A Mixed-Methods Assessment of Residential Housing Tenants' Concerns about Property Habitability and the Implementation of Habitability Laws in Southern Nevada.

Housing is a key health determinant. Habitability laws set minimum standards for adequate housing. However, accessing them to ensure adequate housing may be a challenge for many tenants. This paper explores the need for rental housing policy that would better support adequate and safe housing, particularly for low-income renters. A mixed-methods approach assessed residential tenant habitability concerns in Clark County, Nevada, through calls relayed to the Clark County Landlord-Tenant Hotline (CCLTH). Of the 2865 calls, 74.3% were from ZIP codes that were 80% of the median income and below. There was a significant relationship between the ZIP code-level income and the reporting of at least one essential habitability concern. Of the 266 participants that responded to a follow-up call, 34.6% reported that their complaint was resolved and there was no association between resolution and income. Qualitative data analysis from phone interviews revealed two central themes: (1) resources to navigate landlord-tenant laws are limiting and (2) housing policies need to be strengthened to help tenants and keep people housed. Understanding tenant concerns regarding substandard housing and related inequities can help inform rental housing policy and its implementation to promote healthy homes and improve health outcomes for communities burdened by poor rental housing conditions.

The U.S. Department of Housing and Urban Development BUILD Las Vegas 2019 Event: Lessons Learned in Public Health Community Engagement.

The U.S. Department of Housing and Urban Development (HUD) BUILD Las Vegas 2019 event brought together Las Vegas Lead Hazard Control and Healthy Homes Program (LVLHCHHP) staff, community leaders, and volunteers from multiple organizations for a neighborhood clean-up and community resource fair in a low-income, historic west Las Vegas neighborhood. In preparation for the event, LVLHCHHP staff encountered a lack of published guidance regarding past BUILD events or planning of community-based public health events. To address this gap in the literature, this brief report offers lessons learned from the process of planning and evaluating the HUD BUILD Las Vegas 2019 event. These include taking early planning measures, centering the focus on community needs, and forming strategic partnerships, which can provide a valuable foundation for future events that want to integrate community engagement with public health.

Partial correlation coefficient for a study with repeated measurements.

Repeated data are increasingly collected in studies to investigate the trajectory of change in measurements over time. Determining a link between one repeated measurement with another that is considered as the biomarker for disease progression, may provide a new target for drug development. When a third variable is associated with one of the two measurements, partial correlation after eliminating the effect of that variable is able to provide reliable estimate for association as compared to the existing raw correlation for repeated data. We propose using linear regression models to compute residuals by modeling a relationship between each measurement and a third variable. The computed residuals are then used in a linear mixed model (implemented by SAS Proc Mixed) to compute partial correlation for repeated data. Alternatively, the partial correlation may be computed as the average of partial correlations at each visit. We provide two real examples to illustrate the application of the proposed partial correlation, and conduct extensive numerical studies to compare the proposed partial correlation coefficients.

Where I live: A qualitative analysis of renters living in poor housing.

This article examines the lived experiences of 17 renters residing in Clark County, Nevada. Using a phenomenological study design, we used semistructured interviews to investigate how renters navigate living in substandard housing. The qualitative analysis revealed four main themes: (a) housing serves as a mediator with one's sense of well-being and good health, (b) housing insecurity and displacement occur through various pathways, (c) housing quality can lead to a sense of powerlessness over where one lives, and (d) social networks are key in low-opportunity neighborhoods. The findings support numerous studies that connect housing quality and insecurity to health and well-being, but the findings also highlight the mediating factors to limited housing choices such as the landlord and tenant relationship. Studies of this nature are essential in identifying the various pathways by which housing inequities and disparities can occur, particularly among low-income communities.

Evaluation of the Blood Lead Screening Component of the Southern Nevada Childhood Lead Poisoning Prevention Program.

