Prevalence and associated demographic characteristics of exposure to multiple metals and their species in human populations: The United States NHANES, 2007-2012.

Lead (Pb), cadmium (Cd), mercury (Hg), and arsenic (As) are among the top 10 pollutants of global health concern. Studies have shown that exposures to these metals produce severe adverse effects. However, the mechanisms underlying these effects, particularly joint toxicities, are poorly understood in humans. The objective of this investigation was to identify and characterize prevalent combinations of these metals and their species in the U.S. NHANES population to provide background data for future studies of potential metal interactions. Exposure was defined as urine or blood levels ≥ medians of the NHANES 2007-2012 participants ≥6 years (n = 7408). Adjusted-odds ratios (adj-OR) and 95% confidence intervals were determined for covariates (age, gender, and race/ethnicity, cotinine and body mass index). Species-specific analysis was also conducted for As and Hg including iAs (urinary arsenous acid and/or arsenic acid), met-iAs (urinary monomethylarsonic acid and/or dimethylarsinic acid), and oHg (blood methyl-mercury and/or ethyl-mercury). For combinations of As and Hg species, age- and gender-specific prevalence was determined among NHANES 2011-2012 participants (n = 2342). Data showed that approximately 49.3% of the population contained a combination of three or more metals. The most prevalent unique specific combinations were Pb/Cd/Hg/As, Pb/Cd/Hg, and Pb/Cd. Age was consistently associated with these combinations: adj-ORs ranged from 10.9 (Pb/Cd) to 11.2 (Pb/Cd/Hg/As). Race/ethnicity was significant for Pb/Cd/Hg/As. Among women of reproductive age, frequency of oHg/iAs/met-iAS and oHg/met-iAs was 22.9 and 40.3%, respectively. These findings may help prioritize efforts to assess joint toxicities and their impact on public health.

A Physical Activity Intervention and Changes in Body Mass Index at a Middle School With a Large American Indian Population, Oklahoma, 2004-2009.

School-based interventions can reach children and adolescents and aid in reducing the prevalence of childhood obesity. A physical education class that engaged middle school students in a daily 1-mile walk or run and other team sports was developed in a rural school in southwestern Oklahoma with a large American Indian population. Body mass index z scores decreased among boys and were stable among girls in the intervention group compared with students who did not participate in the intervention. A daily required walk or run may help to establish a physical activity habit with all of its associated benefits.

Changed trends of major causes of visual impairment in Sichuan, China from 1987 to 2006.

AIM: To study the trends of major causes of visual impairment (VI) in adults in Sichuan, China and evaluate the effect of aging on the trends. METHODS: We used data from the National Sample Survey on Disabilities (NSSD) in Sichuan province conducted in 1987 and 2006. The age-adjusted prevalence of major causes of VI and the prevalence stratified by age in each cause were calculated and compared. The association between age and each cause of VI was also analyzed. RESULTS: Retinal disease increased and became the second leading cause of VI in 2006 while blinding trachoma decreased markedly. Cataract and non-trachomatous corneal diseases were among the leading causes of VI in both years. We found associations between age and causes of VI, with age showing the strongest association with cataract and relatively lower associations with other causes. CONCLUSION: In the last two decades, dramatic changes occurred in the major causes of VI with significantly increased retinal disease and decreased blinding trachoma. Aging of the population might be an important factor accounting for the changed trends of VI. Understanding the prevalence of VI, its major causes and trends over time can assist in prioritizing and developing effective interventional strategies and monitoring their impact.

Weight status of American Indian and white elementary school students living in the same rural environment, Oklahoma, 2005-2009.

