Korean Premenopausal Women Research Articles

Height and breast cancer risk in premenopausal Korean women aged under 40 years of age.

Taller women are at an increased risk of breast cancer; however, evidence regarding this in younger women is limited. This study investigated the association between body height and breast cancer risk in premenopausal Korean women aged <40 years. Premenopausal women aged <40 years enroled in the Kangbuk Samsung Health Study (KSHS) and National Health Insurance Service-National Health Information Database (NHIS-NHID) were included in the analysis. Trained staff members performed anthropometry, including height measurements. Breast cancer incidence was followed up until December 2019. Cox regression model and restricted cubic- spline regression were applied. The mean (standard deviation [SD]) age was 33.3 (3.6) years and 32.9 (4.2) in KSHS and NHIS-NHID cohorts, respectively. After adjusting for age at baseline and other confounders, every 10 cm of height was associated with a 1.44-fold increased risk of developing breast cancer (adjusted hazard ratio [aHR], 1.44; 95% confidence interval [CI], 1.17-1.78) in the KSHS. The restricted cubic spline regression showed an almost linear association between height and breast cancer risk. Compared to women with height <155 cm, aHRs (95% CI) among those with height 160-165 cm, 165-170 cm, and ≥170 cm were 1.67 (1.07-2.60), 1.75 (1.09-2.81), and 2.31 (1.18-3.86), respectively (P = 0.009). Results were similar in the NHIS-NHID cohort (aHR, 1.20 [95% CI, 1.10-1.31] per 10-cm increase in height). In young Korean women, greater body height was associated with increased breast cancer risk.

Association between Liver Function Markers and Menstrual Cycle Irregularity in Korean Female Population.

The liver plays an important role in gonadal steroid hormone metabolism, which can affect reproductive health, including the menstrual cycle. However, evidence from large population-based studies is limited. Therefore, this study aimed to investigate the association between liver function markers and menstrual cycle irregularities in premenopausal Korean women using nationwide data. This study analyzed Data from the Korea National Health and Nutrition Examination Survey 2010-2011. We investigated 3,045 premenopausal women aged 19-59 years. Liver function markers including serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma-glutamyl transferase, and fatty liver index were analyzed. Multivariable logistic regression analysis was performed to investigate the association between liver function markers and menstrual cycle irregularity while adjusting for confounding factors. Values were presented as odds ratios (ORs) with 95% confidence intervals (CIs). Subgroup analysis was also performed. Baseline characteristic analysis showed that approximately 14.4% of the study population experienced menstrual cycle irregularity. The mean age was 34.5±0.7 years. The highest quartile of serum ALT and AST levels showed significantly higher ORs for menstrual cycle irregularity (adjusted OR, 1.83; 95% CI, 1.26-2.64 and adjusted OR, 1.67; 95% CI, 1.17-2.39, respectively). A similar result was observed in the subgroup analysis. Liver function markers were positively associated with menstrual cycle irregularities. In clinical settings, women of reproductive age with relatively decreased liver function should be considered for regular followup of their reproductive health status.

Association between Neck Circumference and Thyroid Disease: Findings of a Nationwide Cross-Sectional Study in Korea.

There were contradictory reports about the relationship between neck circumference (NC) and thyroid status. This study aimed to compare the NCs of Korean adults with or without thyroid disease. The data of 8,198 subjects (aged 40-80 yr) that participated in the 2019-2020 Korean National Health and Nutrition Examination Survey were subjected to analysis. NCs were measured by trained staff to an accuracy of ±0.1 cm with a tape measure. Multiple logistic models were used to assess the prevalence of thyroid disease by NC level among men and pre- and postmenopausal women. Approximately 5% of subjects had a history of thyroid disease. In contrast to men and postmenopausal women, premenopausal women with a larger NC had a significantly higher prevalence of thyroid disease (P-value=0.025). A large NC is significantly associated with thyroid disease among premenopausal Korean women.

