The Relationship between Insulin Resistance and Spatial QRS-T Angle in American Adults.

BACKGROUND: Insulin resistance can impair the electrical conductivity of the heart. Spatial QRS-T axis reflects ventricular depolarization and repolarization. The relationship between insulin resistance and spatial QRS-T angle has not been examined in the general population. OBJECTIVE: We examined the relationship between insulin resistance and spatial QRS-T angle in an American population-based sample. METHODS: We used data collected from the National Health and Nutrition Examination Survey III (NHANES III), and a directed acyclic graph to select confounders. We fitted logistic regression models and adjusted for the effect of the confounders. We stratified all analyses by gender. RESULTS: The odds ratios (OR) of the abnormal QRS-T angle and their 95% confidence intervals (CI) for females and males were 1.08 (1.03-1.16) and 1.03 (0.96-1.11), respectively. A 5-unit increase in insulin resistance in females increased the odds of an abnormal QRS-T angle by 47% (OR = 1.47, 95% CI, 1.10-2.10); in males, a 5-unit increase in insulin resistance increased the OR by 17% (OR = 1.17, 95% CI, 0.82-1.70). CONCLUSIONS: Spatial QRS-T angle may be associated with insulin resistance, especially in women. The individuals with a higher insulin resistance value had higher odds for major adverse cardiovascular events. Nevertheless, the results of this study should be verified in prospective studies.

The difference between hypertension determined by self-report versus examination in the adult population of the USA: Continuous NHANES 1999-2016.

BACKGROUND: Studies have considered the validity of self-reported hypertension relative to hypertension detected by examination; no study has explored trends in the difference between these two measures. Our objective was to calculate these differences overtime within subpopulations of the USA. METHODS: We included non-Hispanic white, non-Hispanic black and Hispanic adults who participated in the National Health and Nutrition Examination Surveys from 1999 to 2016, in the analysis (N = 44 333). We subtracted self-reported hypertension from hypertension detected by examination to calculate blood pressure difference (BPD). We fit weighted linear regression models that included important covariates along with all combination of two- and three-way interactions to predict the BPD. We used the fitted lines of the models to depict the patterns of differences in the different subpopulations. RESULTS: Age ≥ 45 years, lack of annual clinical visit, body mass index (BMI) < 25 and time were important factors associated with increased BPD. CONCLUSIONS: People who are ≥ 45 years, have normal BMI, or do not have annual medical visits are more likely to have a bigger BPD. We can use the calculated BPD, to adjust estimates of the prevalence of self-reported hypertension.

Metabolic syndrome and P-wave duration in the American population.

PURPOSE: Metabolic syndrome has a high prevalence in the United States. P-wave duration is a valuable indicator for atrial electrical conduction. Abnormalities in atrial electrical conduction can predispose to atrial fibrillation. Our objective was to estimate the effect of metabolic syndrome on P-wave duration in a nationally representative sample. METHODS: We included 6499 adults who participated in the National Health and Nutrition Examination Survey III (1988-1994). We estimated the effect of metabolic syndrome and its components on P-wave duration after adjusting for confounders such as demographic and lifestyle variables. We stratified the analyses by gender. RESULTS: Irrespective of gender, participants with metabolic syndrome had a longer P-wave duration than that of those without it. In addition, we observed a positive linear dose-response relation between metabolic syndrome components and P-wave duration. CONCLUSIONS: Patients with metabolic syndrome had a longer P-wave duration. They might have been at a higher risk for atrial fibrillation and mortality; they need to be periodically checked by their health care providers. However, the results of this study should be confirmed in prospective studies.

The association of metabolic syndrome and QRS|T angle in US adults (NHANES III).

