Prevalence and Associated Factors of Tinnitus: Data From the Korean National Health and Nutrition Examination Survey 2009–2011

Background

Tinnitus is a common condition and frequently can be annoying to affected individuals. We investigated the prevalence and associated factors for tinnitus in South Korea using the data from the Korea National Health and Nutrition Examination Surveys (KNHANES) during 2009–2011.

Methods

KNHANES is a cross-sectional survey of the civilian, non-institutionalized population of South Korea (n = 21 893). A field survey team that included an otolaryngologist moved with a mobile examination unit and performed interviews and physical examinations.

Results

Among the population over 12 years of age, the prevalence of any tinnitus was 19.7% (95% CI 18.8%–20.6%). Tinnitus was more prevalent in women, and the prevalence rate increased with age (P < 0.001). Among those with any tinnitus, 29.3% (95% CI 27.3%–31.3%) experienced annoying tinnitus that affected daily life. Annoying tinnitus also increased with age (P < 0.001), but no sex difference was demonstrated (P = 0.25). In participants aged 40 years or older, age, quality of life, depressive mood, hearing loss, feeling of dizziness, and rhinitis were associated with any tinnitus (P < 0.05). Age, hearing loss, history of cardiovascular disease, and stress were associated with annoying tinnitus (P < 0.05).

Conclusions

Tinnitus is a common condition, and a large population suffers from annoying tinnitus in South Korea. Public understanding of associated factors might contribute to better management of tinnitus.Key words: tinnitus, epidemiology, associated factor, South Korea     

Socioeconomic status and dyslipidemia in Korean adults: The 2008–2010 Korea National Health and Nutrition Examination Survey

Objective

This study investigated the relationship between socioeconomic status (SES) and dyslipidemia and various parameters of dyslipidemia among Korean adults.

Methods

Data from the 2008–2010 Korea National Health and Nutrition Examination Survey were used in this study. A total of 19,041 Korean adults greater than 19 years old participated in the study. The SES was assessed by monthly household income and education level. The relationship of SES to the risk of dyslipidemia was assessed with multivariate logistic regression analysis after adjusting for potential confounders.

Results

The prevalence of dyslipidemia was 37.4% among Korean adults. In men, household income level was positively associated with prevalence and risks of several parameters of dyslipidemia, and education level had positive associations with the risks of dyslipidemia and parameters of dyslipidemia. However, low SES was linked to increased prevalence and risks of dyslipidemia (P for trend < 0.05) and parameters of dyslipidemia in women.

Conclusions

Socioeconomic disparities in dyslipidemia were found in the Korean population. Also, there were gender differences in the relationship between SES and dyslipidemia. These disparities should be considered when performing risk calculations and screening for dyslipidemia, which will ultimately help prevent cardiovascular disease.     

Blood cadmium concentrations in Korean adolescents: From the Korea National Health and Nutrition Examination Survey 2010–2013

Objective

To assess blood cadmium levels in Korean adolescents with respect to demographic and lifestyle factors.

Vitamin A Intake,Serum Vitamin D and Bone Mineral Density: Analysis of the Korea National Health and Nutrition Examination Survey (KNHANES, 2008–2011)

The association of high vitamin A intake and low bone mineral density (BMD) is still controversial. To determine the association of dietary vitamin A intake and serum 25-hydroxyvitamin D (25(OH)D) concentration with BMD, a total of 6481 subjects (2907 men and 3574 women) aged ≥50 years from the Korean National Health and Nutrition Examination Survey (2008–2011) were divided into groups according to dietary vitamin A intake (tertiles) and serum 25(OH)D (<50, 50–75, >75 nmol/L), and evaluated for BMD after adjusting for relevant variables. Mean dietary vitamin A intakes were 737 and 600 μg RE (Retinol Equivalents) in men and women, respectively. Total hip and femoral neck BMD in men and lumbar spine BMD in women were both positively correlated with dietary vitamin A intake in subjects with serum 25(OH)D >75 nmol/L. Among men with serum 25(OH)D <50 nmol/L, both the top (mean 1353 μg RE) and bottom (mean 218 μg RE) tertiles of dietary vitamin A intake had lower BMD than the middle group (mean 577 μg RE). In this population, BMD was the highest among men and women with serum 25(OH)D = 50–75 nmol/L and that there were no differences in BMD by vitamin A intake in these vitamin D adequate groups. This cross-sectional study indicates that vitamin A intake does not affect bone mineral density as long as the serum 25(OH)D concentration is maintained in the moderate level of 50–75 nmol/L.     