Risk of uterine leiomyomata with menstrual and reproductive factors in premenopausal women: Korea nurses’ health study

BackgroundUterine leiomyomata (UL) are benign smooth muscle tumors that may cause significant morbidity in women of reproductive age. This study aimed to investigate the relationship of menstrual and reproductive factors with the risk of UL in premenopausal women.MethodsThis prospective study included 7,360 premenopausal women aged 22–48 years who were part of the Korea Nurses’ Health Study. Information on the menstrual cycle and reproductive history was assessed between 2014 and 2016, and self-reported cases of UL were obtained through 2021. Cox proportional hazards models were used to estimate the hazard ratios (HRs) and 95% confidence intervals (CIs).ResultsDuring 32,072 person-years of follow-up, 447 incident cases of UL were reported. After adjusting for other risk factors, women with late age at menarche had a lower incidence of UL (≥ 16 vs. 12–13 years: HR 0.68; 95% CI 0.47–0.99; p for trend = 0.026). The risk of UL was inversely associated with current menstrual cycle length (≥ 40 or too irregular to estimate vs. 26–31 days: HR 0.40; 95% CI 0.24–0.66) and cycle length at ages 18–22 years (HR 0.45; 95% CI 0.31–0.67; p for trend < 0.001, each). Parous women had lower risk of UL than nulliparous women (HR 0.40; 95% CI 0.30–0.53) and women who were aged 29–30 years at first birth had a lower risk of UL than those who were aged ≤ 28 years at first birth (HR 0.58; 95% CI 0.34–0.98). There was no significant association of the number of births or breastfeeding with the risk of UL among parous women. Neither a history of infertility nor oral contraceptive use was associated with the risk of UL.ConclusionsOur results suggest that age at menarche, menstrual cycle length, parity, and age at first birth are inversely associated with the risk of UL in premenopausal Korean women. Future studies are warranted to confirm the long-term effects of menstrual and reproductive factors on women’s health.

Association of Coffee or Green Tea with Ferritin or Hemoglobin in Premenopausal Women.

This study aimed to examine the association between coffee or green tea consumption and ferritin or hemoglobin levels in premenopausal women. We used the fifth Korea National Health and Nutrition Examination Survey (2010-2012), and a total of 4,322 individuals were surveyed. In women of reproductive age, average ferritin and hemoglobin levels were calculated according to coffee or green tea consumption. Covariates included in the analysis were demographic variables, such as age, body mass index, education, drinking, smoking, history of hypertension, history of diabetes diagnosis, physical activity, total energy intake, and daily iron intake. In 4,322 participants, the average hemoglobin level was 12.90±0.02 g/dL, and the average level of ferritin was 31.95±0.67 ng/mL. As a result of testing, correlation between ferritin and coffee intake and difference in ferritin levels according to coffee consumption was significant (P<0.05). In this study, a post hoc test indicated that ferritin level significantly differed between one and two cups, two and three cups, and three and one cup groups (overall P<0.001). Additionally, there was a negative correlation between ferritin level and coffee intake; ferritin level decreased by 2.09 ng/mL with a one-cup increase in daily coffee consumption. In premenopausal women, coffee intake is associated with low serum ferritin levels. Our results indicate that drinking >2 cups of coffee significantly affect ferritin levels in Korean premenopausal women.

Association of Breast Cancer Family History With Breast Density Over Time in Korean Women

Evidence suggests that women with a family history of breast cancer (FHBC) in first-degree relatives have a higher level of breast density; however, studies of premenopausal women remain limited. To investigate the association between FHBC and mammographic breast density and breast density changes among premenopausal women. This retrospective cohort study used population-based data obtained from the National Health Insurance Service-National Health Information Database of Korea. We included premenopausal women aged 40 to 55 years who underwent mammography for breast cancer screening once between January 1, 2015, and December 31, 2016 (n = 1 174 214), and women who underwent mammography twice (first in 2015-2016 and again between January 1, 2017 and December 31, 2018) (n = 838 855). Family history of breast cancer was assessed using a self-reported questionnaire, which included information on FHBC in the mother and/or sister. Breast density, based on the Breast Imaging Reporting and Data System, was categorized as dense (heterogeneously or extremely dense) and nondense (almost entirely fat or scattered fibroglandular areas). Multivariate logistic regression was used to assess the association among FHBC, breast density, and changes in breast density from the first to second screening. Data analysis was performed from June 1 to September 31, 2022. Of the 1 174 214 premenopausal women, 34 003 (2.4%; mean [SD] age, 46.3 [3.2] years) reported having FHBC among their first-degree relatives, and 1 140 211 (97.1%; mean [SD] age, 46.3 [3.2] years) reported no FHBC. Odds of having dense breasts was 22% higher (adjusted odds ratio [aOR], 1.22; 95% CI, 1.19-1.26) in women with FHBC than in women without FHBC, and the association varied by affected relatives: mother alone (aOR, 1.15; 95% CI, 1.10-1.21), sister alone (aOR, 1.26; 95% CI, 1.22-1.31), and both mother and sister (aOR, 1.64; 95% CI, 1.20-2.25). Among women with fatty breasts at baseline, the odds of developing dense breasts was higher in women with FHBC than in those without FHBC (aOR, 1.19; 95% CI, 1.11-1.26), whereas among women with dense breasts, higher odds of having persistently dense breasts were observed in women with FHBC (aOR, 1.11; 95% CI, 1.05-1.16) than in those without FHBC. In this cohort study of premenopausal Korean women, FHBC was positively associated with an increased incidence of having increased or persistently dense breasts over time. These findings suggest the need for a tailored breast cancer risk assessment for women with FHBC.

