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Background We aimed to determine the relationship between childhood abuse and mental ill-health in firefighters deployed to a devastating fire that engulfed Fort McMurray Methods A stratified sample of 282 firefighters was selected from a cohort of 1234 for assessment by Structured Clinical Interview (SCID) for DSM-5 diagnostic criteria and the Childhood Experience of Care and Abuse questionnaire (CECA-Q). Diagnoses were grouped as post-traumatic stress disorder (PTSD), anxiety disorders, depressive disorders and substance use disorders. Scales extracted from the CECA-Q included parental loss, antipathy, neglect, physical punishment, sexual abuse and support from a same-age confidant. The relation to diagnostic group was examined by multivariable logistic regression Results 192 SCID interviews and 188 CECA-Qs were completed: 124 met DSM-5 criteria for diagnoses including anxiety disorder (56), depressive disorder (54), PTSD (77) and substance use disorder (43). Childhood sexual abuse was reported by 24 firefighters all of whom met DSM-5 diagnostic criteria. Sexual abuse and a childhood confidant differentiated diagnoses in an initial multivariable model of those with psychiatric disorders. Compared to those without a psychiatric diagnosis, father's antipathy was related to anxiety and substance use, physical punishment to PTSD and substance use. A childhood same-age confidant protected against anxiety, depression and PTSD. Fire exposures related only to PTSD. Limitations The comparison group without mental disorders was small. Childhood abuse information was collected retrospectively and may be biased by current state. Conclusions Firefighters’ mental health is a function of both work-role traumas and childhood events. Occupational health provision must address this complexity.

Perfluorinated acids (PFAs) are prominent and widespread contaminants of human blood. In animal studies there is evidence that suggests certain PFAs can disrupt thyroid hormone homeostasis. A commonly reported condition in exposed animals is hypothyroxinemia, whereby serum free thyroxine (fT4) is decreased despite normal thyroid stimulating hormone (TSH) concentrations. We designed an individually matched case-control study to investigate whether exposure to perfluorooctanoate (PFOA), perfluorohexane sulfonate (PFHxS), and perfluorooctane sulfonate (PFOS) was associated with hypothyroxinemia in pregnant women from Edmonton, Alberta, Canada, in 2005-2006, who underwent a "triple screen" blood test at 15-20 weeks gestation as part of ante-natal care. Thyroid hormones, fT4 and TSH, were measured in serum from 974 women, and from these we measured PFAs in the sera of 96 hypothyroxinemic cases (normal TSH, the lowest 10th percentile of fT4) and 175 controls (normal TSH, fT4 between the 50th and 90th percentiles) matched on age and referring physician. Analyses by conditional logistic regression indicated that the concentrations of PFAs in this population were not associated with hypothyroxinemia among pregnant women. The current findings do not support a causal link between PFA exposure and maternal hypothyroxinemia in the studied population.

This study estimated the level and determinants of airborne benzene concentrations in rural western Canada. A multi-site, multi-month unbalanced two-factorial design was used to collect air samples at 1206 fixed sites across a geographic area associated with primary oil and gas industry in Canadian provinces of Alberta, north-eastern British Columbia, and central and southern Saskatchewan from April 2001 to December 2002. Benzene concentrations integrated over 1 calendar month were determined using passive organic vapour monitors. Linear mixed effects models were applied to identify the determinants of airborne benzene concentrations, in particular the proximity to oil and gas facilities. The observed geometric mean of benzene concentrations was 158 ng m−3, with large geometric standard deviation: 4.9. Benzene concentrations showed a seasonal variation with maxima in winter and minima in summer. Emissions from oil well (within 2 km) and compressor influenced monthly airborne benzene concentrations. However, in our study, being located in the general area of a gas plant seems to be the most important in determining monthly airborne benzene concentrations. These findings support the need for investigation of the impact of oil and gas industry on quality of rural air.

Summary Background Results of observational studies suggest that hormone replacement therapy (HRT) could reduce the risk of coronary heart disease (CHD), but those of randomised trials do not indicate a lower risk in women who use oestrogen plus progestagen. The aim of this study was to ascertain whether or not unopposed oestrogen reduces the risk of further cardiac events in postmenopausal women who survive a first myocardial infarction. Methods The study was a randomised, blinded, placebo controlled, secondary prevention trial of postmenopausal women, age 50–69 years (n=1017) who had survived a first myocardial infarction. Individuals were recruited from 35 hospitals in England and Wales. Women received either one tablet of oestradiol valerate (2 mg; n=513) or placebo (n=504), daily for 2 years. Primary outcomes were reinfarction or cardiac death, and all-cause mortality. Analyses were by intention-to-treat. Secondary outcomes were uterine bleeding, endometrial cancer, stroke or other embolic events, and fractures. Findings Frequency of reinfarction or cardiac death did not differ between treatment groups at 24 months (rate ratio 0·99, 95% CI 0·70–1·41, p=0·97). Similarly, the reduction in all-cause mortality between those who took oestrogen and those on placebo was not significant (0·79, 0·50–1·27, p=0·34). The relative risk of any death (0·56, 0·23–1·33) and cardiac death (0·33, 0·11–1·01) was lowest at 3 months post-recruitment. Interpretation Oestradiol valerate does not reduce the overall risk of further cardiac events in postmenopausal women who have survived a myocardial infarction.

Previous studies have suggested that GST genotypes may play a role in determining susceptibility to lung cancer, though the data are often conflicting. In this study we investigated GSTM1, GSTT1 and GSTP1 status in relation to lung cancer risk in patients attending a Manchester bronchoscopy clinic. Cases were all patients (n=94) currently with, or with a history of, tumours of the lung, trachea or bronchus. The control group were all other patients (n=165) who were free of benign and malignant tumours both at the time of, or prior to, diagnosis. All patients were interviewed for information on lifestyle risk factors, and DNA extracted from bronchial lavage and blood samples was used for genotyping. GSTM1 null genotype was associated with decreased lung cancer risk (odds ratio (OR) 0.50, 95% confidence interval (CI) 0.29-0.87), particularly among men (OR 0.43, 95% CI 0.21-0.87) and those above the median age (OR 0.33, 95% CI 0.15-0.70). No difference in GSTT1 and GSTP1 genotype distribution was seen between cases and controls. The GSTM1 null genotype was associated with a decreased risk of squamous cell carcinoma: the OR, adjusted for age, sex and pack years was 0.32 (95% CI 0.12-0.82). As previous studies have reported that the GSTM1 null genotype is associated with an increased lung cancer risk, further work is required to determine whether the observed association is true, or whether it arises from bias or confounding factors.

Human serum paraoxonase (PON1) hydrolyses diazinonoxon, the active metabolite of diazinon, which is an organophosphate used in sheep dip. In a case-referent study, 175 farmers with ill health that they attributed to sheep dip nominated 234 referent farmers who also dipped sheep and whom they believed to be in good health. We calculated odds ratios for polymorphisms in PON1 at positions 192 and 55, and for PON1 activity with diazinonoxon as substrate. Cases were more likely than referents to have at least one R allele at position 192 (glutamine to arginine aminoacid substitution; odds ratio 1.93, 95% CI 1.24-3.01), both alleles of type LL (1.70, 1.07-2.68) at position 55, and to have diazoxonase activity below normal median (1.77, 1.18-2.67). Our results support the hypothesis that organophosphates contribute to the reported ill health of people who dip sheep.

Discussion de l'importance d'un essai clinique randonise en chirurgie de la reproduction et des avantages d'une analyse de table de vie pour evaluer le succes d'un procede donne