Trends in Prevalence of Overweight and Obesity in Korean Adults, 1998–2009: The Korean National Health and Nutrition Examination Survey

Background

Although obesity is increasing worldwide and becoming a major public health problem, some countries report a trend toward stabilization. We investigated prevalence trends in overweight/obesity and obesity among Korean adults during a 12-year period.

Methods

This study was based on the Korean National Health and Nutrition Examination Survey (KNHANES) I (1998), II (2001), III (2005), and IV (2007–2009). The χ² and ANOVA tests were used to compare the prevalence and mean values for age and BMI, respectively. P-values for trends were determined by linear and logistic regression analyses, with KNHANES phase as the continuous variable.

Results

The prevalences of overweight/obesity in KNHANES I through IV were 50.8%, 57.4%, 62.5%, and 62.6%, respectively, among men (P for trend = 0.002, β = 0.021) and 47.3%, 51.9%, 50.0%, and 48.9% among women (P for trend = 0.017, β = −0.015). The respective prevalences of obesity were 26.0%, 32.4%, 35.1%, and 36.3% among men (P for trend = 0.006, β = 0.018) and 26.5%, 29.3%, 28.0%, and 27.6% among women (P for trend = 0.143, β = −0.008). During the same period, the respective prevalences of grade 2 obesity (BMI ≥30 kg/m²) were 1.7%, 2.8%, 3.6%, and 3.8% among men (P for trend = 0.075, β = 0.005) and 3.0%, 3.5%, 3.4%, and 4.0% among women (P for trend = 0.398, β = 0.003).

Conclusions

The prevalences of overweight/obesity and obesity showed an upward trend among men during the 12-year period, whereas the prevalence of overweight/obesity slightly decreased among women from 2001.Key words: obesity, overweight, prevalence, trend     

Are Mothers’ Working Hours Associated with General and Abdominal Obesity in Children and Adolescents? The Korean National Health and Nutrition Examination Survey (2008–2012)

Objectives Despite an increase in the female work force and recent increase in childhood obesity, the association between working hours of mothers and childhood obesity as well as how such association differs according to mothers’ weight and intake frequency of energy-dense, nutrition-poor (EDNP) foods remain unclear. Methods Data from the Korean National Health and Nutrition Examination Survey (2008–2012) that included samples from 3914 children in 2526 households were analyzed. Two-level (household-children) mixed-effects modeling was performed to investigate the association between mothers’ working hours and childhood obesity based on body mass index (BMI) and waist circumference (WC). Results Long working hours (h) of mothers were associated with both BMI (β = ? 0.14; P = 0.324 for 1–20 h, β = 0.10; P = 0.334 for ≤ 21–40 h; β = 0.09; P = 0.429 for 41–68 h, β = 0.51; P = 0.015 for ≥ 69 h) and WC of the child (β = 0.06; P = 0.809 for 1–20 h; β = 0.46; P = 0.017 for ≤ 21–40 h; β = 0.59; P = 0.004 for 41–68 h, β = 1.35; P < 0.001 for ≥ 69 h), and the mean increase was greater for mothers working ≥ 69 h compared to those working 0 h. We also observed that the association between mothers’ working hours and child’s BMI and WC was greater for children whose mothers were either overweight or obese and frequently consumed energy-dense, nutrient-poor foods (EDNP). Conclusions for Practice Long working hours of mothers are associated with higher BMI and WC in children. Thus, it is important to improve labor welfare for mothers who work long hours, and provide interventions to promote good health behaviors in both children and working mothers.     

Association between blood lead and mercury levels and periodontitis in the Korean general population: analysis of the 2008–2009 Korean National Health and Nutrition Examination Survey data

Objectives

We present data from the Korean National Health and Nutrition Examination Survey 2008–2009 regarding the association between blood lead and mercury levels and periodontitis in a representative sample of the adult South Korean population.

Methods

The analysis was restricted to participants ≥20 years of age who completed the health examination survey, including blood lead, cadmium, and mercury measurements (n = 3,966). Odds ratios (ORs) for periodontitis were calculated for log-transformed blood metal levels and quartiles thereof after covariate adjustment.