Association between pregnancy, and lactation after delivery and depressive symptoms in premenopausal Korean women and multilevel approach according to household composition: Result from the Korea Community Health Survey in 2019

ObjectiveTo evaluate the association between pregnancy, lactation after delivery and depressive symptoms in Korean women and to explore the associations according to household composition. MethodsWe included 34,321 premenopausal women from the Korea Community Health Survey in 2019, a population-based cross-sectional study. We categorized the premenopausal women into 3 groups by questions about whether they were currently in menstruation: reference (women who were not pregnant or lactating after delivery), pregnancy, and lactation after delivery. Depressive symptoms (PHQ-9 ≥ 5) were assessed through questionnaires with trained interviewers. Multiple logistic regression analysis were performed. ResultsAmong 34,321 participants, 20,790 (60.6 %) had depressive symptoms. In the fully adjusted model, we found a significant association between mild depressive symptoms in lactated women after delivery (odds ratio [OR], 95 % confidence interval [CI] = 1.32 [1.04–1.65]) compared to a reference. Compared to reference, the association between women who were lactation after delivery and depressive symptoms was particularly noticeable in women living in families of 2-generation (OR, 95 % CI = 1.29 [1.00–1.65]) and 3-generation (OR, 95 % CI = 2.53 [1.31–4.89]). LimitationsWe utilized self-reported data on pregnancy and lactation after delivery, this exposure variable may be underestimated. ConclusionOur study observed associations between lactated women after delivery and depressive symptoms. This association was more pronounced in women living in 3-generation.

Risk of Endometrial Polyps, Hyperplasia, Carcinoma, and Uterine Cancer After Tamoxifen Treatment in Premenopausal Women With Breast Cancer

The association of tamoxifen use with the risk of uterine diseases, such as endometrial cancer, in premenopausal women with breast cancer remains controversial. However, many studies have reported an increased risk of uterine disease among postmenopausal tamoxifen users. To investigate the association of tamoxifen use with the risk of endometrial cancer and other uterine diseases in premenopausal women with breast cancer. A nationwide, population-based, retrospective longitudinal cohort study with an 18-year study period was conducted using data obtained from the Korean National Health Insurance Service. Participants included premenopausal women aged 20 to 50 years with breast cancer diagnoses between January 2003 and December 2018. Data were analyzed from April to December 2021. Tamoxifen treatment. The incidence of uterine diseases, including endometrial cancer, hyperplasia, polyps, and other uterine cancers, was identified in the study cohort using insurance claim codes. The incidence of uterine diseases per 1000 person-years was compared between women receiving tamoxifen and those not treated with adjuvant hormone therapy. Multivariable Cox proportional hazard regression analysis was performed to determine the risk of each uterine disease. Among 78 320 female participants with a mean (SD) age of 42.1 (6.1) years, 34 637 (44.2%) were categorized into the tamoxifen group and 43 683 (55.8%) were categorized into the control group. Among tamoxifen users, during the mean (SD) follow-up duration of 6.13 (4.15) years, the incidence of newly diagnosed endometrial polyps was 20.13 cases per 1000 person-years, that of endometrial hyperplasia was 13.49 cases per 1000 person-years, that of endometrial cancer was 2.01 cases per 1000 person-years, and that of other uterine cancers was 0.45 cases per 1000 person-years. The risk of endometrial cancer was higher in the tamoxifen group than in the control group (hazard ratio, 3.77; 95% CI, 3.04-4.66) after adjusting for age, body mass index, history of diabetes, hypertension, dyslipidemia, polycystic ovary syndrome, gonadotropin-releasing hormone agonist treatment, and trastuzumab treatment. In this longitudinal cohort study, premenopausal Korean women with breast cancer who received tamoxifen as adjuvant hormone therapy had a significantly increased risk of endometrial hyperplasia, polyps, carcinoma, and other uterine cancers compared with those who were not treated with adjuvant hormone therapy. These findings suggest that clinicians should consider the risk of uterine disease among tamoxifen users, including premenopausal women.

Association of reproductive factors with cardiovascular disease risk in pre-menopausal women: nationwide population-based cohort study.