BACKGROUND: Spatial QRS|T angle is a predictor of cardiovascular events. Those with metabolic syndrome have an increased risk of cardiovascular morbidity and mortality. This study investigated the association between metabolic syndrome and spatial QRS|T angle. METHODS: We obtained data from the National Health and Nutritional Examination Survey III on 6,249 adults. We calculated spatial QRS|T angle from the standard 12-lead electrocardiogram and classified it as abnormal, borderline, or normal. We identified metabolic syndrome if at least three of the following were present: abdominal obesity, elevated blood pressure, elevated triglycerides, decreased high-density lipoprotein (HDL), and impaired fasting glucose. We used weighted logistic regression to estimate the effect of metabolic syndrome and its components on QRS|T angle while stratifying by gender and adjusting for age, race, smoking status, heart rate, PR, QT, and QRS interval, and QRS amplitude. RESULTS: Among men and women, metabolic syndrome, the number of components present, elevated blood pressure, and impaired fasting glucose were positively associated with QRS|T angle. Among women, decreased HDL and abdominal obesity were also positively associated with QRS|T angle. CONCLUSIONS: This study suggests that persons with metabolic syndrome may be at increased risk for ventricular arrhythmias. The use of spatial QRS|T angle to assess this cardiovascular risk is warranted.

Use of Electronic Nicotine Delivery Systems (ENDS) by pregnant women I: Risk of small-for-gestational-age birth.

INTRODUCTION: The 2016 US Surgeon General's Report suggests that the use of electronic nicotine delivery systems (ENDS) is a fetal risk factor. However, no previous study has estimated their effect on adverse pregnancy outcomes. We assessed the prevalence of current ENDS use in pregnant women and explored the effect on birth weight and smallness-for-gestational-age (SGA), correcting for misclassification from nondisclosure of smoking status. METHODS: We conducted a cohort study with 248 pregnant women using questionnaire data and biomarkers (salivary cotinine, exhaled carbon monoxide, and hair nicotine). We evaluated the association between birth weight and the risk of SGA by applying multivariate linear and log-binomial regression to reproductive outcome data for 232 participants. Participants who did not disclose their smoking status were excluded from the referent group. Sensitivity analysis corrected for misclassification of smoking/ENDS use status. RESULTS: The prevalence of current ENDS use among pregnant women was 6.8% (95% CI: 4.4-10.2%); most of these (75%) were concurrent smokers. Using self-reports, the estimated risk ratio of SGA for ENDS users was nearly two times the risk in the unexposed (RR=1.9, 95% CI: 0.6-5.5), and over three times that for ENDS-only users versus the unexposed (RR=3.1, 95% CI: 0.8-11.7). Excluding from the referent group smokers who did not disclose their smoking status, the risk of SGA for ENDS-only use was 5 times the risk in the unexposed (RR=5.1, 95% CI: 1.1- 22.2), and almost four times for all types of ENDS users (RR=3.8, 95% CI: 1.3-11.2). SGA risk ratios for ENDS users, corrected for misclassification due to self-report, were 6.5-8.5 times that of the unexposed. CONCLUSIONS: Our data suggest that ENDS use is associated with an increased risk of SGA.

Using Machine Learning to Predict Progression in the Gastric Precancerous Process in a Population from a Developing Country Who Underwent a Gastroscopy for Dyspeptic Symptoms.

BACKGROUND: Gastric cancer is the fourth most common cancer and the third most common cause of cancer deaths worldwide. Morbidity and mortality from gastric cancer may be decreased by identification of those that are at high risk for progression in the gastric precancerous process so that they can be monitored over time for early detection and implementation of preventive strategies. METHOD: Using machine learning, we developed prediction models for gastric precancerous progression in a population from a developing country with a high rate of gastric cancer who underwent gastroscopies for dyspeptic symptoms. In the data imputed for completeness, we divided the data into a training and a validation test set. Using the training set, we used the random forest method to rank potential predictors based on their predictive importance. Using predictors identified by the random forest method, we conducted best subset linear regressions with the leave-one-out cross-validation approach to select predictors for overall progression and progression to dysplasia or cancer. We validated the models in the test set using leave-one-out cross-validation. RESULTS: We observed for all models that complete intestinal metaplasia and incomplete intestinal metaplasia were the strongest predictors for further progression in the precancerous process. We also observed that a diagnosis of no gastritis, superficial gastritis, or antral diffuse gastritis at baseline was a predictor of no progression in the gastric precancerous process. The sensitivities and specificities were 86% and 79% for the general model and 100% and 82% for the location-specific model, respectively. CONCLUSION: We developed prediction models to identify gastroscopy patients that are more likely to progress in the gastric precancerous process, among whom routine follow-up gastroscopies can be targeted to prevent gastric cancer. Future external validation is needed.

