• 제목/요약/키워드: multivariable linear regression

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Associations between dietary patterns and screen time among Korean adolescents

  • Lee, Jae Yeon;Jun, Nuri;Baik, Inkyung
    • Nutrition Research and Practice
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    • 제7권4호
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    • pp.330-335
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    • 2013
  • Data are limited on the association between dietary patterns and screen time among Korean adolescents. The present study identified dietary patterns of 691 adolescents, aged 13-18 years, who had participated in the Third Korean National Health and Nutrition Examination Survey (KNHANES III) and analyzed their associations with screen time. Screen time was defined as the time spent watching TV, using a computer, or playing video games was calculated as a sum of all these times. Dietary patterns and their factor scores were derived from a food frequency questionnaire using the factor analysis method. To analyze the association between dietary patterns and screen time, we conducted multiple linear regression analysis. We also performed multiple logistic regression analysis to estimate odds ratios (OR) of excessive screen time (2 hours or longer per day) and 95% confidence intervals (CI). We identified 2 dietary patterns labeled "the Korean healthy dietary pattern" and "the Western diet and fast foods pattern". The former included mixed grains, legumes, potatoes, red meat, eggs, fish, dairy products, fruits, vegetables, seaweeds, and mushrooms, whereas the latter included noodles, bread, red meat, poultry, fast foods, snack, and soft drinks. After controlling for potential confounding factors, factor scores for the Korean healthy dietary pattern were inversely associated (P-value for trend < 0.01) and those for the Western diet and fast foods pattern were positively associated with the screen time (P-value for trend < 0.01). Adolescents in the top tertile of the scores for the Korean healthy dietary pattern had a multivariable-adjusted OR [95% CI] of 0.44 (0.25-0.75) for excessive screen time compared with those in the lowest tertile. On the basis of these findings, adolescents who have excessive screen time may need to be encouraged to consume a more healthy diet.

Effect of extraction treatment on upper airway dimensions in patients with bimaxillary skeletal protrusion relative to their vertical skeletal pattern

  • Cho, Ha-Nul;Yoon, Hyun Joo;Park, Jae Hyun;Park, Young-Guk;Kim, Su-Jung
    • 대한치과교정학회지
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    • 제51권3호
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    • pp.166-178
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    • 2021
  • Objective: To investigate dimensional changes in regional pharyngeal airway spaces after premolar extraction in bimaxillary skeletal protrusion (BSP) patients according to vertical skeletal pattern, and to further identify dentoskeletal risk factors to predict posttreatment pharyngeal changes. Methods: Fifty-five adults showing BSP treated with microimplant anchorage after four premolar extractions were included in this retrospective study. The subjects were divided into two groups according to the mandibular plane steepness: hyperdivergent (Frankfort horizontal plane to mandibular plane [FH-MP] ≥ 30) and nonhyperdivergent groups (FH-MP < 30). The control group consisted of 20 untreated adults with skeletal Class I normodivergent pattern and favorable profile. Treatment changes in cephalometric variables were evaluated and compared. The association between posttreatment changes in the dentoskeletal and upper airway variables were analyzed using linear regression analysis. Results: The BSP patients showed no significant decrease in the pharyngeal dimensions to the lower level in comparison with controls, except for middle airway space (MAS, p < 0.01). The upper airway variable representing greater decrease in the hyperdivergent group than in the nonhyperdivergent group was the MAS (p < 0.01). Posttreatment changes in FH-MP had negative correlation with changes in MAS (β = -0.42, p < 0.01) and inferior airway space (β = -0.52, p < 0.01) as a result of multivariable regression analysis adjusted for sagittal skeletal relationship. Conclusions: Decreased pharyngeal dimensions after treatment in BSP patients showed no significant difference from the normal range of pharyngeal dimensions. However, the glossopharyngeal airway space may be susceptible to treatment when vertical dimension increased in hyperdivergent BSP patients.

