Cosmic Ionizing Radiation: A DNA Damaging Agent That May Underly Excess Cancer in Flight Crews.

In the United States, the Federal Aviation Administration has officially classified flight crews (FC) consisting of commercial pilots, cabin crew, or flight attendants as "radiation workers" since 1994 due to the potential for cosmic ionizing radiation (CIR) exposure at cruising altitudes originating from solar activity and galactic sources. Several epidemiological studies have documented elevated incidence and mortality for several cancers in FC, but it has not yet been possible to establish whether this is attributable to CIR. CIR and its constituents are known to cause a myriad of DNA lesions, which can lead to carcinogenesis unless DNA repair mechanisms remove them. But critical knowledge gaps exist with regard to the dosimetry of CIR, the role of other genotoxic exposures among FC, and whether possible biological mechanisms underlying higher cancer rates observed in FC exist. This review summarizes our understanding of the role of DNA damage and repair responses relevant to exposure to CIR in FC. We aimed to stimulate new research directions and provide information that will be useful for guiding regulatory, public health, and medical decision-making to protect and mitigate the risks for those who travel by air.

Prospective associations between strengths of moral character and health: longitudinal evidence from survey and insurance claims data.

PURPOSE: Excellent character, reflected in adherence to high standards of moral behavior, has been argued to contribute to well-being. The study goes beyond this claim and provides insights into the role of strengths of moral character (SMC) for physical and mental health. METHODS: This study used longitudinal observational data merged with medical insurance claims data collected from 1209 working adults of a large services organization in the US. Self-reported physical and mental health as well as diagnostic information on depression, anxiety, and cardiovascular disease were used as outcomes. The prospective associations between SMC (7 indicators and a composite measure) and physical and mental health outcomes were examined using lagged linear and logistic regression models. A series of sensitivity analyses provided evidence for the robustness of results. RESULTS: The results suggest that persons who live their life according to high moral standards have substantially lower odds of depression (by 21-51%). The results were also indicative of positive associations between SMC and self-reports of mental health (ß = 0.048-0.118) and physical health (ß = 0.048-0.096). Weaker indications were found for a protective role of SMC in mitigating anxiety (OR = 0.797 for the indicator of delayed gratification) and cardiovascular disease (OR = 0.389 for the indicator of use of SMC for helping others). CONCLUSIONS: SMC may be considered relevant for population mental health and physical health. Public health policies promoting SMC are likely to receive positive reception from the general public because character is both malleable and aligned with the nearly universal human desire to become a better person.

Demographic Predictors of Complete Well-Being.

This paper examines demographic differences in flourishing, defined as "complete well-being" and consisting of six domains: emotional health, physical health, purpose, character strengths, social connectedness, and financial security. Results are based on a random, cross-sectional sample of 2363 survey respondents drawn from employees of a large, national, self-insured employer based in the United States. We found that well-being across domains tends to increase with age, although there are some variations. Results are similar across most domains for men and women, although women score higher on character strengths, while men had higher scores on financial security. Racial and ethnic differences were striking. Black employees score higher than the reference group (White employees) on the emotional, purpose, and character strengths domains, but considerably lower on financial security. Hispanics also score lower on financial security (though not as low as Blacks), but higher than Whites on purpose, character strengths, and social connectedness. Asians reported higher well-being than Whites across all domains except purpose.

Current recommendations on the selection of measures for well-being.

Measures of well-being have proliferated over the past decades. Very little guidance has been available as to which measures to use in what contexts. This paper provides a series of recommendations, based on the present state of knowledge and the existing measures available, of what measures might be preferred in which contexts. The recommendations came out of an interdisciplinary workshop on the measurement of well-being. The recommendations are shaped around the number of items that can be included in a survey, and also based on the differing potential contexts and purposes of data collection such as, for example, government surveys, or multi-use cohort studies, or studies specifically about psychological well-being. The recommendations are not intended to be definitive, but to stimulate discussion and refinement, and to provide guidance to those relatively new to the study of well-being.