The Association between Salt and Potential Mediators of the Gastric Precancerous Process.

BACKGROUND: The process by which salt affects the gastric precancerous process has not been adequately studied in humans. METHODS: We investigated the effects of salt on gastric inflammation, epithelial damage, the density of Helicobacter pylori infection, and gastric epithelial cell proliferation, all of which may be mediators between salt and gastric precancerous/cancerous lesions. These potential mediators were measured using gastric biopsies as: (a) the density of polymorphonuclear and mononuclear cells (gastric inflammation), (b) mucus depletion (gastric epithelial damage), and (c) the severity of H. pylori infection. Salt intake was measured with spot urine samples (using urinary sodium/creatinine ratios), self-reported frequency of adding salt to food, and as total added salt. RESULTS: The average sodium/creatinine ratio (at baseline and post-treatment at five months) was associated with increased epithelial damage over the 12-year follow-up period among those with a greater severity of chronic inflammation and among those with continued H. pylori infection after treatment at five months. This association was stronger when both severe gastric inflammation and H. pylori infection were present at five months (ß: 1.112, 95% CI: 0.377, 1.848). CONCLUSION: In humans, salt was associated with an increase in epithelial damage in stomachs with more severe previous H. pylori-induced chronic inflammation.

Association between Dietary Salt Intake and Progression in the Gastric Precancerous Process.

Gastric cancer is the third leading cause of cancer mortality worldwide. Studies investigating the effect of salt on gastric cancer have mainly used self-reported measures, which are not as accurate as sodium/creatinine ratios because individuals may not know the amount of salt in their food. Using data from a prospective cohort study, we investigated the effect of salt intake on progression to gastric precancerous lesions. Salt intake was estimated by urinary sodium/creatinine ratios, self-reported frequencies of adding salt to food, and total added table salt. We repeated the analyses among groups with and without Helicobacter pylori infection. We did not observe a positive association between salt intake, measured by urinary sodium/creatinine ratio, and overall progression in the gastric precancerous process (adjusted risk ratio (RR): 0.94; 95% confidence interval (CI) 0.76-1.15). We did observe an association between salt intake and increased risk for progression to dysplasia or gastric cancer overall (adjusted risk ratio (RR): 1.32; 95% confidence interval (CI): 0.96-1.81), especially among those who continued to have H. pylori infection at the five-month follow-up (adjusted RR: 1.53; 95% CI: 1.12-2.09), and among those who had persistent H. pylori infection over 12 years (adjusted RR: 1.49; 95% CI: 1.09-2.05). Salt intake may increase the risk of gastric dysplasia or gastric cancer in individuals with H. pylori infection.

The relation of blood lead and QRS-T angle in American adults.

The QRS-T angle is a key ECG predictor for ventricular arrhythmia. Lead has a strong relation with cardiovascular diseases; however, no study has been conducted to investigate the association between lead exposure and QRS-T angle. Thus, we explored this association in a population-based representative sample: NHANES III. We used the standard 12-lead ECGs to calculate Spatial QRS-T angles. Blood lead concentration was measured using graphite furnace atomic absorption spectrophotometry method. We conducted multivariate weighted logistic regression to adjust for impaired fasting glucose, hypertension, poverty index, age, race, and smoking status. We found that when the log of blood lead increased by one unit, the odds of an abnormal QRS-T angle increased by 34% among men and 4% among women. We suggest the use of QRS-T angle deviation among those who are exposed to lead to detect individuals at risk for adverse cardiovascular outcomes such as arrhythmias.

Excess lung cancer occurrence in poultry plants. Occupational risk factors: Findings for oncogenic viruses exposure and other occupational exposures.

