The human health effects of unconventional oil and gas development (UOGD): A scoping review of epidemiologic studies.

OBJECTIVE: Unconventional oil and gas development (UOGD, sometimes termed "fracking" or "hydraulic fracturing") is an industrial process to extract methane gas and/or oil deposits. Many chemicals used in UOGD have known adverse human health effects. Canada is a major producer of UOGD-derived gas with wells frequently located in and around rural and Indigenous communities. Our objective was to conduct a scoping review to identify the extent of research evidence assessing UOGD exposure-related health impacts, with an additional focus on Canadian studies. METHODS: We included English- or French-language peer-reviewed epidemiologic studies (January 2000-December 2022) which measured exposure to UOGD chemicals directly or by proxy, and where health outcomes were plausibly caused by UOGD-related chemical exposure. Results synthesis was descriptive with results ordered by outcome and hierarchy of methodological approach. SYNTHESIS: We identified 52 studies from nine jurisdictions. Only two were set in Canada. A majority (n = 27) used retrospective cohort and case-control designs. Almost half (n = 24) focused on birth outcomes, with a majority (n = 22) reporting one or more significant adverse associations of UOGD exposure with: low birthweight; small for gestational age; preterm birth; and one or more birth defects. Other studies identified adverse impacts including asthma (n = 7), respiratory (n = 13), cardiovascular (n = 6), childhood acute lymphocytic leukemia (n = 2), and all-cause mortality (n = 4). CONCLUSION: There is a growing body of research, across different jurisdictions, reporting associations of UOGD with adverse health outcomes. Despite the rapid growth of UOGD, which is often located in remote, rural, and Indigenous communities, Canadian research on its effects on human health is remarkably sparse. There is a pressing need for additional evidence.

RéSUMé: OBJECTIF: L'exploitation pétrolière et gazière non conventionnelle (EPGNC, parfois appelée « fracturation ¼ ou « fracturation hydraulique ¼) est un processus industriel d'extraction du méthane et/ou de gisements de pétrole. De nombreux produits chimiques utilisés dans l'EPGNC ont des effets indésirables connus sur la santé humaine. Le Canada est un grand producteur de gaz dérivé de l'EPGNC, dont les puits sont souvent situés à l'intérieur et autour de communautés rurales et autochtones. Nous avons mené une étude de champ pour déterminer l'étendue des données de recherche évaluant les effets sur la santé de l'exposition à l'EPGNC, en nous concentrant plus particulièrement sur les études canadiennes. MéTHODE: Nous avons inclus des études épidémiologiques en anglais ou en français évaluées par les pairs (janvier 2000 à décembre 2022) qui mesuraient l'exposition directe ou indirecte aux produits chimiques de l'EPGNC et dans lesquelles les résultats cliniques étaient plausiblement causés par l'exposition aux produits chimiques liés à l'EPGNC. La synthèse des résultats est descriptive, et les résultats sont ordonnés selon les résultats cliniques et l'approche méthodologique. SYNTHèSE: Nous avons identifié 52 études menées dans neuf juridictions. Deux seulement étaient canadiennes. La majorité (n = 27) faisaient appel à des cohortes rétrospectives ou étaient des études cas-témoins. Près de la moitié (n = 24) portaient sur les issues de la grossesse, et la majorité (n = 22) déclaraient une ou plusieurs associations indésirables significatives entre l'exposition à l'EPGNC et : l'insuffisance de poids à la naissance; la petite taille du bébé pour son âge gestationnel; la naissance avant terme; et une ou plusieurs anomalies congénitales. D'autres études faisaient état d'effets indésirables, dont l'asthme (n = 7), les troubles respiratoires (n = 13), les troubles cardiovasculaires (n = 6), la leucémie aiguë lymphoblastique infantile (n = 2) et la mortalité toutes causes confondues (n = 4). CONCLUSION: Il existe dans différents pays un corpus croissant d'études qui font état d'associations entre l'EPGNC et des résultats sanitaires indésirables. Malgré la croissance rapide de l'EPGNC, souvent présente dans des communautés éloignées, rurales et autochtones, la recherche canadienne sur ses effets sur la santé humaine est remarquablement clairsemée. Il y a un besoin urgent de recueillir d'autres données probantes à ce sujet.

Maternal disability and initiation and duration of breastfeeding: analysis of a Canadian cross-sectional survey.