Cancer prevalence among flight attendants compared to the general population.

BACKGROUND: Flight attendants are an understudied occupational group, despite undergoing a wide range of adverse job-related exposures, including to known carcinogens. In our study, we aimed to characterize the prevalence of cancer diagnoses among U.S. cabin crew relative to the general population. METHODS: In 2014-2015, we surveyed participants of the Harvard Flight Attendant Health Study. We compared the prevalence of their self-reported cancer diagnoses to a contemporaneous cohort in the National Health and Nutrition Examination Survey (NHANES 2013-2014) using age-weighted standardized prevalence ratios (SPRs). We also analyzed associations between job tenure and the prevalence of selected cancers, using logistic regression and adjusting for potential confounders. RESULTS: Compared to NHANES participants with a similar socioeconomic status (n = 2729), flight attendants (n = 5366) had a higher prevalence of every cancer we examined, especially breast cancer, melanoma, and non-melanoma skin cancer among females. SPR for these conditions were 1.51 (95% CI: 1.02, 2.24), 2.27 (95% CI: 1.27, 4.06), and 4.09 (95% CI: 2.70, 6.20), respectively. Job tenure was positively related to non-melanoma skin cancer among females, with borderline associations for melanoma and non-melanoma skin cancers among males. Consistent with previous studies, we observed associations between job tenure and breast cancer among women who had three or more children. CONCLUSIONS: We observed higher rates of specific cancers in flight attendants compared the general population, some of which were related to job tenure. Our results should be interpreted in light of self-reported health information and a cross-sectional study design. Future longitudinal studies should evaluate associations between specific exposures and cancers among cabin crew.

Estimating the health consequences of flight attendant work: comparing flight attendant health to the general population in a cross-sectional study.

BACKGROUND: Flight attendants are an understudied occupational group, despite undergoing a wide and unique range of adverse job-related exposures. In our study, we aimed to characterize the health profile of cabin crew relative to the U.S. general population. METHODS: In 2014-2015, we surveyed participants of the Harvard Flight Attendant Health Study. We compared the prevalence of their health conditions to a contemporaneous cohort in the National Health and Nutrition Examination Survey (NHANES 2013-2014) using age-weighted standardized prevalence ratios (SPRs). We also analyzed associations between job tenure and selected health outcomes, using logistic regression and adjusting for potential confounders. RESULTS: Compared to the NHANES population (n = 2729), flight attendants (n = 5366) had a higher prevalence of female reproductive cancers (SPR = 1.66, 95% CI: 1.18-2.33), cancers at all sites (SPR = 2.15, 95% CI: 1.73-2.67 among females), as well as sleep disorders, fatigue, and depression, with SPRs ranging between 1.98 and 5.57 depending on gender and the specific condition examined. In contrast, we observed a decreased prevalence of cardiac and respiratory outcomes among flight crew relative to NHANES. Health conditions that increased with longer job tenure were sleep disorders, anxiety/depression, alcohol abuse, any cancer, peripheral artery disease, sinusitis, foot surgery, infertility, and several perinatal outcomes. CONCLUSIONS: We observed higher rates of specific adverse health outcomes in U.S. flight attendants compared to the general population, as well as associations between longer tenure and health conditions, which should be interpreted in light of recall bias and a cross-sectional design. Future longitudinal studies should evaluate specific exposure-disease associations among flight crew.

Symptoms related to new flight attendant uniforms.