Results

In a logistic regression analysis using log-transformed blood lead and mercury levels as independent variables after covariate adjustment, including blood lead, mercury, and cadmium, the ORs and 95 % CI values in men for having periodontitis with doubling of blood lead and mercury were 1.699 (1.154–2.503) and 1.394 (1.057–1.838), respectively. Furthermore, in a logistic regression analysis using tertiles of blood lead and mercury as independent variables after covariate adjustment, the ORs and 95 % CIs of men for having periodontitis in the highest tertile were 1.756 (1.184–2.604) and 1.575 (1.507–2.347), respectively. ORs in the logistic regression analysis for men using log-transformed blood cadmium or the tertile of blood cadmium as independent variables after covariate adjustments were not statistically significant in either model. Unlike men, ORs in the logistic regression analyses for women using the same independent variables after covariate adjustment were not statistically significant in any blood metal analysis.

Conclusions

The association between blood lead and mercury levels and periodontitis was significant regardless of the type of variable (continuous or categorical) in the Korean male population.     

Increased erythrocyte lead levels correlate with decreased hemoglobin levels in the Korean general population: analysis of 2008–2010 Korean National Health and Nutrition Examination Survey data

Introduction

We present data from the Korean National Health and Nutrition Examination Survey 2008–2010 on the association between blood lead and hemoglobin levels in a representative sample of the adult South Korean population.

Methods

The analysis was restricted to participants ≥20 years of age who completed the health examination survey, including blood lead measurements (n = 5,951). Multivariate linear regression analyses were performed to estimate adjusted mean differences in hemoglobin level associated with doubling of whole blood and erythrocyte lead or quartiles of the metal after covariate adjustment. Odds ratios (ORs) for having borderline anemia or clinical anemia were calculated for log-transformed whole blood and erythrocyte lead or quartiles of the metal after covariate adjustment.

Results

A twofold increase in whole blood lead or erythrocyte lead was associated with a 0.285 g/dL increase or 0.088 g/dL decrease in hemoglobin level, respectively. There was a 0.416 g/dL increase or 0.143 g/dL decrease in hemoglobin, respectively, in the highest, compared with the lowest tertile of whole blood lead and erythrocyte lead, respectively. Based on ORs, doubling of whole blood lead or erythrocyte lead resulted in a 36.3 % decrease or 36.2 % increase, respectively, in the risk of borderline anemia.

Conclusion

The association of whole blood lead versus erythrocyte lead with hemoglobin level was opposite. In the case of anemia, which is frequently caused by iron deficiency, the effect on the whole blood lead concentration may be very significant, leading to a considerable underestimation of the person’s lead status. Therefore, hematocrit-adjusted blood lead level (i.e., erythrocyte lead) should be applied to the general population. To our knowledge, this is the first study to show that erythrocyte lead levels showed a significant inverse relationship with hemoglobin level at lead levels <10 μg/dL in the general Korean population. In conclusion, increased erythrocyte lead levels may be associated with mildly decreased hemoglobin levels, after adjusting for covariates, in a representative sample of the adult Korean population.     

Dietary intakes and lifestyle patterns of Korean children and adolescents with atopic dermatitis: Using the fourth and fifth Korean National Health and Nutrition Examination Survey (KNHANES IV,V), 2007–11

We investigate dietary intake and lifestyle patterns of atopic children and adolescents (N = 539) by obesity level using a national survey of South Korea. Intakes of calcium, iron, and vitamin C in the underweight group were less than those of other groups. The frequency of drinking milk of the overweight group was higher than that of the normal weight group. Majority of the subjects had not applied nutrition labeling in food choices, had no experience of nutrition education, and were vitamin D deficient. In conclusion, most of the atopic subjects had little knowledge of nutrition and were vitamin D deficient.     

Trends in Serum Lipids and Hypertension Prevalence Among Non-Pregnant Reproductive-Age Women: United States National Health and Nutrition Examination Survey 1999–2008

