Prevalence of methicillin-resistant Staphylococcus aureus (MRSA) nasal colonization among dental professionals

Background. MRSA (methicillin-resistant Staphylococcus aureus) is a multi-drug resistant bacterium that is quite prevalent in social environments where close person-to-person contact and crowding are an issue. In dental settings, the likelihood of transmission of MRSA may be higher than among other healthcare practitioners because of the close proximity between a patient's nose (where MRSA colonizes) and the field of procedure (the mouth) to the dental professional. Objective. To estimate the prevalence of MRSA nasal colonization among dental professionals (dentists and dental hygienists) in the Greater Houston Metropolitan Area, Texas, and analyze its associations with demographic, professional and personal protective equipment-related variables. Methods. 800 dental professionals (400 dentists and 400 dental hygienists) were randomly selected in the Greater Houston Metropolitan Area. Multiple waves of nasal swab kits and a self-administered questionnaire were mailed to increase the response rate of the study population. The swabs were cultured on chromagenic agar growth medium and bacterial growth results were evaluated after 18 hours. Positively selected bacterial colonies were confirmed as MRSA by further culturing these isolated bacteria on blood agar plates. Associations between positive nasal swabs and self-reported professional practice patterns, personal protective equipment use and demographics were analyzed using multiple logistic regression. Main Results. Completed questionnaires and nasal swabs were received from 496 study participants (68%). Fourteen cultures were positive for MRSA (4.2% among dentists and 1.6% among dental hygienists, p=0.07). After adjusting for gender, dental hygienists had a significantly lower prevalence of nasal colonization of MRSA as compared to dentists (OR: 0.20, 95% CI: 0.05–0.75). No other significant associations or interactions were found. Conclusion. The prevalence of nasal colonization with MRSA among dentists is similar to that reported for health care workers in general, whereas prevalence among dental hygienists is only slightly above that of the general population (1%). Differences in practice patterns and use of personal protective equipment did not explain this difference in this study, and was possibly due either to residual confounding or unexplored risk factors. Increased prevalence of MRSA among dentists warrants further investigation as to the reason for the increased rate and to allow implementation of measures to avoid transmission and progression to disease. ^

A novel method for evaluating an interaction effect of correlated continuous covariates in a linear model

Interaction effect is an important scientific interest for many areas of research. Common approach for investigating the interaction effect of two continuous covariates on a response variable is through a cross-product term in multiple linear regression. In epidemiological studies, the two-way analysis of variance (ANOVA) type of method has also been utilized to examine the interaction effect by replacing the continuous covariates with their discretized levels. However, the implications of model assumptions of either approach have not been examined and the statistical validation has only focused on the general method, not specifically for the interaction effect.^ In this dissertation, we investigated the validity of both approaches based on the mathematical assumptions for non-skewed data. We showed that linear regression may not be an appropriate model when the interaction effect exists because it implies a highly skewed distribution for the response variable. We also showed that the normality and constant variance assumptions required by ANOVA are not satisfied in the model where the continuous covariates are replaced with their discretized levels. Therefore, naïve application of ANOVA method may lead to an incorrect conclusion. ^ Given the problems identified above, we proposed a novel method modifying from the traditional ANOVA approach to rigorously evaluate the interaction effect. The analytical expression of the interaction effect was derived based on the conditional distribution of the response variable given the discretized continuous covariates. A testing procedure that combines the p-values from each level of the discretized covariates was developed to test the overall significance of the interaction effect. According to the simulation study, the proposed method is more powerful then the least squares regression and the ANOVA method in detecting the interaction effect when data comes from a trivariate normal distribution. The proposed method was applied to a dataset from the National Institute of Neurological Disorders and Stroke (NINDS) tissue plasminogen activator (t-PA) stroke trial, and baseline age-by-weight interaction effect was found significant in predicting the change from baseline in NIHSS at Month-3 among patients received t-PA therapy.^

