Dose-Response and Risk Assessment of Airborne Hexavalent Chromium and Lung Cancer Mortality

This study evaluates the dose-response relationship for inhalation exposure to hexavalent chromium [Cr(VI)] and lung cancer mortality for workers of a chromate production facility, and provides estimates of the carcinogenic potency. The data were analyzed using relative risk and additive risk dose-response models implemented with both Poisson and Cox regression. Potential confounding by birth cohort and smoking prevalence were also assessed. Lifetime cumulative exposure and highest monthly exposure were the dose metrics evaluated. The estimated lifetime additional risk of lung cancer mortality associated with 45 years of occupational exposure to 1 microg/m3 Cr(VI) (occupational exposure unit risk) was 0.00205 (90%CI: 0.00134, 0.00291) for the relative risk model and 0.00216 (90%CI: 0.00143, 0.00302) for the additive risk model assuming a linear dose response for cumulative exposure with a five-year lag. Extrapolating these findings to a continuous (e.g., environmental) exposure scenario yielded an environmental unit risk of 0.00978 (90%CI: 0.00640, 0.0138) for the relative risk model [e.g., a cancer slope factor of 34 (mg/kg-day)-1] and 0.0125 (90%CI: 0.00833, 0.0175) for the additive risk model. The relative risk model is preferred because it is more consistent with the expected trend for lung cancer risk with age. Based on statistical tests for exposure-related trend, there was no statistically significant increased lung cancer risk below lifetime cumulative occupational exposures of 1.0 mg-yr/m3, and no excess risk for workers whose highest average monthly exposure did not exceed the current Permissible Exposure Limit (52 microg/m3). It is acknowledged that this study had limited power to detect increases at these low exposure levels. These cancer potency estimates are comparable to those developed by U.S. regulatory agencies and should be useful for assessing the potential cancer hazard associated with inhaled Cr(VI).     

Recommended Distributions for Exposure Factors Frequently Used in Health Risk Assessment

Although there has been nearly complete agreement in the scientific community that Monte Carlo techniques represent a significant improvement in the exposure assessment process, virtually all state and federal risk assessments still rely on the traditional point estimate approach. One of the rate-determining steps to a timely implementation of Monte Carlo techniques to regulatory decision making is the development of "standard" data distributions that are considered applicable to any setting. For many exposure variables, there is no need to wait any longer to adopt Monte Carlo techniques into regulatory policy since there is a wealth of data from which a robust distribution can be developed and ample evidence to indicate that the variable is not significantly influenced by site-specific conditions. In this paper, we propose several distributions that can be considered standard and customary for most settings. Age-specific distributions for soil ingestion rates, inhalation rates, body weights, skin surface area, tapwater and fish consumption, residential occupancy and occupational tenure, and soil-on-skin adherence were developed. For each distribution offered in this paper, we discuss the adequacy of the database, derivation of the distribution, and applicability of the distribution to various settings and conditions.     

Sex-dependent associations between daily physical activity and leg exercise blood pressure responses

The authors examined interindividual and sex-specific variation in systolic (SBP) and diastolic (DBP) blood pressure responses to graded leg-extension exercise in healthy older (60-78 yr) women (n = 21) and men (n = 19). Maximal oxygen uptake (VO2max), body composition, physical activity (accelerometry), and vascular function were measured to identify predictors of exercise BP. Neither VO2max nor activity counts were associated with the rise in SBP or DBP during exercise in men. The strongest predictors of these responses in men were age (SBP: r2 = .19, p = .05) and peak exercise leg vasodilation (DBP: r2 = -.21, p < .05). In women, the modest relationship observed between VO2max and exercise BP was abolished after adjusting for central adiposity and activity counts (best predictors, cumulative r2 = .53, p < .05, for both SBP and DBP). These results suggest that determinants of variation in submaximal exercise BP responses among older adults are sex specific, with daily physical activity influencing these responses in women but not men.     

Time to ask and tell: Voices of older gay and bisexual male veterans regarding community services

ABSTRACT

This participatory action study involved lesbian, gay, bisexual, transgender, and queer (LGBTQ) veterans in determining community-based service needs for health and wellness, illuminating perspectives of older LGBTQ veterans regarding community services. This study explored veterans' perceptions of being LGBTQ later in life. The study included data from interviews with gay and bisexual male veterans ages 51 to 87. Participants valued engagement as part of community. Their recommendations for action included communal meals, transportation, housing, and the coming-out process. Community services facilitated community engagement to support health and wellness for LGBTQ older veterans. The authors used participatory action research (PAR), a method of systematic inquiry integrating the perspective of persons living the experience, to organize the study. Further PAR is recommended to implement community services to meeting health and wellness needs of participants.     

Language Maintenance versus Language of Instruction: Spanish Reading Development among Latino and Latina Bilingual Learners

Latino/a children who attend schools in the United States must learn English well for schooling success. However, bilingualism is associated with achievement in both cognition and general literacy, which are core components of academic development. We examined the growth of Spanish reading comprehension among 101 Spanish-English bilingual Latino/a children in second through fifth grade in three urban U.S. districts. The students received literacy instruction in one of three groups: English-only, Spanish-only, and bilingual. Language of instruction had a significant effect on Spanish reading, but students who received Spanish language instruction were losing Spanish literacy skills relative to the norming sample for the reading assessment. English reading and Spanish vocabulary were predictive of Spanish reading, but socioeconomic variables were not. Heritage language loss is described as paradoxical because Spanish and English reading skills are intertwined and biliteracy is associated with better economic opportunities for Latino/as in the U.S. job market.