A retrospective cohort study of the duration of hepatitis B vaccine immunity and associated factors in pediatric dialysis patients

Dialysis patients are at high risk for hepatitis B infection, which is a serious but preventable disease. Prevention strategies include the administration of the hepatitis B vaccine. Dialysis patients have been noted to have a poor immune response to the vaccine and lose immunity more rapidly. The long term immunogenicity of the hepatitis B vaccine has not been well defined in pediatric dialysis patients especially if administered during infancy as a routine childhood immunization.^ Purpose. The aim of this study was to determine the median duration of hepatitis B immunity and to study the effect of vaccination timing and other cofactors on the duration of hepatitis B immunity in pediatric dialysis patients.^ Methods. Duration of hepatitis B immunity was determined by Kaplan-Meier survival analysis. Comparison of stratified survival analysis was performed using log-rank analysis. Multivariate analysis by Cox regression was used to estimate hazard ratios for the effect of timing of vaccine administration and other covariates on the duration of hepatitis B immunity.^ Results. 193 patients (163 incident patients) had complete data available for analysis. Mean age was 11.2±5.8 years and mean ESRD duration was 59.3±97.8 months. Kaplan-Meier analysis showed that the total median overall duration of immunity (since the time of the primary vaccine series) was 112.7 months (95% CI: 96.6, 124.4), whereas the median overall duration of immunity for incident patients was 106.3 months (95% CI: 93.93, 124.44). Incident patients had a median dialysis duration of hepatitis B immunity equal to 37.1 months (95% CI: 24.16, 72.26). Multivariate adjusted analysis showed that there was a significant difference between patients based on the timing of hepatitis B vaccination administration (p<0.001). Patients immunized after the start of dialysis had a hazard ratio of 6.13 (2.87, 13.08) for loss of hepatitis B immunity compared to patients immunized as infants (p<0.001).^ Conclusion. This study confirms that patients immunized after dialysis onset have an overall shorter duration of hepatitis B immunity as measured by hepatitis B antibody titers and after the start of dialysis, protective antibody titer levels in pediatric dialysis patients wane rapidly compared to healthy children.^

Association between cardiorespiratory fitness and Alzheimer's mortality: A prospective cohort study

Context. Alzheimer’s disease is a major source of morbidity and mortality in aging societies. Preventive measures, such as increasing cardiorespiratory fitness, to reduce the risk of Alzheimer’s disease mortality have not been sufficiently examined.^ Objective. To examine the association between levels of cardiorespiratory fitness and Alzheimer’s disease mortality.^ Design, Setting, and Patients. A prospective cohort study of 53,911 men and 18,876 women (mean age, 51.4 [SD, 10.0] years; range 20-88) enrolled in the Cooper Center Longitudinal Study who completed a baseline health examination during 1970-2006. The primary exposure, cardiorespiratory fitness, was assessed via a maximal exercise test. Fitness was categorized according to age- and sex-specific tertiles based on the participants’ distribution of maximal treadmill exercise test duration, in metabolic equivalent tasks (METs). The main outcome measure was Alzheimer’s disease mortality, defined as the underlying or contributing cause of death using the National Death Index and death certificates through December 31, 2006.^ Results. There were 175 Alzheimer’s disease deaths during a mean follow up of 37 years and 1,309,170 person-years of exposure. Women in the high fitness category had a 70% reduction in risk of Alzheimer’s mortality compared to women in the low fitness category (HR=0.3; 95% CI, 0.1-0.8; P=.02), while adjusting for potential confounders. Similarly, women in the moderate fitness category had a 70% reduction in risk for AD mortality compared to women in the low fit category (HR=0.3; 95% CI, 0.1-0.7; P=.005). Among men, the relationship between fitness level and AD mortality risk was examined but none were of statistical significance. The adjusted comparison of men in the high fitness category to low fit men yielded an HR of 0.9 (95% CI, 0.6-1.5; P=.79), while moderately fit men compared to low fit men yielded an HR of 1.3 (95% CI, 0.9-1.9; P=.21).^ Conclusions. Higher levels of cardiorespiratory fitness were associated with decreased risk of AD mortality, in women. No statistically significant association was found among men. Physical fitness may be an important protective factor against Alzheimer’s disease death in women, further supporting its clinical and public health values.^

Retrospective cohort study to determine the effect of metformin on survival of diabetic patients with pancreatic adenocarcinoma

