Response to Buonocore et al. Comments on Wendt Hess et al. "Assessing Agreement in Exposure Classification between Proximity-Based Metrics and Air Monitoring Data in Epidemiology Studies of Unconventional Resource Development." Int. J. Environ. Res. Public Health 2019, 16, 3055.

We appreciate the comments by Buonocore et al [...].

Trends in Cigarette Smoking Prevalence Among Refinery and Petrochemical Plant Workers, 1950 to 1999.

OBJECTIVE: Smoking is a potential confounder in studies of workplace exposures and smoking-related disease, but little data exist to quantitatively adjust for smoking in statistical models. METHODS: We estimated smoking prevalence trends between 1950 and 1999 for 12,299 female and 43,307 male hourly and salaried petrochemical workers using company physical examination data. RESULTS: Nearly half of hourly male and female employees smoked during the study period, compared with 38% of salaried males and 29% of females. Smoking prevalence in the 1950s reached 80% and 66% among female and male hourly workers, respectively, significantly higher than the US general population. CONCLUSIONS: As hourly workers typically comprise higher exposure groups and expected case counts are typically generated from the US general population, biased risk estimates may result from standardized mortality ratio analyses if smoking rate differences are not accounted for.

Temperature, placental abruption and stillbirth.

BACKGROUND: Pregnant women may be vulnerable to changes in ambient temperature and warming climates. Recent evidence suggests that temperature increases are associated with placental abruption, a risk factor for stillbirth. OBJECTIVES: We investigated the effect of acute exposures to apparent temperature on stillbirths in Harris County, Texas, 2008-2013. METHODS: We conducted a case-crossover study to investigate the association between temperature and stillbirth among 708 women. We used data from the National Climatic Data Center to estimate maternal exposure to daily average apparent temperature over the days (lag days 1 through 6) preceding the stillbirth event. We employed symmetric bidirectional sampling to select six control periods one to three weeks before and after each event and applied conditional logistic regression to examine associations between increases of apparent temperature and stillbirths during the warm season (May-September). We adjusted for fine particulate matter (PM2.5), nitrogen dioxide (NO2) and ozone (O3) and used stratified analysis to examine differences in risk by maternal race/ethnicity. We also examined the association among stillbirths with and without placental abruptions. RESULTS: Independent of air pollutant exposures, a 10 °F increase in apparent temperature in the week preceding delivery (lag days 1 to 6) was positively associated with a 45% (adjusted OR = 1.45, 95% confidence interval (CI): 1.18, 1.77) increase in risk for stillbirth. Risks were elevated for stillbirths occurring in June through August, for Hispanic and non-Hispanic Black women, but not for non-Hispanic Whites. We also observed elevated risks associated with temperature increases in the few days preceding delivery among stillbirths caused by placental abruption, with the risk being highest on lag day 1 (OR = 1.93, 95% CI: 1.15, 3.23). CONCLUSIONS: Independent of maternal ambient air pollutant exposure, we found evidence of an association between apparent temperature increases in the week preceding an event and risk of stillbirth. Risks for stillbirth varied by race/ethnicity. Further, in the first study to evaluate the impact of temperature on a specific complication during pregnancy, the risks were higher among mothers with placental abruption.