CONTEXT: While public health programs and policies have worked to reduce lead exposure, lead poisoning remains a major preventable public health concern in the United States. OBJECTIVE: In Clark County, Nevada, blood lead level (BLL) screening has historically been sparse. Thus, the purpose of this study was to evaluate the impact of the Southern Nevada Childhood Lead Poisoning & Prevention Program (CLPPP) in increasing screening efforts and identifying children with elevated blood lead levels (EBLLs). MAIN OUTCOMES: The proportion of children screened after the implementation of the CLPPP and the number of children identified with detectable BLLs. RESULTS: A total of 43 028 BLL results for children younger than 6 years were assessed from 2006 to 2011. More than 19% of children tested during the project period had a detectable BLL. The number of BLL tests for children younger than 6 years increased from 4180 in 2005-2006 to 9304 in just the second year of CLPPP implementation. Once the initial implementation grant was over and additional funding was unavailable, the BLL screening once again declined to 5541 in 2016-2017. CONCLUSION: Evaluation of CLPPP activities suggests that outreach and education efforts, funded by the Centers for Disease Control and Prevention, played a significant role in increasing blood lead screening in Southern Nevada. However, despite these efforts, less than 5% of all children younger than 6 years were screened, which has declined further after the end of federal support.

Fisher's exact approach for post hoc analysis of a chi-squared test.

This research is motivated by one of our survey studies to assess the potential influence of introducing zebra mussels to the Lake Mead National Recreation Area, Nevada. One research question in this study is to investigate the association between the boating activity type and the awareness of zebra mussels. A chi-squared test is often used for testing independence between two factors with nominal levels. When the null hypothesis of independence between two factors is rejected, we are often left wondering where does the significance come from. Cell residuals, including standardized residuals and adjusted residuals, are traditionally used in testing for cell significance, which is often known as a post hoc test after a statistically significant chi-squared test. In practice, the limiting distributions of these residuals are utilized for statistical inference. However, they may lead to different conclusions based on the calculated p-values, and their p-values could be over- o6r under-estimated due to the unsatisfactory performance of asymptotic approaches with regards to type I error control. In this article, we propose new exact p-values by using Fisher's approach based on three commonly used test statistics to order the sample space. We theoretically prove that the proposed new exact p-values based on these test statistics are the same. Based on our extensive simulation studies, we show that the existing asymptotic approach based on adjusted residual is often more likely to reject the null hypothesis as compared to the exact approach due to the inflated family-wise error rates as observed. We would recommend the proposed exact p-value for use in practice as a valuable post hoc analysis technique for chi-squared analysis.

Health Hazards in the Home: An Assessment of a Southern Nevada Community.

As a sub-grantee of a Department of Housing and Urban Development (HUD) Lead Hazard Control and Healthy Homes Program, the University of Nevada, Las Vegas' Department of Environmental and Occupational Health performed lead and Healthy Homes investigations and collected data regarding conditions in the home environment in Henderson, Nevada. The purpose of this research is to characterize housing conditions in southern Nevada, compare data to census data, and to highlight the health outcomes associated with adverse housing conditions. Visual home assessments were conducted in 106 homes in southern Nevada, and specific hazards were characterized using the Healthy Homes Rating System. The results were then compared, when possible, to American Housing Survey (AHS) data for the Las Vegas metropolitan area. Lead, domestic hygiene, carbon monoxide, damp and mold, excess cold and heat, and structural collapse were the most frequently identified hazards, found in at least 101 (90%) of participant households. Median household income of program participants was half (50%) that of the surrounding zip code, which was expected, as classification as "low-income" by HUD standards was a requirement for participation. Our data indicated that the AHS data may not be representative of very low income housing in southern Nevada and may underreport actual conditions. In-home inspections performed by trained personnel provide a more accurate picture of conditions than the self-report method used by the AHS. In addition, we recommend the development of a standardized Healthy Homes visual assessment tool to allow for the comparison of housing conditions between communities.

Determining Childhood Blood Lead Level Screening Compliance Among Physicians.