Background: Pancreatic cancer is the fourth most common cause of cancer death in the United States. Despite advances in cancer treatment, prognosis of pancreatic cancer remains extremely poor with survival rates of 24% and 5% in 1 and 5 years, respectively. Many patients with pancreatic cancer have a history of diabetes and are treated with various antidiabetic regimens including metformin. In multiple retrospective studies, metformin has been associated with decreased risk of cancer and cancer-related mortality. Metformin has also been reported to inhibit the growth of cancer cells, both in vitro and in vivo.^ Methods: We conducted a retrospective cohort study to examine the survival benefit of metformin in diabetic patients with pancreatic cancer at MD Anderson Cancer Center (MDACC). A dataset of 397 patients who carried the diagnosis of "Diabetes Mellitus" and "Pancreatic Cancer" at MD Anderson were screened for this study. ^ Results: Mean age of patients at diagnosis of cancer was 64.0 ± 8.7 years (range 37-84). The majority of the patients were male (65.6%) and of Caucasian race (78.5%). The most common antidiabetic regimen used were insulin and metformin (in 39.1% and 38.7%, respectively). Patients' cancer were staged as resectable in 34.1%, locally advanced unresectable in 29.1%, and disseminated disease in 36.7% of cases. Overall 1-year and 3-year survival rates for all stages combined were 51.8% and 7.6%, respectively. Earlier stage, metformin use, low CA19-9 level, better ECOG performance status, surgical intervention, negative surgical margins, and smaller tumor size were associated with longer survival. Metformin use was associated with a 33% decrease in risk of death (HR: 0.67; 95% CI: 0.51-0.88). Multivariate Cox proportional hazard regression showed hazard ratio of 1.77 (95% CI 1.49-2.10) for cancer stage, 0.65 (95% CI 0.49-0.86) for metformin use, and 1.68 (95% CI 1.26-2.23) for CA 19-9 level above population median. ^ Conclusion: Our study suggests that metformin may improve the outcome in diabetic patients with pancreatic cancer independently of other known prognostic factors. Pancreatic cancer carries extremely poor prognosis; metformin may provide a suitable adjunct therapeutic option for pancreatic cancer in patients with and without diabetes mellitus.^

A cohort study of occupational asbestos-exposure related neoplasms in Texas Gulf Coast area

A cohort study was conducted in Texas and Louisiana Gulf Coast area on individual workers who have been exposed to asbestos for 15 years or more. Most of these workers were employed in petrochemical industries. Of the 15,742 subjects initially selected for the cohort study, 3,258 had positive chest X-ray findings believed to be related to prolonged asbestos exposure. These subjects were further investigated. Their work out included detailed medical and occupational history, laboratory tests and spirometry. One thousand eight-hundred and three cases with positive chest X-ray findings whose data files were considered complete at the end of May 1986 were analyzed and their findings included in this report.^ The prevalence of lung cancer and cancer of the following sights: skin, stomach, oropharyngeal, pancreas and kidneys were significantly increased when compared to data from Connecticut Tumor Registry. The prevalence of other chronic conditions such as hypertension, emphysema, heart disease and peptic ulcer was also significantly high when compared to data for the U.S. and general population furnished by the National Center for Health Statistics (NCHS). In most instances the occurrence of cancer and the chronic ailment previously mentioned appeared to follow 15-25 years of exposure to asbestos. ^

Thrombolytic therapy for acute myocardial infarction: A cohort study to evaluate a selective approach to invasive diagnosis and therapy. The Corpus Christi Heart Project

Coronary perfusion with thrombolytic therapy and selective reperfusion by percutaneous transluminal coronary angioplasty (PTCA) were examined in the Corpus Christi Heart Project, a population-based surveillance program for hospitalized acute myocardial infarction (MI) patients in a biethnic community of Mexican-Americans (MAs) and non-Hispanic whites (NHWs). Results were based on 250 (12.4%) patients who received thromobolytic therapy in a cohort of 2011 acute MI cases. Out of these 107 (42.8%) underwent PTCA with a mean follow-up of 25 months. There were 186 (74.4%) men and 64 (25.6%) women; 148 (59.2%) were NHWs, 86 (34.4%) were MAs. Thrombolysis and PTCA were performed less frequently in women than in men, and less frequently in MAs than in NHWs.^ According to the coronary reperfusion interventions used, patients were divided in two groups, those that received no-PTCA (57.2%) and the other that underwent PTCA (42.8%) after thrombolysis. The case-fatality rate was higher in no-PTCA patients than in the PTCA (7.7% versus 5.6%), as was mortality at one year (16.2% versus 10.5%). Reperfusion was successful in 48.0% in the entire cohort and (51.4% versus 45.6%) in the PTCA and no-PTCA groups. Mortality in the successful reperfusion patients was 5.0% compared to 22.3% in the unsuccessful reperfusion group (p = 0.00016, 95% CI: 1.98-11.6).^ Cardiac catheterization was performed in 86.4% thrombolytic patients. Severe stenosis ($>$75%) obstruction was present most commonly in the left descending artery (52.8%) and in the right coronary artery (52.8%). The occurrence of adverse in-hospital clinical events was higher in the no-PTCA as compared to the PTCA and catheterized patients with the exception of reperfusion arrythmias (p = 0.140; Fisher's exact test p = 0.129).^ Cox regression analysis was used to study the relationship between selected variables and mortality. Apart from successful reperfusion, age group (p = 0.028, 95% CI: 2.1-12.42), site of acute MI index (p = 0.050) and ejection-fraction (p = 0.052) were predictors of long-term survival. The ejection-fraction in the PTCA group was higher than (median 78% versus 53%) in the no-PTCA group. Assessed by logistic regression analysis history of high cholesterol ($>$200mg/dl) and diabetes mellites did have significant prognostic value (p = 0.0233; p = 0.0318) in long-term survival irrespective of treatment status.^ In conclusion, the results of this study support the idea that the use of PTCA as a selective intervention following thrombolysis improves survival of patients with acute MI. The use of PTCA in this setting appears to be safe. However, we can not exclude the possibility that some of these results may have occurred due to the exclusion from PTCA of high risk patients (selection bias). ^