Cardiovascular disease is one of the leading causes of death among reproductive-age women. In this study, we examine trends in the prevalence of dyslipidemia, hypertension, and related clinicians’ advice among reproductive-age women. We conducted trend analysis of these factors among non-pregnant women aged 20–49 years (n = 5,768) using National Health and Nutrition Examination Survey (NHANES) data obtained between 1999 and 2008. Multiple linear regression and logistic regression analyses were used to examine linear trends over a 10-year period after adjusting for covariates. A downward trend was observed for the proportion of women with abnormal levels of low density lipoprotein (LDL; P = 0.038) and high density lipoprotein (HDL; P = 0.008) cholesterol from 1999 to 2008. In contrast, no significant changes were observed in the prevalence of abnormal total cholesterol (P = 0.948) and triglyceride levels (P = 0.300), or hypertension (P = 0.632). Based on the self-reported data, upward trends were observed in the rates of cholesterol checking (P = 0.002), high cholesterol (P = 0.012), receiving clinicians’ advice to use lipid-lowering agents (P < 0.001) and patients’ compliance with their advice (P < 0.001). Although rates of self-reported hypertension did not change over time (P = 0.120), receiving clinicians’ advice to use antihypertensive medications (P = 0.003) and patients’ compliance with these medications (P = 0.015) also increased significantly. Overall improvements in LDL and HDL cholesterol over this time period could be due to increases in related awareness, receiving advice to use medications, and patients’ compliance with this advice. Use of antihypertensive medication has also increased among reproductive-age women in the US.     

What are patient factors associated with the quality of diabetes care?: results from the Korean National Health and Nutrition Examination Survey

ABSTRACT: BACKGROUND: Recently there has been a growing interest in healthcare quality control in Korea. We examined the association between patient factors and quality indicators of diabetic care among Korean adults with diabetes. METHODS: We obtained a sample of 335 adults aged 20 or older diagnosed with diabetes from the 2005 Korean National Health and Nutrition Examination Survey. Patient factors were divided into two categories: socioeconomic position and health-related factors. Quality indicators for diabetes care were defined as receiving preventive care services for diabetes complications (e.g., fundus examination, microalbuminuria examination, diabetes education) and diabetes-related clinical outcomes (e.g., HbA1c, blood pressure, LDL-cholesterol). We performed multiple logistic regression analyses for each quality indicator. RESULTS: We found that people with lower education levels or shorter duration of diabetes illness were less likely to receive preventive care services for diabetes complications. Women or people with longer duration of diabetes were less likely to reach the glycemic target. Obese diabetic patients were less likely to accomplish adequate control of blood pressure and LDL-cholesterol. CONCLUSIONS: Several factors of patients with diabetes, such as education level, duration of illness, gender, and obesity grade are associated with the quality of diabetes care. These findings can help inform policy makers about subpopulations at risk in developing a public health strategy in the future.     

Selecting Adequate Exposure Biomarkers of Diisononyl and Diisodecyl Phthalates: Data from the 2005–2006 National Health and Nutrition Examination Survey

Background

High-molecular-weight phthalates, such as diisononyl phthalate (DINP) and diisodecyl phthalate (DIDP), are used primarily as polyvinyl chloride plasticizers.

Objectives

We assessed exposure to DINP and DIDP in a representative sample of persons ≥ 6 years of age in the U.S. general population from the 2005–2006 National Health and Nutrition Examination Survey (NHANES).

Methods

We analyzed 2,548 urine samples by using online solid-phase extraction coupled to isotope dilution high-performance liquid chromatography–tandem mass spectrometry.

Results

We detected monocarboxyisooctyl phthalate (MCOP), a metabolite of DINP, and monocarboxyisononyl phthalate (MCNP), a metabolite of DIDP, in 95.2% and 89.9% of the samples, respectively. We detected monoisononyl phthalate (MNP), a minor metabolite of DINP, much less frequently (12.9%) and at concentration ranges (> 0.8 μg/L–148.1 μg/L) much lower than MCOP (> 0.7 μg/L– 4,961 μg/L). Adjusted geometric mean concentrations of MCOP and MCNP were significantly higher (p < 0.01) among children than among adolescents and adults.

Conclusions

The general U.S. population, including children, was exposed to DINP and DIDP. In previous NHANES cycles, the occurrence of human exposure to DINP by using MNP as the sole urinary biomarker has been underestimated, thus illustrating the importance of selecting the most adequate biomarkers for exposure assessment.     