Childhood Lead Poisoning Prevention Programs throughout the U.S. have addressed childhood lead poisoning by implementing primary and secondary prevention efforts. While many programs have helped increase screening rates, in some states children under the age of six still have not been tested for lead. This study aims to identify the barriers to childhood blood lead testing and develop a strategy to increase the number of children tested. Clark County physicians who work with children six and under were surveyed about blood lead level (BLL) testing practices, particularly, adherence to Centers for Disease Control and Prevention (CDC) guidelines, and parental compliance with orders to have their children tested to determine their blood lead levels. In addition, select in-person interviews were conducted with physicians who reported high parental compliance to identify best practices and barriers. Of the 77 physicians that provided data, 48% indicated they did not follow CDC guideline compared to 52% who follow guidelines. 18 of the 30 (or 60%) physicians reported more than 80% of parents complied with doctor recommended BLL testing. Twelve physicians identified cost, lack of insurance, and absence of symptomology as persistent barriers to lead screening. This study identified barriers to childhood lead screening including inadequate parental adherence to physician-ordered screenings and physician non-compliance with screening recommendations are two primary contributors. Addressing these issues could increase screening in children and reduce the risk of lead poisoning.

Maternal methylmercury from a wild-caught walleye diet induces developmental abnormalities in zebrafish.

Maternal methylmercury (MeHg) exposure from a contaminated diet causes adverse effects in offspring, but the underlying mechanism(s) remains unclear. In the present study, we investigated the effects of maternal dietary MeHg-exposure on the offspring, using the zebrafish (Danio rerio) as a model system. Female zebrafish were exposed to MeHg (0.88-3.10ppm) by consuming a diet made from wild-caught walleye originally intended for human consumption. While dietary MeHg exposure did not significantly influence fecundity, offspring showed increases in morphologic alterations and mortality, neurobehavioral dysfunction, and dysregulation of global gene expression. Gene expression analysis suggested that MeHg might affect neuronal and muscular development via dysregulation of genes related to transcriptional regulation (such as supt5h) and cell cycle (such as ccnb1). Results from this study provide evidence that food intended for human consumption, with relatively modest levels of MeHg, may induce adverse effects in offspring.

Human placenta processed for encapsulation contains modest concentrations of 14 trace minerals and elements.

Maternal placentophagy has recently emerged as a rare but increasingly popular practice among women in industrialized countries who often ingest the placenta as a processed, encapsulated supplement, seeking its many purported postpartum health benefits. Little scientific research, however, has evaluated these claims, and concentrations of trace micronutrients/elements in encapsulated placenta have never been examined. Because the placenta retains beneficial micronutrients and potentially harmful toxic elements at parturition, we hypothesized that dehydrated placenta would contain detectable concentrations of these elements. To address this hypothesis, we analyzed 28 placenta samples processed for encapsulation to evaluate the concentration of 14 trace minerals/elements using inductively coupled plasma mass spectrometry. Analysis revealed detectable concentrations of arsenic, cadmium, cobalt, copper, iron, lead, manganese, mercury, molybdenum, rubidium, selenium, strontium, uranium, and zinc. Based on one recommended daily intake of placenta capsules (3300 mg/d), a daily dose of placenta supplements contains approximately 0.018 ± 0.004 mg copper, 2.19 ± 0.533 mg iron, 0.005 ± 0.000 mg selenium, and 0.180 ± 0.018 mg zinc. Based on the recommended dietary allowance (RDA) for lactating women, the recommended daily intake of placenta capsules would provide, on average, 24% RDA for iron, 7.1% RDA for selenium, 1.5% RDA for zinc, and 1.4% RDA for copper. The mean concentrations of potentially harmful elements (arsenic, cadmium, lead, mercury, uranium) were well below established toxicity thresholds. These results indicate that the recommended daily intake of encapsulated placenta may provide only a modest source of some trace micronutrients and a minimal source of toxic elements.