화학물질 우선순위 선정기법(CRS)을 활용한 허가대상 후보물질 선정 연구 (A Study on the Selection of Candidates for Substances Subject to Permission Using Chemicals Ranking and Scoring (CRS))

  • 김효동;박교식
    • 한국산업보건학회지
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    • 제32권3호
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    • pp.253-267
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    • 2022
  • Objectives: This study was performed to check whether the CRS (Chemical Ranking and Scoring) system is appropriate as a method to determine substances as candidates for substances subject to permission and to apply this system to the selection of candidates for substances subject to permission. Methods: A risk score was obtained by multiplying the hazard score and the exposure score and then ranking them. The hazard sub-indicators are carcinogenicity, germ cell mutagenicity, reproductive toxicity, specific target organ toxicity-repeated exposure, respiratory sensitization and endocrine disrupting chemicals. Exposure sub-indicators are persistence, bioaccumulation and emission volume. Sensitivity analysis was performed for missing values. Correlation analysis and multivariable linear regression analysis were performed among hazard, exposure and risk in order to confirm that CRS was an appropriate method. Results: As a result of the sensitivity analysis on missing values, it was confirmed that the effect on the risk ranking was not sensitive. Correlation and regression analysis confirmed that exposure had a greater effect on risk than hazard. Conclusions: The CRS system, which derives a risk score using a hazard and exposure score, is judged to be appropriate as a method for the selection of preliminary of candidates for substances subject to permission. Benzene, cadmium, nickel, and cobalt were selected as priority candidates for substances subject to permission.

여자 청소년 및 젊은 여성의 비타민 D 결핍과 빈혈과의 연관성 분석 (Association between vitamin D deficiency and anemia among Korean adolescent girls and young women)

  • 장하은;박성희;박경
    • Journal of Nutrition and Health
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    • 제52권6호
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    • pp.552-558
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    • 2019
  • 본 연구는 2008 ~ 2014년까지 수행된 국민건강영양조사 자료를 활용하였다. 본 분석 대상자는 12 ~ 29세 여자 청소년 및 젊은 여성이며, 이들을 대상으로 비타민 D 결핍 여부에 따른 빈혈 및 철 결핍성 빈혈과의 연관성 분석을 실시하였다. 그 결과, 교란인자를 보정한 다중 로지스틱 회귀분석 모델에서 비타민 D 결핍군이 충분군보다 빈혈 및 철 결핍성 빈혈의 유병률이 유의적으로 높았다. 또한 혈청 25(OH)D 농도가 증가함에 따라 빈혈 및 철 결핍성 빈혈의 유병률이 낮아지는 선형 관계가 나타났다. 본 연구의 결과는 청소년 및 젊은 여성에서 문제가 되고 있는 비타민 D 결핍과 빈혈에 대한 예방 및 관리에 기초자료를 제공할 수 있다고 기대된다. 추후 전향적인 코호트 연구 및 임상시험 연구 설계를 이용한 후속 연구를 수행하여 비타민 D와 빈혈 사이의 명확한 인과관계를 확인할 필요가 있다고 사료된다.

드론과 광학원격탐사 기법을 이용한 천해 수심측량 (Coastal Shallow-Water Bathymetry Survey through a Drone and Optical Remote Sensors)

