Project ECHO Brain Health: Assessing the Impact of a Pilot Program to Promote Self-Efficacy Among Community Health Workers

This mixed-methods study sought to examine the impact of the Project ECHO Brain Health program on participating community health workers' (CHWs') self-efficacy to address dementia, promote brain health, and advocate for research among Latinx South Texas communities. Using an explanatory sequential design, quantitative data collected from pre- and post-program surveys were analyzed to inform the collection of qualitative data, followed by an interpretation of all findings to better understand the impact of the program on self-efficacy. Pre- and post-surveys were collected from 25 CHWs, 13 of whom later participated in individual interviews. There was a statistically significant increase in mean self-efficacy scores between the pre- and post-surveys among participants. Three categories reflecting the experiences of participants were identified from the qualitative data: addressing training needs; impact on CHWs and their practice; and community of learning. The findings suggest that Project ECHO Brain Health program is a timely intervention that may facilitate increased self-efficacy among CHWs as they navigate the impacts of dementia in their communities.

Propensity score analysis for health care disparities: a deweighting approach

BACKGROUND

Propensity score weighting is a useful tool to make causal or unconfounded comparisons between groups. According to the definition by the Institute of Medicine (IOM), estimates of health care disparities should be adjusted for health-status factors but not for socioeconomic status (SES) variables. There have been attempts to use propensity score weighting to generate estimates that are concordant with IOM's definition. However, the existing propensity score methods do not preserve SES distributions in minority and majority groups unless SES variables are independent of health status variables.

METHODS

The present study introduces a deweighting method that uses two types of propensity scores. One is a function of all covariates of health status and SES variables and is used to weight study subjects to adjust for them. The other is a function of only the SES variables and is used to deweight the subjects to preserve the original SES distributions.

RESULTS

The procedure of deweighting is illustrated using a dataset from a right heart catheterization (RHC) study, where it was used to examine whether there was a disparity between black and white patients in receiving RHC. The empirical example provided promising evidence that the deweighting method successfully preserved the marginal SES distributions for both racial groups but balanced the conditional distributions of health status given SES.

CONCLUSIONS

Deweighting is a promising tool for implementing the IOM-definition of health care disparities. The method is expected to be broadly applied to quantitative research on health care disparities.

Erratum: Toward standardization, harmonization, and integration of social determinants of health data: A Texas Clinical and Translational Science Award institutions collaboration - CORRIGENDUM

[This corrects the article DOI: 10.1017/cts.2024.2.].

Toward standardization, harmonization, and integration of social determinants of health data: A Texas Clinical and Translational Science Award institutions collaboration

Introduction

The focus on social determinants of health (SDOH) and their impact on health outcomes is evident in U.S. federal actions by Centers for Medicare & Medicaid Services and Office of National Coordinator for Health Information Technology. The disproportionate impact of COVID-19 on minorities and communities of color heightened awareness of health inequities and the need for more robust SDOH data collection. Four Clinical and Translational Science Award (CTSA) hubs comprising the Texas Regional CTSA Consortium (TRCC) undertook an inventory to understand what contextual-level SDOH datasets are offered centrally and which individual-level SDOH are collected in structured fields in each electronic health record (EHR) system potentially for all patients.

Methods

Hub teams identified American Community Survey (ACS) datasets available via their enterprise data warehouses for research. Each hub's EHR analyst team identified structured fields available in their EHR for SDOH using a collection instrument based on a 2021 PCORnet survey and conducted an SDOH field completion rate analysis.

Results

One hub offered ACS datasets centrally. All hubs collected eleven SDOH elements in structured EHR fields. Two collected Homeless and Veteran statuses. Completeness at four hubs was 80%-98%: Ethnicity, Race; < 10%: Education, Financial Strain, Food Insecurity, Housing Security/Stability, Interpersonal Violence, Social Isolation, Stress, Transportation.

Conclusion

Completeness levels for SDOH data in EHR at TRCC hubs varied and were low for most measures. Multiple system-level discussions may be necessary to increase standardized SDOH EHR-based data collection and harmonization to drive effective value-based care, health disparities research, translational interventions, and evidence-based policy.

Heterogeneity of COVID-19 symptoms and associated factors: Longitudinal analysis of laboratory-confirmed COVID-19 cases in San Antonio

Few studies have examined heterogeneous associations of risk factors with Coronavirus Disease-2019 (COVID-19) symptoms by type. The objectives of this study were to estimate the prevalence of and risk factors associated with COVID-19 symptoms and to investigate whether the associations differ by the type of symptoms. This study obtained longitudinal data over 6 months from laboratory-confirmed COVID-19 cases in a citywide sample in San Antonio. Sixteen symptoms of COVID-19 infection, measured at baseline and three follow-up times (1, 3, and 6 months), were analyzed using generalized estimating equations (GEE) to investigate potential risk factors while accounting for the repeated measurements. The risk factors included time in months, sociodemographic characteristics, and past or current medical and psychiatric conditions. To obtain interpretable results, we categorized these sixteen symptoms into five categories (cardiopulmonary, neuro-psychological, naso-oropharyngeal, musculoskeletal, and miscellaneous). We fitted GEE models with a logit link using each category as the outcome variable. Our study demonstrated that the associations were heterogeneous by the categories of symptoms. The time effects were the strongest for naso-oropharyngeal symptoms but the weakest for neuro-psychological symptoms. Female gender was associated with increased odds of most of the symptoms. Hispanic ethnicity was also associated with higher odds of neuro-psychological, musculoskeletal, and miscellaneous symptoms. Depression was the most robust psychiatric condition contributing to most of the symptoms. Different medical conditions seemed to contribute to different symptom expressions of COVID-19 infection.

Effects of Adjusting for Instrumental Variables on the Bias and Precision of Propensity Score Weighted Estimators: Analysis Under Complete, Near, and No Positivity Violations

Purpose

To demonstrate that using an instrumental variable (IV) with monotonicity reduces the accuracy of propensity score (PS) weighted estimators for the average treatment effect (ATE).

Methods

Monotonicity in the relationship between a binary IV and a binary treatment variable is an important assumption to identify the ATE for compliers who would only take treatment when encouraged by the IV. We perform theoretical and numerical investigations to study the impact of using the IV that satisfies monotonicity on the PS of treatment in terms of the positivity assumption, which requires that the PS be strictly between 0 and 1, and the accuracy of PS weighted estimators. Two versions of monotonicity that result in one-sided or two-sided noncompliance are considered.

Results

The PS adjusting for the IV always violates the positivity assumption when noncompliance occurs in one direction (one-sided noncompliance) and is more extreme than without the IV under two-sided noncompliance. These results are valid if the probability of being encouraged to get treatment and the compliance score, the probability of being a complier, are strictly between 0 and 1.

Conclusion

Using a binary IV with monotonicity as a covariate for the PS model makes the estimated PSs unnecessarily extreme, reducing the accuracy of the PS weighted estimators.

Metabolomic profiles associated with physical activity in White and African American adult men

BACKGROUND

Physical activity (PA) is associated with various health benefits, especially in improving chronic health conditions. However, the metabolic changes in host metabolism in response to PA remain unclear, especially in racially/ethnically diverse populations.

OBJECTIVE

This study is to assess the metabolic profiles associated with the frequency of PA in White and African American (AA) men.

METHODS

Using the untargeted metabolomics data collected from 698 White and AA participants (mean age: 38.0±8.0, age range: 20-50) from the Louisiana Osteoporosis Study (LOS), we conducted linear regression models to examine metabolites that are associated with PA levels (assessed by self-reported regular exercise frequency levels: 0, 1-2, and ≥3 times per week) in White and AA men, respectively, as well as in the pooled sample. Covariates considered for statistical adjustments included race (only for the pooled sample), age, BMI, waist circumstance, smoking status, and alcohol drinking.