INTRODUCTION: Studies have assessed rates of childhood obesity in diverse populations, but few have been able to compare the weight status of American Indian and white children living in the same community and attending the same schools. The objective of this study was to measure and compare the weight status of American Indian and white elementary school students (kindergarten through 5th grade) from 2005 through 2009 in an Oklahoma school district. METHODS: We assessed height, weight, age, and sex to calculate body mass index, body mass percentile, and categorical weight status of students, based on the Centers for Disease Control and Prevention 2000 Growth Charts. We used binomial regression to generate risk ratios (RRs) to compare student weight status by race, sex, and age. RESULTS: An average of 753 students was measured in each year; mean age was 8.3 years. From 2005 through 2009, 45.4% of American Indian students and 65.1% of white students were healthy weight or underweight. Greater proportions of American Indian children were very obese (weighted average RR, 2.0); obese (weighted average RR, 1.6), or overweight (weighted average RR, 1.8) compared with white children. The overall prevalence of excess weight changed little during the study period. CONCLUSION: American Indian children had a greater risk of being overweight, obese, or very obese than white children from the same rural environment.

Changes in the prevalence of visual impairment due to blinding trachoma in Sichuan province, China: a comparative study between 1987 and 2006.

PURPOSE: The aim of this study was to assess the changes in the prevalence of visual impairment due to blinding trachoma in Sichuan, China between 1987 and 2006. METHODS: Over 125,000 residents of Sichuan province participated in the National Sample Survey on Disabilities, conducted in both 1987 and 2006. Changes in the prevalence of visual impairment due to blinding trachoma were analyzed while accounting for other factors including gender, age and residence (urban vs. rural). RESULTS: In 1987, blinding trachoma ranked second among the eight major visual impairment causes assessed with a prevalence of 172.9 (95% CI: 152.2-196.6) per 100,000, while in 2006 it ranked eighth with a prevalence of 58.1 (95% CI: 45.5-73.0) per 100,000. The prevalence in 2006 decreased significantly compared to 1987 in both rural and urban areas, as well as in both genders. Furthermore, in both 1987 and 2006, visual impairment due to blinding trachoma tended to be concentrated among individuals over 40, although it was also seen in young people. CONCLUSION: In the past 20 years, the prevalence and percentage of visual impairment due to blinding trachoma was significantly reduced in Sichuan province, and we anticipate a further decrease in the future.

Tobacco use and cardiovascular disease among American Indians: the strong heart study.

Tobacco use among American Indians has a long and complicated history ranging from its utilization in spiritual ceremonies to its importance as an economic factor for survival. Despite this cultural tradition and long history, there are few studies of the health effects of tobacco in this population. The Strong Heart Study is a prospective observational study of cardiovascular disease (CVD) in 13 American Indian tribes in Arizona, Oklahoma, and North and South Dakota with 4,549 participants. Baseline examinations were followed by two examinations at regular intervals and 16 years of morbidity and mortality follow-up. Hazard ratios (HRs) for non-fatal CVD for current smokers vs. non-smokers after adjusting for other risk factors were significant in women (HR = 1.94, 95% CI 1.54 to 2.45) and men (HR = 1.59, 95% CI 1.16 to 2.18). Hazard ratios for fatal CVD for current smokers vs. non-smokers after adjusting for other risk factors were significant in women (HR = 1.64, 95% CI 1.04 to 2.58), but not in men. Individuals who smoked and who were diagnosed with diabetes mellitus, hypertension or renal insufficiency were more likely to quit smoking than those without these conditions. On average, American Indians smoke fewer cigarettes per day than other racial/ethnic groups; nevertheless, the ill effects of habitual tobacco use are evident in this population.

Advantages of video questionnaire in estimating asthma prevalence and risk factors for school children: findings from an asthma survey in American Indian youth.