Optimal adaptive two-stage designs for early phase II clinical trials.

Simon's optimal two-stage design has been widely used in early phase clinical trials for Oncology and AIDS studies with binary endpoints. With this approach, the second-stage sample size is fixed when the trial passes the first stage with sufficient activity. Adaptive designs, such as those due to Banerjee and Tsiatis (2006) and Englert and Kieser (2013), are flexible in the sense that the second-stage sample size depends on the response from the first stage, and these designs are often seen to reduce the expected sample size under the null hypothesis as compared with Simon's approach. An unappealing trait of the existing designs is that they are not associated with a second-stage sample size, which is a non-increasing function of the first-stage response rate. In this paper, an efficient intelligent process, the branch-and-bound algorithm, is used in extensively searching for the optimal adaptive design with the smallest expected sample size under the null, while the type I and II error rates are maintained and the aforementioned monotonicity characteristic is respected. The proposed optimal design is observed to have smaller expected sample sizes compared to Simon's optimal design, and the maximum total sample size of the proposed adaptive design is very close to that from Simon's method. The proposed optimal adaptive two-stage design is recommended for use in practice to improve the flexibility and efficiency of early phase therapeutic development.

Implications of the new Centers for Disease Control and Prevention blood lead reference value.

The Centers for Disease Control and Prevention recently established a new reference value (≥ 5 µg/dL) as the standard for identifying children with elevated blood lead levels (EBLs). At present, 535,000 US children aged 1 to 5 years (2.6%) are estimated to have EBLs according to the new standard, versus 0.8% according to the previous standard (≥ 10 µg/dL). Because EBLs signify the threshold for public health intervention, this new definition increases demands on lead poisoning prevention efforts. Primary prevention has been proven to reduce lead poisoning cases and is also cost effective; however, federal budget cuts threaten the existence of such programs. Protection for the highest-risk children necessitates a reinstatement of federal funding to previous levels.

Analysis of mercury in rock varnish samples in areas impacted by coal-fired power plants.

Rock varnish is a manganese-iron rich coating that forms on rocks, most often in arid climates. To assess its utility as an environmental monitor of mercury contamination, cold vapor atomic absorption spectrometry (CVAAS) was used for analysis. Samples were collected in the fallout patterns of two coal-fired power plants in southern Nevada: the defunct Mohave Power Plant (MPP) and the operating Reid Gardner Power Plant (RGPP). The resultant Hg concentrations in rock varnishes were plotted as a function of the distance from each power plant. The highest concentrations of Hg occurred at locations that suggest the power plants are the main source of pollutants. In addition, past tracer plume studies carried out at MPP show that the highest tracer concentrations coincide with the highest rock varnish Hg concentrations. However, additional samples are required to further demonstrate that power plants are indeed the sources of mercury in varnishes.

An evaluation of lead concentrations in imported hot sauces.

In the last decade, the U.S. Food and Drug Administration (FDA) has issued several warnings and recalls for food products that exceed FDA standards for lead. Products containing chili peppers and salt were often suspected as sources of lead contamination, and included items such as candy that are routinely investigated. However, products such as hot sauces that contain similar ingredients have not been the focus of evaluations. This study quantified lead concentrations in imported hot sauces, evaluated product compliance to existing United States standards, and calculated potential dietary lead exposure for children using the Integrated Exposure Uptake Biokinetic Model. Finally, recommendations for reducing the risk of lead exposure from hot sauces are provided. Twenty-five (25) bottles of imported hot sauces manufactured in Mexico and South America were purchased in Clark County, Nevada. All hot sauces were analyzed for lead concentrations, pH, and leaded packaging. Hot sauces were analyzed by inductively coupled plasma mass spectrometry and packaging was analyzed using x-ray fluorescence technology. Four brands of hot sauces (16%) exceeded 0.1 ppm lead, the current FDA action level for lead in candy. Hot sauces with lead concentrations >0.1 ppm lead contained salt and were manufactured in Mexico. Subsequent analysis of additional lots of hot sauces exceeding 0.1 ppm lead revealed inconsistent lead concentrations between and within manufacturer lots. The lead concentrations of the plastic hot sauce lids ranged from below the limit of detection to 2,028 ppm lead. There was no association between lead concentrations in hot sauces and pepper type. These results indicate the need for more rigorous screening protocols for products imported from Mexico, the establishment of an applicable standard for hot sauce, and resources to allow for the enforcement of existing food safety policies. The data reported herein represent the first known investigation of lead concentrations in hot sauces.