RESULTS

Of the 1133 untargeted compounds, we identified 7 metabolites associated with PA levels in the pooled sample after covariate adjustment with a false discovery rate of 0.15. Specifically, compared to participants who did not exercise, those who exercised at a frequency ≥3 times/week showed higher abundances in uracil, orotate, 1-(1-enyl-palmitoyl)-2-oleoyl-GPE (P-16:0/18:1) (GPE), threonate, and glycerate, but lower abundances in salicyluric glucuronide and adenine in the pooled sample. However, in Whites, salicyluric glucuronide and orotate were not significant. Adenine, GPE, and threonate were not significant in AAs. In addition, the seven metabolites were not significantly different between participants who exercised ≥3 times/week and 1-2 times/week, nor significantly different between participants with 1-2 times/week and 0/week in the pooled sample and respective White and AA groups.

CONCLUSIONS

Metabolite responses to PA are dose sensitive and may differ between White and AA populations. The identified metabolites may help advance our knowledge of guiding precision PA interventions. Studies with rigorous study designs are warranted to elucidate the relationship between PA and metabolites.

Endogenous adenine mediates kidney injury in diabetic models and predicts diabetic kidney disease in patients

Diabetic kidney disease (DKD) can lead to end-stage kidney disease (ESKD) and mortality; however, few mechanistic biomarkers are available for high-risk patients, especially those without macroalbuminuria. Urine from participants with diabetes from the Chronic Renal Insufficiency Cohort (CRIC) study, the Singapore Study of Macro-angiopathy and Micro-vascular Reactivity in Type 2 Diabetes (SMART2D), and the American Indian Study determined whether urine adenine/creatinine ratio (UAdCR) could be a mechanistic biomarker for ESKD. ESKD and mortality were associated with the highest UAdCR tertile in the CRIC study and SMART2D. ESKD was associated with the highest UAdCR tertile in patients without macroalbuminuria in the CRIC study, SMART2D, and the American Indian study. Empagliflozin lowered UAdCR in nonmacroalbuminuric participants. Spatial metabolomics localized adenine to kidney pathology, and single-cell transcriptomics identified ribonucleoprotein biogenesis as a top pathway in proximal tubules of patients without macroalbuminuria, implicating mTOR. Adenine stimulated matrix in tubular cells via mTOR and stimulated mTOR in mouse kidneys. A specific inhibitor of adenine production was found to reduce kidney hypertrophy and kidney injury in diabetic mice. We propose that endogenous adenine may be a causative factor in DKD.

BLZ8 activates a plastidial peroxiredoxin and a ferredoxin to protect Chlamydomonas reinhardtii against oxidative stress

Reactive oxygen species (ROS) cause damage to various cellular processes in almost all organisms, in particular photosynthetic organisms that depend on the electron transfer chain for CO2 fixation. However, the detoxifying process to mitigate ROS damage has not been studied intensively in microalgae. Here, we characterized the ROS detoxifying role of a bZIP transcription factor, BLZ8, in Chlamydomonas reinhardtii. To identify downstream targets of BLZ8, we carried out comparative genome-wide transcriptomic profiling of BLZ8 OX and its parental CC-4533 under oxidative stress conditions. Luciferase reporter activity assays and RT-qPCR were performed to test whether BLZ8 regulates downstream genes. We performed an in silico functional gene network analysis and an in vivo immunoprecipitation assay to identify the interaction between downstream targets of BLZ8. Comparative transcriptomic analysis and RT-qPCR revealed that overexpression of BLZ8 increased the expression levels of plastid peroxiredoxin1 (PRX1) and ferredoxin-5 (FDX5) under oxidative stress conditions. BLZ8 alone could activate the transcriptional activity of FDX5 and required bZIP2 to activate transcriptional activity of PRX1. Functional gene network analysis using FDX5 and PRX1 orthologs in A. thaliana suggested that these two genes were functionally associated. Indeed, our immunoprecipitation assay revealed the physical interaction between PRX1 and FDX5. Furthermore, the complemented strain, fdx5 (FDX5), recovered growth retardation of the fdx5 mutant under oxidative stress conditions, indicating that FDX5 contributes to oxidative stress tolerance. These results suggest that BLZ8 activates PRX1 and FDX5 expression, resulting in the detoxification of ROS to confer oxidative stress tolerance in microalgae.

Collaborative Program to Evaluate Real World Data for Use in Clinical Studies and Regulatory Decision Making

The 21^st Century Cures Act allows the US Food and Drug Administration to consider real world data (RWD) for new indications or post approval study requirements. However, there is limited guidance as to the relative quality of different RWD types. The ACE-RWD program will compare the quality of EHR clinical data, EHR billing data, and linked healthcare claims data to traditional clinical trial data collection methods. ACE-RWD is being conducted alongside 5-10 ancillary studies, with five sponsors, across multiple therapeutic areas. Each ancillary study will be conducted after or in parallel with its parent clinical study at a minimum of two clinical sites. Although not required, it is anticipated that EHR clinical and EHR billing data will be obtained via EHR-to-eCRF mechanisms that are based on the Health Level Seven (HL7) Fast Healthcare Interoperability Resources (FHIR®) standard.

Profiling compliers and noncompliers for instrumental variable analysis with covariates: A weighting approach

Instrumental variable (IV) estimation is an essential tool to estimate the causal effect of a treatment in randomized experiments when noncompliance exists. In such studies, standard statistical approaches can be biased because compliers and noncompliers can differ in unmeasured ways that affect both the compliance behavior and outcome. Based on a few assumptions such as monotonicity, the IV estimand represents the causal effect of compliers. Profiling compliers and noncompliers has important implications because the IV estimand applies only to compliers. A method for estimating the covariate means for compliers and noncompliers has recently been proposed in political sciences literature. However, this approach requires an assumption that the instrument is randomly assigned, which confines the application of this approach to randomized experiments. In this study, we present two weighting methods for profiling compliers and noncompliers when the instrument and compliance behavior are confounded by several covariates. The proposed approach can be used for both experimental and nonexperimental studies, and hence is more broadly applicable. For the development, an instrumental propensity score is adopted to account for confounded instruments. We demonstrate the utility of the proposed methods based on simulation and real data experiments.

Role of endogenous adenine in kidney failure and mortality with diabetes

Diabetic kidney disease (DKD) can lead to end-stage kidney disease (ESKD) and mortality, however, few mechanistic biomarkers are available for high risk patients, especially those without macroalbuminuria. Urine from participants with diabetes from Chronic Renal Insufficiency Cohort (CRIC), Singapore Study of Macro-Angiopathy and Reactivity in Type 2 Diabetes (SMART2D), and the Pima Indian Study determined if urine adenine/creatinine ratio (UAdCR) could be a mechanistic biomarker for ESKD. ESKD and mortality were associated with the highest UAdCR tertile in CRIC (HR 1.57, 1.18, 2.10) and SMART2D (HR 1.77, 1.00, 3.12). ESKD was associated with the highest UAdCR tertile in patients without macroalbuminuria in CRIC (HR 2.36, 1.26, 4.39), SMART2D (HR 2.39, 1.08, 5.29), and Pima Indian study (HR 4.57, CI 1.37-13.34). Empagliflozin lowered UAdCR in non-macroalbuminuric participants. Spatial metabolomics localized adenine to kidney pathology and transcriptomics identified ribonucleoprotein biogenesis as a top pathway in proximal tubules of patients without macroalbuminuria, implicating mammalian target of rapamycin (mTOR). Adenine stimulated matrix in tubular cells via mTOR and stimulated mTOR in mouse kidneys. A specific inhibitor of adenine production was found to reduce kidney hypertrophy and kidney injury in diabetic mice. We propose that endogenous adenine may be a causative factor in DKD.