Although the morbidity and mortality of cardiovascular diseases (CVD) are rising in young women, the risk factors of CVD among Korean pre-menopausal women have not been intensively investigated. To determine how age at menarche and other female reproductive factors are associated with the risk of CVD in pre-menopausal women. A total of 1 088 992 pre-menopausal women who participated in health screening in 2009 were included. The study outcomes were myocardial infarction (MI) and ischaemic stroke. Cox proportional hazards regression analysis was conducted with adjustment of traditional CVD risk factors and reproductive factors. Mean age was 43.8 ± 5.3 years (98.9%, < 55 years), 3.5% were current smokers, and 1.2% were heavy drinkers. During a mean follow-up of 8.3years [9 032 685.9 person-years (PY)], there were 10 876 CVD events (1.0 per 1000 PY).With later menarche, the risk of CVD increased; ≤12 years [adjusted hazard ratio (HR) 1.04, 95% confidence interval 0.93-1.16], 13 years (reference), 14 years (1.06, 0.98-1.14), 15 years (1.15, 1.07-1.24), 16 years (1.23, 1.14-1.34), and ≥17 years (1.33, 1.24-1.44). Compared with non-users, oral contraceptives (OC) users (≥1 year) had an increased risk of CVD (1.11, 1.01-1.22) (P for trend = 0.007). Later menarche than the mean age at menarche (13 years old) and the use of OC (≥1 year) were associated with a higher risk of CVD, after adjusting for traditional cardiovascular risk factors. This study suggests that female reproductive factors could be unique risk factors for CVD in pre-menopausal women.

Intra-Individual Changes in Total Procollagen-Type 1 N-terminal Propeptide in a Korean Adult Population.

We aimed to investigate intra-individual changes in total procollagen-type 1 N-terminal pro-peptide (P1NP), a biochemical marker of bone turnover, to understand patient populations and test utilization in a Korean adult population while considering different definitions of least significant changes by sex, age, and medical institution type. Overall, 31,501 P1NP tests were performed on 24,644 Korean adults (3389 men and 21,255 women) with a median age of 68.9 years (interquartile range, IQR, 61.2–77.2) for osteoporosis evaluation. Among these, 1331 (5.4%) patients (127 men and 1204 women) underwent ≥3 follow-up P1NP measurements. The median follow-up period was 12.5 months (IQR, 11.7–15.9). Among 1331 patients, 64.4% experienced a decrease in P1NP and 35.6% experienced an increase in P1NP during follow-up. Among these, the proportion of patients who experienced serum P1NP changes ≥14.4% from baseline was 92.3%, and the proportion of patients who achieved ≤40 ng/mL (a median level of premenopausal Korean women) during follow-up was 31.8%. The overall proportion of patients that experienced a serum P1NP change exceeding the least significant change during follow-up was not significantly different by the type of medical institution.

Nonalcoholic Fatty Liver Disease and Risk of Early-Onset Vasomotor Symptoms in Lean and Overweight Premenopausal Women.

The role of nonalcoholic fatty liver disease (NAFLD) in vasomotor symptom (VMS) risk in premenopausal women is unknown. We examined the prevalence of early-onset VMSs according to NAFLD status in lean and overweight premenopausal women. This cross-sectional study included 4242 premenopausal Korean women (mean age 45.4 years). VMSs (hot flashes and night sweats) were assessed using the Korean version of the Menopause-Specific Quality of Life questionnaire. Hepatic steatosis was determined using liver ultrasound; lean was defined as a body mass index of <23 kg/m2. Participants were categorized into four groups: NAFLD-free lean (reference), NAFLD-free overweight, lean NAFLD, and overweight NAFLD. Compared with the reference, the multivariable-adjusted prevalence ratios (PRs) (95% confidence intervals (CIs)) for VMSs in NAFLD-free overweight, lean NAFLD, and overweight NAFLD were 1.22 (1.06–1.41), 1.38 (1.06–1.79), and 1.49 (1.28–1.73), respectively. For moderate-to-severe VMSs, the multivariable-adjusted PRs (95% CIs) comparing NAFLD-free overweight, lean NAFLD, and overweight NAFLD to the reference were 1.38 (1.10–1.74), 1.73 (1.16–2.57), and 1.74 (1.37–2.21), respectively. NAFLD, even lean NAFLD, was significantly associated with an increased risk of prevalent early-onset VMSs and their severe forms among premenopausal women. Further studies are needed to determine the longitudinal association between NAFLD and VMS risk.

Inverse Association of Serum Folate Level with Metabolic Syndrome and Its Components in Korean Premenopausal Women: Findings of the 2016-2018 Korean National Health Nutrition Examination Survey.