Certain viruses naturally infect and cause cancer in chickens and turkeys. Humans are widely exposed. The viruses cause cancer in primates, and transform human cells in vitro, but it is not known if they cause cancer in humans, mainly because of the lack of epidemiologic evidence. We conducted cohort mortality studies of workers in poultry slaughtering/processing plants across the United States, because they have the highest human exposures. An excess of lung cancer and other deaths was recorded in the poultry workers. Here, we report on a case-cohort study of the lung cancer deaths nested within these cohorts, that was conducted to provide epidemiologic evidence linking these viruses with human cancer occurrence, while adjusting for possible confounders, including workplace chemical carcinogens. We obtained interviews for 339 lung cancer deaths and 457 controls, selected from our combined cohorts of 30,411 poultry plant workers and 16,405 non-poultry workers, belonging to United Food & Commercial Workers unions. Data was analyzed by both logistic regression and Cox regression, adjusting for smoking and other confounders. Lung cancer risk was independently associated with tasks or work areas indicative of exposure to both poultry oncogenic viruses and to workplace chemical carcinogens. The study provides an incremental piece of evidence (epidemiologic), indirectly linking the oncogenic viruses of poultry with the occurrence of cancer in humans, and thus may have public health implications, but the limitations highlighted must be considered. Confirmatory studies, particularly molecular studies providing definitive proof of poultry oncogenic retrovirus integration in human DNA are needed, before the findings observed in this study can be put into proper perspective.

Association Between Urinary Cadmium and QRS|T Angle Among Adults in the United States.

OBJECTIVE: Cadmium's effect on QRS|T angle has not been studied. An abnormal QRS|T angle deviation may increase the risk for ventricular dysrhythmias. METHODS: We calculated the orientation of spatial QRS|T angle using QRS and T amplitudes of leads V2, V5, V6, and AVF from the National Health and Nutritional Examination Survey III. Cadmium concentration was measured in urine. We fit weighted unadjusted and adjusted logistic regressions to calculate odds ratios and their corresponding 95% confidence intervals. RESULTS: A unit increase in the logarithm of urinary cadmium increased the odds of QRS|T angle deviation by 30% [1.30 (1.01 to 1.61)]. CONCLUSIONS: Cadmium exposure was associated with an abnormal QRS|T angle in women but not in men. Women exposed to cadmium should be periodically evaluated to detect QRS|T angle deviation, which can predispose them to ventricular dysrhythmias.

Morbidity and mortality from farm tractor-related injuries in Arkansas.

This study applied a text string search algorithm to ascertain suspect farm tractor or agricultural machinery-related injuries in data sources available for 2000-2014 in the state of Arkansas. The occurrences of tractor or other agricultural machinery-related injuries were compared with data available from the Centers for Disease Control and Prevention's National Center for Health Statistics (NCHS) and the Bureau of Labor Statistics' Census of Fatal Occupational Injuries (CFOI). For death certificates that assigned an external cause of death, the authors first collected all those that were coded as related to agricultural machinery, based on search strings for occupation and industry and a description of how the injury occurred. They then inspected each case individually and removed those that were likely unrelated to agricultural machinery. This approach significantly increased (by 7.8 times) the number of suspect agricultural machinery-related fatalities compared to the number reported to CFOI, but there was only a 17% (not statistically significant) increase compared to NCHS. All hospital records with any discharge diagnosis coded as related to agricultural machinery were selected. Descriptive analysis of the fatalities and hospital records showed a significantly increased risk among men above retirement age, peaks during the summer, and an increased risk in the Mississippi delta region. About one-third of the agricultural machinery-related fatalities were due to overturns. The use of the algorithm can improve ascertainment of fatal agricultural machinery-related injuries in Arkansas. The death records were found to be rich in data on the circumstances of the injuries, which can be used to screen for tractor-related fatalities and, if confirmed, translated into action to improve the safety of Arkansas farmers.

The Association between SNPs and a Quantitative Trait: Power Calculation.

A power calculation for a study with a quantitative outcome requires information on the outcome distribution under the alternative hypothesis. Researchers face challenges when they concisely specify alternative distributions in genetic studies because power depends on genotype frequencies and the average effect of each genotype. In GWAS, investigators evaluate hundreds of thousands of associations; therefore it is unrealistic to specify gene frequencies and gene effects for each test and some simplification is needed. Software packages are available to calculate power, but many of them have limited flexibility and / or may have a steep learning curve. In this review, we describe to researchers and graduate students the essentials of a power calculation for testing for an association between a quantitative trait and genotypes. In addition, we provide them with the codes of the different available software packages-free and commercial-to calculate this power. The calculations can be carried out using virtually any computer language that computes the cumulative distribution function of a non-central F-distribution.