Occupation and glioma: The Harris County Brain Tumor Study, 2001--2010

The relationship between occupational exposures and glioma has not been adequately assessed due to the lack of studies in current scientific literature. To address this disparity, the Harris County Brain Tumor Study, an ongoing population-based case-control study, began in January 2001. Longest-held occupation for 382 cases and 629 controls were frequency matched on age (within 5 years), sex, and race and placed into 14 predetermined occupational categories. Adjusted odds ratios and 95% confidence intervals were calculated for each category using multiple logistic regression. Potential confounders assessed included sex, age, smoking status, education and income. For all subjects, significantly elevated adjusted odds ratios were found in health-related (aOR=1.66; 95%CI=1.03, 2.68), teaching (aOR=1.84; 95%CI=1.17, 2.88), and protective service (aOR=3.6; 95%CI=1.05, 12.31) occupational categories after controlling for sex and education. A significantly lowered odds ratio was seen in the writers, artists, and entertainers category (aOR=0.14; 95%CI=0.03, 0.58). In the stratified analyses, which controlled for education, males had a significantly elevated odds ratio for protective service workers (aOR=4.83; 95%CI=1.24, 18.83) while a significantly lower odds ratio was found in mechanics and machine operators (aOR=0.33; 95%CI=0.12,0.87). In females, we observed a significantly elevated odds ratio in teachers (aOR=1.99; 95%CI=1.20,3.31) and a significantly lower odds ratio in clerical workers (aOR=0.63; 95%CI=0.45,0.90). These analyses revealed several significant associations and allowed for separate analyses by gender, distinguishing this study from many glioma studies. Further analyses should provide a large enough sample size to stratify by gender as well as histological subtype.^

Penetrating injuries of the thorax and abdomen: Type of medical-care institution and case fatality

The purpose of this study was to determine, for penetrating injuries (gunshot, stab) of the chest/abdomen, the impact on fatality of treatment in trauma centers and shock trauma units compared with general hospitals. Medical records of all cases of penetrating injury limited to chest/abdomen and admitted to and discharged from 7 study facilities in Baltimore city 1979-1980 (n = 581) were studied: 4 general hospitals (n = 241), 2 area-wide trauma centers (n = 298), and a shock trauma unit (n = 42). Emergency center and transferred cases were not studied. Anatomical injury severity, measured by modified Injury Severity Score (mISS), was a significant prognostic factor for death, as were cardiovascular shock (SBP $\le$ 70), injury type (gunshot vs stab), and ambulance/helicopter (vs other) transport. All deaths occurred in cases with two or more prognostic factors. Unadjusted relative risks of death compared with general hospitals were 4.3 (95% confidence interval = 2.2, 8.4) for shock trauma and 0.8 (0.4, 1.7) for trauma centers. Controlling for prognostic factors by logistic regression resulted in these relative risks: shock trauma 4.0 (0.7, 22.2), and trauma centers 0.8 (0.2, 3.2). Factors significantly associated with increased risk had the following relative risks by multiple logistic regression: SBP $\le$ 70 (RR = 40.7 (11.0, 148.7)), highest mISS (42 (7.7, 227)), gunshot (8.4 (2.1, 32.6)), and ambulance/helicopter transport (17.2 (1.3, 228.1)). Controlling for age, race, and gender did not alter results significantly. Actual deaths compared with deaths predicted from a multivariable model of general-hospital cases showed 3.7 more than predicted deaths in shock trauma (SMR = 1.6 (0.8, 2.9)) and 0.7 more than predicted deaths in area-wide trauma centers (SMR = 1.05 (0.6, 1.7)). Selection bias due to exclusion of transfers and emergency center cases, and residual confounding due to insufficient injury information, may account for persistence of adjusted high case fatality in shock trauma. Studying all cases prospectively, including emergency center and transferred cases, is needed. ^

Low birthweight and the risk of developing subsequent high blood pressure and/or dyslipidemia in childhood