Anesthetic choices and breast cancer recurrence: A retrospective cohort study of risk factors

Background: The impact of anesthetic techniques for breast cancer surgery traditionally has been centered on the incidence of acute pain syndromes and complications immediately after surgery. Evaluating anesthesia management beyond short-term effects is an emerging science. Several animal studies have concluded that regional anesthesia independently reduces cancer recurrence and metastasis. A small number of retrospective clinical studies indicate that reductions in cancer recurrence are attributable to anesthesia technique; however, individual risk factors need to be taken into consideration. ^ Purpose: The aims were to: 1) investigate differences in patient, disease and treatment factors between women who received surgical treatment for breast cancer with paravertebral regional and general anesthesia compared to women who received general anesthesia alone; 2) explore patient, disease and treatment factors associated with recurrence of breast cancer; and 3) test the association between type of anesthesia and breast cancer recurrence and survival over 22–46 months following surgery. ^ Methods: This retrospective cohort study included 358 patients with stage 0-III disease who received a partial or total mastectomy without axillary node dissection between October 2006 and October 2008 at a large academic cancer center. Follow-up ended in August 2010 with a median follow-up time of 28.8 months. ^ Results: The patient demographics were equally represented across anesthesia groups. Mean BMI (kg/m2) was greater for the patients who received general anesthesia (GA) alone (29±6.8) compared to those that received paravertebral regional block (PVB) with GA (28±5.1), p=0.001. The PVB with GA group had more advanced stages of disease (p=0.01) and longer surgeries (p=0.01) than the GA only group. Breast cancer recurrence was detected in only 1.7% of the study population. The mean age was 51±18 in those who had a recurrence compared to 58±11 in the non-recurrent group (p=0.06). Overall, no association between anesthesia type and recurrence was found (p=0.53), with an unadjusted estimated hazard ratio of 1.84 (95% CI 0.34–10.08). ^ Conclusions: In contrast to previous retrospective studies in cancer patients receiving surgical and anesthesia treatment, this study was unable to detect a difference in relating type of anesthesia with decreased breast cancer recurrence. Nonetheless, a significant association between BMI and type of anesthesia was observed and should be taken into account in future studies. Because the overall rate of recurrence was very small in this population, a larger study would be needed to detect any differences in rates of recurrence attributable to type of anesthesia. ^

Impact of traffic pollution on telomere length and chronic diseases: Results from the multi-ethnic study of atherosclerosis and the Mexican-American cohort study

Exposure to air pollutants in urban locales has been associated with increased risk for chronic diseases including cardiovascular disease (CVD) and pulmonary diseases in epidemiological studies. The exact mechanism explaining how air pollution affects chronic disease is still unknown. However, oxidative stress and inflammatory pathways have been posited as likely mechanisms. ^ Data from the Multi-Ethnic Study of Atherosclerosis (MESA) and the Mexican-American Cohort Study (2003-2009) were used to examine the following aims, respectively: 1) to evaluate the association between long-term exposure to ambient particulate matter (PM) (PM10 and PM2.5) and nitrogen oxides (NO x) and telomere length (TL) among approximately 1,000 participants within MESA; and 2) to evaluate the association between traffic-related air pollution with self-reported asthma, diabetes, and hypertension among Mexican-Americans in Houston, Texas. ^ Our results from MESA were inconsistent regarding associations between long-term exposure to air pollution and shorter telomere length based on whether the participants came from New York (NY) or Los Angeles (LA). Although not statistically significant, we observed a negative association between long-term air pollution exposure and mean telomere length for NY participants, which was consistent with our hypothesis. Positive (statistically insignificant) associations were observed for LA participants. It is possible that our findings were more influenced by both outcome and exposure misclassification than by the absence of a relationship between pollution and TL. Future studies are needed that include longitudinal measures of telomere length as well as focus on effects of specific constituents of PM and other pollutant exposures on changes in telomere length over time. ^ This research provides support that Mexican-American adults who live near a major roadway or in close proximity to a dense street network have a higher prevalence of asthma. There was a non-significant trend towards an increased prevalence of adult asthma with increasing residential traffic exposure especially for residents who lived three or more years at their baseline address. Even though the prevalence of asthma is low in the Mexican-origin population, it is the fastest growing minority group in the U.S. and we would expect a growing number of Mexican-Americans who suffer from asthma in the future. Future studies are needed to better characterize risks for asthma associated with air pollution in this population.^