BACKGROUND: Flight attendants at Alaska Airlines reported health symptoms after the introduction of new uniforms in 2011. The airline replaced the uniforms in 2014 without acknowledging harm. To understand possible uniform-related health effects, we analyzed self-reported health symptoms in crew who participated in the Harvard Flight Attendant Health Study between 2007 and 2015, the period before, during, and after the introduction of new uniforms. METHODS: We calculated a standardized prevalence of respiratory, dermatological and allergic symptoms at baseline, as well as during and after uniform changes in 684 flight attendants with a varying number of surveys completed across each time point. We used Generalized Estimating Equations (GEE) to model the association between symptoms at baseline versus the exposure period after adjusting for age, gender and smoking status and weighting respondents for the likelihood of attrition over the course of the study period. RESULTS: We found the following symptom prevalence (per 100) increased after the introduction of new uniforms: multiple chemical sensitivity (10 vs 5), itchy/irritated skin (25 vs 13), rash/hives (23 vs 13), itchy eyes (24 vs 14), blurred vision (14 vs 6), sinus congestion (28 vs 24), ear pain (15 vs 12), sore throat (9 vs 5), cough (17 vs 7), hoarseness/loss of voice (12 vs 3), and shortness of breath (8 vs 3). The odds of several symptoms significantly increased compared to baseline after adjusting for potential confounders. CONCLUSION: This study found a relationship between health complaints and the introduction of new uniforms in this longitudinal occupational cohort.

Correction to: Airplane pilot mental health and suicidal thoughts: a cross-sectional descriptive study via anonymous web-based survey.

CORRECTION: After publication of the article [1], it has been brought to our attention that the specificity of the tool was reported as 88%. This specificity is for Major Depressive Disorder. The specificity of the tool for all depressive disorders, the outcome of interest in the study, is 93%.

PBDE flame retardants, thyroid disease, and menopausal status in U.S. women.

BACKGROUND: Women have elevated rates of thyroid disease compared to men. Environmental toxicants have been implicated as contributors to this dimorphism, including polybrominated diphenyl ethers (PBDEs), flame retardant chemicals that disrupt thyroid hormone action. PBDEs have also been implicated in the disruption of estrogenic activity, and estrogen levels regulate thyroid hormones. Post-menopausal women may therefore be particularly vulnerable to PBDE induced thyroid effects, given low estrogen reserves. The objective of this study was to test for an association between serum PBDE concentrations and thyroid disease in women from the United States (U.S.), stratified by menopause status. METHODS: Serum PBDE concentrations (BDEs 47, 99, 100 and 153) from the National Health and Examination Survey (NHANES) and reports on thyroid problems were available in the NHANES 2003-2004 cycle. Odds ratios (ORs) were calculated using multivariate logistic regression models accounting for population-weighted survey techniques and controlling for age, body mass index (BMI), education, smoking, alcohol consumption and thyroid medication. Menopause status was obtained by self-reported absence of menstruation in the previous 12 months and declared menopause. RESULTS: Women in the highest quartile of serum concentrations for BDEs 47, 99, and 100 had increased odds of currently having thyroid disease (ORs: 1.5, 1.8, 1.5, respectively) compared to the reference group (1st and 2nd quartiles combined); stronger associations were observed when the analysis was restricted to postmenopausal women (ORs: 2.2, 3.6, 2.0, respectively). CONCLUSION: Exposure to BDEs 47, 99, and 100 is associated with thyroid disease in a national sample of U.S. women, with greater effects observed post-menopause, suggesting that the disruption of thyroid signaling by PBDEs may be enhanced by the altered estrogen levels during menopause.

Airplane pilot mental health and suicidal thoughts: a cross-sectional descriptive study via anonymous web-based survey.