The association between birthweight and blood pressure (BP), and birthweight and serum lipid concentrations at age 7 through 11 years was examined in 1446 black and white children. The prevalence ratio (with 95% confidence interval) for being in the race-, sex- and age-specific upper decile of diastolic BP in children born with low birthweight (LBW, $<$2500 grams) versus children with birthweight $\geq$2500 grams was for black boys, 2.66 (1.24-5.70). In the other race-sex groups for diastolic BP, and in all race-sex groups for systolic BP this ratio did not differ from one. Among white boys with LBW, but not in the other race-sex groups, higher than expected percentages of subjects were in the highest decile group of triglyceride concentrations (0.01 $<$ p $<$ 0.05). The prevalence ratio was 2.42 (1.19-4.91). When prematures were excluded only more than expected white girls with LBW were in the highest decile group of triglyceride concentrations. The prevalence ratio was 3.23 (1.16-9.00). Prevalence ratios for triglyceride concentrations in black boys and girls, and for LDL/HDL-C ratio, cholesterol and VLDL-C concentrations in all race-sex groups were not different from one in analyses including and in those excluding prematures. Mean triglyceride concentrations stratified by tertiles of Quetelet Index, race and sex showed a strongly positive association between triglyceride concentrations and Quetelet Index, and in the upper tertile of the Quetelet Index an association between LBW and raised triglyceride concentrations. Multiple linear regression analyses showed that after adjusting for sex, race and age present Quetelet Index (p $<$ 0.001) is a much stronger predictor of systolic and diastolic BP, and also of LDL-C/HDL-C ratio and triglyceride concentrations in this age group than birthweight (p $>$ 0.05). Thus, an association between LBW and subsequent risk for elevated BP was confirmed for diastolic BP in black boys, but not for the other race-sex groups, and not for systolic BP in any group. This is the first study finding an association between LBW and elevated triglyceride concentrations in boys (white and black) and girls (white). A follow-up study to assess whether the findings can be confirmed at adult age is recommended. ^

Hispanic incorporation and access to health care in Houston and Harris County, Texas: Adopting an Hispanic perspective to the Aday and Andersen model

This study examines Hispanic levels of incorporation and access to health care. Applying the Aday and Andersen framework for the study of access, the study examined the relationship between two levels of Hispanic incorporation into U.S. society, i.e., mainstream versus ethnic, and potential and realized measures of access to health care. Data for the study were drawn from a 1992 telephone survey of 600 randomly selected Hispanics in Houston and Harris County.^ The hypotheses tested were: (1) Hispanics who are incorporated into mainstream society are more likely to have better potential and realized access to health care than those who are incorporated into ethnic-group enclaves regardless of their socioeconomic status (SES), health status and health needs, and (2) there is no interaction between the levels of incorporation (mainstream or ethnic) and SES, health status, and health needs in predicting potential and realized access.^ The data analysis supported Hypothesis One for the two measures of potential access. The results of bivariate and multiple logistic regression analyses indicated that for Hispanics in Houston and Harris County, being in the "mainstream" incorporation category increased their potential access to care, having "health insurance" and a "regular place of care". For the selected measure of realized access, having a "regular check-up", the analysis did not demonstrate statistically significant differences in having a regular check-up among Hispanics incorporated in the ethnic or mainstream incorporation categories.^ Hypothesis Two, that there is no interaction between the levels of incorporation and socioeconomic characteristics, health status, and health needs in predicting potential and realized access among Hispanics was supported by the data. The results of the logistic regression analysis showed that, after adjusting for socioeconomic status, health status, and health needs, the association between "level of incorporation" and the two measures of potential access ("health insurance" and having a "usual place of care") was not modified by the control variables nor by their interaction with level of incorporation. That is, the effect of incorporation on Hispanics' health insurance coverage, and having a usual place of care, was homogenous across Hispanics with different SES and health status.^ The main research implication of this dissertation is the employment of a theoretical framework for the assessment of cultural factors essential to research on migrating heterogeneous subpopulations. It also provided strategies to solve practical and methodological difficulties in the secondary analyses of data on these populations. ^

The role of serotonin in depression and clotting in the coronary artery disease population