  • 오찬영;안경모;박재성;박성우
    • 한국해안·해양공학회논문집
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    • 제29권3호
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    • pp.162-168
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    • 2017
  • 드론을 이용하여 고도 100 m에서 촬영한 고해상도 카메라 이미지를 분석하여 천해 해저지형 측량을 시도하였다. 쇄파대 내의 수심측량은 해안침식의 원인분석 등 관련 연구를 위해 가장 중요한 입력자료 중의 하나이다. 특히 이동한계수심 이내의 천해 수심자료는 연안 침퇴적 수치모델링을 위한 가장 중요한 입력자료 임에도 불구하고 정확한 해저지형측량 자료를 얻을 수 없었다. 그 이유는 선박을 이용한 상세 수심측량이 흘수 등을 고려할 때 수심 2 m 이내에서는 거의 불가능하며, 또한 쇄파와 연안류로 인해 선박 또는 사람이 직접 충분한 해상도로 측량하기에 매우 어렵기 때문이다. 따라서 소형 드론과 고해상도 카메라 이미지를 이용한 광학원격탐사는 매우 효과적인 천해수심측량 수단이 될 수 있다. 본 연구에서는 경북 월포해수욕장에서 드론으로 촬영한 고해상도 카메라 이미지의 적색, 녹색, 청색 그리고 회색 밴드 이미지를 다변수 선형회귀분석법으로 분석하여 천해 수심을 추정하고 실측한 수심자료와 비교하여 천해수심측량의 가능성과 정확도를 검토하였다. 드론에서 촬영한 이미지를 해저 지질, 바닷물의 색상, 부유사의 농도 등의 영향을 고려하지 않고 수심추정 알고리즘을 이용하여 분석한 결과 수심 5 m 이내에서 상관계수 0.99 이상, 절대오차 0.2 m 이하로 수심을 정확하게 추정할 수 있음을 확인하였다.

Quantitative Ultrasound Radiofrequency Data Analysis for the Assessment of Hepatic Steatosis in Nonalcoholic Fatty Liver Disease Using Magnetic Resonance Imaging Proton Density Fat Fraction as the Reference Standard

  • Sun Kyung Jeon;Jeong Min Lee;Ijin Joo;Sae-Jin Park
    • Korean Journal of Radiology
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    • 제22권7호
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    • pp.1077-1086
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    • 2021
  • Objective: To investigate the diagnostic performance of quantitative ultrasound (US) parameters for the assessment of hepatic steatosis in patients with nonalcoholic fatty liver disease (NAFLD) using magnetic resonance imaging proton density fat fraction (MRI-PDFF) as the reference standard. Materials and Methods: In this single-center prospective study, 120 patients with clinically suspected NAFLD were enrolled between March 2019 and January 2020. The participants underwent US examination for radiofrequency (RF) data acquisition and chemical shift-encoded liver MRI for PDFF measurement. Using the RF data analysis, the attenuation coefficient (AC) based on tissue attenuation imaging (TAI) (AC-TAI) and scatter-distribution coefficient (SC) based on tissue scatter-distribution imaging (TSI) (SC-TSI) were measured. The correlations between the quantitative US parameters (AC and SC) and MRI-PDFF were evaluated using Pearson correlation coefficients. The diagnostic performance of AC-TAI and SC-TSI for detecting hepatic fat contents of ≥ 5% (MRI-PDFF ≥ 5%) and ≥ 10% (MRI-PDFF ≥ 10%) were assessed using receiver operating characteristic (ROC) analysis. The significant clinical or imaging factors associated with AC and SC were analyzed using linear regression analysis. Results: The participants were classified based on MRI-PDFF: < 5% (n = 38), 5-10% (n = 23), and ≥ 10% (n = 59). AC-TAI and SC-TSI were significantly correlated with MRI-PDFF (r = 0.659 and 0.727, p < 0.001 for both). For detecting hepatic fat contents of ≥ 5% and ≥ 10%, the areas under the ROC curves of AC-TAI were 0.861 (95% confidence interval [CI]: 0.786-0.918) and 0.835 (95% CI: 0.757-0.897), and those of SC-TSI were 0.964 (95% CI: 0.913-0.989) and 0.935 (95% CI: 0.875-0.972), respectively. Multivariable linear regression analysis showed that MRI-PDFF was an independent determinant of AC-TAI and SC-TSI. Conclusion: AC-TAI and SC-TSI derived from quantitative US RF data analysis yielded a good correlation with MRI-PDFF and provided good performance for detecting hepatic steatosis and assessing its severity in NAFLD.

