Publications

OBJECTIVE

We aimed to ascertain risk factors for acute mountain sickness (AMS) in miners exposed to chronic intermittent high altitude conditions.

METHODS

All new hires (2009-2012) for mine employment (4000 m above sea level) were followed up for 12 months after first ascent. Demographics, physiologic data, and cigarette smoking were assessed at preemployment screening. Mine site clinic care for AMS defined incident events. Cox regression analysis estimated risk of AMS associated with smoking and selected covariates.

RESULTS

There were 46 AMS cases among 569 individuals during the first 12 months of employment. Adjusted for age, sex, and altitude of permanent residence, cigarettes smoked per day before hiring were prospectively associated with AMS (hazard ratio [HR], 1.9; 95% CI, 1.1 to 3.2 per 10 cigarettes smoked). This risk was higher in the subset of workers with less demanding physical work (n=336; HR, 3.3; 95% CI, 1.7 to 6.3), whereas among those with more physically demanding jobs (n=233), smoking was not associated with increased risk (HR, 0.6; 95% CI, 0.1 to 2.3).

CONCLUSIONS

In workers newly hired to work at high altitude, smoking increases the likelihood of AMS, but this effect appears to be operative only among those with less physically demanding work duties.

We evaluated whether a 76-locus polygenic risk score (PRS) and Breast Imaging Reporting and Data System (BI-RADS) breast density were independent risk factors within three studies (1643 case patients, 2397 control patients) using logistic regression models. We incorporated the PRS odds ratio (OR) into the Breast Cancer Surveillance Consortium (BCSC) risk-prediction model while accounting for its attributable risk and compared five-year absolute risk predictions between models using area under the curve (AUC) statistics. All statistical tests were two-sided. BI-RADS density and PRS were independent risk factors across all three studies (P interaction = .23). Relative to those with scattered fibroglandular densities and average PRS (2(nd) quartile), women with extreme density and highest quartile PRS had 2.7-fold (95% confidence interval [CI] = 1.74 to 4.12) increased risk, while those with low density and PRS had reduced risk (OR = 0.30, 95% CI = 0.18 to 0.51). PRS added independent information (P < .001) to the BCSC model and improved discriminatory accuracy from AUC = 0.66 to AUC = 0.69. Although the BCSC-PRS model was well calibrated in case-control data, independent cohort data are needed to test calibration in the general population.

Aging is the major determinant of cancer incidence, which, in turn, is likely dictated in large part by processes that influence the progression of early subclinical (occult) cancers. However, there is little understanding of how aging informs changes in aggregate host signaling that favor cancer progression. In this study, we provide direct evidence that aging can serve as an organizing axis to define cancer progression-modulating processes. As a model system to explore this concept, we employed adolescent (68 days), young adult (143 days), middle-aged (551 days), and old (736 days) C57BL/6 mice as syngeneic hosts for engraftment of Lewis lung cancer to identify signaling and functional processes varying with host age. Older hosts exhibited dysregulated angiogenesis, metabolism, and apoptosis, all of which are associated with cancer progression. TGFβ1, a central player in these systemic processes, was downregulated consistently in older hosts. Our findings directly supported the conclusion of a strong host age dependence in determining the host tumor control dynamic. Furthermore, our results offer initial mechanism-based insights into how aging modulates tumor progression in ways that may be actionable for therapy or prevention.

Burnout and professional dissatisfaction are threats to the primary care workforce. We investigated the relationship between panel management capability, team culture, cynicism, and perceived "do-ability" of primary care among primary care providers (PCPs) and staff in primary care practices. We surveyed 326 PCPs and 142 staff members in 10 county-administered, 6 university-run, and 3 Veterans Affairs primary care clinics in a large urban area in 2013. Predictor variables included capability for performing panel management and perception of team culture. Outcome variables included 2 work experience measures--the Maslach Burnout Inventory cynicism scale and a 1-item measure of the "do-ability" of primary care this year compared with last year. Generalized Estimation Equation (GEE) models were used to account for clustering at the clinic level. Greater panel management capability and higher team culture were associated with lower cynicism among PCPs and staff and higher reported "do-ability" of primary care among PCPs. Panel management capability and team culture interacted to predict the 2 work experience outcomes. Among PCPs and staff reporting high team culture, there was little association between panel management capability and the outcomes, which were uniformly positive. However, there was a strong relationship between greater panel management capability and improved work experience outcomes for PCPs and staff reporting low team culture. Team-based processes of care such as panel management may be an important strategy to protect against cynicism and dissatisfaction in primary care, particularly in settings that are still working to improve their team culture.

OBJECTIVES

To explore the relationships of perceived stress and depressive symptoms to sleep problems, testing for mediation by adaptive and maladaptive coping strategies.

METHODS

Alternative high school students (N = 1676) completed self-report surveys. Cross-sectional data were analyzed via Preacher and Hayes' procedures for multiple mediation.

RESULTS

The positive relationship between depressive symptoms and sleep problems was mediated partially by anger coping (positively related to sleep problems). The positive relationship between perceived stress and sleep problems was not mediated by coping strategies.

CONCLUSIONS

Findings provide information on psychological factors that may lead to poor sleep outcomes, and are useful for developing health promotion interventions to impact lifelong health behaviors.