Background: The mechanisms underlying the relationship between depression and acute coronary syndrome (ACS) remain unclear. Platelet serotonin has been associated with both depression and coronary artery disease in stable outpatients. Understanding the association between depression and platelet serotonin, during ACS, may explain some of the acute cardiovascular events seen in some individuals with depression. ^ Objectives: This study was designed to evaluate whether levels of platelet serotonin, during ACS, differ between individuals who screen positive for depression and individuals who screen negative for depression and to determine if a dose-response relationship exists between depressive symptoms and platelet serotonin levels. ^ Methods: In this cross-sectional study, data was collected on 51 patients hospitalized for ACS. Multiple linear regression models were used to determine if a relationship exists between depression and platelet serotonin levels. ^ Results: Of the 51 ACS patients, 24 screened positive for depression and 27 screened negative for depression. Platelet serotonin levels were not significantly different between the depressed group (942.10 ± 461.3) and the non-depressed group (1192.41 ± 764.3) (p= .293 and β= -4.093) and a dose-response relationship between depressive symptoms and platelet serotonin levels was not found (p= .250 and β= -.254). ^ Discussion: In this study, a relationship between depression and platelet serotonin levels was not found. Future research should focus on gaining a better understanding of the variables that may influence platelet serotonin levels in the ACS population. ^

Investigating the effects of the 2007 Texas tobacco tax increase on the smoking behavior of adults

Smoking is major cause of premature mortality and morbidity in the United States. The health consequences of tobacco usage are increasingly concentrated in minority and lower socioeconomic groups. One of the most effective means of deterring tobacco consumption and generating revenue to fund prevention activities is the levying of excise taxes. In 2007 the state of Texas increased the excise tax on cigarettes by $1.00 per pack. This study sought to determine if there was a significant effect on smoking prevalence in the state by examining Behavioral Risk Factor Surveillance System (BRFSS) data for two years leading up to the tax increase-2005 and 2006- and two years post tax increase -2007 and 2008. Results were compared against a chi square distribution and three multiple logistic regression models were created to adjust for race/ethnicity, age, education and income. Results from this study show that there was not a significant decrease in smoking prevalence for most of the groups stratified by age, income and ethnicity. There was not a significant decrease in the younger adults aged 18-34 by income, ethnicity, or education. Smoking prevalence increased for some groups, e.g., Hispanic females. In the regression models, the tax effect was not significant. While overall prevalence decreased by 9%, there were not significant reductions among non-White or Hispanic survey participants. Taxed sales dropped by approximately 17% according to the Texas Comptroller. Without BRFSS data measuring daily cigarette consumption among current smokers, now not assessed, it is impossible to determine whether the discrepancy in reported prevalence and taxes sales is attributable to consumption of fewer cigarettes among smokers or tax avoidance.^

Tuberculosis in HIV-infected individuals in Ho Chi Minh City, Vietnam

Early and accurate detection of TB disease in HIV-infected individuals is a critical step for a successful TB program. In Vietnam, the diagnosis of TB disease, which is based predominantly on the clinical examination, chest radiography (CXR) and acid fast bacilli (AFB) sputum smear, has shown to be of low sensitivity in immunocompromised patients. The sputum culture is not routinely performed for patients with AFB negative smears, even in HIV-infected individuals.^ In that background, we conducted this cross-sectional study to estimate the prevalence of sputum culture-confirmed pulmonary tuberculosis (PTB), smear-negative PTB, and multidrug-resistant TB (MDR-TB) in the HIV-infected population in Ho Chi Minh City (HCMC), the largest city in Vietnam where both TB and HIV are highly prevalent. We also evaluated the diagnostic performance of various algorithms based on routine available tools in Vietnam such as symptoms screening, CXR, and AFB smear. Nearly 400 subjects were consecutively recruited from HIV-infected patients seeking care at the An Hoa Clinic in District 6 of Ho Chi Minh City from August 2009 through June 2010. Participants’ demographic data, clinical status, CXR, and laboratory results were collected. A multiple logistic regression model was developed to assess the association of covariates and PTB. ^ The prevalence of smear-positive TB, smear-negative TB, resistant TB, and MDR-TB were 7%, 2%, 5%, 2.5%, and 0.3%, respectively. Adjusted odds ratios for low CD4+ cell count, positive sputum smear, and CXR to positive sputum culture were 3.17, 32.04, and 4.28, respectively. Clinical findings alone had poor sensitivity, but the combination of CD4+ cell count, sputum smear, and CXR proved to perform a more accurate diagnosis.^ This study results support the routine use of sputum culture to improve the detection of TB disease in HIV-infected individuals in Vietnam. When routine sputum culture is not available, an algorithm combining CD4+ cell count, sputum smear, and CXR is recommended for diagnosing PTB. Future studies on more affordable, rapid, and accurate tests for TB infection would also be necessary to timely provide specific treatments for patients in need, reduce mortality, and minimize TB transmission to the general population.^