BACKGROUND: The Germanwings Flight 9525 crash has brought the sensitive subject of airline pilot mental health to the forefront in aviation. Globally, 350 million people suffer from depression-a common mental disorder. This study provides further information on this important topic regarding mental health especially among female airline pilots. This is the first study to describe airline pilot mental health-with a focus on depression and suicidal thoughts-outside of the information derived from aircraft accident investigations, regulated health examinations, or identifiable self-reports, which are records protected by civil aviation authorities and airline companies. METHODS: This is a descriptive cross-sectional study via an anonymous web-based survey administered between April and December 2015. Pilots were recruited from unions, airline companies, and airports via convenience sampling. Data analysis included calculating absolute number and prevalence of health characteristics and depression scores. RESULTS: One thousand eight hundred thirty seven (52.7%) of the 3485 surveyed pilots completed the survey, with 1866 (53.5%) completing at least half of the survey. 233 (12.6%) of 1848 airline pilots responding to the Patient Health Questionnaire 9 (PHQ-9), and 193 (13.5%) of 1430 pilots who reported working as an airline pilot in the last seven days at time of survey, met depression threshold-PHQ-9 total score ≥ 10. Seventy-five participants (4.1%) reported having suicidal thoughts within the past two weeks. We found a significant trend in proportions of depression at higher levels of use of sleep-aid medication (trend test z = 6.74, p < 0.001) and among those experiencing sexual harassment (z = 3.18, p = 0.001) or verbal harassment (z = 6.13, p < 0.001). CONCLUSION: Hundreds of pilots currently flying are managing depressive symptoms perhaps without the possibility of treatment due to the fear of negative career impacts. This study found 233 (12.6%) airline pilots meeting depression threshold and 75 (4.1%) pilots reporting having suicidal thoughts. Although results have limited generalizability, there are a significant number of active pilots suffering from depressive symptoms. We recommend airline organizations increase support for preventative mental health treatment. Future research will evaluate additional risk factors of depression such as sleep and circadian rhythm disturbances.

Green space and mortality following ischemic stroke.

BACKGROUND: Residential proximity to green space has been associated with physical and mental health benefits, but whether green space is associated with post-stroke survival has not been studied. METHODS: Patients ≥ 21 years of age admitted to the Beth Israel Deaconess Medical Center (BIDMC) between 1999 and 2008 with acute ischemic stroke were identified. Demographics, presenting symptoms, medical history and imaging results were abstracted from medical records at the time of hospitalization for stroke onset. Addresses were linked to average Normalized Difference Vegetation Index, distance to roadways with more than 10,000 cars/day, and US census block group. Deaths were identified through June 2012 using the Social Security Death Index. RESULTS: There were 929 deaths among 1645 patients with complete data (median follow up: 5 years). In multivariable Cox models adjusted for indicators of medical history, demographic and socioeconomic factors, the hazard ratio for patients living in locations in the highest quartile of green space compared to the lowest quartile was 0.78 (95% Confidence Interval: 0.63-0.97) (p-trend = 0.009). This association remained statistically significant after adjustment for residential proximity to a high traffic road. CONCLUSIONS: Residential proximity to green space is associated with higher survival rates after ischemic stroke in multivariable adjusted models. Further work is necessary to elucidate the underlying mechanisms for this association, and to better understand the exposure-response relationships and susceptibility factors that may contribute to higher mortality in low green space areas.

The self-reported health of U.S. flight attendants compared to the general population.

BACKGROUND: Few studies have examined the broad health effects of occupational exposures in flight attendants apart from disease-specific morbidity and mortality studies. We describe the health status of flight attendants and compare it to the U.S. population. In addition, we explore whether the prevalence of major health conditions in flight attendants is associated with length of exposure to the aircraft environment using job tenure as a proxy. METHODS: We surveyed flight attendants from two domestic U.S. airlines in 2007 and compared the prevalence of their health conditions to contemporaneous cohorts in the National Health and Nutrition Survey (NHANES), 2005-2006 and 2007-2008. We weighted the prevalence of flight attendant conditions to match the age distribution in the NHANES and compared the two populations stratified by gender using the Standardized Prevalence Ratio (SPR). For leading health conditions in flight attendants, we analyzed the association between job tenure and health outcomes in logistic regression models. RESULTS: Compared to the NHANES population (n =5,713), flight attendants (n = 4,011) had about a 3-fold increase in the age-adjusted prevalence of chronic bronchitis despite considerably lower levels of smoking. In addition, the prevalence of cardiac disease in female flight attendants was 3.5 times greater than the general population while their prevalence of hypertension and being overweight was significantly lower. Flight attendants reported 2 to 5.7 times more sleep disorders, depression, and fatigue, than the general population. Female flight attendants reported 34% more reproductive cancers. Health conditions that increased with longer job tenure as a flight attendant were chronic bronchitis, heart disease in females, skin cancer, hearing loss, depression and anxiety, even after adjusting for age, gender, body mass index (BMI), education, and smoking. CONCLUSIONS: This study found higher rates of specific diseases in flight attendants than the general population. Longer tenure appears to explain some of the higher disease prevalence. Conclusions are limited by the cross-sectional design and recall bias. Further study is needed to determine the source of risk and to elucidate specific exposure-disease relationships over time.