Is obesity associated with major depression? Results from the Third National Health and Nutrition Examination Survey

Data from the Third National Health and Nutrition Examination Survey (1988-1994) were used to examine the relation between obesity and depression. Past-month depression was defined using criteria from the Diagnostic and Statistical Manual of Mental Disorders, Third Edition, and was measured with the Diagnostic Interview Schedule. Obesity was defined as a body mass index (weight (kg)/height (m)2) of 30 or higher. The authors compared risks of depression in obese and normal-weight (body mass index 18.5-24.9) persons. Obesity was associated with past-month depression in women (odds ratio (OR)=1.82, 95% confidence interval (CI): 1.01, 3.3) but was not significantly associated in men (OR=1.73, 95% CI: 0.56, 5.37). When obesity was stratified by severity, heterogeneity in the association with depression was observed. Class 3 (severe) obesity (body mass index > or =40) was associated with past-month depression in unadjusted analyses (OR=4.98, 95% CI: 2.07, 11.99); the association remained strong after results were controlled for age, education, marital status, physician's health rating, dieting for medical reasons, use of psychiatric medicines, cigarette smoking, and use of alcohol, marijuana, and cocaine. These findings suggest that obesity is associated with depression mainly among persons with severe obesity. Prospective studies will be necessary to clarify the obesity-depression relation but await the identification of potential risk factors for depression in the obese.     

Increased Prevalence of low High-density Lipoprotein Cholesterol (HDL-C) Levels in Korean Adults: Analysis of the Three Korean National Health and Nutrition Examination Surveys (KNHANES 1998–2005)

Objectives

High-density lipoprotein cholesterol (HDL-C) is an independent risk factor for cardiovascular diseases that has shown a remarkable increase, but little is known about the prevalence of low HDL-C in Korea. This study aimed to evaluate changing trends of low HDL-C prevalence, and indicate other risk factors associated with low HDL-C.

Methods

We selected subjects aged ≥20 years from the Korean National Health and Nutrition Examination Survey (KNHANES) 1998, 2001, and 2005 (n = 7962, 6436, and 6412). The mean level of HDL-C and the prevalence of low HDL-C was calculated, and cardiovascular risk factors associated with low HDL-C, as well as demographic, anthropometric, lifestyle, and nutrition factors, were assessed using the KNHANES 2005 data.

Results

Mean HDL-C levels in men and women between KNHANES 1998 and 2005 decreased significantly, from 48.1 to 42.3 and from 51.6 to 47.1 mg/dL, respectively (both p < 0.001). The decrease was slightly less for women compared with men for the same period, and women had higher HDL-C levels at all periods. Covariate-adjusted OR revealed that body mass index, waist circumference, and non-alcohol drinker in both men and women were associated with low HDL-C levels by KNHANES 2005, as were employed and light physical activity in men and low fat intake in women.

Conclusion

The prevalence of low HDL-C increased significantly from KNHANES 1998 to 2001 and 2005 (p < 0.001) in both men and women. body mass index, waist circumference, and non-alcohol drinker were identified as associated with low HDL-C in Korean adults.     

Tree Nut Consumption Is Associated with Better Nutrient Adequacy and Diet Quality in Adults: National Health and Nutrition Examination Survey 2005–2010

Nutrient adequacy of tree nut consumers has not been examined. The National Health and Nutrition Examination Survey 2005–2010 data were used to assess the association of tree nut consumption by adults 19+ years (n = 14,386) with nutrient adequacy and diet quality. Covariate adjusted usual intake was determined using two 24-h dietary recalls and the National Cancer Institute method. Percentages of the consumption groups below the Estimated Average Requirement (EAR) or above the Adequate Intake (AI) were determined. Diet quality was determined using the Healthy Eating Index-2005 (HEI) score. Usual intake data showed consumers of tree nuts had a lower percentage (p < 0.0001) of the population below the EAR for vitamins A (22 ± 5 vs. 49 ± 1), E (38 ± 4 vs. 94 ± 0.4) and C (17 ± 4 vs. 44 ± 1); folate (2.5 ± 1.5 vs. 12 ± 0.6); calcium (26 ± 3 vs. 44 ± 1); iron (3 ± 0.6 vs. 9 ± 0.4); magnesium (8 ± 1 vs. 60 ± 1); and zinc (1.5 ± 1 vs. 13 ± 1). Tree nut consumers had a higher percentage (p < 0.0001) of the population above the AI for fiber (33 ± 3 vs. 4 ± 0.3) and potassium (12 ± 3 mg vs. 2 ± 0.2 mg). HEI-2005 total score was higher (p < 0.0001) in tree nut consumers (61 ± 0.7 vs. 52 ± 0.3) than non-consumers. Health professionals should encourage the use of tree nuts as part of a dietary approach to healthy eating.     