Clinical Implications of Focal Mineral Deposition in the Globus Pallidus on CT and Quantitative Susceptibility Mapping of MRI

  • Hyojin Kim;Jinhee Jang;Junghwa Kang;Seungun Jang;Yoonho Nam;Yangsean Choi;Na-young Shin;Kook-Jin Ahn;Bum-soo Kim
    • Korean Journal of Radiology
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    • 제23권7호
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    • pp.742-751
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    • 2022
  • Objective: To assess focal mineral deposition in the globus pallidus (GP) by CT and quantitative susceptibility mapping (QSM) of MRI scans and evaluate its clinical significance, particularly cerebrovascular degeneration. Materials and Methods: This study included 105 patients (66.1 ± 13.7 years; 40 male and 65 female) who underwent both CT and MRI with available QSM data between January 2017 and December 2019. The presence of focal mineral deposition in the GP on QSM (GPQSM) and CT (GPCT) was assessed visually using a three-point scale. Cerebrovascular risk factors and small vessel disease (SVD) imaging markers were also assessed. The clinical and radiological findings were compared between the different grades of GPQSM and GPCT. The relationship between GP grades and cerebrovascular risk factors and SVD imaging markers was assessed using univariable and multivariable linear regression analyses. Results: GPCT and GPQSM were significantly associated (p < 0.001) but were not identical. Higher GPCT and GPQSM grades showed smaller gray matter (p = 0.030 and p = 0.025, respectively) and white matter (p = 0.013 and p = 0.019, respectively) volumes, as well as larger GP volumes (p < 0.001 for both). Among SVD markers, white matter hyperintensity was significantly associated with GPCT (p = 0.006) and brain atrophy was significantly associated with GPQSM (p = 0.032) in at univariable analysis. In multivariable analysis, the normalized volume of the GP was independently positively associated with GPCT (p < 0.001) and GPQSM (p = 0.002), while the normalized volume of the GM was independently negatively associated with GPCT (p = 0.040) and GPQSM (p = 0.035). Conclusion: Focal mineral deposition in the GP on CT and QSM might be a potential imaging marker of cerebral vascular degeneration. Both were associated with increased GP volume.

Prevalence, Risk Factors and Consequent Effect of Dystocia in Holstein Dairy Cows in Iran

  • Atashi, Hadi;Abdolmohammadi, Alireza;Dadpasand, Mohammad;Asaadi, Anise
    • Asian-Australasian Journal of Animal Sciences
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    • 제25권4호
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    • pp.447-451
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    • 2012
  • The objective of this research was to determine the prevalence, risk factors and consequent effect of dystocia on lactation performance in Holstein dairy cows in Iran. The data set consisted of 55,577 calving records on 30,879 Holstein cows in 30 dairy herds for the period March 2000 to April 2009. Factors affecting dystocia were analyzed using multivariable logistic regression models through the maximum likelihood method in the GENMOD procedure. The effect of dystocia on lactation performance and factors affecting calf birth weight were analyzed using mixed linear model in the MIXED procedure. The average incidence of dystocia was 10.8% and the mean (SD) calf birth weight was 42.13 (5.42) kg. Primiparous cows had calves with lower body weight and were more likely to require assistance at parturition (p<0.05). Female calves had lower body weight, and had a lower odds ratio for dystocia than male calves (p<0.05). Twins had lower birth weight, and had a higher odds ratio for dystocia than singletons (p<0.05). Cows which gave birth to a calf with higher weight at birth experienced more calving difficulty (OR (95% CI) = 1.1(1.08-1.11). Total 305-d milk, fat and protein yield was 135 (23), 3.16 (0.80) and 6.52 (1.01) kg less, in cows that experienced dystocia at calving compared with those that did not (p<0.05).

