlife women.

Associations between temperature and cardiovascular (CVD) mortality have been reported, but the underlying biological mechanisms remain uncertain. We explored the association between apparent temperature and serum biomarkers for CVD. Using linear mixed effects models, we examined the relationships between residence-proximate apparent temperature (same day and 1, 7, and 30 days prior) and several inflammatory, hemostatic, and lipid biomarkers for midlife women from 1999 through 2004. Our study population consisted of 2,306 women with mean age of 51 years (± 3 years) enrolled in Study of Women's Health Across the Nation (SWAN) in Chicago, Illinois; Detroit, Michigan; Los Angeles and Oakland, California; Newark, New Jersey; and Pittsburgh, Pennsylvania. Mean daily apparent temperature was calculated using temperature and relative humidity data provided by the National Climatic Data Center and the US Environmental Protection Agency, while daily data for fine particles, ozone, carbon monoxide, and nitrogen dioxide from the US Environmental Protection Agency Air Quality Data Mart were considered as confounders. All analyses were stratified by warm and cold seasons. More significant (p < 0.10) negative associations were found during the warm season for various lag times, including hs-CRP, fibrinogen, tissue plasminogen activator antigen (tPA-ag), tissue plasminogen activator antigen (PAI-1), Factor VIIc, high-density lipoprotein (HDL), and total cholesterol. During the cold season, significant negative associations for fibrinogen and HDL, but significant positive associations for tPA-ag, PAI-1, and triglycerides were observed for various lag times. With the exception of ozone, pollutants did not confound these associations. Apparent temperature was associated with several serum biomarkers of CVD risk in midlife women, shedding light on potential mechanisms.

A Time-Stratified Case-Crossover Study of Ambient Ozone Exposure and Emergency Department Visits for Specific Respiratory Diagnoses in California (2005-2008).

BACKGROUND: Studies have explored ozone's connection to asthma and total respiratory emergency department visits (EDVs) but have neglected other specific respiratory diagnoses despite hypotheses relating ozone to respiratory infections and allergic responses. OBJECTIVE: We examined relationships between ozone and EDVs for respiratory visits, including specifically acute respiratory infections (ARI), asthma, pneumonia, chronic obstructive pulmonary disease (COPD), and upper respiratory tract inflammation (URTI). METHODS: We conducted a multi-site time-stratified case-crossover study of ozone exposures for approximately 3.7 million respiratory EDVs from 2005 through 2008 among California residents living within 20 km of an ozone monitor. Conditional logistic regression was used to estimate associations by climate zone. Random effects meta-analysis was then applied to estimate pooled excess risks (ER). Effect modification by season, distance from the monitor and individual demographic characteristics (i.e., age, race/ethnicity, sex, and payment method), and confounding by other gaseous air pollutants were also investigated. Meta-regression was utilized to explore how climate zone-level meteorological, demographic, and regional differences influenced estimates. RESULTS: We observed ozone-associated increases in all respiratory, asthma, and ARI visits, which were slightly larger in the warm season [asthma ER per 10-ppb increase in mean of same and previous 3 days ozone exposure (lag03) = 2.7%, 95% CI: 1.5, 3.9; ARI ERlag03 = 1.4%, 95% CI: 0.8, 1.9]. EDVs for pneumonia, COPD, and URTI were also significantly associated with ozone exposure over the whole year, but typically more consistently so during the warm season. CONCLUSIONS: Short-term ozone exposures among California residents living near an ozone monitor were positively associated with EDVs for asthma, ARI, pneumonia, COPD, and URTI from 2005 through 2008. Those associations were typically larger and more consistent during the warm season. Our findings suggest that these outcomes should be considered when evaluating the potential health benefits of reducing ozone concentrations. CITATION: Malig BJ, Pearson DL, Chang YB, Broadwin R, Basu R, Green RS, Ostro B. 2016. A time-stratified case-crossover study of ambient ozone exposure and emergency department visits for specific respiratory diagnoses in California (2005-2008). Environ Health Perspect 124:745-753; http://dx.doi.org/10.1289/ehp.1409495.

The effect of temperature on hospital admissions in nine California counties.

OBJECTIVES: This study examined the association between mean daily apparent temperature and hospital admissions for several diseases in nine California counties from May to September, 1999 to 2005. METHODS: We conducted a time-stratified case-crossover study limited to cases with residential zip codes located within 10 km of a temperature monitor. County-specific estimates were combined, using a random effects meta-analysis. The analyses also considered the effects of ozone and particulate matter (PM(2.5)). RESULTS: We found that a 10 degrees F increase in mean apparent temperature was associated with a 3.5% [95% confidence interval (CI) 1.5-5.6] increase in ischemic stroke and increases in several other disease-specific outcomes including all respiratory diseases (2.0%, 95% CI 0.7-3.2), pneumonia (3.7%, 95% CI 1.7-3.7), dehydration (10.8%, 95% CI 8.3-13.6), diabetes (3.1%, 95% CI 0.4-5.9), and acute renal failure (7.4%, 95% CI 4.0-10.9). There was little evidence that the temperature effects we found were due to confounding by either PM(2.5) or ozone. CONCLUSION: Our results indicate that increases in ambient temperature have important public health impacts on morbidity.

Estimating the mortality effect of the July 2006 California heat wave.