Release of Oxytocin and Cortisol Is Associated With Neurobehavioral Patterns in Premature Infants

OBJECTIVE

To examine relationships among salivary oxytocin and cortisol levels in parents and preterm infants and neurobehavioral functioning in preterm infants after skin-to-skin contact.

DESIGN

A secondary analysis of a randomized crossover study.

SETTING

NICU.

PARTICIPANTS

Twenty-eight stable premature infants and their mothers and fathers.

METHODS

Participating infants contributed 108 saliva samples that we collected 45 minutes after skin-to-skin contact and tested for oxytocin and cortisol. We randomized data collection by whether the infant was held first by the mother or by the father. We conducted linear regression to test if summary scores on the NICU Network Neurobehavioral Scale were associated with salivary oxytocin and cortisol levels.

RESULTS

We found a significant negative relationship between infant oxytocin levels and the Stress scores (b = -0.07, p < .01) and the Excitability scores (b = -1.12, p = .04) among infants held skin-to-skin with their mothers. We found a significant positive relationship between infant oxytocin levels and the Self-Regulatory scores (b = 0.38, p = .05) among infants held skin-to-skin with their mothers. We found a significant positive relationship between infant cortisol level and the Stress scores (b = 0.05, p = .04), Excitability scores (b = 1.06, p = 0.05), and Asymmetrical Reflexes scores (b = 1.21, p = .03) among infants held skin-to-skin with their mothers. We only found a negative significant relationship between infant cortisol levels and the Stress scores (b = -0.03, p = .04) among infants held skin-to-skin with their fathers.

CONCLUSION

We found that oxytocin is an important biomarker that may improve infant neurobehavioral functioning. The data showed a difference in oxytocin responses after skin-to-skin contact with mothers compared to fathers.

Antiracism Work in Schools: Using Dialectical Behavior Therapy Skills to Empower South Texas Educators

OBJECTIVE

Implicit biases within school systems contribute to racist school cultures and policies. Black and Hispanic students are more likely to be over-policed in schools and to be penalized, especially by White teachers. Dialectical behavior therapy (DBT) skills can be taught to educators to support antiracist efforts in schools.

METHOD

A virtual 2-day Train-the-Trainer antiracism workshop incorporating DBT skills was delivered to South Texas educators. DBT skills were integrated as life skills in antiracism situational role play, small group discussions, and meta-cognitive activities. Participants also received books on antiracism and an educators' toolkit to DBT and antiracism. Descriptive analysis described results from the workshop application, pre/post-workshop survey, and 6-month follow-up survey.

RESULTS

Twelve educators completed the workshop application, with 10 educators reporting no history of antiracism trainings at their schools. Nine educators attended the workshop. Workshop feedback was overwhelmingly positive. A pre/post-workshop survey demonstrated growth in both teaching and use of all measured DBT skills and antiracism attitudes. Confidence in teaching and using DBT skills and changes in antiracism attitudes were sustained 6 months later. Five educators reported leading an antiracism initiative in their schools since the attendance of the workshop.

CONCLUSION

A DBT-centered Train-the-Trainer antiracism workshop instilled confidence in educators to lead antiracism efforts, which resulted in the initiation of several initiatives in South Texas schools. Training educators, including teachers, counselors, and administrators, encouraged systemic antiracist change in school systems. The virtual training format may facilitate accessibility to educators who lack access to trainings; however, it may also add difficulty in building community among participants.

Examining the Delivery of a Tailored Chinese Mind-Body Exercise to Low-Income Community-Dwelling Older Latino Individuals for Healthy Aging: Feasibility and Acceptability Study

Background

Older Latino individuals are disproportionally affected by various chronic conditions including impairments in physical and cognitive functions, which are essential for healthy aging and independent living.

Objective

This study aimed to evaluate the feasibility and acceptability of FITxOlder, a 12-week mind-body exercise program, in community-dwelling low-income, predominantly older Latino individuals, and assess its preliminary effects on health parameters relevant to healthy aging and independent living.

Methods

This 12-week, single-arm, stage 1B feasibility study had a pre- and poststudy design. A total of 13 older adults (mean age 76.4, SD 7.9 years; 11/13, 85% Latino) of a congregate meal program in a senior center were enrolled. FITxOlder was a tailored Chinese mind-body exercise program using Five Animal Frolics led by a bilingual community health worker (CHW) participating twice a week at the senior center and facilitated by mobile health technology for practice at home, with incrementally increasing goals moving from once a week to at least 3 times a week. The feasibility and acceptability of the study were examined using both quantitative and qualitative data. Healthy aging–related outcomes (eg, physical and cognitive function) were assessed using paired 2-tailed t tests. Qualitative interview data were analyzed using thematic analysis.

Results

The attendance rate for the 24 exercise sessions was high (22.7/24, 95%), ranging from 93% (1.8/2) to 97% (1.9/2) over the 12 weeks. Participants were compliant with the incremental weekly exercise goals, with 69.2% (9/13) and 75.0% (9/12) meeting the home and program goals in the last 4 weeks, respectively. Approximately 83% (10/12) to 92% (11/12) of the participants provided favorable feedback on survey questions regarding the study and program implementation, such as program content and support, delivery by the CHW, enjoyment and appeal of the Five Animal Frolics, study burden and incentives, and safety concerns. The qualitative interview data revealed that FITxOlder was well accepted; participants reported enjoyment and health benefits and the desire to continue to practice and share it with others. The 5-time sit-to-stand test (mean change at posttest assessment=−1.62; P<.001; Cohen d=0.97) and 12-Item Short Form Health Survey physical component scores (mean change at post intervention=5.71; P=.01; Cohen d=0.88) exhibited changes with large effect sizes from baseline to 12 weeks; the other parameters showed small or medium effect sizes.

Conclusions

The research findings indicated that the CHW-led and mobile health–facilitated Chinese qigong exercise program is feasible and acceptable among low-income Latino older adults. The trending health benefits of the 12-week FITxOlder program suggest it is promising to promote physical activity engagement in underserved older populations to improve health outcomes for healthy aging and independent living. Future research with larger samples and longer interventions is warranted to assess the health benefits and suitability of FITxOlder.

Disparities in Cancer Genetic Testing and Variants of Uncertain Significance in the Hispanic Population of South Texas

PURPOSE

Racial and ethnic disparities have included a lack of access to both genetic testing and research, resulting in poor understanding of the genomic architecture in under-represented populations. The South Texas population is primarily of Hispanic background and has been largely devoid of genetic services. We extended access to this underserved population and uncovered genetic variants previously not observed, emphasizing the need to continually improve both genomic databases and clarification of variant significance to provide meaningful patient counseling.

METHODS

This study consisted of a retrospective cohort review of patients seen through a cancer genetics education and service program across 24 counties in South Texas. In total, 1,595 individuals were identified as appropriate for cancer genetic counseling and 1,377 completed genetic testing.

RESULTS

Eighty percent of those receiving genetic counseling self-identified as Hispanic, 16% as non-Hispanic White (NHW), 3% as African American, and 1% as other race/ethnicity. Of reported variants, 18.8% were pathogenic and 13.7% were reported as a variant of uncertain significance (VUS). VUS was reported in 17.2% of the Hispanic individuals compared with 9% NHW (P = .005).

CONCLUSION

Individuals of Hispanic ethnicity were significantly more likely to harbor a VUS compared with NHW. The extended reach into our regional communities revealed a gap in the ability to accurately interpret genomic variation with implications for advising patients on screening, prevention, and management strategies. A higher percentage of VUS also emphasizes the challenge of continued follow-up amid existing barriers that led to disparities in access. As understanding of the variants develops, hopefully gaps in knowledge of the genomic landscape will be lessened with increased clarity to provide accurate cancer risk assessment and recommendations for implementing prevention initiatives.