Cross-sectional study examining the role of acculturation in self-reported hypertension among Mexican Americans in Harris County, Texas

The objective of this secondary analysis was to examine the role of acculturation and self-reported hypertension in a Mexican-American cohort from Harris County, Texas. Specifically, we examined the acculturation measures of language-based Bidimensional Acculturation Scale (BAS), nativity, and length of United States (U.S) residency. Of 6,229 participants aged 40 and older, 38.0% self-reported hypertension at baseline. ^ Multiple logistic regression was used to estimate the prevalence odds ratios (pOR) for the association of each acculturation measure and hypertension while controlling for confounding. When adjusted for age, gender, body mass index, number of comorbidities, and family history of hypertension, U.S.-born participants were 1.37 times more likely to report having hypertension compared to Mexico-born participants (95% CI: 1.21, 1.55). Similarly, immigrants residing in the U.S. for more than 20 years had an adjusted pOR of 1.40 (95% CI: 1.16, 1.70) as compared to immigrants living in the U.S. for less than 10 years. ^ In conclusion, individuals who were born in the U.S. or emigrated to the U.S. over 20 years ago were more likely to report having hypertension compared to individuals born in Mexico or compared to those who emigrated more recently to the U.S. This study will contribute to the literature in demonstrating the need for more initiatives in prevention of cardiovascular disease, specifically hypertension, in the acculturating Mexican American population.^

The role and impact of transitional care utilization in colorectal cancer

BACKGROUND Although one out of every five gastrointestinal cancer patients needs transitional care (home-based skilled care or placement in skilled nursing or rehabilitation facilities) following treatment, few studies have examined outcomes in this population compared to patients who return home without assistance. This study has two primary goals: 1. To evaluate long-term cancer-specific outcomes in colorectal cancer patients utilizing transitional care compared to those that return home without assistance following therapy 2. To compare results using standard regression techniques and propensity scores. ^ METHODS Patients undergoing curative surgery for colorectal adenocarcinoma will be identified using data from a tertiary care Veterans Administration hospital. Survival and recurrence will then be determined from VA records and the Social Security Death Index. ^ The association between transitional care utilization and overall and disease-free survival will be evaluated using Cox proportional hazards regression to adjust for confounding factors. Predictors of transitional care utilization will be assessed using multiple logistic regression to generate a propensity score which will also be used to assess differences in survival based on transitional care use. ^ POTENTIAL SIGNIFICANCE If transitional care utilization is associated with worse survival and recurrence following therapy then it will be important to subsequently assess the mechanism in order to target interventions to improve outcomes. If there is no difference in cancer-specific outcomes, then this project can potentially highlight benefits of supportive therapy following colorectal cancer resection.^

Identification of genetic variants that influence atherosclerosis in young persons