Effectiveness of EarthTec(®) for killing invasive quagga mussels (Dreissena rostriformis bugensis) and preventing their colonization in the Western United States.

Quagga mussels (Dreissena rostriformis bugensis) have created economic and ecological impacts in the western United States since their discovery in 2007. This study focuses on chemical control for preventing the spread of these mussels. The effectiveness of EarthTec(®) in killing quagga mussels (adults, juveniles, and veligers) in Lake Mead, Nevada-Arizona, was evaluated over time across six concentrations: 0, 1, 5, 10, 17, and 83 ppm. One hundred percent mortality of adult and juvenile mussels was achieved after 96 h with 17 ppm and 5 ppm (respectively), and 100% veliger mortality occurred within 30 min at 3 ppm. From December 2010 to February 2011, the effectiveness of EarthTec(®) in preventing veliger colonization was also evaluated and the results showed that 2.8 ppm was effective in preventing veliger colonization on fiberglass panels. This study indicates that EarthTec(®) has the potential to be an effective control agent against the invasive quagga mussel, and more specifically, in preventing the colonization of veligers.

Efforts to identify at-risk children for blood lead screening in pediatric clinics--Clark County, Nevada.

BACKGROUND: Childhood lead poisoning continues to be a public health problem; however, lead screening rates remain low in many areas. Our objective is to increase screening in pediatric clinics, while testing a questionnaire for its predictability of elevated blood lead levels (BLLs). METHODS: Participants were approached at pediatric clinics in Las Vegas, Nevada. A brief questionnaire assessed the child's potential exposure to lead and a blood sample was collected from each child. RESULTS: Of 564 children tested, 35 had detectable BLLs. Two questions from the questionnaire demonstrated significant differences in proportions (Fisher's exact test: P < .05) of affirmative/negative responses, for the 35 participants with detectable BLLs. CONCLUSION: The questionnaire failed to identify reliable associations between detectable BLLs and affirmative responses, limiting its use as an in-office tool. More research is recommended to identify and alleviate barriers to childhood lead screening in the clinical setting and to develop more applicable risk assessment tools.

Mercury in tadpoles collected from remote alpine sites in the southern Sierra Nevada mountains, California, USA.

Amphibians in alpine wetlands of the Sierra Nevada mountains comprise key components of an aquatic-terrestrial food chain, and mercury contamination is a concern because concentrations in fish from this region exceed thresholds of risk to piscivorous wildlife. Total mercury concentrations were measured in whole tadpoles of the Sierra chorus frog, Pseudacris sierra, two times at 27 sites from high elevations (2786-3375 m) in the southern Sierra Nevada. Median mercury concentrations were 14 ng/g wet weight (154 ng/g dry weight), which were generally low in comparison to tadpoles of 15 other species/location combinations from studies that represented both highly contaminated and minimally contaminated sites. Mercury concentrations in P. sierra were below concentrations known to be harmful in premetamorphic tadpoles of another species and below threshold concentrations for risk to predaceous wildlife. Concentrations in tadpoles were also lower than those observed in predaceous fish in the study region presumably because tadpoles in the present study were much younger (1-2 months) than fish in the other study (3-10 years), and tadpoles represent a lower trophic level than these fish. Mercury concentrations were not related to distance from the adjacent San Joaquin Valley, a source of agricultural and industrial pollutants.

