Prospective validation of a clinical prediction score for survival in patients with spinal metastases: the New England Spinal Metastasis Score.

BACKGROUND CONTEXT: The New England Spinal Metastasis Score (NESMS) was proposed as an intuitive and accessible prognostic tool for predicting survival in patients with spinal metastases. We designed an appropriately powered, prospective, longitudinal investigation to validate the NESMS. PURPOSE: To prospectively validate the NESMS. STUDY DESIGN: Prospective longitudinal observational cohort study. PATIENT SAMPLE: Patients, aged 18 and older, presenting for treatment with spinal metastatic disease. OUTCOME MEASURES: One-year mortality (primary); 6-month mortality and mortality at any time point following enrollment (secondary). METHODS: The date of enrollment was set as time zero for all patients. The NESMS was assigned based on data collected at the time of enrollment. Patients were prospectively followed to one of two predetermined end-points: death, or survival at 365 days following enrollment. Survival was visually assessed with Kaplan-Meier curves and then analyzed using multivariable logistic regression, followed by Bayesian regression to assess for robustness of point estimates and 95% confidence intervals (CI). RESULTS: This study included 180 patients enrolled between 2017 and 2018. Mortality within 1-year occurred in 56% of the cohort. Using NESMS 3 as the referent, those with a score of 2 had significantly greater odds of mortality (odds ratio 7.04; 95% CI 2.47, 20.08), as did those with a score of 1 (odds ratio 31.30; 95% CI 8.82, 111.04). A NESMS score of 0 was associated with perfect prediction, as 100% of individuals with this score were deceased at 1-year. Similar determinations were encountered for mortality at 6-months and overall. CONCLUSIONS: This study validates the NESMS and demonstrates its utility in prognosticating survival for patients with spinal metastatic disease, irrespective of selected treatment strategy. This is the first study to prospectively validate a prognostic utility for patients with spinal metastases. The NESMS can be directly applied to patient care, hospital-based practice and health-care policy.

Clinician Experiences in Treatment Decision-Making for Patients with Spinal Metastases: A Qualitative Study.

BACKGROUND: Effective management of metastatic disease requires multidisciplinary input and entails high risk of disease-related and treatment-related morbidity and mortality. The factors that influence clinician decision-making around spinal metastases are not well understood. We conducted a qualitative study that included a multidisciplinary cohort of physicians to evaluate the decision-making process for treatment of spinal metastases from the clinician's perspective. METHODS: We recruited operative and nonoperative clinicians, including orthopaedic spine surgeons, neurosurgeons, radiation oncologists, and physiatrists, from across North America to participate in either a focus group or a semistructured interview. All interviews were audiorecorded and transcribed verbatim. We then performed a thematic analysis using all of the available transcript data. Investigators sequentially coded transcripts and identified recurring themes that encompass overarching patterns in the data and directly bear on the guiding study question. This was followed by the development of a thematic map that visually portrays the themes, the subthemes, and their interrelatedness, as well as their influence on treatment decision-making. RESULTS: The thematic analysis revealed that numerous factors influence provider-based decision-making for patients with spinal metastases, including clinical elements of the disease process, treatment guidelines, patient preferences, and the dynamics of the multidisciplinary care team. The most prominent feature that resonated across all of the interviews was the importance of multidisciplinary care and the necessity of cohesion among a team of diverse health-care providers. Respondents emphasized aspects of care-team dynamics, including effective communication and intimate knowledge of team-member preferences, as necessary for the development of appropriate treatment strategies. Participants maintained that the primary role in decision-making should remain with the patient. CONCLUSIONS: Numerous factors influence provider-based decision-making for patients with spinal metastases, including multidisciplinary team dynamics, business pressure, and clinician experience. Participants maintained a focus on shared decision-making with patients, which contrasts with patient preferences to defer decisions to the physician, as described in prior work. CLINICAL RELEVANCE: The results of this thematic analysis document the numerous factors that influence provider-based decision-making for patients with spinal metastases. Our results indicate that provider decisions regarding treatment are influenced by a combination of clinical characteristics, perceptions of patient quality of life, and the patient's preferences for care.