Atherosclerosis is widely accepted as a complex genetic phenotype and is the usual cause of cardiovascular disease, the world’s leading killer. Genetic factors have been proven to be important risk contributors for atherosclerosis and much work has been done to identify promising candidates that might play a role in the development of atherosclerosis. It is well known that many independent replications are needed to unequivocally establish a valid genotype-phenotype association across different populations before the findings are extended to clinical settings and to the expensive follow-up studies designed to identify causal genetic variants. Aiming to replicate the association with atherosclerosis in the Pathobiological Determinants of Atherosclerosis in Youth (PDAY) study, we assessed the relationship of 32 atherosclerosis candidate SNPs to atherosclerosis in the PDAY cohort, consisting of AA and EA young people aged 15-34 years who died of non-medical causes. Two association studies, a whole sample study and a 1:1 matched case control study were performed by use of multiple linear regression and logistic regression analyses, respectively. For the whole sample association study, 32 SNPs among 2,650 individuals (1,369 AA and 1,281 EA) were tested for the association with six early atherosclerosis phenotypes: abdominal aorta fatty streaks, abdominal aorta raised lesions, right coronary artery fatty streaks, right coronary artery raised lesions, thoracic aorta fatty streaks, and thoracic aorta raised lesions. For the matched case-control association study, 337 case-control paired samples were included; cases were chosen with the highest total raised lesion scores from the studied population, while controls were randomly selected from individuals that had no raised lesions and matched to cases by age, gender and race. Sixteen SNPs in 13 genes were found to be significantly associated with atherosclerosis in at least one of the PDAY association studies. Among these 16 findings: eight SNPs (rs9579646, rs6053733, rs3849150, rs10499903, rs2148079, rs5073691, rs10116277, and rs17228212) successfully replicated previous results, six SNPs (rs17222814, rs10811661, rs7028570, rs7291467, rs16996148 and rs10401969) were reported as new findings exclusive to our study, the last two of the 16 SNPs, rs501120 and rs6922269, showed either intriguing or conflicting result. SNP rs17222814 in ALOX5AP and SNP rs3849150 in LRRC18 were consistently associated with atherosclerosis in both prior and the two PDAY association studies. SNP rs3849150 was also identified to be highly correlated with a non-synonymous coding SNP, rs17772611, which may damage the protein (polyphen score = 0.996), suggesting that SNP rs17772611 may be the causal functional variant.^ In conclusion, our study added more support for the association of these candidate genes with atherosclerosis. SNPs rs3849150 and rs17772611 of LRRC18, as well as SNP rs17222814 of ALOX5AP, were the most significant findings from our study, and may be ranked among the best for further study.^

A comparison of worker risk of injury while working on fully automated side loaders and other residential collection trucks at a large solid waste collection company

The study aim was to determine whether using automated side loader (ASL) trucks in higher proportions compared to other types of trucks for residential waste collection results in lower injury rates (from all causes). The primary hypothesis was that the risk of injury to workers was lower for those who work with ASL trucks than for workers who work with other types of trucks used in residential waste collection. To test this hypothesis, data were collected from one of the nation’s largest companies in the solid waste management industry. Different local operating units (i.e. facilities) in the company used different types of trucks to varying degrees, which created a special opportunity to examine refuse collection injuries and illnesses and the risk reduction potential of ASL trucks.^ The study design was ecological and analyzed end-of-year data provided by the company for calendar year 2007. During 2007, there were a total of 345 facilities which provided residential services. Each facility represented one observation.^ The dependent variable – injury and illness rate, was defined as a facility’s total case incidence rate (TCIR) recorded in accordance with federal OSHA requirements for the year 2007. The TCIR is the rate of total recordable injury and illness cases per 100 full-time workers. The independent variable, percent of ASL trucks, was calculated by dividing the number of ASL trucks by the total number of residential trucks at each facility.^ Multiple linear regression models were estimated for the impact of the percent of ASL trucks on TCIR per facility. Adjusted analyses included three covariates: median number of hours worked per week for residential workers; median number of months of work experience for residential workers; and median age of residential workers. All analyses were performed with the statistical software, Stata IC (version 11.0).^ The analyses included three approaches to classifying exposure, percent of ASL trucks. The first approach included two levels of exposure: (1) 0% and (2) >0 - <100%. The second approach included three levels of exposure: (1) 0%, (2) ≥ 1 - < 100%, and (3) 100%. The third approach included six levels of exposure to improve detection of a dose-response relationship: (1) 0%, (2) 1 to <25%, (3) 25 to <50%, (4) 50 to <75%, (5) 75 to <100%, and (6) 100%. None of the relationships between injury and illness rate and percent ASL trucks exposure levels was statistically significant (i.e., p<0.05), even after adjustment for all three covariates.^ In summary, the present study shows that there is some risk reduction impact of ASL trucks but not statistically significant. The covariates demonstrated a varied yet more modest impact on the injury and illness rate but again, none of the relationships between injury and illness rate and the covariates were statistically significant (i.e., p<0.05). However, as an ecological study, the present study also has the limitations inherent in such designs and warrants replication in an individual level cohort design. Any stronger conclusions are not suggested.^

Geographic variation in the utilization and survival associated with oxaliplatin chemotherapy in patients with stage III colon cancer