OBJECTIVES: The aims of the present study were to estimate the prevalence and risk factors of asthma among a sample of American Indian youth and to evaluate survey instruments used in determining asthma prevalence and risk factors. METHODS: Three hundred and fifty-two adolescents aged 9 to 21 years enrolled in an Indian boarding school completed an asthma screening. The survey instruments were a written questionnaire and a video-illustrated questionnaire prepared from the International Study of Asthma and Allergies in Childhood (ISAAC), school health records, and a health questionnaire. Participants also underwent spirometry testing. RESULTS: The prevalence of self-reported asthma varied from 12.7% to 13.4% depending upon the instrument used and the questions asked. A history of hay fever, respiratory infections, and family history of asthma were found to be risk factors for asthma by all instruments. Female gender and living on a reservation were significantly associated with asthma by some, but not all, instruments. Airway obstruction was highly associated with one asthma symptom (wheeze) shown in the video questionnaire. Associations for most risk factors with asthma were strongest for the video questionnaire. CONCLUSIONS: The prevalence of self-reported asthma among these American Indian youth was similar to rates reported for other ethnic groups. The video-based questionnaire may be the most sensitive tool for identifying individuals at risk for asthma.

Evaluation of a community-based participatory physical activity promotion project: effect on cardiovascular disease risk profiles of school employees.

BACKGROUND: The efficacy of physical activity in improving cardiovascular disease (CVD) risk profiles has been well established. However, the effectiveness of health promotion programs implemented at the community level remains controversial. This study evaluated a school-based work-site physical activity program. METHODS: Using a community-based participatory research model, a work-site wellness intervention was implemented in a rural public school system in Southwestern Oklahoma. During the 2005-2006 school year, 187 participants (mean age 45 years) completed a pre intervention screening for CVD risk factors followed by a physical activity promotion program. Post intervention screening was conducted after a 6 month period. During both screening sessions, body composition, blood pressure, lipids, glucose and self-reported physical activity levels were assessed. The focus of the intervention was on promoting physical activity. Opportunities for in school physical activity were created by marking hallways, adding a treadmill in each school, and allowing teachers to use planning periods for physical activity. RESULTS: During the post intervention screening, compared to pre intervention levels, participants had lower total, low, and high density lipoprotein-cholesterol (t = 5.9, p < 0.0001, t = 2.6, p = 0.01, and t = 13.2, p < 0.0001 respectively), lower systolic blood pressure (t = 2.9, p = 0.004), and higher self-reported physical activity levels (Sign t = -1.901, p = 0.06). CONCLUSIONS: A successful participatory program was associated with improvements in several CVD risk factors among school employees. Limitations of this study such as seasonal variation in the outcome variables and lack of a control group limit our ability to draw solid conclusions about the effectiveness of the intervention.

The Healthy Adults Project in rural Oklahoma.

CONTEXT: Screening to identify individuals at risk for cardiovascular disease is sorely needed in rural areas of Oklahoma. OBJECTIVE: The Healthy Adults Project was started as a screening program for public school employees in a rural school district in southwest Oklahoma. DESIGN, SETTING, AND PARTICIPANTS: The screening project is a collaborative effort between the Anadarko Public School district and the University of Oklahoma Prevention Research Center. Two hundred twenty-four (224) employees participated in the screening in 2004, and 206 employees participated in 2005. FINDINGS: Approximately 50% of females and 80% of males had two or more modifiable risk factors for cardiovascular disease in 2004 and 2005. CONCLUSIONS: Worksite screening is a valuable tool to raise awareness of risk factors for cardiovascular disease, particularly in less densely populated areas where wages are low and few preventive services are available. Knowledge of individual risk is the first step in improving health outcomes.

Blood pressure screening of school children in a multiracial school district: the Healthy Kids Project.