BACKGROUND: The World Health Organization recommends breastfeeding as the best method for infant feeding. Known risk factors for breastfeeding non-initiation and early cessation of breastfeeding are diverse and include low breastfeeding self-efficacy, poverty, smoking, obesity, and chronic illness. Although women with disabilities experience elevated rates of these risk factors, few studies have examined their breastfeeding outcomes. Our objective was to examine breastfeeding non-initiation and early cessation of breastfeeding in women with and without disabilities. METHODS: We used data from the 2017-2018 Canadian Community Health Survey. Included were n = 4,817 women aged 15-55 years who had a birth in the last five years, of whom 26.6% had a disability, ascertained using the Washington Group Short Set on Functioning. Prevalence ratios (aPR) of breastfeeding non-initiation, and of early cessation of any and exclusive breastfeeding before 6 months, were calculated for women with versus without disabilities. We also examined disability by severity (moderate/severe and mild, separately) and number of action domains impacted (≥ 2 and 1, separately). The main multivariable models were adjusted for maternal age, marital status, level of education, annual household income level, and immigrant status. RESULTS: There were no differences between women with and without disabilities in breastfeeding non-initiation (9.6% vs. 8.9%; aPR 0.88, 95% CI 0.63, 1.23). Women with disabilities were more likely to have early cessation of any (44.4% vs. 35.7%) and exclusive breastfeeding before 6 months (66.9% vs. 61.3%), with some attenuation in risk after adjustment for sociodemographic factors (aRR 1.15, 95% CI 0.99, 1.33 and aRR 1.07, 95% 0.98, 1.16, respectively). Disparities were larger for women with moderate/severe disabilities and disabilities in ≥ 2 domains, with differences attenuated by adjustment for socio-demographics. CONCLUSIONS: Women with disabilities, and particularly those with moderate/severe and multiple disabilities, could benefit from tailored, accessible breastfeeding supports that attend to the social determinants of health.

Proximity and density of unconventional natural gas wells and mental illness and substance use among pregnant individuals: An exploratory study in Canada.

BACKGROUND: Hydraulic fracturing (fracking) is a method used to extract unconventional natural gas (UNG). Living near UNG operations has been associated with various health outcomes, but few have explored the association between UNG and mental health and substance use. Our objective was to evaluate the association between metrics of residential UNG well density/proximity and mental illness and substance use among pregnant individuals in Northeastern British Columbia, Canada. METHODS: Individuals who gave birth at the Fort St John hospital between December 30, 2006 and December 29, 2016 (n = 6278) were included in the study. Exposure was determined using inverse distance weighting (IDW) to calculate the density and proximity of UNG wells to the postal code centroid ofindividual's residential address at delivery. Four exposure metrics, categorized by quartiles, were calculated based on 50, 10, 5 and 2.5 km buffer zones around each postal code centroid. Logistic regression was used to separately evaluate associations between IDW quartiles of each metric and diagnosis of depression and anxiety prior to or during pregnancy, and self-reported substance use during pregnancy, controlling for relevant and available confounders. RESULTS: The second and third quartile (Q) of the 10 km IDW were associated with greater odds of depression (Q2: adjusted (aOR) 1.30, 95% (confidence interval) CI 1.03-1.64; Q3: aOR 1.35, 95% CI 1.07-1.70) compared to the first quartile, but not the fourth. Using the 5 km IDW, we observed a suggestive positive association with depression in the second and third quartile (aOR Q2: 1.21, 95% CI 0.96-1.53; aOR Q3: 1.24, 95% CI 0.98-1.57) compared to the first quartile. No statistically significant association was observed using the 2.5 km IDW exposure metric. CONCLUSION: We observed some evidence of greater odds of mental illness prior to or during pregnancy, and substance use during pregnancy in pregnant individuals living in postal codes with increased UNG well density/proximity, although associations were not observed in smaller buffer zones. This study adds to the growing literature on the adverse health outcomes surrounding living in proximity to UNG operations.

Phenols and parabens in relation to reproductive and thyroid hormones in pregnant women.

INTRODUCTION: Phenols and parabens are ubiquitous environmental contaminants. Evidence from animal studies and limited human data suggest they may be endocrine disruptors. In the current study, we examined associations of phenols and parabens with reproductive and thyroid hormones in 106 pregnant women recruited for the prospective cohort, "Puerto Rico Testsite for Exploring Contamination Threats (PROTECT)". METHODS: Urinary exposure biomarkers (bisphenol A, triclosan, benzophenone-3, 2,4-dichlorophenol, 2,5-dichlorophenol, butyl, methyl and propyl paraben) and serum hormone levels (estradiol, progesterone, sex hormone-binding globulin (SHBG), free triiodothyronine (FT3), free thyroxine (FT4) and thyroid stimulating hormone) were measured at up to two time points during pregnancy (16-20 weeks and 24-28 weeks). We used linear mixed models to assess relationships between exposure biomarkers and hormone levels across pregnancy, controlling for urinary specific gravity, maternal age, BMI and education. In sensitivity analyses, we evaluated cross-sectional relationships between exposure and hormone levels stratified by study visit using linear regression. RESULTS: An IQR increase in methyl paraben was associated with a 7.70% increase (95% CI 1.50, 13.90) in SHBG. Furthermore, an IQR increase in butyl paraben as associated with an 8.46% decrease (95% CI 16.92, 0.00) in estradiol, as well as a 9.34% decrease (95% CI -18.31,-0.38) in estradiol/progesterone. Conversely, an IQR increase in butyl paraben was associated with a 5.64% increase (95% CI 1.26, 10.02) in FT4. Progesterone was consistently negatively associated with phenols, but none reached statistical significance. After stratification, methyl and propyl paraben were suggestively negatively associated with estradiol at the first time point (16-20 weeks), and suggestively positively associated with estradiol at the second time point (24-28 weeks). CONCLUSIONS: Within this ongoing birth cohort, certain phenols and parabens were associated with altered reproductive and thyroid hormone levels during pregnancy. These changes may contribute to adverse health effects in mothers or their offspring, but additional research is required.