confounding variables.RESULTS: The BMD of the total femur and Ward's triangle were significantly different according to the potassium intake among men (P = 0.031 and P = 0.010, respectively). Women in the top tertile for potassium intake showed higher BMD than those in the bottom tertile at all measurement sites (all P < 0.05). Daily potassium intake was significantly related to a decreased risk of osteoporosis at the lumbar spine in postmenopausal women (odds ratios: 0.68, 95% confidence interval: 0.48-0.96, P trend = 0.031). However, the dietary potassium level was not related to the risk of osteoporosis in men.CONCLUSION: Current findings indicate that higher dietary potassium levels have a favorable effect on bone health and preventing osteoporosis in older Korean women.]]>
Absorptiometry, Photon ; Adult ; Bone Density ; Bone Diseases, Metabolic ; Calcium ; Confounding Factors (Epidemiology) ; Cross-Sectional Studies ; Epidemiology ; Female ; Femur ; Femur Neck ; Hip ; Humans ; Logistic Models ; Male ; Methods ; Nutrition Surveys ; Osteoporosis ; Population Surveillance ; Potassium ; Potassium, Dietary ; Prevalence ; Retrospective Studies ; Spine ; Vitamin D

OBJECTIVES: Nicotine narrows uterine blood vessels reducing the flow of oxygen and nutrients to the developing fetus. This study examined the effects of fetal exposure to secondhand smoke on neonatal anthropometry. METHODS: This cross sectional study recruited 128 pregnant women in the third trimester of single pregnancies who had no chronic illness, were not active or ex-smokers, and who were willing to participate in the study. Pregnant women who were exposed to secondhand smoke had umbilical cord blood nicotine concentrations of ≥ 1 ng/mL. Neonatal anthropometry was assessed according to the newborn birth weight and length. The independent t-test was used to determine the neonatal difference in mean birth weight and length between the women who were exposed to secondhand smoke, and those who were not exposed. A multiple linear regression analysis was employed to assess the effect of secondhand smoke exposure on birth weight and birth length, controlling for potential confounding variables (weight gain during pregnancy, body mass index, parity, maternal age, and maternal hemoglobin). RESULTS: There were 35 women exposed to secondhand smoke (nicotine ≥ 1 ng/mL). Neonate birth weight and birth length were lower among mothers who were exposed to secondhand smoke. However, only neonate birth weight was significantly reduced by exposure to secondhand smoke (p = 0.005). The mean birth weight of these neonates was 2,916.5 g ± 327.3 g which was 205.6 g less than in unexposed fetuses. CONCLUSION: Exposure of mothers to secondhand smoke during pregnancy reduces fetal development and neonatal weight.
Anthropometry ; Birth Weight ; Blood Vessels ; Body Mass Index ; Chronic Disease ; Confounding Factors (Epidemiology) ; Female ; Fetal Blood ; Fetal Development ; Fetus ; Humans ; Infant, Newborn ; Linear Models ; Maternal Age ; Mothers ; Nicotine ; Oxygen ; Parity ; Parturition ; Pregnancy ; Pregnancy Trimester, Third ; Pregnant Women ; Tobacco Smoke Pollution ; Umbilical Cord

Our study aimed to analyze the clinical characteristics and psychotropic prescription patterns of a history of suicide attempts in South Koreans with bipolar disorder (BD), by using only Korean data from the Research on Asian Psychotropic Prescription Pattern for Bipolar disorder. The patterns of clinical characteristics and psychotropic drug use were compared among 53 patients with a history of suicide attempts and 297 without this history; the potential effects of confounding variables were adjusted with binary logistic analyses for discrete variables and analyses of covariance for continuous variables. After adjusting the effects of age, sex, duration of illness, and enrollment as an outpatient, patients with a history of suicide attempts were characterized by a significantly more prevalent depressive episode, lower prevalent remission state, lower levels of hemoglobin, and more use of antidepressants, anxiolytics, and hypnotics compared to those without lifetime suicide attempt. The inability to plan goal-directed behavior may be an intervening factor in the relationship between suicide attempts and depression in BD. Relatively low hemoglobin levels can be associated with manic episodes in patients with a history of suicide attempts and the use of antidepressants, anxiolytics, or hypnotics can be associated with suicide attempts in BD patients.
Anti-Anxiety Agents ; Antidepressive Agents ; Asian Continental Ancestry Group ; Bipolar Disorder ; Confounding Factors (Epidemiology) ; Depression ; Drug Prescriptions ; Humans ; Hypnotics and Sedatives ; Korea ; Outpatients ; Prescriptions ; Suicide