BACKGROUND: There are few studies of the prevalence of elevated blood pressure (BP) that include American Indian school children. Therefore, the intent of this study was to examine the relationships between BP and risk factors in a multiracial, predominantly American Indian, school district. METHODS: A total of 1,829 American Indian, white, Hispanic, and African American students, 5-17 years old, were included in this study. The mean of two BP measurements, taken at the initial screening with an electronic BP monitor, were categorized as normal, prehypertensive, or hypertensive using the 2004 Fourth Report BP screening recommendations. Prevalence of prehypertensive and hypertensive BP measurements by race, gender, age, and body mass index (BMI) were determined, and their associations analyzed with logistic regression. RESULTS: The prevalence of prehypertensive measurements was 16.7% and prevalence of hypertensive measurements was 13.8% at first screen. Obesity was a risk factor for elevated BP for females and males (adjusted odds ratio (OR) = 4.01 and 4.33, respectively). Older age was also significantly associated with prehypertensive and hypertensive BP measurements, especially among males (adjusted OR = 6.91). Among females, American Indian race was protective against elevated BP (adjusted OR = 0.61). CONCLUSIONS: Obesity was consistently associated with an increased risk for elevated BP. American Indian race was associated with decreased risk of elevated BP measurements in females. The high prevalence of obesity-related hypertensive measurements in this population that includes American Indian children was similar to levels found in other multiracial populations of school children when using BP measurements from a single assessment.

Hypothalamic-pituitary-adrenal axis function: relative contributions of perceived stress and obesity in women.

OBJECTIVE: A range of behavioral and psychosocial factors may contribute to a chronically stimulated hypothalamic-pituitary-adrenal (HPA) axis and subsequently altered diurnal patterns. The goal of this cross-sectional study was to examine associations among diurnal cortisol levels, perceived stress, and obesity patterns. METHODS: Seventy-eight women (aged 24-72 years) employed in a rural public school system completed the perceived stress scale, collected diurnal saliva samples, and underwent anthropometric assessments. Reduced peak-to-nadir cortisol values across the day were considered a sign of impairment in HPA function. A series of linear regression models determined the best predictors of diurnal cortisol variation. RESULTS: There was a marginal linear trend in stress levels across body mass index (BMI) categories, with obese women reporting the highest levels of stress (p = 0.07). Perceived stress was the only significant predictor of the degree of flattening of the diurnal cortisol curve in the sample as a whole (beta = -0.042, R(2) = 0.11, F = 8.6, p = 0.005), indicating reduction in the normal diurnal pattern. Among overweight women (BMI = 25-29.9 kg/m(2)), stress and waist circumference combined predicted 35% of the variability in diurnal cortisol. In contrast, among obese women (BMI > or = 30 kg/m(2)), BMI predicted 31% of the variability in diurnal cortisol (F = 13.8, p = 0.001), but stress was no longer significantly related to diurnal cortisol. CONCLUSIONS: Psychological stress predicts a significant portion of HPA axis functioning. In overweight women, perceived stress and waist circumference were of approximately equal importance in predicting adrenal cortisol secretion. However, among obese women, a major portion of the diurnal cortisol variation was predicted by BMI alone, not stress or waist circumference. This may help elucidate the mechanisms linking obesity to increased risk of cardiovascular disease (CVD).

Overweight and obesity in an ethnically diverse rural school district: the Healthy Kids Project.

OBJECTIVE: Data on Native American children and adolescents are rarely reported along with other racial and ethnic groups. The Healthy Kids Project is part of an effort to describe the prevalence of overweight and obesity in a racially mixed rural area where Native American, Hispanic, African American, and white children reside. METHODS AND PROCEDURES: We measured height and weight of students in Anadarko, Oklahoma public schools (n = 1,980) in 2002-2003. All available students (95.7%) whose parents had not opted out of school health assessments were included. From these data, we calculated BMI (weight (kg) / height (m(2))) and used the International Obesity Task Force reference to classify children into BMI categories. RESULTS: Native American, Hispanic, African American, and white children who live and attend school in the same surroundings are at risk of overweight and obesity. White children had the lowest combined prevalence of overweight and obesity (37.6%), and Native American children had the highest (53.8%) followed closely by African American (51.7%) and Hispanic children (50.5%). DISCUSSION: The childhood obesity epidemic includes all racial and ethnic groups to different degrees. In a rural public school, Native American, Hispanic, and African children had higher rates of overweight/obesity than white children.