A Community Health Worker-Led mHealth-Enabled Diabetes Self-Management Education and Support Intervention in Rural Latino Adults: Single-Arm Feasibility Trial (Preprint)

Background

Latinos living in rural South Texas have a higher prevalence of diabetes, but their access to diabetes self-management education and support (DSMES) is limited.

Objective

We aimed to test the feasibility of a community health worker-led, mobile health (mHealth)-based DSMES intervention to reduce disparities in accessing DSMES in underserved rural Latino residents in South Texas.

Methods

This 12-week, single-arm, pre-post trial was delivered by trained community health workers to 15 adults with type 2 diabetes. The intervention consisted of digital diabetes education, self-monitoring, a cloud-based connected platform, and community health worker support. Feasibility was evaluated as retention, actual intervention use, program satisfaction, and barriers to implementation. We also explored the intervention’s effect on weight loss and hemoglobin A_1c (HbA_1c).

Results

All 15 participants were Latino (mean age 61.87 years, SD 10.67; 9/15 female, 60%). The retention rate at posttest was 14 of 15 (93%). On average, the participants completed 37 of 42 (88%) digital diabetes education lessons with 8 participants completing all lessons. Participants spent 81/91 days (89%) step tracking, 71/91 days (78%) food logging, 43/91 days (47%) blood glucose self-monitoring, and 74/91 days (81%) weight self-monitoring. The level of program satisfaction was high. On average, participants lost 3.5 (SD 3.2) kg of body weight (P=.001), while HbA_1c level remained unchanged from baseline (6.91%, SD 1.28%) to posttest (7.04%, SD 1.66%; P=.668).

Conclusions

A community health worker-led mHealth-based intervention was feasible and acceptable to improve access to DSMES services for Latino adults living in rural communities. Future randomized controlled trials are needed to test intervention efficacy on weight loss and glycemic control.

Subclassification estimation of the weighted average treatment effect

Weighting and subclassification are popular approaches using propensity scores (PSs) for estimation of causal effects. Weighting is appealing in that it gives consistent estimators for various causal estimands if appropriate weights are well defined and the PS model is correctly specified. Subclassification is known to be more robust to model misspecification than weighting, but its application to diverse causal estimands is limited. In this article, we propose generalized stratum weights to implement subclassification estimators for various causal estimands. These weights include stratum weights for the average treatment effect (ATE) of the overall population and those for the ATE of the treated as special cases. For this, we incorporate strata into the expression of the weighted average treatment effect (WATE). Particularly, we identify stratum weights for the ATE for the overlap population (ATO), for which the weighting estimator is known to be most efficient among the class of WATE estimators. We show that the identified stratum weights for ATO are equivalent to the optimal stratum weights, which are the inverse variances of the stratum-specific estimators. Simulation studies demonstrate that the proposed subclassification estimator for ATO is more robust to model misspecification than the weighting estimator for ATO. We also propose augmented subclassification estimators, which are shown to be less biased than the subclassification estimators when only the outcome model is correctly specified. The practical utility of the proposed methods is illustrated in a study of right heart catheterization.

Instrumental variable estimation of truncated local average treatment effects

Instrumental variable (IV) analysis is used to address unmeasured confounding when comparing two nonrandomized treatment groups. The local average treatment effect (LATE) is a causal estimand that can be identified by an IV. The LATE approach is appealing because its identification relies on weaker assumptions than those in other IV approaches requiring a homogeneous treatment effect assumption. If the instrument is confounded by some covariates, then one can use a weighting estimator, for which the outcome and treatment are weighted by instrumental propensity scores. The weighting estimator for the LATE has a large variance when the IV is weak and the target population, i.e., the compliers, is relatively small. We propose a truncated LATE that can be estimated more reliably than the regular LATE in the presence of a weak IV. In our approach, subjects who contribute substantially to the weak IV are identified by their probabilities of being compliers, and they are removed based on a pre-specified threshold. We discuss interpretation of the proposed estimand and related inference method. Simulation and real data experiments demonstrate that the proposed truncated LATE can be estimated more precisely than the standard LATE.

Machine learning outcome regression improves doubly robust estimation of average causal effects

BACKGROUND

Doubly robust estimation produces an unbiased estimator for the average treatment effect unless both propensity score (PS) and outcome models are incorrectly specified. Studies have shown that the doubly robust estimator is subject to more bias than the standard weighting estimator when both PS and outcome models are incorrectly specified.

METHOD

We evaluated whether various machine learning methods can be used for estimating conditional means of the potential outcomes to enhance the robustness of the doubly robust estimator to various degrees of model misspecification in terms of reducing bias and standard error. We considered four types of methods to predict the outcomes: least squares, tree-based methods, generalized additive models and shrinkage methods. We also considered an ensemble method called the Super Learner (SL), which is a linear combination of multiple learners. We conducted simulations considering different scenarios by the complexity of PS and outcome-generating models and some ranges of treatment prevalence.

RESULTS

The shrinkage methods performed well with robust doubly robust estimates in term of bias and mean squared error across the scenarios when the models became rich by including all 2-way interactions of the covariates. The SL performed similarly to the best method in each scenario.

CONCLUSIONS

Our findings indicate that machine learning methods such as the SL or the shrinkage methods using interaction models should be used for more accurate doubly robust estimators.

Bias testing, bias correction, and confounder selection using an instrumental variable model

Instrumental variable (IV) analysis can be used to address bias due to unobserved confounding when estimating the causal effect of a treatment on an outcome of interest. However, if a proposed IV is correlated with unmeasured confounders and/or weakly correlated with the treatment, the standard IV estimator may be more biased than an ordinary least squares (OLS) estimator. Several methods have been proposed that compare the bias of the IV and OLS estimators relying on the belief that measured covariates can be used as proxies for the unmeasured confounder. Despite these developments, there is lack of discussion about approaches that can be used to formally test whether the IV estimator may be less biased than the OLS estimator. Thus, we have developed a testing framework to compare the bias and a criterion to select informative measured covariates for bias comparison and regression adjustment. We also have developed a bias-correction method, which allows one to use an invalid IV to correct the bias of the OLS or IV estimator. Numerical studies demonstrate that the proposed methods perform well with realistic sample sizes.

Assessing the effect of patient navigator assistance for psychosocial support services on health-related quality of life in a randomized clinical trial in Latino breast, prostate, and colorectal cancer survivors

BACKGROUND

After a diagnosis of prostate, breast, or colorectal cancer, Latinos experience higher mortality rates and lower health-related quality of life (HRQOL) in comparison with other ethnic/racial groups. Patient navigation (PN) and lay community health workers or promotores are effective in increasing cancer screening and early-stage diagnosis among Latinos. However, little is known about the effect of PN on HRQOL among Latino cancer survivors.

METHODS

Latinos previously diagnosed with breast, prostate, or colorectal cancer (n = 288) were randomized to 1 of 2 conditions: 1) the Patient Navigator LIVESTRONG Cancer Navigation Services (PN-LCNS) survivor care program or 2) PN only. HRQOL was measured with the Functional Assessment of Cancer Therapy-General, and cancer-specific HRQOL was measured with the Functional Assessment of Cancer Therapy-Breast, the Functional Assessment of Cancer Therapy-Prostate, and the Functional Assessment of Cancer Therapy-Colorectal for breast, prostate, and colorectal cancer survivors, respectively, at the baseline and at 3 follow-up time points. Generalized estimating equation analyses were conducted to estimate the effect of condition on HRQOL with adjustments for covariates and baseline HRQOL.

RESULTS

PN-LCNS demonstrated a significant improvement in HRQOL in comparison with PN only for colorectal cancer survivors but not for breast and prostate cancer survivors.