Laboratory markers as useful prognostic measures for survival in patients with spinal metastases.

BACKGROUND CONTEXT: Laboratory values have been found to be useful predictive measures of survival following surgery. The utility of laboratory values for prognosticating outcomes among patients with spinal metastases has not been studied. PURPOSE: To determine the prognostic capacity of laboratory values at presentation including white blood cell count, serum albumin and platelet-lymphocyte ratio (PLR) in patients with spinal metastases. STUDY DESIGN: Retrospective review of records from two tertiary care centers (2005-2017). PATIENT SAMPLE: Patients, aged 40 to 80, who received operative or nonoperative management for spinal metastases. OUTCOME MEASURES: Survival, complications, or hospital readmissions within 90 days of treatment and a composite measure for treatment failure accounting for changes in ambulatory function and mortality at 6 months following presentation. METHODS: Multivariable Cox proportional hazard regression analysis was used to analyze the relationship between laboratory values and length of survival, adjusting for confounders. Multivariable logistic regression was used in analyses related to 6-month and 1-year mortality, complications, readmissions, and treatment failure. A scoring rubric was developed based on the performance of laboratory values in the multivariable tests. Internal validation was performed using a bootstrap simulation that consisted of sampling with replacement and 1,000 replications. RESULTS: We included 1,216 patients. Thirty-seven percent of patients received a surgical intervention and 63% were treated nonoperatively. Median survival for the cohort as a whole was 255 days (interquartile range 93-642 days). The PLR (hazard ratio [HR] 1.53; 95% confidence interval [CI] 1.29, 1.80; p<.001) and albumin (HR 0.54; 95% CI 0.45, 0.64; p<.001) were significantly associated with survival, whereas WBC count (HR 1.08; 95% CI 0.86, 1.36; p=.50) was not associated with this outcome. Similar findings were encountered for 6-month and 1-year mortality as well as the composite measure for treatment failure. The PLR and albumin performed well in our scoring rubric and findings were preserved in the bootstrapping validation. CONCLUSIONS: Individuals with low serum albumin and elevated PLR should be advised regarding the impact of these laboratory markers on outcomes including survival, irrespective of treatments received. An effort should also be made to optimize nutrition and PLR, if practicable, before treatment to minimize the potential for development of adverse events.

Design of the prospective observational study of spinal metastasis treatment (POST).

BACKGROUND CONTEXT: There are several prognostic scores available that intend to inform decision-making for patients with spinal metastases. Many of these have not been found to reliably predict survival across the continuum of care. Recently, our group developed the New England Spinal Metastasis Score (NESMS). While the NESMS demonstrated many of the necessary attributes of a useful prediction tool, it has yet to be validated prospectively. PURPOSE: To describe the prospective observational study of spinal metastasis treatment (POST). This investigation examined the performance of the NESMS, compared its predictive capacity with other scoring systems and determined its ability to identify patients who benefit the most from surgery. STUDY DESIGN: Prospective observational study at two medical centers. PATIENT SAMPLE: Patients age 18 and older with spinal metastases involving the spine. OUTCOME MEASURES: Survival, post-treatment morbidity and health-related quality of life outcomes. METHODS: The POST study assessed patients at baseline and at 1-month, 3-month, 6-month, and 12-month time-points. During the baseline assessment patient demographics, past medical history and assessment of co-morbidities, surgical history, primary tumor histology, and ambulatory status were recorded along with the designated treatment strategy (eg, operative or nonoperative). The NESMS and other predictive scores for each patient were calculated based on baseline data. Study-specific surveys administered at all time-points consisted of the EuroQuol 5-Dimension and Short-Form (SF)-12, Visual Analog Scale (VAS) for pain, and PROMIS assessment of global health. RESULTS: Two hundred patients were enrolled in POST from 2017 to 2019. Patients were followed to one of the two predetermined study end-points (ie, mortality, or completion of the 12-month follow-up). Survival was considered the principle dependent variable. Post-treatment morbidity and health-related quality of life outcomes were considered secondarily. Analyses, by aim, relied on Cox proportional hazards regression, repeated measures logistic regression, propensity score matching and multivariable logistic regression. CONCLUSION: The POST's findings are anticipated to provide evidence regarding the prognostic capabilities of the NESMS as well as that of other popular grading schemes for survival, post-treatment complications and physical as well as mental function.