Body mass index and blood pressure screening in a rural public school system: the Healthy Kids Project.

INTRODUCTION: All students (N = 2053) in Anadarko public schools, grades kindergarten through 12, were invited to be screened for height, weight, and blood pressure to assess the health status of this multiracial, multiethnic (American Indian, white, African American, and Hispanic) population in southwestern Oklahoma. METHODS: The Centers for Disease Control and Prevention's 2000 growth charts were used to determine body mass index (BMI) percentiles, and standards from the National High Blood Pressure Education Program Working Group on Hypertension Control in Children and Adolescents were used to assess blood pressure. RESULTS: Seven hundred sixty-nine students with active consent participated in the screening. Of these, approximately 28% were overweight. American Indians were at significantly greater risk of being overweight or at risk for overweight than whites (relative risk [RR], 1.4; 95% confidence interval [CI], 1.1-1.7) as were African Americans (RR, 1.5; 95% CI, 1.1-2.0), whereas Hispanics (RR, 1.3; 95% CI, 0.9-2.0) did not have a statistically significant increased risk compared with whites. BMI at or above the 95th percentile was strongly associated with elevated blood pressure (> or =90th percentile) (RR, 3.8; 95% CI, 2.6-5.4). CONCLUSION: Students who participated in this BMI screening in the Anadarko public school system evidenced high rates of excess weight, with American Indians and African Americans at greatest risk. Elevated BMI was strongly associated with elevated blood pressure.

Relationship of the 1793G-A and 677C-T polymorphisms of the 5,10-methylenetetrahydrofolate reductase gene to coronary artery disease.

Numerous studies have investigated the relationship between polymorphisms, in particular 677C-T and 1298A-C, of the methylene-tetrahydrofolate reductase (MTHFR) gene and coronary artery disease (CAD) with conflicting results. This study investigates the potential association of two point mutations in MTHFR, 677C-T and 1793G-A, along with other risk factors, with CAD. This is the first hospital-based study to investigate 1793G-A in this context. Genotype analysis was performed on 729 Caucasians and 66 African Americans undergoing coronary angiography using a novel PCR-based assay involving formation of Holliday junctions. Allelic frequencies for 677C-T were 66.2% C and 33.8% T for Caucasians and 90.9% C and 9.1% T for African Americans. With respect to the 1793G-A polymorphism, allelic frequencies were 94.7% G and 5.3% A for Caucasians and 99.2% G and 0.8% A for African Americans. Disease associations were examined in the Caucasian patients due to their greater genotype variability and larger number in the patient cohort. Results suggest that neither 677CT heterozygotes (OR-1.36; 95% CI 0.95 to 1.96) nor mutant homozygotes (OR-0.73; 95% CI 0.44 to 1.20) have either an increased or decreased risk for CAD compared to the 677CC genotype. Likewise, the 1793GA genotype did not demonstrate a statistically significant association with CAD compared to 1793GG patients (OR-0.79; 95% CI 0.47 to 1.33). Mean homocysteine levels (mumol/L) increased from normal to mutant for 677C-T (677CC: 10.2; 677CT: 11.0; 677TT: 11.6) and normal to heterozygous in 1793G-A (1793GG: 10.7; 1793GA: 11.5). These MTHFR polymorphisms did not contribute to the prediction of clinically defined CAD in Caucasians.

Neural network predictions of significant coronary artery stenosis in men.