Associations Between Selected Xenobiotics and Antinuclear Antibodies in the National Health and Nutrition Examination Survey, 1999–2004

Background:

Potential associations between background environmental chemical exposures and autoimmunity are understudied.

Objectives:

Our exploratory study investigated exposure to individual environmental chemicals and selected mixtures in relation to the presence of antinuclear antibodies (ANA), a widely used biomarker of autoimmunity, in a representative sample of the U.S. population.

Methods:

This cross-sectional analysis used data on 4,340 participants from the National Health and Nutrition Examination Survey (1999–2004), of whom 14% were ANA positive, to explore associations between ANA and concentrations of dioxins, dibenzofurans, polychlorinated biphenyls, organochlorines, organophosphates, phenols, metals, and other environmental exposures and metabolites measured in participants’ serum, whole blood, or urine. For dioxin-like compounds with toxic equivalency factors, we developed and applied a new statistical approach to study selected mixtures. Lognormal models and censored-data methods produced estimates of chemical associations with ANA in males, nulliparous females, and parous females; these estimates were adjusted for confounders and accommodated concentrations below detectable levels.

Results:

Several associations between chemical concentration and ANA positivity were observed, but only the association in males exposed to triclosan remained statistically significant after correcting for multiple comparisons (mean concentration ratio = 2.8; 95% CI: 1.8, 4.5; p < 0.00001).

Conclusions:

These data suggest that background levels of most xenobiotic exposures typical in the U.S. population are not strongly associated with ANA. Future studies should ideally reduce exposure misclassification by including prospective measurement of the chemicals of concern and should track changes in ANA and other autoantibodies over time.

Citation:

Dinse GE, Jusko TA, Whitt IZ, Co CA, Parks CG, Satoh M, Chan EKL, Rose KM, Walker NJ, Birnbaum LS, Zeldin DC, Weinberg CR, Miller FW. 2016. Associations between selected xenobiotics and antinuclear antibodies in the National Health and Nutrition Examination Survey, 1999–2004. Environ Health Perspect 124:426–436; http://dx.doi.org/10.1289/ehp.1409345     

Prevalence of Inadequate Hydration Among US Children and Disparities by Gender and Race/Ethnicity: National Health and Nutrition Examination Survey, 2009–2012