CONCLUSIONS

Enhanced PN improves HRQOL among Latino colorectal cancer survivors. Future research should identify the best strategies for engaging Latino survivors in PN programs. PN programs should also be adapted to address HRQOL concerns among Latina breast cancer survivors.

Acetylcholine precursor, citicoline (cytidine 5'-diphosphocholine), reduces hypoglycaemia-induced neuronal death in rats

Citicoline (cytidine 5'-diphosphocholine) is an important precursor for the synthesis of neuronal plasma membrane phospholipids, mainly phosphatidylcholine. The administration of citicoline serves as a choline donor for the synthesis of acetylcholine. Citicoline has been shown to reduce the neuronal injury in animal models with cerebral ischaemia and in clinical trials of stroke patients. Citicoline is currently being investigated in a multicentre clinical trial. However, citicoline has not yet been examined the context of hypoglycaemia-induced neuronal death. To clarify the therapeutic impact of citicoline in hypoglycaemia-induced neuronal death, we used a rat model with insulin-induced hypoglycaemia. Acute hypoglycaemia was induced by i.p. injection of regular insulin (10 U kg^-1 ) after overnight fasting, after which iso-electricity was maintained for 30 minutes. Citicoline injections (500 mg/kg, i.p.) were started immediately after glucose reperfusion. We found that post-treatment of citicoline resulted in significantly reduced neuronal death, oxidative injury and microglial activation in the hippocampus compared to vehicle-treated control groups at 7 days after induced hypoglycaemia. Citicoline administration after hypoglycaemia decreased immunoglobulin leakage via blood-brain barrier disruption in the hippocampus compared to the vehicle group. Citicoline increased choline acetyltransferase expression for phosphatidylcholine synthesis after hypoglycaemia. Altogether, the present findings suggest that neuronal membrane stabilisation by citicoline administration can save neurones from the degeneration process after hypoglycaemia, as seen in several studies of ischaemia. Therefore, the results suggest that citicoline may have therapeutic potential to reduce hypoglycaemia-induced neuronal death.

Dietary total, animal, vegetable calcium and type 2 diabetes incidence among Korean adults: The Korean Multi-Rural Communities Cohort (MRCohort)

BACKGROUND AND AIMS

Although a possible mechanism for developing type 2 diabetes in relation to calcium intake has been suggested, there is currently little epidemiological evidence on the association between dietary calcium and type 2 diabetes (T2D). This study aimed to evaluate the prospective association between dietary calcium and T2D incidence among adults 40 years of age or over, from the Multi-rural Communities Cohort (MRCohort), South Korea.

METHODS AND RESULTS

In total, 8313 participants (3033 men and 5280 women) who did not have diabetes at baseline were recruited between 2005 and 2013. The incidence rate ratio (IRR) was estimated using a modified Poisson regression model with a robust error estimator. During follow-up (31,570 person-years), 322 T2D cases were newly diagnosed. Dietary calcium (total and vegetable calcium) were inversely associated with the risk of T2D incidence among women (IRR = 0.61, 95% CI = 0.43-0.86, P for trend = 0.007 in third tertile of baseline total calcium intake comparing to the first tertile; IRR = 0.57, 95% CI = 0.39-0.84, P for trend = 0.006 for baseline vegetable calcium intake), not for men. The tendency of those inverse associations remained in both the normal fasting blood glucose group and the impaired fasting blood glucose group and were independent of obesity, smoking, and magnesium intake.

CONCLUSIONS

Total and vegetable calcium may be inversely associated with T2D incidence among women, regardless of impaired fasting blood glucose group or normal group. The associations may be potentially dose-responsive. Moderate dietary calcium may be related to lower risk of T2D incidence comparing to low intake group among women.

On two-stage estimation of structural instrumental variable models

Two-stage least squares estimation is popular for structural equation models with unmeasured confounders. In such models, both the outcome and the exposure are assumed to follow linear models conditional on the measured confounders and instrumental variable, which is related to the outcome only via its relation with the exposure. We consider data where both the outcome and the exposure may be incompletely observed, with particular attention to the case where both are censored event times. A general class of two-stage minimum distance estimators is proposed that separately fits linear models for the outcome and exposure and then uses a minimum distance criterion based on the reduced-form model for the outcome to estimate the regression parameters of interest. An optimal minimum distance estimator is identified which may be superior to the usual two-stage least squares estimator with fully observed data. Simulation studies demonstrate that the proposed methods perform well with realistic sample sizes. Their practical utility is illustrated in a study of the comparative effectiveness of colon cancer treatments, where the effect of chemotherapy on censored survival times may be confounded with patient status.

High reproduction number of Middle East respiratory syndrome coronavirus in nosocomial outbreaks: mathematical modelling in Saudi Arabia and South Korea

Background

Effective countermeasures against emerging infectious diseases require an understanding of transmission rate and basic reproduction number (R₀). R₀ for severe acute respiratory syndrome is generally considered to be >1, whereas that for Middle East respiratory syndrome (MERS) is considered to be <1. However, this does not explain the large-scale outbreaks of MERS that occurred in Kingdom of Saudi Arabia (KSA) and South Korean hospitals.

Aim: To estimate R₀ in nosocomial outbreaks of MERS.

Methods

R₀ was estimated using the incidence decay with an exponential adjustment model. The KSA and Korean outbreaks were compared using a line listing of MERS cases compiled using publicly available sources. Serial intervals to estimate R₀ were assumed to be six to eight days. Study parameters [R₀ and countermeasures (d)] were estimated by fitting a model to the cumulative incidence epidemic curves using Matlab.

Findings

The estimated R₀ in Korea was 3.9 in the best-fit model, with a serial interval of six days. The first outbreak cluster in a hospital in Pyeongtaek had an R₀ of 4.04, and the largest outbreak cluster in a hospital in Samsung had an R₀ of 5.0. Assuming a six-day serial interval, the KSA outbreaks in Jeddah and Riyadh had R₀ values of 3.9 and 1.9, respectively.

Conclusion

R₀ for the nosocomial MERS outbreaks in KSA and South Korea was estimated to be in the range of 2–5, which is significantly higher than the previous estimate of <1. Therefore, more comprehensive countermeasures are needed to address these infections.

The long-term relationship between dietary pantothenic acid (vitamin B5) intake and C-reactive protein concentration in adults aged 40 years and older

BACKGROUND AND AIMS

Low-grade inflammation, represented by minor C-reactive protein (CRP) elevation, has a critical role in the early stages of atherosclerosis, and pantothenic acid (PA) may have an antioxidant effect in inflammatory process. However, the long-term relationship between PA intake and CRP has not yet been studied. The objective of the present study was to evaluate the long-term relationship of PA intake to CRP concentration in healthy adults aged 40 years or older living in a rural area of South Korea.

METHODS AND RESULTS

A total of 908 subjects (349 men, 559 women) with repeated data on dietary PA intake and CRP concentration were included in the final analysis. To represent the long-term effect of PA intake, both PA intake at the baseline and average PA intake were used as the exposure, and CRP concentration at the third visit and its change from the baseline to the third visit were used as the outcome. After adjustment for potential confounders, a significant inverse relationship between PA intake and CRP concentration at the third visit was observed (P for trend = 0.001, β = -0.07 (P-value = 0.001) for PA _baseline; P for trend = <0.0001, β = -0.11 (P-value = 0.0004) for PA _{average (baseline, 2nd, 3rd)}). Higher PA intake was significantly related to lower or attenuated increase in CRP concentration (P for trend = 0.002, β = -0.24 (P-value = 0.002) for PA _baseline; P for trend = 0.001, β = -0.35 (P-value = 0.001) for PA _{average (baseline, 2nd, 3rd)}).

