Instability of revised Korean Developmental Screening Test classification in first year of life.

Background: Early development is characterized by considerable variability.

Purpose: To investigate the stability of the revised Korean Developmental Screening Test (K-DST) classification of the development of healthy term 4-6 and 10-12 month-old infants.

Methods: This study used data from the Korean Children's Environmental Health study, a nationwide prospective birth cohort study.

Association between phthalate exposure and sleep quality in pregnant women: Results from the Korean Children's Environmental Health Study with repeated assessment of exposure.

Background: Evidence linking environmental toxicants to sleep quality is growing; however, these associations during pregnancy remain unclear. We examined the associations of repeated measures of urinary phthalates in early and late pregnancy with multiple markers of sleep quality among pregnant women.

Methods: The study population included 2324 pregnant women from the Korean Children's Environmental Health Study.

Ambient particulate matter and surrounding greenness in relation to sleep quality among pregnant women: A nationwide cohort study.

Background: Particulate air pollution and residential greenness are associated with sleep quality in the general population; however, their influence on maternal sleep quality during pregnancy has not been assessed.

Objective: This cross-sectional study investigated the individual and interactive effects of exposure to particulate matter (PM) air pollution and residential greenness on sleep quality in pregnant women.

Methods: Pregnant women (n = 4933) enrolled in the Korean Children's Environmental Health Study with sleep quality information and residential address were included.

High-Performance Organic Source-Gated Transistors Enabled by the Indium-Tin Oxide-Diketopyrrolopyrrole Polymer Interface.

Source-gated transistors are a new driver of low-power high-gain thin-film electronics. However, source-gated transistors based on organic semiconductors are not widely investigated yet despite their potential for future display and sensor technologies. We report on the fabrication and modeling of high-performance organic source-gated transistors utilizing a critical junction formed between indium-tin oxide and diketopyrrolopyrrole polymer.

The relationship between alcohol consumption and knee osteoarthritis in Korean population over 50 years-old: Results from Korea National Health and Nutrition Examination Survey.

There is still debate regarding the pathogenic relationship between alcohol intake and osteoarthritis (OA). This study investigated the association between alcohol consumption and knee OA in a Korean population.Among 8058 subjects who participated in the Korea National Health and Nutrition Examination Survey (KNHANES) 2012, a total of 2917 subjects over the age of 50 and taken plain radiography was included in this analysis.

Effects of Socio-demographic Factors on the Decreasing Trend in the Sex Ratio at Birth in Korea, 1997-2017.

Objectives: This study investigated the effects of socio-demographic factors on the decreasing trend in the sex ratio at birth from 1997 to 2017 in Korea.

Methods: Data from 10 349 602 live births registered with Statistics Korea from 1997 to 2017 were analyzed. The secondary sex ratio (SSR), defined as the ratio of male to female live births, during the study period (1997-1999 [phase I], 2000-2002 [phase II], 2003-2005 [phase III], 2006-2008 [phase IV], 2009-2011 [phase V], 2012-2014 [phase VI], and 2015-2017 [phase VII]) was calculated according to selected socio-demographic factors, such as parental age, education, occupation, and birth order.

Association of head circumference with cognitive decline and symptoms of depression in elderly: a 3-year prospective study.

Background: Brain volume is associated with dementia and depression in the elderly. An easy way to predict relative brain volume is to measure head circumference. In this study, we investigated the relationship between head circumference and cognition as well as depression in a non-demented elderly community.

Impact of Changes in Maternal Age and Parity Distribution on the Increasing Trends in the Low Birth Weight and Very Low Birth Weight Rates in South Korea, 2005-2015.

Objectives: The aim of this study was to evaluate the impact of shifts in maternal age and parity on the increasing trends in the low birth weight (LBW) and very low birth weight (VLBW) rates from 2005 to 2015 in South Korea.

Methods: Data from 4 993 041 live births registered with Statistics Korea during the period between 2005 and 2015 were analyzed. Applying a modified standardization method, we partitioned the total increment in the LBW and VLBW rates into (1) the increase in the LBW and VLBW rates due to changes in the maternal age and parity distribution (AP-dis) and (2) the increase due to changes in the age-specific and parity-specific rates (AP-spe) of LBW and VLBW for singleton and multiple births, respectively.

Cohort profile: Beyond birth cohort study - The Korean CHildren's ENvironmental health Study (Ko-CHENS).