Knowledge, Attitudes, and Practices Regarding Tuberculosis in Timor-Leste: Results From the Demographic and Health Survey 2016

  • Pengpid, Supa;Peltzer, Karl
    • Journal of Preventive Medicine and Public Health
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    • 제52권2호
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    • pp.115-122
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    • 2019
  • Objectives: The aim of this study was to assess knowledge, attitudes, and practices regarding tuberculosis (TB) in the general population in Timor-Leste. Methods: In the nationally representative cross-sectional 2016 Timor-Leste Demographic and Health Survey, 4622 men (aged 15-59 years) and 12 607 women (aged 15-49 years) were randomly selected using stratified multistage sampling and interviewed. Results: Overall, 66.9% of men and 62.8% of women were aware of TB, 4.4% of men and 12.6% of women had TB courtesy stigma, and 83.3% of men and 88.6% of women reported intention to receive TB treatment. The $mean{\pm}standard$ deviation overall TB knowledge score was $3.9{\pm}2.0$ (out of 8) among men and $3.0{\pm}1.8$ among women. In a multivariable linear regression analysis, among both men and women, older age, higher education, rural residence, and sources of TB information (family/friends, school/workplace, health care provider, Internet, television, and newspaper) were associated with higher TB knowledge scores. In addition, among women, higher wealth status and having heard about TB from the radio were associated with higher TB knowledge scores. Negative associations with TB courtesy stigma were found for urban residence and having heard about TB from family or friends among men, and for older age, higher TB knowledge, and TB information sources (family/friends and school/workplace) among women. Among both men and women, higher TB knowledge scores and having heard of TB from a health care provider were associated with intention to receive TB treatment. Conclusions: This study identified socio-demographic risk factors for deficiences in population-based TB knowledge in Timor-Leste; these findings should be considered when designing TB communication, prevention, and control strategies.

Effects of Altered Calcium Metabolism on Cardiac Parameters in Primary Aldosteronism

  • Lim, Jung Soo;Hong, Namki;Park, Sungha;Park, Sung Il;Oh, Young Taik;Yu, Min Heui;Lim, Pil Yong;Rhee, Yumie
    • Endocrinology and Metabolism
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    • 제33권4호
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    • pp.485-492
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    • 2018
  • Background: Increasing evidence supports interplay between aldosterone and parathyroid hormone (PTH), which may aggravate cardiovascular complications in various heart diseases. Negative structural cardiovascular remodeling by primary aldosteronism (PA) is also suspected to be associated with changes in calcium levels. However, to date, few clinical studies have examined how changes in calcium and PTH levels influence cardiovascular outcomes in PA patients. Therefore, we investigated the impact of altered calcium homeostasis caused by excessive aldosterone on cardiovascular parameters in patients with PA. Methods: Forty-two patients (mean age $48.8{\pm}10.9$ years; 1:1, male:female) whose plasma aldosterone concentration/plasma renin activity ratio was more than 30 were selected among those who had visited Severance Hospital from 2010 to 2014. All patients underwent adrenal venous sampling with complete access to both adrenal veins. Results: The prevalence of unilateral adrenal adenoma (54.8%) was similar to that of bilateral adrenal hyperplasia. Mean serum corrected calcium level was $8.9{\pm}0.3mg/dL$ (range, 8.3 to 9.9). The corrected calcium level had a negative linear correlation with left ventricular end-diastolic diameter (LVEDD, ${\rho}=-0.424$, P=0.031). Moreover, multivariable regression analysis showed that the corrected calcium level was marginally associated with the LVEDD and corrected QT (QTc) interval (${\beta}=-0.366$, P=0.068 and ${\beta}=-0.252$, P=0.070, respectively). Conclusion: Aldosterone-mediated hypercalciuria and subsequent hypocalcemia may be partly involved in the development of cardiac remodeling as well as a prolonged QTc interval, in subjects with PA, thereby triggering deleterious effects on target organs additively.