Objectives. We evaluated the hydration status of US children and adolescents.Methods. The sample included 4134 participants aged 6 to 19 years in the National Health and Nutrition Examination Survey from 2009 to 2012. We calculated mean urine osmolality and the proportion with inadequate hydration (urine osmolality > 800 mOsm/kg). We calculated multivariable regression models to estimate the associations between demographic factors, beverage intake, and hydration status.Results. The prevalence of inadequate hydration was 54.5%. Significantly higher urine osmolality was observed among boys (+92.0 mOsm/kg; 95% confidence interval [CI] = 69.5, 114.6), non-Hispanic Blacks (+67.6 mOsm/kg; 95% CI = 31.5, 103.6), and younger children (+28.5 mOsm/kg; 95% CI = 8.1, 48.9) compared with girls, Whites, and older children, respectively. Boys (OR = 1.76; 95% CI = 1.49, 2.07) and non-Hispanic Blacks (odds ratio [OR] = 1.34; 95% CI = 1.04, 1.74) were also at significantly higher risk for inadequate hydration. An 8-fluid-ounce daily increase in water intake was associated with a significantly lower risk of inadequate hydration (OR = 0.96; 95% CI = 0.93, 0.98).Conclusions. Future research should explore drivers of gender and racial/ethnic disparities and solutions for improving hydration status.Adequate hydration is essential for health. Water is crucial for the proper function of several physiological processes, including circulatory function, metabolism, temperature regulation, and waste removal.1 Dehydration, a state in which total body water is inadequate for proper cell, organ, and system functioning, is associated with poor health. Although excessive dehydration is associated with serious health problems, such as impaired renal, immune, and gastrointestinal functioning, confusion, and delirium, even mild dehydration can worsen health and well-being.2 Mild dehydration is associated with headache, irritability, poorer physical performance, and reduced cognitive functioning among both children and adults.2–5Children’s hydration status could have implications for both health and school performance. Two studies have shown that inadequate hydration, defined as urine osmolality of 800 milliosmoles per kilogram or higher, is associated with poorer performance on cognitive tests.6,7 However, despite a substantial body of research examining children’s beverage intake,8 little is known about children’s hydration status and whether it may be a population health concern. Kant et al. found that as of the period 2005 to 2006, US children and adolescents, on average, did not consume adequate water for their age group as defined by the Institute of Medicine,9 but hydration status was not evaluated. A small study in 2 major US cities using urine osmolality as an indicator of hydration status found that over 60% of a convenience sample of children aged 9 to 11 years were inadequately hydrated and that most children did not consume plain water, putting them at higher risk of inadequate hydration.10 However, we have identified no study describing children’s hydration status nationally. Additionally, although a review of international studies found significant differences in hydration status by age, gender, race/ethnicity, and culture,11 there is limited evidence about the population distribution of urine osmolality and inadequate hydration among US children, particularly whether disparities in hydration status exist across population groups defined by race/ethnicity, household income, gender, or age. Although small, laboratory-based studies of adults suggest that higher beverage intake is associated with better hydration status (regardless of beverage type),12,13 preliminary evidence has suggested that plain water may be associated with better hydration status in children.10 Given that little is known about how consumption of different beverages may affect population hydration status in children, the potential solutions to reducing inadequate hydration are unclear.Measuring hydration status outside of severe dehydration has proven challenging because the level of fluid in the body is constantly fluctuating. Plasma osmolality, a measure of the amount of solutes in the blood stream, is often used to measure severe dehydration, but it has a very limited range and is tightly regulated by homeostasis, rendering it insensitive to smaller changes in hydration status.12,14–16 Measures involving urine, such as urine volume or urine osmolality, are more sensitive to less dramatic changes in body water; however, the volume and timing of water intake can bias measurements. If individuals rapidly consume large amounts of water, their urine osmolality will be low and urine volume high as the body rapidly excretes the water, but their hydration status will be unaffected as the body will get rid of the excess water before it has a chance to rehydrate. Twenty-four-hour urine osmolality and 24-hour urine volume may be the most sensitive measures of 24-hour hydration status as time lags are better controlled.11,14–16 Although a single measure of urine osmolality may not accurately reflect an individual’s typical hydration status because of fluctuation in urine osmolality, it may still be useful for estimating population averages. We would expect that observed fluctuations in the population would not be systematically biased above or below the mean.We examined the prevalence of elevated urine osmolality and its population distribution by age, race/ethnicity, gender, and family income in a nationally representative sample of participants aged 6 to 19 years from the National Health and Nutrition Examination Survey (NHANES), 2009 to 2012,17 controlling for sample design and time of day the data were collected. We also examined whether consuming different types of beverages on the day before data collection, including water, milk, 100% juice, sugar-sweetened beverages (SSBs), and diet drinks, was associated with urine osmolality in this age group, hypothesizing that increased intake of water (compared with other beverages) would be associated with reduced urine osmolality.     

Has Income-related Inequity in Health Care Utilization and Expenditures Been Improved? Evidence From the Korean National Health and Nutrition Examination Survey of 2005 and 2010

Objectives

The purpose of this study is to examine and explain the extent of income-related inequity in health care utilization and expenditures to compare the extent in 2005 and 2010 in Korea.

Methods

We employed the concentration indices and the horizontal inequity index proposed by Wagstaff and van Doorslaer based on one- and two-part models. This study was conducted using data from the 2005 and 2010 Korean National Health and Nutrition Examination Survey. We examined health care utilization and expenditures for different types of health care providers, including health centers, physician clinics, hospitals, general hospitals, dental care, and licensed traditional medical practitioners.

Results

The results show the equitable distribution of overall health care utilization with pro-poor tendencies and modest pro-rich inequity in the amount of medical expenditures in 2010. For the decomposition analysis, non-need variables such as income, education, private insurance, and occupational status have contributed considerably to pro-rich inequality in health care over the period between 2005 and 2010.

Conclusions

We found that health care utilization in Korea in 2010 was fairly equitable, but the poor still have some barriers to accessing primary care and continuing to receive medical care.     