The Korean CHildren's ENvironmental health Study (Ko-CHENS) is a nationwide prospective birth cohort showing the correlation between the environmental exposures and the health effects to prevent the environmental diseases in children, and it provides the guidelines for the environmental hazardous factors, applying the life-course approach to the environmental-health management system. The Ko-CHENS consists of 5000 Core and 65,000 Main Cohorts. The children in the Core Cohort are followed up at 6 months, every year before their admission into the elementary school, and every 3 years from the first year after this admission.

Effect of tumour necrosis factor-alpha inhibitors on renal function in patients with rheumatoid arthritis from the KOBIO registry from 2012 to 2016.

Objectives: The effect of biological disease-modifying anti-rheumatic drugs (bDMARDs) on renal function in patients with rheumatoid arthritis (RA) has not been well established. We assessed whether tumour necrosis factor (TNF) inhibitors could affect renal function in RA.

Methods: A total of 2110 patients with RA enrolled in the Korean College of Rheumatology Biologics (KOBIO) registry were analysed.

Maternal and paternal serum concentrations of persistent organic pollutants and the secondary sex ratio: A population-based preconception cohort study.

Recent declines in the secondary sex ratio (SSR), defined as the ratio of males to females at birth, in some industrialized countries may be attributed to exposure to environmental toxicants such as persistent organic pollutants (POPs). This study aimed to evaluate the association of couples' preconception exposure to POPs with the SSR. The study cohort comprised 235 couples who were enrolled in the Longitudinal Investigation of Fertility and the Environment (LIFE) Study between 2005 and 2009 prior to conception and prospectively followed through delivery of a singleton birth.

Preconception stress and the secondary sex ratio in a population-based preconception cohort.

Objective: To examine the association between preconception parental stress and the secondary sex ratio, defined as the ratio of males to females at birth.

Design: A population-based preconception cohort.

Setting: Not applicable.

Human semen quality and the secondary sex ratio.

The aim of this study was to evaluate the association between semen quality and the secondary sex ratio (SSR), defined as the ratio of male to female live births. Our study cohort comprised 227 male partners who were enrolled prior to conception in Michigan and Texas between 2005 and 2009, and prospectively followed through delivery of a singleton birth. The male partners provided a baseline and a follow-up semen sample a month apart.

Couples' urinary concentrations of benzophenone-type ultraviolet filters and the secondary sex ratio.

The secondary sex ratio (SSR), defined as the ratio of males to females at birth, has been investigated in relation to endocrine disruptors to search for environmental toxicants perturbing human sex selection. Benzophenone (BP)-type ultraviolet (UV) filters, which are used in sunscreens and personal care products, have been reported to exert estrogenic and anti-androgenic activities. This study aimed to evaluate the association between maternal, paternal, and couple urinary concentrations of BP-type UV filters and the SSR, given the absence of previous investigation.

Urinary concentrations of benzophenone-type ultraviolet light filters and semen quality.

Objective: To assess benzophenone-type ultraviolet (UV) filter concentrations, chemicals used in sunscreen and personal care products, and semen endpoints.

Design: Cohort.

Setting: Not applicable.

Maternal and paternal serum concentrations of perfluoroalkyl and polyfluoroalkyl substances and the secondary sex ratio.

Select persistent environmental chemicals have been associated with a reduction in the secondary sex ratio (SSR), or the ratio of male to female live births. We evaluated preconception maternal, paternal, and couple serum concentrations of perfluoroalkyl and polyfluoroalkyl substances (PFASs) in relation to the SSR, given the absence of previous investigation. Two hundred thirty-three couples from Michigan and Texas were enrolled prior to conception and prospectively followed through delivery of a singleton birth, 2005-2009.

Influence of asthma on the longitudinal trajectories of cigarette use behaviors from adolescence to adulthood using latent growth curve models.

Objectives: While epidemiologic research indicates that the prevalence of risk-taking behaviors including cigarette smoking among young people with asthma is substantial, the longitudinal patterns of cigarette smoking in this vulnerable population have received little attention. The aim of this study was to evaluate differences in the longitudinal trajectories of cigarette use behaviors from adolescence to adulthood between young people with and without asthma.

Methods: Data from the National Longitudinal Study of Adolescent to Adult Health (Add Health) during the years 1994 to 1995 (Wave I, adolescence), 2001 to 2002 (Wave III, young adulthood), and 2007 to 2008 (Wave IV, adulthood) were analyzed (n=12 244).

Couples' urinary bisphenol A and phthalate metabolite concentrations and the secondary sex ratio.

