Promise and pitfalls in the application of big data to occupational and environmental health

EditorialIs “big data” merely a catchphrase, or does the approach hold real promise in informing occupational and environmental health? Can challenges related to messy and unrepresentative data and spurious findings be overcome

Maternal Exposure to Aeroallergens and the Risk of Early Delivery.

BACKGROUND: Daily changes in aeroallergens during pregnancy could trigger early labor, but few investigations have evaluated this issue. This study aimed to investigate the association between exposure to aeroallergens during the week preceding birth and the risk of early delivery among preterm and term pregnancies. METHODS: We identified data on 225,234 singleton births that occurred in six large cities in the province of Ontario, Canada, from 2004 to 2011 (April to October) from a birth registry. We obtained daily counts of pollen grains and fungal spores from fixed-site monitoring stations in each city and assigned them to pregnancy period of each birth. Associations between exposure to aeroallergens in the preceding week and risk of delivery among preterm (<37 gestational weeks), early-term (37-38 weeks), and full-term (≥39 weeks) pregnancies were evaluated with Cox regression models, adjusting for maternal characteristics, meteorologic parameters, and air pollution concentrations, and pooled across the six cities. RESULTS: The risk of delivery increased by 3% per interquartile range width (IQRw = 22.1 grains/m) increase in weed pollen the day before birth among early-term (hazard ratio [HR] = 1.03; 95% confidence interval [CI]: 1.01, 1.05) and full-term pregnancies (HR = 1.03; 95% CI: 1.01, 1.04). Exposure to fungal spores cumulated over 0 to 2 lagged days was associated with increased risk of delivery among full-term pregnancies only (HR = 1.07; 95% CI: 1.01, 1.12). We observed no associations among preterm deliveries. CONCLUSIONS: Increasing concentrations of ambient weed pollen and fungal spores may be associated with earlier delivery among term births

Verifying a questionnaire diagnosis of asthma in children using health claims data

<p>Abstract</p> <p>Background</p> <p>Childhood asthma prevalence is widely measured by parental proxy report of physician-diagnosed asthma in questionnaires. Our objective was to validate this measure in a North American population.</p> <p>Methods</p> <p>The 2884 study participants were a subsample of 5619 school children aged 5 to 9 years from 231 schools participating in the Toronto Child Health Evaluation Questionnaire study in 2006. We compared agreement between "questionnaire diagnosis" and a previously validated "health claims data diagnosis". Sensitivity, specificity and kappa were calculated for the questionnaire diagnosis using the health claims diagnosis as the reference standard.</p> <p>Results</p> <p>Prevalence of asthma was 15.7% by questionnaire and 21.4% by health claims data. Questionnaire diagnosis was insensitive (59.0%) but specific (95.9%) for asthma. When children with asthma-related symptoms were excluded, the sensitivity increased (83.6%), and specificity remained high (93.6%).</p> <p>Conclusions</p> <p>Our results show that parental report of asthma by questionnaire has low sensitivity but high specificity as an asthma prevalence measure. In addition, children with "asthma-related symptoms" may represent a large fraction of under-diagnosed asthma and they should be excluded from the inception cohort for risk factor studies.</p

Do Questions Reflecting Indoor Air Pollutant Exposure from a Questionnaire Predict Direct Measure of Exposure in Owner-Occupied Houses?

Home characteristic questions are used in epidemiological studies and clinical settings to assess potentially harmful exposures in the home. The objective of this study was to determine whether questionnaire-reported home characteristics can predict directly measured pollutants. Sixty home inspections were conducted on a subsample of the 2006 population-based Toronto Child Health Evaluation Questionnaire. Indoor/outdoor air and settled dust samples were analyzed. Mean Fel d 1 was higher (p < 0.0001) in homes with a cat (450.58 μg/g) versus without (22.28 μg/g). Mean indoor NO2 was higher (p = 0.003) in homes with gas stoves (14.98 ppb) versus without (8.31 ppb). Self-reported musty odours predicted higher glucan levels (10554.37 μg/g versus 6308.58 μg/g, p = 0.0077). Der f 1 was predicted by the home’s age, but not by reports of carpets, and was higher in homes with mean relative humidity > 50% (61.30 μg/g, versus 6.24 μg/g, p = 0.002). Self-reported presence of a cat, a gas stove, musty odours, mice, and the home’s age and indoor relative humidity over 50% predicted measured indoor levels of cat allergens, NO2, fungal glucan, mouse allergens and dust mite allergens, respectively. These results are helpful for understanding the significance of indoor exposures ascertained by self-reporting in large epidemiological studies and also in the clinical setting

Spatiotemporal Variations in Ambient Ultrafine Particles and the Incidence of Childhood Asthma.