OBJECTIVE: As a result of the California heat wave in July 2006, county coroners reported that the high temperatures during that period caused approximately 147 deaths. However, heat wave-related deaths are likely to be underreported due to a lack of a clear case definition and the multi-factorial nature of heat-related mortality. Public health policy suggests a need for a careful assessment of mortality following a heat wave. In addition, it is useful to provide a comparison of the mortality impact per degree change during heat waves versus high temperatures observed during non-heat wave periods. DESIGN: Daily data were collected for mortality, weather and ozone in seven California counties impacted by the July 2006 heat wave. The association between apparent temperature and daily mortality was assessed using a Poisson regression model and combined across counties in a meta-analysis. These results were then used to estimate the increases in the number of deaths during the heat wave. RESULTS: Our analysis indicated that during the July heat wave, there was a 9% (95% CI = 1.6, 16.3) increase in daily mortality per 10 degrees Fahrenheit (F) change in apparent temperature for all counties combined. This estimate is almost 3 times larger than the effect estimated for the full warm season of May-September, during the non-heat wave years. Our estimates also determined that actual mortality during the July 2006 heat wave was 2-3 times greater than the coroner estimates. CONCLUSION: This multi-county analysis provides additional evidence that the attributable risk of mortality following a heat wave may be underestimated by examining only direct heat-related deaths. In addition, we have found that the mortality effect per degrees F is several times higher than that reported during non-heat wave periods.

Residential exposure to traffic and spontaneous abortion.

BACKGROUND: Studies have shown associations between air pollution or traffic exposure and adverse birth outcomes, such as low birth weight. However, very few studies have examined the effect of traffic emissions on spontaneous abortion (SAB). OBJECTIVE: The goal of this study was to determine whether residential exposure to vehicular traffic was associated with SAB. METHODS: Pregnant women from a prepaid health plan in California were recruited into a prospective cohort study in 1990-1991. Three measures of traffic exposure were constructed for the 4,979 participants using annual average daily traffic (AADT) counts near each residence and distance from residence to major roads. SAB was examined in relation to the traffic exposure measures using logistic regression adjusting for a number of demographic and lifestyle variables. RESULTS: Of the traffic measures, maximum annual average traffic within 50 m showed the strongest association with SAB, although it was not statistically significant. The adjusted odds ratio (AOR) for the top 90th percentile (AADT greater than 15,199) versus the bottom 75th percentile (AADT = 0-1,089) was 1.18 [95% confidence interval (CI), 0.87-1.60]. However, subgroup analyses showed statistically significant associations for traffic with SAB among African Americans (AOR = 3.11; 95% CI, 1.26-7.66) and nonsmokers (AOR = 1.47; 95% CI, 1.07-2.04). CONCLUSION: In this cohort, living within 50 m of a road with AADT of 15,200 or more was significantly associated with SAB among African Americans and nonsmokers. Further research is needed to confirm these results and possibly elucidate the mechanisms responsible for the findings.

Agricultural dust exposure and respiratory symptoms among California farm operators.

OBJECTIVE: To study whether dust exposure in California agriculture is a risk factor for respiratory symptoms. METHODS: A population-based survey of 1947 California farmers collected respiratory symptoms, occupational and personal exposures. Associations between dust and respiratory symptoms were assessed by logistic regression models. RESULTS: The prevalence of persistent wheeze was 8.6%, chronic bronchitis 3.8%, chronic cough 4.2%, and asthma 7.8%. Persistent wheeze was independently associated with dust in a dose-response fashion odds ratio, 1.2 (95% confidence interval[CI]=0.8-2.0) and 1.8 (95% CI=1.1-3.2) for low and high time in dust. A borderline significant association between chronic bronchitis and dust exposure was found. Asthma was associated with keeping livestock, but not with dust exposure. CONCLUSIONS: Occupational dust exposure among California farmers, only one third of whom tended animals, was independently associated with chronic respiratory symptoms.

The relation of occupational organic solvent exposure to symptom reporting in a sample of white and Chinese midlife women.

OBJECTIVE: This study examined the relation of occupational solvent exposure to menopausal and other symptoms in midlife women. METHODS: We conducted a cross-sectional study of 480 Chinese and 494 white women, aged 40-55 years, in Northern California. Levels of exposure to organic solvents (none, low, medium, or high) were assigned to each current job using a job-exposure matrix. RESULTS: A lower proportion of women with low occupational organic solvent exposure reported hot flashes or night sweats than working women with no solvent exposure (adjusted prevalence odds ratio [APOR] = 0.48, 95% confidence interval [CI] = 0.19-1.21). A greater proportion of women with high solvent exposure reported forgetfulness than women with no exposure (APOR = 2.51, 95% CI = 1.12-5.63). CONCLUSIONS: Some symptom reporting in midlife women was related to their occupational organic solvent exposure.

Proximity of California public schools to busy roads.

Residential proximity to busy roads has been associated with adverse health outcomes, and school location may also be an important determinant of children's exposure to traffic-related pollutants. The goal of this study was to examine the characteristics of public schools (grades K-12) in California (n = 7,460) by proximity to major roads. We determined maximum daily traffic counts for all roads within 150 m of the school using a statewide road network and a geographic information system. Statewide, 173 schools (2.3%) with a total enrollment of 150,323 students were located within 150 m of high-traffic roads (greater than or equal to 50,000 vehicles/day); 536 schools (7.2%) were within 150 m of medium-traffic roads (25,000-49,999 vehicles/day). Traffic exposure was related to race/ethnicity. For example, the overall percentage of nonwhite students was 78% at the schools located near high-traffic roads versus 60% at the schools with very low exposure (no streets with counted traffic data within 150 m). As the traffic exposure of schools increased, the percentage of both non-Hispanic black and Hispanic students attending the schools increased substantially. Traffic exposure was also related to school-based and census-tract-based socioeconomic indicators, including English language learners. The median percentage of children enrolled in free or reduced-price meal programs increased from 40.7% in the group with very low exposure to 60.5% in the highest exposure group. In summary, a substantial number of children in California attend schools close to major roads with very high traffic counts, and a disproportionate number of those students are economically disadvantaged and nonwhite.