With limited research focusing on non-persistent chemicals as exogenous factors affecting human sex selection, this study aimed to evaluate the association of urinary bisphenol A (BPA) and phthalate metabolite concentrations with the secondary sex ratio (SSR), defined as the ratio of male to female live births. The current analysis is limited to singleton live births (n=220, 43.9%) from the Longitudinal Investigation of Fertility and the Environment (LIFE) Study, in which couples discontinuing contraception with the intention of becoming pregnant were enrolled and followed while trying for pregnancy and through delivery for those achieving pregnancy.

The effect of vitamin C intake on the risk of hyperuricemia and serum uric acid level in Korean Multi-Rural Communities Cohort.

Objective: The aim of this study was to determine the association between vitamin C intake and risk of hyperuricemia or serum uric acid levels in male and female subjects in the Korean Multi-Rural Communities Prospective Cohort.

Methods: This cross-sectional analysis was conducted in 9400 subjects enrolled in the Korean Multi-Rural Communities Cohort Study. The risk of hyperuricemia was assessed in five quintiles (Q1 to Q5) according to dietary and total vitamin C intake using multivariate-adjusted logistic regression models.

The effect of coffee, tea, and caffeine consumption on serum uric acid and the risk of hyperuricemia in Korean Multi-Rural Communities Cohort.

Caffeine, a commonly consumed food constituent, is known to exert beneficial physiological effects in humans. There is a lack of comprehensive population data for the effects of caffeine intake on urate metabolism. Therefore, the aim of this study was to determine whether coffee, tea, and caffeine intake influences serum uric acid and the risk of hyperuricemia in the Korean Multi-Rural Communities Cohort.

Performance of Routine Assessment of Patient Index Data 3 (RAPID3) for assessment of rheumatoid arthritis in clinical practice: differential agreement of RAPID3 according to disease activity categories.

To evaluate the performance of Routine Assessment of Patient Index Data 3 (RAPID3) with the disease activity score 28 (DAS28) and the clinical/simplified disease activity index (CDAI/SDAI) in a Korean population with rheumatoid arthritis (RA). Four hundred patients with RA were consecutively enrolled. All patients completed disease activity indices such as RAPID3, DAS28, SDAI, and CDAI.

TNFAIP3 gene polymorphisms associated with differential susceptibility to rheumatoid arthritis and systemic lupus erythematosus in the Korean population.

Objective: We investigated the relationship between polymorphisms in the TNF-a-induced protein 3 (TNFAIP3) gene and genetic susceptibility to SLE and RA in the Korean population.

Methods: The present case control study included 422 patients with RA, 133 patients with SLE and 422 healthy controls. Genotyping for TNFAIP3 gene polymorphisms rs5029941 (C>T), rs2230926 (T>G), rs5029930 (C>A), rs5029937 (G>T) and rs5029939 (G>C) in TNFAIP3 gene polymorphisms was performed.

Higher consumption of sugar-sweetened soft drinks increases the risk of hyperuricemia in Korean population: The Korean Multi-Rural Communities Cohort Study.

Objective: The clinical implication of sugar-sweetened soft drinks on the risk of hyperuricemia has increased, especially in Western population studies. The aim of this study is to clarify the association between sugar-sweetened soft drinks and fruit drinks made from oranges and apples and the risk of hyperuricemia in the Korean Multi-Rural Communities Cohort.

Methods: A total of 9400 subjects were enrolled in the Korean Multi-Rural Communities Cohort Study, and a cross-sectional analysis was performed.

Lack association of body mass index with disease activity composites of rheumatoid arthritis in Korean population: cross-sectional observation.

The debate regarding the influence of body mass index (BMI) on clinical disease activity in rheumatoid arthritis (RA) remains unsolved. This study investigates whether BMI is associated with disease activity composites and clinical parameters in Korean patients with RA. A total of 568 patients with RA were consecutively enrolled in this study.

Differences in cigarette use behaviors by age at the time of diagnosis with diabetes from young adulthood to adulthood: results from the National Longitudinal Study of Adolescent Health.

Objectives: Previous observations propose that risk-taking behaviors such as cigarette smoking are prevailing among young people with chronic conditions including diabetes. The purpose of this study was to examine whether cigarette smoking is more prevalent among diabetics than non-diabetics and whether it differs by age at the time of diagnosis with diabetes from young adulthood (YAH) to adulthood (AH).

Methods: We used US panel data from the National Longitudinal Study of Adolescent Health (Add Health Study) during the years 2001 to 2002 (Wave III, YAH) and 2007 to 2008 (Wave IV, AH).