Non-operative management of spinal metastases: A prognostic model for failure.

OBJECTIVES: To describe patient-specific characteristics associated with non-operative failure leading to surgery. PATIENTS AND METHODS: We conducted a retrospective review of patients treated for spinal metastases from 2005 to 2017. We deemed patients as failures if they were treated non-operatively and then received a surgical intervention within one year of starting a non-operative regimen. We used multivariable Poisson regression to identify factors associated with non-operative failure. We conducted internal validation using bootstrapping with 1000 replications. RESULTS: We identified 1205 patients with spinal metastases, of whom 834 were initially treated non-operatively and constituted the analytic sample. Of these 77 (9%) went on to have surgery within 1-year of presentation and were deemed non-operative treatment failures. We identified vertebral body collapse and/or pathologic fracture (adjusted Risk Ratio [RR] 1.75; 95% Confidence Interval [CI] 1.11, 2.76) and neurologic signs or symptoms at presentation (RR 1.90; 95% CI 1.19, 3.03) as factors independently associated with an increased risk of non-operative failure. Platelet-lymphocyte ratio >155, a marker for inflammatory state, was also associated with an increased risk of failure (RR 2.32; 95% CI 1.15, 4.69). Failure rates among those with 0, 1, 2 or all three of these risk factors were 5%, 7%, 12% and 20%, respectively (p = 0.004). CONCLUSION: We found that 9% of patients with spinal metastases initially treated non-operatively received surgery within 1-year of commencing care. The likelihood of surgery increased with the number of risk factors. These results can be used in counseling and shared decision making at the time of initial presentation.

Prognosticating outcomes and survival for patients with lumbar spinal metastases: Results of a bayesian regression analysis.

OBJECTIVES: To assess the impact of surgical intervention on survival, ambulatory capacity, complications and readmissions following treatment for lumbar metastases. PATIENTS AND METHODS: We identified all adult patients treated for lumbar metastases between 2005-2017. To limit the potential for inherent bias to influence determinations, we used principal component analysis to identify confounders to be included in multivariable testing. Multivariable logistic regression was performed, followed by Bayesian analysis to generate conservative estimates of effect size and 95% confidence intervals (CI). In a sensitivity test, analyses were repeated in a population where patients who died before they could initiate treatment were excluded. RESULTS: In the period under study, we identified 571 patients who met inclusion criteria. Twenty-one percent of the cohort received a surgical intervention. Bayes regression indicated surgical intervention was independently associated with decreased mortality at 6-months (odds ratio [OR] 0.49; 95% CI 0.34, 0.68) and 1-year (OR 0.63; 95% CI 0.51, 0.76), along with lower odds of being non-ambulatory at 6-months following presentation (OR 0.29; 95% CI 0.18, 0.45). Surgery was also associated with increased odds of complications (OR 1.60; 95% CI 1.24, 2.06) and readmissions (OR 1.37; 95% CI 1.09, 1.72). Numerous clinical characteristics were found to be associated with the outcomes of interest including serum albumin, lung metastases and vertebral body collapse. CONCLUSIONS: Given the favorable outcomes associated with the incorporation of surgery as a component of treatment, we believe that such interventions may be considered part of the treatment approach in patients with lumbar metastases.

Disparities in Rates of Surgical Intervention Among Racial and Ethnic Minorities in Medicare Accountable Care Organizations.