Prospective associations of multidimensional well-being with work distraction and job satisfaction: a two-wave study of US employees.

Previous studies on the associations between well-being and work outcomes, such as work distraction and job satisfaction, have largely been cross-sectional and typically focused on only one or two aspects of well-being. Using two waves of data from a sample of employees at a United States health insurance company (n = 1,234), the present brief research report examines prospective associations between six domains of well-being (emotional health, physical health, meaning & purpose, character strengths, social connectedness, and financial security) and two work outcomes (work distraction and job satisfaction). Lagged regression analyses provided some evidence indicating that higher-level well-being in several domains was associated with subsequent reduced work distraction and increased job satisfaction assessed approximately 1 year later, but the magnitude of associations with each outcome did vary by specific domain. Emotional health and social connectedness were most strongly associated with work distraction and job satisfaction. We discuss some implications of the findings, including the importance of applying a multidimensional approach to studying employee well-being and potential opportunities for organizations to support the well-being of their employees.

Exposure to flame retardant chemicals on commercial airplanes.

BACKGROUND: Flame retardant chemicals are used in materials on airplanes to slow the propagation of fire. These chemicals migrate from their source products and can be found in the dust of airplanes, creating the potential for exposure. METHODS: To characterize exposure to flame retardant chemicals in airplane dust, we collected dust samples from locations inside 19 commercial airplanes parked overnight at airport gates. In addition, hand-wipe samples were also collected from 9 flight attendants and 1 passenger who had just taken a cross-country (USA) flight. The samples were analyzed for a suite of flame retardant chemicals. To identify the possible sources for the brominated flame retardants, we used a portable XRF analyzer to quantify bromine concentrations in materials inside the airplanes. RESULTS: A wide range of flame retardant compounds were detected in 100% of the dust samples collected from airplanes, including BDEs 47, 99, 153, 183 and 209, tris(1,3-dichloro-isopropyl)phosphate (TDCPP), hexabromocyclododecane (HBCD) and bis-(2-ethylhexyl)-tetrabromo-phthalate (TBPH). Airplane dust contained elevated concentrations of BDE 209 (GM: 500 ug/g; range: 2,600 ug/g) relative to other indoor environments, such as residential and commercial buildings, and the hands of participants after a cross-country flight contained elevated BDE 209 concentrations relative to the general population. TDCPP, a known carcinogen that was removed from use in children's pajamas in the 1970's although still used today in other consumer products, was detected on 100% of airplanes in concentrations similar to those found in residential and commercial locations. CONCLUSION: This study adds to the limited body of knowledge regarding exposure to flame retardants on commercial aircraft, an environment long hypothesized to be at risk for maximum exposures due to strict flame retardant standards for aircraft materials. Our findings indicate that flame retardants are widely used in many airplane components and all airplane types, as expected. Most flame retardants, including TDCPP, were detected in 100% of dust samples collected from the airplanes. The concentrations of BDE 209 were elevated by orders of magnitude relative to residential and office environments.

Impact of simulated flight conditions on supraventricular and ventricular ectopy.