Allostatic Load in Foreign-Born and US-Born Blacks: Evidence From the 2001–2010 National Health and Nutrition Examination Survey

Objectives. We tested whether the immigrant health advantage applies to non-Hispanic Black immigrants and examined whether nativity-based differences in allostatic load exist among non-Hispanic Blacks.Methods. We used pooled data from the 2001–2010 National Health and Nutrition Examination Survey to compare allostatic load scores for US-born (n = 2745) and foreign-born (n = 152) Black adults. We used multivariate logistic regression techniques to assess the association between nativity and high allostatic load scores, controlling for gender, age, health behaviors, and socioeconomic status.Results. For foreign-born Blacks, length of stay and age were powerful predictors of allostatic load scores. For older US-born Blacks and those who were widowed, divorced, or separated, the risk of high allostatic load was greater.Conclusions. Foreign-born Blacks have a health advantage in allostatic load. Further research is needed that underscores a deeper understanding of the mechanisms driving this health differential to create programs that target these populations differently.There is growing interest in improving population health because Healthy People 2020 and the Patient Protection and Affordable Care Act include important provisions to reduce health disparities.1,2 Recent research suggests that certain racial/ethnic groups in the United States, particularly non-Hispanic Blacks, have higher rates of morbidity and all-cause mortality than do Whites. However, non-Hispanic Blacks are a heterogeneous group that includes a growing population of immigrants from a variety of countries and cultural backgrounds. Recent estimates suggest the foreign-born segment of the Black population has almost tripled over the past 3 decades—with the majority migrating from the Caribbean and Africa—and represents roughly 8% of the Black population.3,4 Despite this marked increase, little is known about the health of foreign-born Blacks.Previous research suggests that Caribbean and African immigrants differ from their US-born counterparts in various physical5–8 and mental health indicators.9 Some research suggests that foreign-born Blacks have better health outcomes than do US-born Blacks because of the healthy immigrant effect.10,11 The healthy immigrant effect posits that immigrants have healthier lifestyles in their home countries, are among the healthiest from their home country, and are the group most willing and able to endure the stressors associated with immigration, therefore placing them at a health advantage. However, the health advantage declines with increased time spent in the United States, as immigrants adapt to the US sociocultural environment.10 Research suggests Caribbean and African immigrants have worse health over time because they have higher levels of psychological stress related to immigration and adjusting to new sociocultural environments.9 Additionally, the impact of exposure to racism in the United States may be particularly stressful for immigrants from regions of the world where they were a demographic majority.8,9To measure the deleterious effects of stress on the body, the concept of allostatic load has been introduced as a unique approach to understanding the underlying biological processes that might explain health vulnerability. Allostatic load accounts for the cumulative impact of physiological responses to acute, chronic, or long-term psychosocial stressors generated by social conditions that continuously activate hormonal responses to stressful conditions. Prolonged activation of these physiological systems is thought to place persons at risk for the development for both physical and mental disorders.12,13 The literature on allostatic load suggests that overexposure to adverse conditions while adapting to US culture can create a buildup of stressors endemic to the immigrant experience, particularly for immigrants of color.Some studies document the deleterious effects for foreign-born populations of psychosocial stress on the body and dysregulation of physiological systems known to protect the individual from disease.14 Much of this research has focused on Hispanics, partly because they are one of the largest immigrant ethnic groups, there is available survey data, and there is scientific interest in the Hispanic health paradox.15,16 This paradox—that Hispanics exhibit better health outcomes than do non-Hispanic Whites despite their lower than expected socioeconomic status—has been challenged in various studies in which time in the United States has been shown to be the predictor that is most associated with health declines.17 Kaestner et al.18 found that with increased time in the United States, the probability of having a high allostatic load score increased for foreign-born Mexicans. Peek et al.19 reported that among foreign-born Mexicans, those who had lived in the United States for more than 10 years were more likely to have high allostatic load scores. In this way, allostatic load offers a viable reason for the health decline among immigrants but has not been extensively studied in foreign-born Black populations.The only study to investigate the association between allostatic load and chronic health conditions for a population of Latinos that can identify themselves as Black or of African descent20 found that increasing allostatic load scores were significantly associated with abdominal obesity, hypertension, diabetes, self-reported cardiovascular disease, and arthritis for Puerto Ricans.21 However, to our knowledge, no study has examined the relationship between nativity and allostatic load among US- and foreign-born Blacks. Testing this hypothesis will provide knowledge about whether allostatic load operates in a similar way for this understudied population as evidenced in the Latino immigrant literature. We used the 2001–2010 National Health and Nutrition Examination Survey (NHANES)—one of the largest surveys designed to assess the health and nutritional status of adults residing in the United States—to examine nativity-based differentials in allostatic load. On the basis of previous research on immigrant health, we expected to observe a health advantage in allostatic load for foreign-born over US-born Blacks similar to what has been documented in studies focused on Mexican-born individuals.