OBJECTIVE: To assess the effect of Accountable Care Organizations (ACOs) on the use of surgical services among racial and ethnic minorities. BACKGROUND: Health reform efforts were expected to reduce healthcare disparities. The impact of ACOs on existing disparities in access to surgical care remains unknown. METHODS: We used national Medicare data (2009-2014) to compare rates of surgery among white, African American, Hispanic, and Asian Medicare beneficiaries for coronary artery bypass grafting, colectomy, total hip arthroplasty, hip fracture repair, and lumbar spine surgery. We performed a pre-post difference in differences analysis between African American, Hispanic, and Asian patients receiving surgical care in ACO and non-ACO organizations before and after the implementation of ACOs. The time period 2009 to 2011 was considered the pre-ACO period, and 2012 to 2014 the post-ACO period. RESULTS: Rates of surgical intervention in the ACO cohort were significantly lower (P < 0.001) as compared to non-ACOs for whites, African Americans, Hispanics, and Asians in both the pre- and post-ACO periods. There was no significant difference in the adjusted change in the rate of surgical interventions among minority patients as compared to whites in ACOs and non-ACOs between 2009 to 2011 and 2012 to 2014. The odds of receiving surgical intervention were lowest for minority patients in ACOs during the post-ACO period (P < 0.001). CONCLUSIONS: We found persistent differences in the use of surgery among racial and ethnic minorities between the time periods 2009 to 2011 and 2012 to 2014. These disparities were not impacted by the formation of ACOs. Programs that specifically incentivize ACOs to improve surgical access for minorities may be necessary.

Does Orthopaedic Outpatient Care Reduce Emergency Department Utilization After Total Joint Arthroplasty?

BACKGROUND: Emergency department (ED) visits after elective surgical procedures are a potential target for interventions to reduce healthcare costs. More than 1 million total joint arthroplasties (TJAs) are performed each year with postsurgical ED utilization estimated in the range of 10%. QUESTIONS/PURPOSES: We asked whether (1) outpatient orthopaedic care was associated with reduced ED utilization and (2) whether there were identifiable factors associated with ED utilization within the first 30 and 90 days after TJA. METHODS: An analysis of adult TRICARE beneficiaries who underwent TJA (2006-2014) was performed. TRICARE is the insurance program of the Department of Defense, covering > 9 million beneficiaries. ED use within 90 days of surgery was the primary outcome and postoperative outpatient orthopaedic care the primary explanatory variable. Patient demographics (age, sex, race, beneficiary category), clinical characteristics (length of hospital stay, prior comorbidities, complications), and environment of care were used as covariates. Logistic regression adjusted for all covariates was performed to determine factors associated with ED use. RESULTS: We found that orthopaedic outpatient care (odds ratio [OR], 0.73; 95% confidence interval [CI], 0.68-0.77) was associated with lower odds of ED use within 90 days. We also found that index hospital length of stay (OR, 1.07; 95% CI, 1.04-1.10), medical comorbidities (OR, 1.16; 95% CI, 1.08-1.24), and complications (OR, 2.47; 95% CI, 2.24-2.72) were associated with higher odds of ED use. CONCLUSIONS: When considering that at 90 days, only 3928 patients sustained a complication, a substantial number of ED visits (11,486 of 15,414 [75%]) after TJA may be avoidable. Enhancing access to appropriate outpatient care with improved discharge planning may reduce ED use after TJA. Further research should be directed toward unpacking the situations, outside of complications, that drive patients to access the ED and devise interventions that could mitigate such behavior. LEVEL OF EVIDENCE: Level III, therapeutic study.

Outpatient Spine Clinic Utilization is Associated With Reduced Emergency Department Visits Following Spine Surgery.