Electronic Nicotine Delivery Systems and Smoking Cessation in Arkansas, 2014.

OBJECTIVES: As of October 2015, evidence needed to make a recommendation about the use of electronic nicotine delivery systems (ENDS) for smoking cessation was limited. We used the 2014 Arkansas Behavioral Risk Factor Surveillance System with additional state-specific questions to determine the prevalence of ENDS use, the impact of ENDS use on smoking cessation, and beliefs about ENDS use in Arkansas. Our objectives were to determine if (1) ENDS use was associated with lower odds of quitting smoking, (2) ENDS users believed that ENDS use was not harmful to their health, and (3) ENDS users believed that switching to ENDS reduced their tobacco-related health risks. METHODS: We conducted a cross-sectional study of 4465 respondents to the Arkansas Behavioral Risk Factor Surveillance System and used weighted analyses to account for the complex survey design. We used a subset of records formed by (1) formers smokers who quitted smoking in the last 5 years and (2) current smokers to assess the odds of quitting. RESULTS: In 2014, 6.1% (95% confidence interval [CI], 5.0%-7.4%) of Arkansas adults were currently using ENDS. Of the 1083 participants who were current smokers or had quit smoking within the past 5 years, 515 (54.1%) had used ENDS. Of the 515 ENDS users, 404 (80.3%) had continued smoking. ENDS use was significantly associated with reduced odds of quitting smoking (weighted odds ratio = 0.53; 95% CI, 0.34-0.83). Although 2437 of 3808 participants (62.5%) believed that it was harmful for nonsmokers to start using ENDS and 1793 of 3658 participants (47.0%) believed that switching to ENDS did not reduce tobacco-related health risks, only 80 of 165 (41.3%) and 50 of 168 (33.9%) ENDS users shared these same respective beliefs. CONCLUSIONS: Most smokers who indicated smoking in the past 5 years and who tried ENDS did not stop smoking. ENDS use was inversely associated with smoking cessation. Tobacco cessation programs should tell cigarette smokers that ENDS use may not help them quit smoking.

Community Team-Based Care for Hypertension Management: A Public-Private Partnership in Rural Arkansas.

Hypertension is a major public health problem in Arkansas. Team-based care (TBC), delivered by health care professionals such as a nurse, dietician, social worker, or community health worker rather than a physician alone, has been shown to improve blood pressure control.

High-normal blood pressure is associated with visit-to-visit blood pressure variability in the US adults.

OBJECTIVES: High-normal blood pressure and visit-to-visit blood pressure variability are common in clinical settings. They are associated with cardiovascular outcomes. No population based studies have assessed the association between these two phenomena. Our objective was to test the relationship of high-normal blood pressure with visit-to-visit blood pressure variability. DESIGN: A cross-sectional study. METHODS: We used data from the cross-sectional Third National Health and Nutrition Examination Survey to test the relationship between high-normal blood pressure and visit-to-visit blood pressure variability; we conducted multivariable regression analyses to evaluate the relationship between these two variables. RESULTS: The analysis included 6,071 participants. The participants' mean age was 37.16 years. The means of visit-to-visit systolic and diastolic blood pressure variability were 5.84 mmHg and 5.26 mmHg. High-normal blood pressure was significantly associated with systolic and diastolic blood pressure variability (p values <0.05). CONCLUSIONS: High-normal blood pressure is associated with visit-to-visit blood pressure variability. Additional research is required to replicate the reported results in prospective studies and evaluate approaches to reduce blood pressure variability observed in clinical settings among patients with high-normal blood pressure to reduce the subsequent complications of blood pressure variability.

Use of electronic nicotine delivery systems and recent initiation of smoking among US youth.

OBJECTIVES: We assessed whether the prevalence of recent (within a year) initiation of cigarette smoking was associated with reports of ever using electronic delivery systems (ENDS) in the National Youth Tobacco Survey (NYTS) and whether the association varied by age. METHODS: Weighted cross-sectional analysis of use of ENDS, cigarette smoking, age at interview and age at initiation of smoking collected systematically through the 2011-2013 NYTS cycles. RESULTS: In multivariate analyses those who ever used ENDS were twice as likely as nonusers of ENDS to have tried cigarette smoking in the last year (multivariate PR: 2.3; 95 % CI 1.9, 2.7). This average hid significant variations by age: a 4.1-fold increase (95 %; 2.6, 6.4) among those 11-13 years of age, compared to a smaller increase among those 16-18 years: 1.4-fold (95 % CI 1.1, 1.8). CONCLUSIONS: Use of ENDS by adolescents was associated with initiation of cigarette smoking in the last year. This association was stronger in younger adolescents.