OBJECTIVE: This study aimed to examine the association between normal-but-low folate levels and cognitive function in the elderly population using a prospective cohort study. METHODS: We analyzed 3,910 participants whose serum folate levels were within the normal reference range (1.5–16.9 ng/mL) at baseline evaluation in the population-based prospective cohort study named the “Korean Longitudinal Study on Cognitive Aging and Dementia.” The association between baseline folate quartile categories and baseline cognitive disorders [mild cognitive impairment (MCI) or dementia] was examined using binary logistic regression analysis adjusting for confounding variables. The risks of incident MCI and dementia associated with the decline of serum folate level during a 4-year follow-up period were examined using multinomial logistic regression analysis. RESULTS: The lowest quartile group of serum folate (≥1.5, ≤5.9 ng/mL) showed a higher risk of cognitive disorders than did the highest quartile group at baseline evaluation (odds ratio 1.314, p=0.012). Over the 4 years of follow-up, the risk of incident dementia was 2.364 times higher among subjects whose serum folate levels declined from the 2nd–4th quartile group to the 1st quartile than among those for whom it did not (p=0.031). CONCLUSION: Normal-but-low serum folate levels were associated with the risk of cognitive disorders in the elderly population, and a decline to normal-but-low serum folate levels was associated with incident dementia. Maintaining serum folate concentration above 5.9 ng/mL may be beneficial for cognitive status.
Aged ; Cognition ; Cognition Disorders ; Cognitive Aging ; Cohort Studies ; Confounding Factors (Epidemiology) ; Dementia ; Folic Acid ; Follow-Up Studies ; Humans ; Logistic Models ; Longitudinal Studies ; Prospective Studies ; Reference Values

PURPOSE: To determine the relationship between uterine leiomyoma and female sexual dysfunction (FSD) among premenopausal and postmenopausal women. MATERIALS AND METHODS: The study population consisted of consecutive women who underwent gynecologic screening tests, including transvaginal ultrasound, and completed the questionnaires on FSD. A total of 841 women were included from January 2010 to December 2011. FSD was defined as Female Sexual Function Index (FSFI) ≤26.55. The relationship between uterine leiomyoma and FSD were compared according to menopausal status. RESULTS: In premenopausal group (n=564), there were no differences in the frequency of FSD (55.0% vs. 58.8%, p=0.387) and total FSFI score. However, in postmenopausal group (n=277), women with uterine leiomyoma had a lower frequency of FSD than those without uterine leiomyoma (71.3% vs. 86.4%, p=0.003). This relationship between uterine leiomyoma and lower frequency of FSD in postmenopausal women remained significant after adjusting for confounding variables. CONCLUSION: The relationship between uterine leiomyoma and FSD is different depending on the menopausal status.
Confounding Factors (Epidemiology) ; Dyspareunia ; Female ; Humans ; Leiomyoma ; Mass Screening ; Menopause ; Sexual Behavior ; Ultrasonography