STUDY DESIGN: Review of TRICARE claims (2006-2014) data to assess Emergency Department (ED) utilization following spine surgery. OBJECTIVE: The aim of this study was to determine utilization rates and predictors of ED utilization following spine surgical interventions. SUMMARY OF BACKGROUND DATA: Visits to the ED following surgical intervention represent an additional stress to the healthcare system. While factors associated with readmission following spine surgery have been studied, drivers of postsurgical ED visits, including appropriate and inappropriate use, remain underinvestigated. METHODS: TRICARE claims were queried to identify patients who had undergone one of three common spine procedures (lumbar arthrodesis, discectomy, decompression). ED utilization at 30- and 90 days was assessed as the primary outcome. Outpatient spine surgical clinic utilization was considered the primary predictor variable. Multivariable logistic regression was used to adjust for confounders. RESULTS: Between 2006 and 2014, 48,868 patients met inclusion criteria. Fifteen percent (n = 7183) presented to the ED within 30 days postdischarge. By 90 days, 29% of patients (n = 14,388) presented to an ED. The 30- and 90-day complication rates were 6% (n = 2802) and 8% (n = 4034), respectively, and readmission rates were 5% (n = 2344) and 8% (n = 3842), respectively. Use of outpatient spine clinic services significantly reduced the likelihood of ED utilization at 30 [odds ratio (OR) 0.48; 95% confidence interval (95% CI) 0.46-0.53] and 90 days (OR 0.55; 95% CI 0.52-0.57). CONCLUSION: Within 90 days following spine surgery, 29% of patients sought care in the ED. However, only one-third of these patients had a complication recorded, and even fewer were readmitted. This suggests a high rate of unnecessary ED utilization. Outpatient utilization of spine clinics was the only factor independently associated with a reduced likelihood of ED utilization. LEVEL OF EVIDENCE: 3.

Heteroaggregation, transformation and fate of CeO2 nanoparticles in wastewater treatment.

Wastewater Treatment Plants (WWTPs) are a key pathway by which nanoparticles (NPs) enter the environment following release from NP-enabled products. This work considers the fate and exposure of CeO2 NPs in WWTPs in a two-step process of heteroaggregation with bacteria followed by the subsequent reduction of Ce(IV) to Ce(III). Measurements of NP association with solids in sludge were combined with experimental estimates of reduction rate constants for CeO2 NPs in Monte Carlo simulations to predict the concentrations and speciation of Ce in WWTP effluents and biosolids. Experiments indicated preferential accumulation of CeO2 NPs in biosolids where reductive transformation would occur. Surface functionalization was observed to impact both the distribution coefficient and the rates of transformation. The relative affinity of CeO2 NPs for bacterial suspensions in sludge appears to explain differences in the observed rates of Ce reduction for the two types of CeO2 NPs studied.

Monte Carlo simulations of the transformation and removal of Ag, TiO2, and ZnO nanoparticles in wastewater treatment and land application of biosolids.

The use of nano-enabled materials in industry and consumer products is increasing rapidly and with it, the more imperative it becomes to understand the consequences of such materials entering the environment during production, use or disposal. The novel properties of engineered nanomaterials (ENMs) that make them desirable for commercial applications also present the possibility of impacting aquatic and terrestrial environments in ways that may differ from materials in bulk format. Modeling techniques are needed to proactively predict the environmental fate and transport of nanomaterials. A model for nanoparticle (NP) separation and transformation in water treatment was parameterized for three metal and metal-oxide NPs. Functional assays to determine NP specific distribution and transformation were used to parameterize the model and obtain environmentally relevant concentrations of NPs and transformation byproducts leaving WWTPs in effluent and biosolids. All three NPs were predicted to associate >90% with the solid phase indicating significant accumulation in the biosolids. High rates of transformation for ZnO and Ag NPs resulted in ~97% transformation of the NPs that enter the plant despite differences in transformation rate in aerobic versus anaerobic environments. Due to high insolubility and negligible redox transformation, the only process predicted to impact TiO2 NP fate and transport in WWTPs was distribution between the solid and liquid phases. Subsequent investigation of ZnO NP species fate and transport when land applied in biosolids indicated that steady state concentrations of ZnO phases would likely be achieved after approximately 150days under loading conditions of biosolids typical in current practice.