OBJECTIVE: A neural network system was designed to predict whether coronary arteriography on a given patient would reveal any occurrence of significant coronary stenosis (>50%), a degree of stenosis which often leads to coronary intervention. METHODOLOGY: A dataset of 2004 records from male cardiology patients was derived from a national cardiac catheterization database. The catheterizations selected for analysis from the database were first-time and elective, and they were precipitated by chest pain. Eleven patient variables were used as inputs in an artificial neural network system. The network was trained on the earliest 902 records in the dataset. The next 902 records formed a cross-validation file, which was used to optimize the training. A third file composed of the next 100 records facilitated the choice of a cutoff number between 0 and 1. The cutoff number was applied to the last 100 records, which comprised a test file. RESULTS: When a cutoff of 0.25 was compared to the network outputs of all 100 records in the test file, 12 of 46 (specificity=26%) patients without significant stenosis had outputs0.25 (sensitivity=100%). Therefore, the network identified a fraction of the patients in the test file who did not have significant coronary artery stenosis, while at the same time the network identified all of the patients in the test file who had significant stenosis capable of causing chest pain. CONCLUSION: Artificial neural networks may be helpful in reducing unnecessary cardiac catheterizations.

Tobacco use among American Indians in Oklahoma: an epidemiologic view.

OBJECTIVES: With the exception of national surveys that sample the entire U.S. population, little information exists on tobacco habits among American Indians. This study is a comparison of tobacco use findings in the 1990s among American Indians in Oklahoma, a state with a large and diverse American Indian population (39 tribes). METHODS: Data on current tobacco use are presented from two statewide surveys, the Oklahoma Youth Tobacco Survey and the Native American Behavioral Risk Factor Survey, as well as two large epidemiologic studies of chronic disease among American Indians-the Cherokee Diabetes Study and the Strong Heart Study. Three of these four sources of data involve research/surveys exclusively about American Indians. RESULTS: Nontraditional use of tobacco by American Indians occurs frequently, according to each instrument. Initiation to this habit begins in middle school and increases dramatically during high school. After age 50, reporting by individuals that they currently smoke declines steadily. CONCLUSIONS: Despite sampling different individuals for the surveys and different tribes for the epidemiologic research, results were comparable in age groups that overlapped. These findings support national data indicating that American Indians have higher prevalence rates of smoking than other racial/ethnic groups. American Indians report smoking on average about a half a pack of cigarettes per day. Individuals reporting using tobacco solely for ceremonial purposes were far fewer than habitual users. Buying tobacco products in American Indian smoke shops helps tribal economies; this fact needs to be considered for prevention programs to succeed.

Apolipoprotein E polymorphism and cardiovascular disease: a HuGE review.

This review examines the association between the apolipoprotein (apo) var epsilon gene polymorphism (or its protein product (apo E)), metabolic regulation of cholesterol, and cardiovascular disease. The apo var epsilon gene is located at chromosome 19q13.2. Among the variants of this gene, alleles (*) epsilon2, (*) epsilon3, and (*) epsilon4 constitute the common polymorphism found in most populations. Of these variants, apo (*) epsilon3 is the most frequent (>60%) in all populations studied. The polymorphism has functional effects on lipoprotein metabolism mediated through the hepatic binding, uptake, and catabolism of chylomicrons, chylomicron remnants, very low density lipoprotein (VLDL), and high density lipoprotein subspecies. Apo E is the primary ligand for two receptors, the low density lipoprotein (LDL) receptor (also known as the B/E receptor) found on the liver and other tissues and an apo E-specific receptor found on the liver. The coordinate interaction of these lipoprotein complexes with their receptors forms the basis for the metabolic regulation of cholesterol. Allelic variation in apo var epsilon is consistently associated with plasma concentrations of total cholesterol, LDL cholesterol, and apo B (the major protein of LDL, VLDL, and chylomicrons). Apo var epsilon has been studied in disorders associated with elevated cholesterol levels or lipid derangements (i.e., hyperlipoproteinemia type III, coronary heart disease, strokes, peripheral artery disease, and diabetes mellitus). The apo var epsilon genotype yields poor predictive values when screening for clinically defined atherosclerosis despite positive, but modest associations with plaque and coronary heart disease outcomes. In addition to genotype-phenotype associations with vascular disease, the alleles and isoforms of apo var epsilon have been related to dementias, most commonly Alzheimer's disease.