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.

Seroprevalence and demographic determinants of human T-lymphotropic virus type 1 and 2 infections among first-time blood donors--United States, 2000-2009.

BACKGROUND: Human T-lymphotropic virus type 1 (HTLV-1) and HTLV-2 are prevalent at low levels among US blood donors, but recent data on their prevalence is lacking. METHODS. Data on all first-time blood donors in a large network of US blood centers were examined during 2000-2009. HTLV-1 and HTLV-2 antibodies were measured by enzyme immunoassay (EIA) with confirmation by immunofluorescence or recombinant immunoblot. Prevalence rates were calculated, and odds ratios were assessed using multivariable logistic regression. RESULTS: Among 2 047 740 first-time donors, 104 were seropositive for HTLV-1 (prevalence, 5.1 cases/per 100 000; 95% confidence interval [CI], 4.1-6.1), and 300 were seropositive for HTLV-2 (prevalence, 14.7 cases/per 100 000; 95% CI, 13.0-16.3). The prevalence was lower than reported in the 1990s but stable from 2000 to 2009. HTLV-1 seropositivity was associated with female sex, older age, and black and Asian race/ethnicity. HTLV-2 seropositivity was associated with female sex, older age, nonwhite race/ethnicity, lower educational level, and residence in the western and southwestern United States. CONCLUSIONS: The HTLV-1 and HTLV-2 prevalences among US blood donors has declined since the early 1990s. A higher prevalence of HTLV-2 in the west and southwest may be attributed to endemic foci among Amerindians.