Transformation of pristine and citrate-functionalized CeO2 nanoparticles in a laboratory-scale activated sludge reactor.

Engineered nanomaterials (ENMs) are used to enhance the properties of many manufactured products and technologies. Increased use of ENMs will inevitably lead to their release into the environment. An important route of exposure is through the waste stream, where ENMs will enter wastewater treatment plants (WWTPs), undergo transformations, and be discharged with treated effluent or biosolids. To better understand the fate of a common ENM in WWTPs, experiments with laboratory-scale activated sludge reactors and pristine and citrate-functionalized CeO2 nanoparticles (NPs) were conducted. Greater than 90% of the CeO2 introduced was observed to associate with biosolids. This association was accompanied by reduction of the Ce(IV) NPs to Ce(III). After 5 weeks in the reactor, 44 ± 4% reduction was observed for the pristine NPs and 31 ± 3% for the citrate-functionalized NPs, illustrating surface functionality dependence. Thermodynamic arguments suggest that the likely Ce(III) phase generated would be Ce2S3. This study indicates that the majority of CeO2 NPs (>90% by mass) entering WWTPs will be associated with the solid phase, and a significant portion will be present as Ce(III). At maximum, 10% of the CeO2 will remain in the effluent and be discharged as a Ce(IV) phase, governed by cerianite (CeO2).

Validation and sensitivity of the FINE Bayesian network for forecasting aquatic exposure to nano-silver.

The adaptive nature of the Forecasting the Impacts of Nanomaterials in the Environment (FINE) Bayesian network is explored. We create an updated FINE model (FINEAgNP-2) for predicting aquatic exposure concentrations of silver nanoparticles (AgNP) by combining the expert-based parameters from the baseline model established in previous work with literature data related to particle behavior, exposure, and nano-ecotoxicology via parameter learning. We validate the AgNP forecast from the updated model using mesocosm-scale field data and determine the sensitivity of several key variables to changes in environmental conditions, particle characteristics, and particle fate. Results show that the prediction accuracy of the FINEAgNP-2 model increased approximately 70% over the baseline model, with an error rate of only 20%, suggesting that FINE is a reliable tool to predict aquatic concentrations of nano-silver. Sensitivity analysis suggests that fractal dimension, particle diameter, conductivity, time, and particle fate have the most influence on aquatic exposure given the current knowledge; however, numerous knowledge gaps can be identified to suggest further research efforts that will reduce the uncertainty in subsequent exposure and risk forecasts.

Effectiveness of a web-based protocol for the screening and phenotyping of individuals with Tourette syndrome for genetic studies.

Genome-wide association studies (GWAS) and other emerging technologies offer great promise for the identification of genetic risk factors for complex psychiatric disorders, yet such studies are constrained by the need for large sample sizes. Web-based collection offers a relatively untapped resource for increasing participant recruitment. Therefore, we developed and implemented a novel web-based screening and phenotyping protocol for genetic studies of Tourette syndrome (TS), a childhood-onset neuropsychiatric disorder characterized by motor and vocal tics. Participants were recruited over a 13-month period through the membership of the Tourette Syndrome Association (TSA; n = 28,878). Of the TSA members contacted, 4.3% (1,242) initiated the questionnaire, and 79.5% (987) of these were enrollment eligible. 63.9% (631) of enrolled participants completed the study by submitting phenotypic data and blood specimens. Age was the only variable that predicted study completion; children and young adults were significantly less likely to be study completers than adults 26 and older. Compared to a clinic-based study conducted over the same time period, the web-based method yielded a 60% larger sample. Web-based participants were older and more often female; otherwise, the sample characteristics did not differ significantly. TS diagnoses based on the web-screen demonstrated 100% accuracy compared to those derived from in-depth clinical interviews. Our results suggest that a web-based approach is effective for increasing the sample size for genetic studies of a relatively rare disorder and that our web-based screen is valid for diagnosing TS. Findings from this study should aid in the development of web-based protocols for other disorders.