Rationale: Little is known regarding the impact of ambient ultrafine particles (UFPs; <0.1 μm) on childhood asthma development. Objectives: To examine the association between prenatal and early postnatal life exposure to UFPs and development of childhood asthma. Methods: A total of 160,641 singleton live births occurring in the City of Toronto, Canada between April 1, 2006, and March 31, 2012, were identified from a birth registry. Associations between exposure to ambient air pollutants and childhood asthma incidence (up to age 6) were estimated using random effects Cox proportional hazards models, adjusting for personal- and neighborhood-level covariates. We investigated both single-pollutant and multipollutant models accounting for coexposures to particulate matter ≤2.5 μm in aerodynamic diameter (PM2.5) and NO2. Measurements and Main Results: We identified 27,062 children with incident asthma diagnosis during the follow-up. In adjusted models, second-trimester exposure to UFPs (hazard ratio per interquartile range increase, 1.09; 95% confidence interval, 1.06-1.12) was associated with asthma incidence. In models additionally adjusted for PM2.5 and nitrogen dioxide, UFPs exposure during the second trimester of pregnancy remained positively associated with childhood asthma incidence (hazard ratio per interquartile range increase, 1.05; 95% confidence interval, 1.01-1.09). Conclusions: This is the first study to evaluate the association between perinatal exposure to UFPs and the incidence of childhood asthma. Exposure to UFPs during a critical period of lung development was linked to the onset of asthma in children, independent of PM2.5 and NO2

The association between low level exposures to ambient air pollution and term low birth weight: a retrospective cohort study

BACKGROUND: Studies in areas with relatively high levels of air pollution have found some positive associations between exposures to ambient levels of air pollution and several birth outcomes including low birth weight (LBW). The purpose of this study was to examine the association between LBW among term infants and ambient air pollution, by trimester of exposure, in a region of lower level exposures. METHODS: The relationship between LBW and ambient levels of particulate matter up to 10 um in diameter (PM(10)), sulfur dioxide (SO(2)) and ground-level ozone (O(3)) was evaluated using the Nova Scotia Atlee Perinatal Database and ambient air monitoring data from the Environment Canada National Air Pollution Surveillance Network and the Nova Scotia Department of Environment. The cohort consisted of live singleton births (≥37 weeks of gestation) between January1,1988 and December31,2000. Maternal exposures to air pollution were assigned to women living within 25 km of a monitoring station at the time of birth. Air pollution was evaluated as a continuous and categorical variable (using quartile exposures) for each trimester and relative risks were estimated from logistic regression, adjusted for confounding variables. RESULTS: There were 74,284 women with a term, singleton birth during the study period and with exposure data. In the analyses unadjusted for year of birth, first trimester exposures in the highest quartile for SO(2 )and PM(10)suggested an increased risk of delivering a LBW infant (relative risk = 1.36, 95% confidence interval = 1.04 to 1.78 for SO(2 )exposure and relative risk = 1.33, 95% confidence interval = 1.02 to 1.74 for PM(10)). After adjustment for birth year, the relative risks were attenuated somewhat and not statistically significant. A dose-response relationship for SO(2 )was noted with increasing levels of exposure. No statistically significant effects were noted for ozone. CONCLUSION: Our results suggest that exposure during the first trimester to relatively low levels of some air pollutants may be associated with a reduction in birth weight in term-born infants. These findings have implications for the development of effective risk management strategies to minimize the public health impacts for pregnant women

Term birth weight and ambient air pollutant concentrations during pregnancy, among women living in Monroe County, New York

Increased ambient air pollutant concentrations during pregnancy have been associated with reduced birth weight, but the etiologically relevant pregnancy time window(s) is/are unclear. In 76,500 singleton births in Monroe County, NY (2005–2016), who were 37–42 gestational weeks at delivery, we used generalized linear models to regress term birth weight against mean gestational month pollutant concentrations, adjusting for mean temperature, and maternal, infant, and medical service use characteristics. Overall, there were no clear patterns of term birth weight change associated with increased concentrations of any pollutant across gestational months. However, among Hispanic women only, increases in all pollutants, except O3, in multiple gestational months, were associated with decreased term birth weight. Each 3.25 µg/m3 increase in PM2.5 concentration in the 6th gestational month was associated with a −20.4 g (95% CI = −34.0, −6.8) reduction in term birth weight among Hispanic women, but a 4.1 g (95% CI = −2.5, 10.8) increase among non-Hispanic mothers (p for interaction &lt; 0.001). Although ambient air pollutant concentrations during pregnancy were not associated with reduced term birth weight among women of all ethnicities living in Monroe County, this observed association in Hispanic mothers may be a result of less exposure misclassification and bias (due to closer residential proximity to the monitoring site)