Neighborhood and Acute Myocardial Infarction Mortality as Related to the Driving Time to Percutaneous Coronary Intervention-Capable Hospital.

BACKGROUND: Driving time to a percutaneous coronary intervention (PCI)-capable hospital is important in timely treatment of acute myocardial infarction (AMI). Our objective was to determine whether driving time from one's residence to a PCI-capable hospital contributes to AMI deaths. We conducted a cross-sectional study of age- and sex-adjusted mortality in census block groups to evaluate this question. METHODS AND RESULTS: We studied all (14 027) AMI deaths that occurred during 2008-2012 in Arkansas to assess the relationship between driving time from the population center of a block group (neighborhood) to the nearest PCI-capable hospital. We estimated standardized mortality ratios in block groups that were adjusted for education (population over 25 years of age who did not graduate from high school), poverty (population living below federal poverty level), population density (population per square mile), mobility (population residing at the same address as 1 year ago), black (population that is black), rurality (rural households), geodesic distance, and driving time. The median geodesic distance and driving time were 12.8 miles (interquartile range 3.6-30.1) and 28.3 minutes (interquartile range 9.6-58.7), respectively. Risks in neighborhoods with long driving times (90th percentile) were 26% greater than risks in neighborhoods with short driving times (10th percentile), even after adjusting for education, poverty, population density, rurality, and black race (P<0.0001). CONCLUSIONS: AMI mortality increases with increasing driving time to the nearest PCI-capable hospital. Improving the healthcare system by reducing time to arrive at a PCI-capable hospital could reduce AMI deaths.

The Effect of Metformin Use on Left Ventricular Ejection Fraction and Mortality Post-Myocardial Infarction.

BACKGROUND: Animal studies showed that the use of metformin after myocardial infarction (MI) resulted in a protective effect on cardiac myocytes. In this study, we examined the effect of metformin in patients with diabetes mellitus (DM) on left ventricular ejection fraction (LVEF) and post-MI mortality. METHODS: We reviewed charts of patients with MI admitted to the UAMS medical center. Baseline characteristics and 12-month follow up data were collected. Patients were classified into three groups: Control group- no DM (n = 464), Metformin group- DM + MI (n = 88) and No-Metformin group- DM + MI (n = 168). First, we compared Metformin and No-Metformin groups to the Control group. Second, we performed propensity-score matching in patients with DM, and compared Metformin to No-Metformin groups. RESULTS: All-cause 30-day and 12-month mortality was significantly higher in the No-Metformin group compared to controls (13.5 vs 9.3% p = 0.03 at 30 days, 23.7 vs 15.9 % p = 0.03 at 12 months). However, all-cause 30-day and 12-month mortality were similar in the Controls and Metformin group (9.3 vs 6.8 % p = 0.93 at 30 days, 15.9 vs 11.4 % p = 0.97 at 12 months). Mean LVEF on presentation (45 % in the three groups) and at follow up (47.84, 46.38 and 43.62 % in Control, Metformin, and No-Metformin groups, respectively) were not statistically different. There were no significant differences in regard to re-hospitalization, re-intervention, new stroke, CHF development, new MI, or identifiable arrhythmias. Metformin was an independent predictor of lower 30-day and 12-month all-cause mortality in patients with DM (HR 0.25, p = 0.02 and HR 0.32, p = 0.01, respectively). In the matched analysis, 30-day all-cause mortality was significantly higher in the No-Metformin compared to the Metformin group (21.1 vs 8.8 %, p = 0.05). However the difference in 12-month all-cause mortality did not reach statistical significance (24.6 vs 15.8 %, p = 0.15). CONCLUSION: This proof-of-concept study shows that use of metformin in patients with DM is associated with lower 30-day all-cause mortality and tendency for a lower 12-month all-cause mortality following MI without discernible improvement in LVEF.