Size-dependent Pb sorption to nanohematite in the presence and absence of a microbial siderophore.

This study focused on the effects of particle size (40, 8.6, and 3.6 nm) and the presence of the microbial ligand desferrioxamine B (DFOB) on Pb(II) sorption to hematite, based on sorption edge experiments (i.e., sorption as a function of pH). Effects of hematite nanoparticle size on sorption edges, when plotted either as sorption density or as % Pb uptake, depended on whether the experiments were normalized to account for differences in specific surface area within the reaction vessels or postnormalized after the fact. Accounting for specific surface area within reaction vessels is needed to maintain comparable ratios of sorbate to sorbent surface sites. When normalized for BET specific surface area (A(s,BET)) within the reaction vessels, the Pb(II) sorption edge shifted ∼0.5 pH units to the left for <10 nm hematite particles, but maximum sorption density (at pH ≥ 6) was unaffected by particle size. DFOB had little or no effect on Pb(II) sorption to <10 nm particles, but DFOB decreased Pb(II) sorption to the 40 nm particles at pH ≥ 6 by ∼20%. Hematite (nano)particle size thus exerts subtle effects on Pb(II) sorption, but the effects may be more pronounced in the presence of a metal complexing agent.

Size-dependent bioavailability of hematite (α-Fe2O3) nanoparticles to a common aerobic bacterium.

The size-dependent bioavailability of hematite (α-Fe(2)O(3)) nanoparticles to obligate aerobic Pseudomonas mendocina bacteria was examined using the natural siderophore-producing wild type strain and a siderophore(-) mutant strain. Results showed that Fe from hematite less than a few tens of nm in size appears to be considerably more bioavailable than Fe associated with larger particles. This increased bioavailability is related to the total available particle surface area, and depends in part on greater accessibility of the Fe to the chelating siderophore(s). Greater bioavailability is also related to mechanism(s) that depend on cell/nanomineral proximity, but not on siderophores. Siderophore(-) bacteria readily acquire Fe from particles <10 nm but must be in direct physical proximity to the nanomineral; the bacteria neither produce a diffusible Fe-mobilizing agent nor accumulate a reservoir of dissolved Fe in supernatant solutions. Particles <10 nm appear to be capable of penetrating the outer cell wall, offering at least one possible pathway for Fe acquisition. Other cell-surface-associated molecules and/or processes could also be important, including a cell-wall associated reducing capability. The increased bioavailability of <10 nm particles has implications for both biogeochemical Fe cycling and applications involving engineered nanoparticles, and raises new questions regarding biogenic influences on adsorbed contaminants.

Alleviating perinatal depressive symptoms and stress: a nurse-community health worker randomized trial.

To determine whether a Nurse-Community Health Worker (CHW) home visiting team, in the context of a Medicaid enhanced prenatal/postnatal services (EPS), would demonstrate greater reduction of depressive symptoms and stress and improvement of psychosocial resources (mastery, self-esteem, social support) when compared with usual Community Care (CC) that includes Medicaid EPS delivered by professionals. Greatest program benefits were expected for women who reported low psychosocial resources, high stress, or both at the time of enrollment. Medicaid eligible pregnant women (N = 613) were randomly assigned to either usual CC or the Nurse-CHW team. Mixed effects regression was used to analyze up to five prenatal and postnatal psychosocial assessments. Compared to usual CC, assignment to the Nurse-CHW team resulted in significantly fewer depressive symptoms, and as hypothesized, reductions in depressive symptoms were most pronounced for women with low psychosocial resources, high stress, or both high stress and low resources. Outcomes for mastery and stress approached statistical significance, with the women in the Nurse-CHW group reporting less stress and greater mastery. Women in the Nurse-CHW group with low psychosocial resources reported significantly less perceived stress than women in usual CC. No differences between the groups were found for self-esteem and social support. A Nurse-CHW team approach to EPS demonstrated advantage for alleviating depressive symptoms in Medicaid eligible women compared to CC, especially for women at higher risk.