BACKGROUND: Shift work is associated with a higher risk of cardiovascular diseases. Here, we sought to assess the relationship between shift work and plasma homocysteine levels. Determining the correlations between shift work and homocysteine levels may provide a better understanding of the mechanisms underlying cardiovascular diseases. METHODS: This study was performed using data from routine health examinations of steel workers in 2017. In total, 431 male workers (70 daytime workers and 361 shift workers) employed on a rolling departure schedule were recruited. Plasma homocysteine levels > 15 μmol/L were considered elevated. The χ2, analysis of variance, and multiple logistic regression analyses were used to examine the association between shift work and plasma homocysteine levels. RESULTS: In comparison to daytime workers, the odds ratio (OR) of hyperhomocysteinemia in individuals with < 10 years of shift work was 1.14 (95% confidence interval [CI]: 0.64–2.03), compared to 2.01 (95% CI: 1.14–3.54) for workers with ≥ 10 years of experience. After adjusting for confounding variables, the adjusted OR for shift workers with < 10 years of experience was 0.95 (95% CI: 0.50–1.80), compared to 2.00 (95% CI: 1.07–3.74) for workers with ≥ 10 years of experience. CONCLUSIONS: The risk of hyperhomocysteinemia was significantly higher in shift workers compared to those working normal daytime hours, particularly among long-term shift workers.
Appointments and Schedules ; Cardiovascular Diseases ; Confounding Factors (Epidemiology) ; Homocysteine ; Humans ; Hyperhomocysteinemia ; Logistic Models ; Male ; Odds Ratio ; Plasma ; Steel

OBJECTIVES: The purpose of this study was to investigate the association between the components of metabolic syndrome (MetS) (waist circumference, hyperglycemia, hypertriglyceridemia, low levels of high-density lipoprotein cholesterol, and hypertension) and periodontitis in Korean adults aged 35–79 years. METHODS: In this study, data from the Sixth Korean National Health and Nutrition Examination Survey (KNHANES, 2013–2015) were analyzed. Among the 22,948 participants of the Sixth KNHANES, 8,314 participants, who were aged 35–79 years and had completed all systemic and oral health examinations and questionnaires, were included in this study. Confounding variables associated with the demographics and socioeconomic status and systemic and oral health-related behaviors were age, gender, household income, the educational level, smoking and drinking habits, the physical activity status, and frequency of daily toothbrushing. The independent variables were components of MetS, and the dependent variable was periodontitis. RESULTS: Periodontitis was diagnosed in 37.0% of the participants. The incidence of periodontitis among participants with MetS was 47.9%. The incidences of periodontitis among participants with three, four, and five components of MetS were 44.8%, 50.0%, and 56.2%, respectively. The odds ratio (OR) for periodontitis among participants with MetS was 1.43 (95% confidence interval [CI]: 1.27–1.61). The participants with three, four, and five components of MetS showed a significantly higher OR for periodontitis than those with no components of MetS (three components, OR=1.18, 95% CI: 1.02–1.36; four components, OR=1.34, 95% CI: 1.14–1.59; five components, OR=1.68, 95% CI: 1.29–2.20). CONCLUSIONS: A higher number of components of MetS augments the OR of periodontitis.
Adult ; Cholesterol ; Confounding Factors (Epidemiology) ; Demography ; Drinking ; Epidemiology ; Family Characteristics ; Humans ; Hyperglycemia ; Hypertriglyceridemia ; Incidence ; Lipoproteins ; Motor Activity ; Nutrition Surveys ; Odds Ratio ; Oral Health ; Periodontitis ; Smoke ; Smoking ; Social Class ; Toothbrushing

BACKGROUND: The seropositivity rate of hepatitis B surface antigen (anti-HBs) antibodies is known to be ≥95% after hepatitis B virus vaccination during infancy. However, a low level or absence of anti-HBs in healthy children is discovered in many cases. Recent studies in adults reported that a reduced anti-HBs production rate is related to obesity.PURPOSE: To investigate whether body mass index (BMI) affects anti-HBs levels in healthy children following 3 serial dose vaccinations in infancy.METHODS: We recruited 1,200 healthy volunteers aged 3, 5, 7, or 10 years from 4-day care centers and 4 elementary schools. All subjects completed a questionnaire including body weight, height, and vaccine type received. Levels of serum hepatitis B surface antigen (HBsAg) and anti-HBs in all subjects were analyzed using electrochemiluminescence immunoassay. The standardized scores (z score) for each sex and age were obtained using the lambda-mu-sigma method in the 2017 Korean National Growth Charts for children and adolescents.RESULTS: Our subjects (n=1,200) comprised 750 males (62.5%) and 450 females (37.5%). The overall anti-HBs seropositivity rate was 57.9% (695 of 1,200). We identified significant differences in mean BMI values between seronegative and seropositive groups (17.45 vs. 16.62, respectively; P<0.001). The anti-HBs titer was significantly decreased as the BMI z score increased adjusting for age and sex (B=-15.725; standard error=5.494; P=0.004). The probability of anti-HBs seropositivity based on BMI z score was decreased to an OR of 0.820 after the control for confounding variables (95% confidence interval, 0.728–0.923; P=0.001).CONCLUSION: There was a significant association between anti-HBs titer and BMI z score after adjustment for age and sex. Our results indicate that BMI is a potential factor affecting anti-HBs titer in healthy children.
Adolescent ; Adult ; Antibodies ; Body Mass Index ; Body Weight ; Child ; Confounding Factors (Epidemiology) ; Female ; Growth Charts ; Healthy Volunteers ; Hepatitis B Surface Antigens ; Hepatitis B virus ; Hepatitis B ; Hepatitis ; Humans ; Immunoassay ; Male ; Methods ; Obesity ; Vaccination