Background: Overall objectives of this dissertation are to examine the geographic variation and socio-demographic disparities (by age, race and gender) in the utilization and survival of newly FDA-approved chemotherapy agents (Oxaliplatin-containing regimens) as well as to determine the cost-effectiveness of Oxaliplatin in a large nationwide and population-based cohort of Medicare patients with resected stage-III colon cancer. Methods: A retrospective cohort of 7,654 Medicare patients was identified from the Surveillance, Epidemiology and End Results – Medicare linked database. Multiple logistic regression was performed to examine the relationship between receipt of Oxaliplatin-containing chemotherapy and geographic regions while adjusting for other patient characteristics. Cox proportional hazard model was used to estimate the effect of Oxaliplatin-containing chemotherapy on the survival variation across regions using 2004-2005 data. Propensity score adjustments were also made to control for potential bias related to non-random allocation of the treatment group. We used Kaplan-Meier sample average estimator to calculate the cost of disease after cancer-specific surgery to death, loss-to follow-up or censorship. Results: Only 51% of the stage-III patients received adjuvant chemotherapy within three to six months of colon-cancer specific surgery. Patients in the rural regions were approximately 30% less likely to receive Oxaliplatin chemotherapy than those residing in a big metro region (OR=0.69, p=0.033). The hazard ratio for patients residing in metro region was comparable to those residing in big metro region (HR: 1.05, 95% CI: 0.49-2.28). Patients who received Oxalipaltin chemotherapy were 33% less likely to die than those received 5-FU only chemotherapy (adjusted HR=0.67, 95% CI: 0.41-1.11). KMSA-adjusted mean payments were almost 2.5 times higher in the Oxaliplatin-containing group compared to 5-FU only group ($45,378 versus $17,856). When compared to no chemotherapy group, ICER of 5-FU based regimen was $12,767 per LYG, and ICER of Oxaliplatin-chemotherapy was $60,863 per LYG. Oxaliplatin was found economically dominated by 5-FU only chemotherapy in this study population. Conclusion: Chemotherapy use varies across geographic regions. We also observed considerable survival differences across geographic regions; the difference remained even after adjusting for socio-demographic characteristics. The cost-effectiveness of Oxaliplatin in Medicare patients may be over-estimated in the clinical trials. Our study found 5-FU only chemotherapy cost-effective in adjuvant settings in patients with stage-III colon cancer.^

Bullied status and physical activity in Texas youths

Data from the 2009–2011 School Physical Activity and Nutrition (SPAN) project were analyzed to examine the association between bullied status at school during the past six months and engaging in five or more days of physical activity during the past seven days in a population of 8th and 11th grade Texas youths after stratifying by gender. As a secondary aim, this study also examined the association between weight status and the prevalence of bullied status at school. The final sample size for this study, after excluding missing data, consisted of 6,246 8th and 11th grade youths (girls, n= 3,237; boys, n=3,009) representing a total of 518,838 youths from 8th and 11th grade. Results from the multiple logistic regression adjusting for weight status, grade, and ethnicity, indicate that girls with a bullied status of at least two or three times per month had significantly lower odds of engaging in five or more days of physical activity during the past seven days than girls who were never bullied at school (ORadj=0.62; 95% CI, 0.40, 0.96). Conversely, girls who reported a bullied status of at least once per week were significantly more likely to engage in five or more days of physical activity during the past seven days compared to girls who were never bullied at school (ORadj=3.44; 95% CI, 1.56, 7.63). No significant associations between bullied status and engaging in five or more days of physical activity during the past seven days were found for boys. Bullied status differed significantly across weight status for 8th grade girls (χ2(6)=63.7, p<.05) and 11th grade boys (χ2(6) =94.93, p<.05), with overweight and obese youths reporting a higher prevalence of being bullied once or twice, at least two or three times per month, and at least once per week than their normal weight peers. Our finding that girls with bullied status of at least once per week were more likely to engage in five or more days of physical activity than girls who were never bullied warrants future qualitative research to identify potential explanations for such results. Future research on relational and weight-based bullying is also needed and may help explain the inconsistent findings between bullied status and engaging in physical activity in girls.^