Impact of racial differences in medical care on breast cancer survival: Findings from a large nationwide and retrospective cohort study

Background: No studies have attempted to determine whether nodal surgery utilization, time to initiation and completion of chemotherapy or surveillance mammography impact breast cancer survival. ^ Objectives and Methods: To determine whether receipt of nodal surgery, initiation and completion of chemotherapy, and surveillance mammography impact of racial disparities in survival among breast cancer patients in SEER areas, 1992-2005. ^ Results: Adjusting for nodal surgery did not reduce racial disparities in survival. Patients who initiated chemotherapy more than three months after surgery were 1.8 times more likely to die of breast cancer (95% CI 1.3-2.5) compared to those who initiated chemotherapy less than a month after surgery, even after controlling for known confounders or controlling for race. Despite correcting for chemotherapy initiation and completion and known predictors of outcome, African American women still had worse disease specific survival than their Caucasian counterparts. We found that non-whites underwent surveillance mammography less frequently compared with whites and mammography use during a one- or two-year time interval was associated with a small reduced risk of breast-cancer-specific and all-cause mortality. Women who received a mammogram during a two-year interval could expect the same disease-specific survival benefit or overall survival benefit as women who received a mammogram during a one-year interval. We found that while adjustment for surveillance mammography receipt and physician visits reduced differences in mortality between blacks and whites, these survival disparities were eliminated after adjusting for the number of surveillance mammograms received. ^ Conclusions: The disparities in survival among African American and Hispanic women with breast cancer are not explained by nodal surgery utilization or chemotherapy initiation and chemotherapy completion. Surveillance mammograms, physician visits and number of mammograms received may play a major role in achieving equal outcomes for breast cancer-specific mortality for women diagnosed with primary breast cancer. Racial disparities in all-cause mortality were explained by racial differences in surveillance mammograms to certain degree, but were no longer significant after controlling for differences in comorbidity. Focusing on access to quality care and post treatment surveillance might help achieve national goals to eliminate racial disparities in healthcare and outcomes. ^

A cohort study of body fatness and coronary mortality in middle -aged men

Data from the Chicago Western Electric Study were used to investigate whether central fat distribution, as estimated by the ratio of subscapular-to-triceps skinfold, was associated with 25-year risk of death from coronary heart disease in a cohort of 1,945 middle-aged employed men. Subscapular-triceps skinfold ratio was found positively and significantly associated with risk of coronary death after adjustment for age and body mass index. The age-adjusted proportional hazards regression coefficient was 0.2078 with 95% confidence interval of 0.0087 to 0.4069. A difference of 1.1 in the subscapular-triceps skinfold ratio (the difference between the mean of the fifth quintile and of the first and second quintiles combined) was associated with a relative risk of 1.31 with 95% confidence interval of 1.06 to 1.62. The coefficient was decreased to 0.1961 (95% confidence interval of ($-$0.0028 to 0.3950) after adjustment for diastolic blood pressure, serum cholesterol and cigarette smoking as well as age and body mass index. At least some of the effect of central fat on coronary risk is probably mediated by blood pressure and serum lipids, but whether all of the effect can be accounted for blood pressure and serum lipids is uncertain.^ This study supports the concept that central fat distribution is a risk factor for 25-year risk of coronary death in middle-aged men. ^

Feasibility and utility of population-level geospatial injury profiling : prospective, national cohort study

The Health Services Research Unit receives funding from the Chief Scientist Office of the Scottish Government Health and Social Care Directorates. The opinions expressed in this article are those of the authors alone. The GEOS study was funded by the North of Scotland Planning Group.

Biological stress systems, adverse life events and the onset of chronic multisite musculoskeletal pain : a 6-year cohort study

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