Though billions of passengers and crew travel by air each year and are exposed to altitude equivalents of 7000-8000 feet, the health impact of cabin oxygenation levels has not been well studied. The hypoxic environment may produce ectopic heartbeats that may increase the risk of acute in-flight cardiac events. We enrolled forty older and at-risk participants under a block-randomized crossover design in a hypobaric chamber study to examine associations between flight oxygenation and both ventricular (VE) and supraventricular ectopy (SVE). We monitored participant VE and SVE every 5 min under both flight and control conditions to investigate the presence and rate of VE and SVE. While the presence of VE did not differ according to condition, the presence of SVE was higher during flight conditions (e.g. OR ratio = 1.77, 95% CI: 1.21, 2.59 for SVE couplets). Rates of VE and SVE were higher during flight conditions (e.g. RR ratio = 1.25, 95% CI: 1.03, 1.52 for VE couplets, RR ratio = 1.76, 95% CI: 1.39, 2.22 for SVE couplets). The observed higher presence and rate of ectopy tended to increase with duration of the flight condition. Further study of susceptible passengers and crew may elucidate the specific associations between intermittent or sustained ectopic heartbeats and hypoxic pathways.

Working from home and subsequent work outcomes: Pre-pandemic evidence.

Frequent working from home (WFH) may stay as a new work norm after the COVID-19 pandemic. Prior observational studies on WFH and work outcomes under non-pandemic circumstances are mostly cross-sectional and often studied employees who worked from home in limited capacity. To provide additional insights that might inform post-pandemic work policies, using longitudinal data collected before the COVID-19 pandemic (June 2018 to July 2019), this study aims to examine the associations between WFH and multiple subsequent work-related outcomes, as well as potential modifiers of these associations, in a sample of employees among whom frequent or even full-time WFH was common (N = 1,123, Meanage = 43.37 years). In linear regression models, each subsequent work outcome (standardized score was used) was regressed on frequencies of WFH, adjusting for baseline values of the outcome variables and other covariates. The results suggested that WFH for 5 days/week versus never WFH was associated with subsequently less work distraction (ß = -0.24, 95% CI = -0.38, -0.11), greater perceived productivity/engagement (ß = 0.23, 95% CI = 0.11, 0.36), and greater job satisfaction (ß = 0.15, 95% CI = 0.02, 0.27), and was associated with subsequent work-family conflicts to a lesser extent (ß = -0.13, 95% CI = -0.26, 0.004). There was also evidence suggesting that long work hours, caregiving responsibilities, and a greater sense of meaningful work can all potentially attenuate the benefits of WFH. As we move towards the post-pandemic era, further research will be needed to understand the impacts of WFH and resources for supporting employees who work from home.

Psychological caring climate at work, mental health, well-being, and work-related outcomes: Evidence from a longitudinal study and health insurance data.

Psychological climate for caring (PCC) is a psychosocial factor associated with individual work outcomes and employee well-being. Evidence on the impacts of various psychological climates at work is based mostly on self-reported health measures and cross-sectional data. We provide longitudinal evidence on the associations of PCC with subsequent diagnosed depression and anxiety, subjective well-being, and self-reported work outcomes. Employees of a US organization with a worker well-being program provided data for the analysis. Longitudinal survey data merged with data from personnel files and health insurance claims records comprising medical information on diagnosis of depression and anxiety were used to regress each outcome on PCC at baseline, adjusting for prior values of all outcomes and other covariates. PCC was found to be associated with lower odds of subsequent diagnosed depression, an increase in overall well-being, mental health, physical health, social connectedness, and financial security, as well as a decrease in distraction at work, an increase in productivity/engagement and possibly in job satisfaction. There was little evidence of associations between PCC and subsequent diagnosed anxiety, character strengths, and work-family conflict. Work policies focused on improving PCC may create a promising pathway to promoting employee health and well-being as well as improving work-related outcomes.