CONCLUSIONS

In conclusion, dietary PA intake was inversely related to subsequent CRP concentration in both men and women aged 40 years or older in South Korea.

Characteristics of pleural effusions in systemic lupus erythematosus: differential diagnosis of lupus pleuritis

We investigated the clinical characteristics of pleural effusion in systemic lupus erythematosus (SLE). A prospective analysis of 17 SLE patients with pleural effusion (seven lupus pleuritis, eight transudative effusions and two parapneumonic effusions) was performed. Thirty non-SLE patients with pleural effusion were recruited as controls. A pleural fluid ANA titer ≥1:160 was found in 8/17 (47.1%) SLE patients and none of the 30 non-SLE patients (p = 0.0001). Pleural fluid to serum C3 ratios were significantly lower in SLE than in non-SLE (median (minimum-maximum) 0.29 (0.03-0.43) versus 0.52 (0.26-0.73), p = 0.0002). Among SLE patients, pleural fluid ANA titers ≥1:160 were more frequently found in patients with lupus pleuritis than in those with pleural effusion from causes other than lupus itself (85.7% versus 20.0%, p = 0.0152). Serum CRP levels were significantly increased in patients with lupus pleuritis compared with SLE patients with transudative pleural effusion (2.30 (0.30-5.66) versus 0.7 (0.12-1.47) mg/dl, p = 0.0062). In conclusion, pleural fluid ANA titer and serum CRP levels are significantly increased in lupus pleuritis.

The association of radiographic progression with serum R-spondin 1 (RSPO1) levels or Dickkopf-1 (DKK1)/RSPO1 ratios in rheumatoid arthritis patients: clinical evidence for reciprocal inhibition between DKK1 and RSPO1

OBJECTIVES

To investigate the clinical implications of serum levels of R-spondin 1 (RSPO1), a natural antagonist for Dickkopf-1 (DKK1), and of DKK1/RSPO1 ratios in rheumatoid arthritis (RA) patients.

METHOD

Serum DKK1 and RSPO1 levels were measured in 102 RA patients and 39 age- and gender-matched healthy controls. In addition, DKK1 and RSPO1 levels were determined prior to and 3 months after anti-tumour necrosis factor alpha (anti-TNF-α) therapy in 15 RA patients. Clinical and laboratory data and baseline radiographs of the hands and feet were obtained. Serial radiographs were evaluated in 83 RA patients. Radiographic joint damage was assessed by the modified Sharp/van der Heijde score (SHS).

RESULTS

Serum RSPO1 levels were significantly reduced whereas serum DKK1 levels and DKK1/RSPO1 ratios were significantly increased in RA patients compared with controls (all p < 0.0001). Anti-TNF-α treatment significantly suppressed DKK1/RSPO1 ratios (p < 0.01). In contrast to DKK1 or RSPO1 levels, the ratios were significantly associated with erosive disease, elevated acute phase reactants, Disease Activity Score in 28 joints (DAS28) > 3.2, and radiographic progression rate (all p < 0.05). Although the RA patients with radiographic progression exhibited significantly increased DKK1 and reduced RSPO1 levels (p < 0.05), only the DKK1/RSPO1 ratio (log-transformed) was found to be a significant predictor of subsequent radiographic progression [odds ratio (OR) 2.07, p < 0.01].

CONCLUSIONS

In this study, the presence of RSPO1 in the circulation was shown for the first time. Our results suggest that the serum DKK1/RSPO1 ratio represents a better predictor of structural progression than either DKK1 or RSPO1 levels alone in RA patients.

Harmful and beneficial relationships between alcohol consumption and subclinical atherosclerosis

BACKGROUND AND AIMS

Arterial stiffness and increased intima-media wall thickness are two of the main predictors of cardiovascular disease (CVD). We evaluated whether brachial-ankle pulse wave velocity (baPWV) and common carotid artery intima-media wall thickness (CCA-IMT) are correlated with alcohol consumption in a cross-sectional study among Korean men and women aged 40 years and over.

METHODS AND RESULTS

All 5539 subjects (2121 men and 3418 women) were participants in the Multi-Rural Communities cohort (MRcohort) study, a part of the Korean Genome Epidemiology Study (KoGES). The baPWV was positively correlated with alcohol consumption in men (p for trend <0.0001). Age (middle-aged versus elderly) modified the effect of alcohol consumption on PWV. On the other hand CCA-IMT decreased with alcohol consumption in men. There was no favorable zone of alcohol consumption in terms of baPWV and CCA-IMT. Adjustment for lipid profiles substantially attenuated the relationship between alcohol consumption and CCA-IMT. There was no clear relation between alcohol consumption and baPWV/CCA-IMT in women.

CONCLUSIONS

Along with a linear harmful relationship between alcohol consumption and arterial stiffness in men there may also be a beneficial relationship between alcohol consumption and carotid intima-wall thickness. The effect of alcohol on arterial stiffness may be slightly stronger in elderly men, and the effect of alcohol on CCA-IMT may be mediated by lipid factors.

Costs of illness and quality of life in patients with systemic lupus erythematosus in South Korea

OBJECTIVE

To assess the costs of illness, health-related quality of life (HRQOL) and their associated factors in patients with systemic lupus erythematosus (SLE) in South Korea.

METHOD

Two hundred and one patients with SLE were enrolled at the Rheumatology clinic of Seoul National University Hospital. Direct, indirect and total costs and HRQOL were measured using hospital electronic data and face-to-face interview. Socio-demographic and clinical factors associated with cost of illness and HRQOL were analyzed using multiple regression and multivariate logistic regression.

RESULTS

The average total cost of illness was estimated to be KRW 9.82 million (US $ 8993) per year, of which 41.6% was accounted for by direct costs and 58.4% by indirect costs. In multivariate regression, patients with renal involvement and those with depression incurred an average increment in annual total costs of 37.6% (p = 0.050) and 49.1% (p = 0.024), respectively, and an average increment in annual direct costs of 26.4% (p = 0.050) and 43.3% (p = 0.002), respectively, compared with patients without renal involvement and depression, respectively. In addition, disease damage was positively associated with an average increment in annual total and direct costs (55.3%, p = 0.006; 33.3%, p = 0.013, respectively), and the occurrence of indirect costs (OR 2.21, 1.09-4.88). There was no significant difference in HRQOL between patients with and without renal involvement (0.655 vs. 0.693, p = 0.203) CONCLUSION: Renal involvement, depression, and disease damage were major factors associated with higher total and medical costs for patients with SLE in South Korea. Effective treatment of renal disorders and depression may reduce the high economic burden of SLE.

A cross-sectional analysis of the relationship between daily alcohol consumption and serum adiponectin levels among adults aged 40 years or more in a rural area of Korea

BACKGROUND/OBJECTIVES

Light-to-moderate alcohol consumption has been proposed to raise serum adiponectin levels, but this view is controversial. There is little information on the effect of heavy drinking. The aim of this study was to examine the relationship between alcohol consumption and serum adiponectin levels in healthy Koreans.

SUBJECTS/METHODS

The design of the study was cross-sectional, using data from the Korean Multi-Rural Communities Cohort Study (MRCohort), which is a part of the Korean Genome Epidemiology Study (KoGES). The subjects were 1542 individuals (635 men and 907 women) aged ≥ 40 years who were recruited in Yangpyeong-Gun, Kyunggi province, South Korea, in 2005 and 2006. Daily alcohol consumption was calculated from average frequency of alcohol consumption and the amount of alcohol consumed per occasion using a structured questionnaire and serum adiponectin levels were measured.