High-risk human papillomavirus (HPV) screening and detection in healthy patient saliva samples: a pilot study.

BACKGROUND: The human papillomaviruses (HPV) are a large family of non-enveloped DNA viruses, mainly associated with cervical cancers. Recent epidemiologic evidence has suggested that HPV may be an independent risk factor for oropharyngeal cancers. Evidence now suggests HPV may modulate the malignancy process in some tobacco- and alcohol-induced oropharynx tumors, but might also be the primary oncogenic factor for inducing carcinogenesis among some non-smokers. More evidence, however, is needed regarding oral HPV prevalence among healthy adults to estimate risk. The goal of this study was to perform an HPV screening of normal healthy adults to assess oral HPV prevalence. METHODS: Healthy adult patients at a US dental school were selected to participate in this pilot study. DNA was isolated from saliva samples and screened for high-risk HPV strains HPV16 and HPV18 and further processed using qPCR for quantification and to confirm analytical sensitivity and specificity. RESULTS: Chi-square analysis revealed the patient sample was representative of the general clinic population with respect to gender, race and age (p < 0.05). Four patient samples were found to harbor HPV16 DNA, representing 2.6% of the total (n = 151). Three of the four HPV16-positive samples were from patients under 65 years of age and all four were female and Hispanic (non-White). No samples tested positive for HPV18. CONCLUSIONS: The successful recruitment and screening of healthy adult patients revealed HPV16, but not HPV18, was present in a small subset. These results provide new information about oral HPV status, which may help to contextualize results from other studies that demonstrate oral cancer rates have risen in the US among both females and minorities and in some geographic areas that are not solely explained by rates of tobacco and alcohol use. The results of this study may be of significant value to further our understanding of oral health and disease risk, as well as to help design future studies exploring the role of other factors that influence oral HPV exposure, as well as the short- and long-term consequences of oral HPV infection.

Susceptibility of quagga mussels (Dreissena rostriformis bugensis) to hot-water sprays as a means of watercraft decontamination.

The recent spread of dreissenid mussels to various bodies of water in the western US has sparked interest by many state and federal agencies to develop protocols to stop further expansion. Quagga mussels (Dreissena rostriformis bugensis) are of particular importance as they are currently the most widespread dreissenid species in the region. This project examined the susceptibility of quagga mussels to hot-water sprays at different temperatures and durations of spray contact at Lake Mead (Nevada-Arizona, USA). Emersed adult quagga mussels were exposed to hot-water sprays at 20, 40, 50, 54, 60, 70, and 80°C for 1, 2, 5, 10, 20, 40, 80, and 160 s. Sprays at ≥60°C for 5 s were shown to be 100% lethal. Sprays of 54°C for 10 s, 50°C for 20 s, and 40°C for 40 s also resulted in 100% mortality. A spray temperature of 60°C for 5 s is recommended for mitigating fouling by quagga mussels.

Mercury concentrations in largemouth bass (Micropterus salmoides) collected from Ash Meadows National Wildlife Refuge, Nye County, Nevada.

Mercury is a known neurotoxin and contaminant of concern worldwide. Mercury may occur at elevated concentrations adjacent to industrial sources, such as coal-fired power plants, or in remote environments and newly filled water bodies. Mercury tissue concentrations were determined for a sample of largemouth bass (Micropterus salmoides) from Crystal Reservoir, Ash Meadows National Wildlife Refuge, Nye County, Nevada. This investigation was triggered by (1) the presence of several conditions in soil and water that facilitate mercury bioaccumulation, (2) previous investigations that detected mercury in source springs, and (3) the presence of game fish and endangered pupfish within the reservoir. Mercury concentrations were significantly correlated with both fish mass and condition, but were lower than national human health and safety standards. It is possible that high pH and salinity inhibited methylation and subsequent bioaccumulation; however, additional studies are needed to determine causation of the low concentration in fish tissue compared with ambient conditions.