Addressing mental health and stress in Medicaid-insured pregnant women using a nurse-community health worker home visiting team.

OBJECTIVE: To describe the conceptual framework and program features of a nurse-community health worker (CHW) team home visiting intervention, the trial design to test the program, and the results of a comparative evaluation of prenatal program participation. DESIGN: In the context of a community-based, randomized trial, we compared participation in a nurse-CHW team intervention with the standard community care that included a state Medicaid program (enhanced prenatal services) with nurse home visiting. SAMPLE: Medicaid-eligible pregnant women (n=530), who maintained their pregnancies, had a live birth, retained custody of the child, completed more than an enrollment assessment, did not move out of the county, and were not lost to follow-up. MEASUREMENTS: Provider reports of face-to-face prenatal contacts and demographic and psychosocial risk assessments obtained at study enrollment. RESULTS: Significant differences in the number of women with prenatal program contact and the total amount of contact were found, favoring the nurse-CHW team approach. More women with risk characteristics were reached in the nurse-CHW team group, with the exception of women with alcohol and drug use risks. CONCLUSIONS: A nurse-CHW team approach demonstrated advantage in reaching women who had barriers to participation and delivering more intensive services.

Does literacy mediate the relationship between education and health outcomes? A study of a low-income population with diabetes.

OBJECTIVES: We sought to determine whether literacy mediates the relationship between education and glycemic control among diabetes patients. METHODS: We measured educational attainment, literacy using the Short Test of Functional Health Literacy in Adults (s-TOFHLA), and glycemic control (HbA1c) in 395 diabetes patients at a U.S. public hospital. We performed path analysis to compare two competing models to explain glycemic control. The direct effects model estimated how education was related to HbA1c; the mediational model estimated the strength of the direct relationship when the additional pathway from education to literacy to HbA1c was added. RESULTS: Both the model with a direct effect of education on HbA1c and the model with literacy as a mediator were supported by good fit to observed data. The mediational model, however, was a significant improvement, with the additional path from literacy to HbA1c reducing the discrepancy from observed data (p < 0.01). After including this path, the direct relationship between education and HbA1c fell to a non-significant threshold. CONCLUSIONS: In a low-income population with diabetes, literacy mediated the relationship between education and glycemic control. This finding has important implications for both education and health policy.

Parallel deficits in linear growth and mental development in low-income Mexican infants in the second year of life.

OBJECTIVE: To explore anthropometric indicators and mental development in very-low-income children in the second year of life. DESIGN: Cross-sectional survey. SETTING: Low-income areas (income <20th percentile) in semi-urban Mexico (defined as towns or cities with 2,500-50,000 inhabitants). SUBJECTS: Eight hundred and ninety-six children aged 12.5-23.5 months surveyed from September to December 2001. METHODS: Questionnaire survey and anthropometric survey of households. Multivariate regression models evaluated differences across age in anthropometry (height-for-age Z-score (HAZ) and weight-for-height Z-score) and cognitive function (Mental Development Index (MDI) of the Bayley Scales of Infant Development) while controlling for socio-economic and parental characteristics. RESULTS: There was a significant decline in HAZ and in age-adjusted MDI score across the second year of life. Although the children showed MDI scores close to the mean, normed US values at 13-14 months, the scores were significantly lower than expected in older children (P < 0.0001), even after controlling for socio-economic status and parental characteristics. At 13-14 months, only 3% of children received scores below 70 (less than minus two standard deviations), whereas by 19-20 months, almost 17% of children were performing below this level. No socio-economic or parental characteristics were significant predictors of HAZ or MDI. CONCLUSIONS: Parallel deficits are evident in both height-for-age and cognitive functioning during the second year of life in low-income Mexican infants. The consistency of these growth and development findings further stresses the need for targeted interventions to reduce the vulnerability of low-income Mexican children very early in life.