RESULTS

Although adiponectin levels appeared to be higher in those consuming moderate levels of alcohol than in nondrinkers, the difference was not statistically significant. Heavy drinking (≥ 90.0 g/day) was significantly related to reduced serum adiponectin levels (P=0.003), although the significance of the relationship was reduced after adjusting for potential confounders (P=0.061) such as age, waist/hip ratio, blood pressure, fasting blood glucose, current smoker, higher education, protein intake, vitamin C intake and vitamin E intake in men. The relation seemed to be stronger in individuals consuming alcohol in the form of takju (Korean rice wine; P=0.022).

CONCLUSIONS

Heavy alcohol drinking (≥ 90.0 g/day) may be related to lower serum adiponectin levels in Korean men.

Metabolomic approach for age discrimination of Panax ginseng using UPLC-Q-Tof MS

An ultraperformance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q-Tof MS)-based metabolomic technique was applied for metabolite profiling of 60 Panax ginseng samples aged from 1 to 6 years. Multivariate statistical methods such as principal component analysis and hierarchical clustering analysis were used to compare the derived patterns among the samples. The data set was subsequently applied to various metabolite selection methods for sophisticated classification with the optimal number of metabolites. The results showed variations in accuracy among the classification methods for the samples of different ages, especially for those aged 4, 5, and 6 years. This proposed analytical method coupled with multivariate analysis is fast, accurate, and reliable for discriminating the cultivation ages of P. ginseng samples and is a potential tool to standardize quality control in the P. ginseng industry.

The expression of phospho-AKT, phospho-mTOR, and PTEN in extrahepatic cholangiocarcinoma

PURPOSE

The protein kinase B (AKT) pathway plays a key role in the regulation of cellular survival, apoptosis, and protein translation, and has been shown to have prognostic significance in a number of cancers. We sought to define its role in extrahepatic cholangiocarcinoma.

EXPERIMENTAL DESIGN

Two hundred twenty-one extrahepatic cholangiocarcinoma patients with clinicopathologic data, including survival, were arrayed into tissue microarrays. Phosphorylated AKT (p-AKT), phosphorylated mammalian target of rapamycin (p-mTOR), and total phosphatase and tensin homolog deleted on chromosome 10 (PTEN) protein expressions were studied with multiplex tissue immunoblotting assay.

RESULTS

Expressions of p-AKT and p-mTOR were significantly increased in extrahepatic cholangiocarcinoma cases compared with normal and dysplastic bile duct epithelium (P < 0.05 both). Decreased PTEN expression was observed in patients with increasing depth of invasion (P < 0.05), T classification (P < 0.05), and stage grouping (P < 0.05), and the presence of invasion of the pancreas (P < 0.05) and duodenum (P < 0.05). Decreased PTEN expression (P = 0.004) as well as decreased PTEN/p-AKT (P = 0.003) and PTEN/p-mTOR (P = 0.009) expression showed shorter survival by univariate but not by multivariate analysis.

CONCLUSIONS

The AKT pathway is activated in a subset of extrahepatic cholangiocarcinoma. Elevated PTEN expression correlates with longer survival. Quantitative data obtained by multiplex tissue immunoblotting may provide additional information than assessment of immunohistochemistry alone. Quantitative analysis of PTEN, PTEN/p-AKT and PTEN/p-mTOR shows differences in survival by univariate analysis.

Segregation of enlarged vestibular aqueducts in families with non-diagnostic SLC26A4 genotypes

BACKGROUND

Hearing loss with enlarged vestibular aqueduct (EVA) can be inherited as an autosomal recessive trait caused by bi-allelic mutations of SLC26A4. However, many EVA patients have non-diagnostic SLC26A4 genotypes with only one or no detectable mutant alleles.

METHODS AND RESULTS

In this study, the authors were unable to detect occult SLC26A4 mutations in EVA patients with non-diagnostic genotypes by custom comparative genomic hybridisation (CGH) microarray analysis or by sequence analysis of conserved non-coding regions. The authors sought to compare the segregation of EVA among 71 families with two (M2), one (M1) or no (M0) detectable mutant alleles of SLC26A4. The segregation ratios of EVA in the M1 and M2 groups were similar, but the segregation ratio for M1 was significantly higher than in the M0 group. Haplotype analyses of SLC26A4-linked STR markers in M0 and M1 families revealed discordant segregation of EVA with these markers in eight of 24 M0 families.

CONCLUSION

The results support the hypothesis of a second, undetected SLC26A4 mutation that accounts for EVA in the M1 patients, in contrast to non-genetic factors, complex inheritance, or aetiologic heterogeneity in the M0 group of patients. These results will be helpful for counselling EVA families with non-diagnostic SLC26A4 genotypes.

Identities and frequencies of mutations of the otoferlin gene (OTOF) causing DFNB9 deafness in Pakistan

Mutations in OTOF, encoding otoferlin, cause non-syndromic recessive hearing loss. The goal of our study was to define the identities and frequencies of OTOF mutations in a model population. We screened a cohort of 557 large consanguineous Pakistani families segregating recessive, severe-to-profound, prelingual-onset deafness for linkage to DFNB9. There were 13 families segregating deafness consistent with linkage to markers for DFNB9. We analyzed the genomic nucleotide sequence of OTOF and detected probable pathogenic sequence variants among all 13 families. These include the previously reported nonsense mutation p.R708X and 10 novel variants: 3 nonsense mutations (p.R425X, p.W536X, and p.Y1603X), 1 frameshift (c.1103_1104delinsC), 1 single amino acid deletion (p.E766del) and 5 missense substitutions of conserved residues (p.L573R, p.A1090E, p.E1733K, p.R1856Q and p.R1939W). OTOF mutations thus account for deafness in 13 (2.3%) of 557 Pakistani families. This overall prevalence is similar, but the mutation spectrum is different from those for Western populations. In addition, we demonstrate the existence of an alternative splice isoform of OTOF expressed in the human cochlea. This isoform must be required for human hearing because it encodes a unique alternative C-terminus affected by some DFNB9 mutations.

Lack of association between LTA and LGALS2 polymorphisms and myocardial infarction in Japanese and Korean populations

To investigate the recently reported associations of polymorphisms in lymphotoxin-alpha (LTA) and galectin-2 (LGALS2) with myocardial infarction (MI), we analyzed a single nucleotide polymorphism of LTA (LTA 252A>G in LTA intron 1) and that of LGALS2 (LGALS2 3279C>T in LGALS2 intron 1) in Japanese and Korean populations. Although significant associations with MI were not observed in either population, we found that LTA 252GG was significantly associated with the severity of the disease for both the Japanese and Korean populations (P=0.017 and P=0.001, respectively). On the other hand, the polymorphism of LGALS2 was not associated with the severity of coronary atherosclerosis. These observations showed that, while the LTA 252GG genotype might modify the development of coronary atherosclerosis, the relation of LTA and LGALS2 to MI itself remained much less certain.

Relationship between the change in overweight status from childhood to adolescence and metabolic syndrome phenotypes: a 9-year retrospective study

OBJECTIVE

To evaluate how the changes in overweight status from childhood to adolescence are related to metabolic syndrome phenotypes in adolescents.

SUBJECTS AND METHODS

A total 375 adolescents aged 16 years. The overweight status from childhood to adolescence (from 7 years of age to 16 years) was determined by body mass index (BMI, kg/m(2)) calculated from records of the School Physical Examination data. The change in body weight was classified into four groups: normal weight to normal weight (NW-NW); overweight to normal (OW-NW); normal to overweight (NW-OW); overweight to overweight (OW-OW). Metabolic syndrome phenotypes were examined from a cross-sectional survey.

RESULTS

The mean values of all phenotypes except for body fatness (BMI and waist) and the cluster score of phenotypes at 16 years of age were not different between the NW-NW group and the OW-NW group, nor between the NW-OW group and the OW-OW group. However, the score as well as the level of body fatness and blood glucose were significantly different between current overweight and normal adolescents regardless of overweight status during childhood (P<0.05).