BACKGROUND: This study evaluated the association between nicotine dependence and depressive mood in patients who visited a secondary hospital for smoking cessation treatment.METHODS: From March 2016 to February 2017, a total of 48 patients who visited the smoking cessation clinic of a secondary hospital in Seoul were surveyed through questionnaires. Nicotine dependence was assessed by the Fagerström Test for Nicotine Dependence. The Beck Depression Inventory (BDI) was used to assess depressive mood.RESULTS: The mean BDI score was positively associated with nicotine dependence (P=0.01). In multivariable logistic regression analysis, increasing BDI was associated with higher odds (1.21, 95% confidence interval; 1.02–1.44) of high nicotine dependence after adjusting for all confounding variables.CONCLUSION: Depressive mood was positively associated with nicotine dependence among patients who visited a smoking cessation clinic. Consideration of depressive mood in smoking cessation treatment may be helpful for smoking cessation among patients with a willingness to quit smoking.
Confounding Factors (Epidemiology) ; Depression ; Humans ; Logistic Models ; Nicotine ; Seoul ; Smoke ; Smoking Cessation ; Smoking ; Tobacco Use Disorder

BACKGROUND: The ankle-brachial index (ABI) is a simple, noninvasive clinical test that is useful in the diagnosis of peripheral artery disease (PAD). The borderline ABI value is 0.91–0.99 and has also been reported in endothelial dysfunction and preclinical PAD. We investigated the relationship between resting heart rate as a surrogate marker of autonomic balance and borderline ABI in apparently healthy individuals.METHODS: We evaluated the association between resting heart rate and borderline ABI in 618 participants (348 male and 270 female) in a health examination program. The odds ratios for borderline ABI were calculated using a multivariable logistic regression analysis after adjusting for confounding variables across heart rate quartiles (Q1≤56, Q2=57–62, Q3=63–68, and Q4≥69 beats/min).RESULTS: The overall prevalence of borderline ABI was 13.9%. The age- and sex-adjusted resting heart rate was significantly higher in the borderline ABI group than in the control group (66.9±0.9 vs. 63.0±0.4 beats/min, P < 0.001). The odds ratios (95% confidence intervals) for the borderline ABI in each heart rate quartile were 1.00, 1.04 (0.43–2.52), 1.69 (0.73–3.93), and 3.52 (1.55–7.97) after adjusting for age, sex, smoking status, alcohol intake, regular exercise, body mass index, systolic blood pressure, fasting plasma glucose level, triglyceride level, high-density lipoprotein-cholesterol level, white blood cell count, C-reactive protein level, uric acid level, γ-glutamyltransferase level, hypertension medication, diabetes medication, and dyslipidemia medication.CONCLUSION: These findings indicate that a higher resting heart rate is independently associated with borderline ABI.
Ankle Brachial Index ; Biomarkers ; Blood Glucose ; Blood Pressure ; Body Mass Index ; C-Reactive Protein ; Confounding Factors (Epidemiology) ; Diagnosis ; Dyslipidemias ; Fasting ; Heart Rate ; Heart ; Humans ; Hypertension ; Leukocyte Count ; Logistic Models ; Male ; Odds Ratio ; Peripheral Arterial Disease ; Prevalence ; Smoke ; Smoking ; Triglycerides ; Uric Acid