CONCLUSION

There was a linear relationship between overweight status during childhood and metabolic syndrome phenotypes in adolescence but current overweight status (adolescence overweight) was more closely related to the adolescent risk of metabolic syndrome than childhood overweight status.

A seroprevalence study of poliovirus antibody among primary schoolchildren in Korea

We aimed to determine the seroprevalence of poliovirus antibody in Korea by using the cell culture neutralization method recommended by the WHO. A total of 500 sera collected from children at eight primary schools in Kyunggi province were used for this study. We found that 82.2% of children were positive for all three types of poliovirus and antibody-positive rates for types I, II and III were 94.4, 96.6 and 86.8% respectively, indicating that seropositive rates for types I and II were considerably higher than for type III (P<0.0001). This result implies that the type III component of the oral polio vaccine should be evaluated further. Although a greater number of children, including young infants, need to be tested for seroprevalence, this study still provides us with valuable information on the effectiveness of vaccination against polioviruses in Korea.

Rubella antibody loss rates in Korean children

We followed students in eight elementary schools for rubella antibody from 1993 to 1996 (602 pairs) and 1996-9 (588 pairs) in Gyeonggi Province, Korea. We tested rubella IgG and administered rubella vaccine to the children with the titres < 10 IU/ml. The loss rates of rubella IgG during the follow-up periods were 14.3 and 15.8%, respectively. Among vaccinated groups, the loss rate was 18.8%, which was significantly higher than 13.8% of the mixture of natural and vaccine-induced immunity groups. The group that had the lower preceding antibody titre had a higher loss rate of 24.8% compared to 7.2% for the group whose titre was 40 IU/ml or above. In a multivariate analysis, age and gender were not related to antibody loss rate. Under this higher rubella antibody loss rate, in order to prevent congenital rubella syndrome, the immunization for women at childbearing age appears necessary until rubella can be eliminated or controlled.

Preparation of alginate beads for floating drug delivery system: effects of CO(2) gas-forming agents

Floating beads were prepared from a sodium alginate solution containing CaCO(3) or NaHCO(3) as gas-forming agents. The solution was dropped to 1% CaCl(2) solution containing 10% acetic acid for CO(2) gas and gel formation. The effects of gas-forming agents on bead size and floating properties were investigated. As gas-forming agents increased, the size and floating properties increased. Bead porosity and volume average pore size, as well as the surface and cross-sectional morphology of the beads were examined with Mercury porosimetry and Scanning Electron Microscopy. NaHCO(3) significantly increased porosity and pore diameter than CaCO(3). Incorporation of CaCO(3) into alginate solution resulted in smoother beads than those produced with NaHCO(3). Gel strength analysis indicated that bead strength decreased with increasing gas-forming agent from 9 to 4 N. Beads incorporating CaCO(3) exhibited significantly increased gel strength over control and NaHCO(3)-containing samples. Release characteristics of riboflavin as a model drug were studied in vitro. Release rate of riboflavin increased proportionally with addition of NaHCO(3). However, increasing weight ratios of CaCO(3) did not appreciably accelerate drug release. The results of these studies indicate that CaCO(3) is superior to NaHCO(3) as a gas forming agent in alginate bead preparations. The enhanced buoyancy and sustained release properties of CaCO(3)-containing beads make them an excellent candidate for floating drug dosage systems (FDDS).

Multicenter study on the prevalence of perennial allergic rhinitis and allergy-associated disorders

Multicenter Study on the Prevalence of Perennial Allergic Rhinitis and Allergy-Associated Disorders This study was aimed to determine the prevalence of perennial allergic rhinitis (PAR) using the skin test, radioallergosorbent test (RAST), or multiple allergosorbent test (MAST) and to clarify the clinical aspects of the patients diagnosed as having PAR by the questionnaire survey and rhinologic examination. The 71,120 subjects who had visited the 23 otolaryngology clinics at the randomly selected tertiary referral hospitals in Korea between November 1, 1999 and April 30, 2000 were studied. PAR was diagnosed when subjects complained of two or more associated symptoms and the skin test, RAST, or MAST using perennial inhalant allergens was positive. The questionnaire survey and rhinologic examination were performed in subjects with PAR. The prevalence of PAR was 3.93%. We could find no significant difference in the prevalence of PAR between the two sexes. However, there was a significant difference in the prevalence of PAR between the child and adult groups. The chief complaints were, in order of decreasing frequency, nasal obstruction, watery rhinorrhea, and sneezing. There was a family history of PAR in 40.2% of the subjects. The 39.6% of the subjects had associated allergic diseases, being atopic dermatitis most common. In conclusion, the prevalence of PAR in tertiary referral hospitals in Korea is 3.93%. Many subjects with PAR have family history and appear to be associated with other allergic diseases.

Association between Helicobacter pylori infection and the risk of gastric cancer in the Korean population: prospective case-controlled study

BACKGROUND

Gastric cancer is still the most common malignant tumor in Koreans. Although many reports have supported the association of Helicobacter pylori infection and the development of gastric cancer, few studies have been adjusted by variable factors such as age. sex, education, and economic status. Furthermore, most results from areas with a high incidence of gastric cancer, such as China and Korea, have failed to document any relationship between H. pylori infection and gastric cancer. We conducted a prospective case-controlled study, with controls matched for and adjusted by age, sex, education, and economic status, to evaluate the causal relationship between H. pylori infection and gastric cancer in Korean people.

METHODS

From March 1997 to October 1998, 136 consecutive patients with gastric cancer, diagnosed by endoscopic histology, and 136 age- and sex-matched control subjects, confirmed to be free of gastric cancer by endoscopy during the same period, were enrolled in the study. The presence of H. pylori infection was determined by enzyme immunoassay (EIA) serology test.

RESULTS

Seventy-two of the 136 gastric cancer patients (53%) were positive for H. pylori infection and 54 of the 136 control subjects (40%) were positive for H. pylori infection. The odds ratio (OR), adjusted by variable risk factors, such as age, sex, education, and economic status, for gastric cancer in H. pylori-infected patients was 1.82 (95% confidence internal [CI], 1.10-3.00; P = 0.019). The age- and sex-matched OR by conditional logistic regression was 1.6 (95% CI., 1.01-2.53; P = 0.043).

CONCLUSIONS

H. pylori infection may be one of the important risk factors for the development of gastric cancer in Korea, an area of high prevalence of H. pylori infection and a high incidence of gastric cancer.

Clinical application of continent anal plug in bedridden patients with intractable diarrhea

PURPOSE

Some patients bedridden from various causes such as stroke or spinal cord injury experience poor control of bowel movement. This causes fecal leakage and diarrhea, increases the risk of perianal excoriation and bed sores, and is a burden on caregivers. To evaluate the efficacy of fecal evacuation and the prevention and treatment of skin complications in intractable diarrhea patients using a new device.

METHODS

A continent anal plug (US Patent No. 5 569 216) comprises an inner balloon surrounded by an outer balloon, both of which are mounted on a silicone tube containing a pair of air passages and an enema fluid inlet. The tube is secured in place in the rectum by the inflatable outer balloon and is designed to drain fecal matter through a thin collapsible hose situated in the anal canal. Thirty-two patients (21 male; median age 61 (range, 28-76) years) were evaluated after fully informed consent. Median duration was 12 (range, 3-37) days.

RESULTS

The continent anal plug evacuated efficiently in those patients with loose or watery stools who only required irrigation once daily or not at all. Skin excoriations improved in three to seven days. Minimal leakage was seen around the anus. There was no anorectal mucosal injury noted over 37 days.

CONCLUSIONS

The continent anal plug is an efficient method of treating patients with loss of bowel control and incontinence because it enables controlled fecal evacuation and helps reduce skin complications without causing anorectal mucosal injury.