Research on the association of serum folate levels with metabolic syndrome (MetS) in premenopausal women is lacking. This study was aimed to investigate this association in 1730 premenopausal women using the 2016 to 2018 Korean National Health and Nutrition Examination Survey data. Participants’ mean age and BMI were 35.9 years and 22.7 kg/m2, respectively. Participants were divided into three groups according to serum folate tertiles. Odds ratios (OR) and 95% confidence intervals (CIs) for abdominal obesity, elevated blood pressure (BP), high fasting plasma glucose (FPG), high triglycerides (TG), low high-density lipoprotein cholesterol (HDL-C), and MetS were calculated in multiple logistic regression models adjusted for possible confounders, by serum folate level tertiles. Prevalence of MetS (14.9, 11.0, and 8.6%); abdominal obesity (17.8, 16.0, and 11.4%); high TG (17.5, 14.0, and 11.1%); and low HDL-C (50.3, 44.6, and 42.5%) decreased with increasing folate level tertile. Prevalence of elevated BP (14.3, 12.0, and 11.7%) and high FPG (11.9, 15.8, and 13.0%) showed no significant differences according to serum folate level tertiles. The multivariate-adjusted ORs (95% CIs) for MetS, abdominal obesity, elevated BP, high TG, and low HDL-C in the highest folate level tertile were 2.17 (1.46–3.22), 1.80 (1.25–2.60), 1.77 (1.16–2.70), 1.90 (1.35–2.67), and 1.49 (1.14–1.94), respectively. The ORs for high FPG did not show significant differences according to serum folate level tertiles. In conclusion, serum folate levels were inversely associated with an increased risk of MetS in Korean premenopausal women. These results suggest that MetS can be prevented and managed by improving the serum folate levels in premenopausal women.

Association between Oral Contraceptive Use and the High-Sensitivity C-Reactive Protein Level in Premenopausal Korean Women.

Although oral contraceptives (OCs) are widely used, few national epidemiological studies have evaluated the association between OC use and serum high-sensitivity C-reactive protein (hs-CRP) levels in Korean women. This population-based cross-sectional study was conducted with data from the 2015–2018 National Health and Nutrition Examination Survey. In the sample of 5332 premenopausal women aged ≥19 years, hs-CRP concentrations were 1.087 mg/L among OC users and 0.953 mg/L among OC non-users. After adjustment for confounders, OC users had an increased likelihood of having risky (>1.0 mg/L) hs-CRP levels (adjusted odds ratio (aOR) = 1.58; 95% confidence interval (CI), 1.25–1.98) compared with OC non-users. In addition, the aOR for high-risk (>3.0 mg/L) hs-CRP levels in OC users compared with non-users was 1.51 (95% CI, 1.06–2.16). These findings demonstrate that OC use alters the concentration of hs-CRP, a biomarker of chronic low-grade inflammation, and suggest that long-term OC use is a risk factor in the pathogenesis of inflammatory diseases, including cardiovascular diseases.

Insulin resistance and the development of breast cancer in premenopausal women: the Kangbuk Samsung Health Study.

Research on the role of insulin resistance (IR) in breast cancer risk in premenopausal women is scarce. We aimed to investigate the relationship between IR and the development of breast cancer in premenopausal women. We analyzed the prospective association of IR and incident breast cancer in premenopausal women without breast cancer at baseline using a subsample of the Kangbuk Samsung Health Study. Among 134,488 Korean premenopausal women, 696 women developed incident breast cancers during a median follow-up of 4.34years. After adjustment for dense breast and other potential confounders, HR (95% CI) for incident breast cancer comparing HOMA-IR quintiles 2, 3, 4, and 5 to the first quintile was 0.91 (0.71-1.17), 0.89 (0.69-1.15), 0.75 (0.57-0.98), and 0.87 (0.65-1.16), respectively (P for trend = 0.117), while HR (95% CI) comparing insulin quintiles 2, 3, 4, and 5 to the first quintile was 1.02 (0.80-1.30), 0.90 (0.69-1.16), 0.72 (0.54-0.96), and 0.96 (0.72-1.28), respectively (P for trend = 0.151). This pattern did not significantly differ by obesity. These results were attenuated and no longer significant in time-dependent analyses where updated status of insulin and other covariates over time were treated as time-varying covariates. Our findings do not support the positive relationship of IR with the development of breast cancer in premenopausal women, unlike in postmenopausal women. Thus, the role of IR as a risk factor for breast cancer may differ by menopausal status.

A Structural Equation Modelling Approach to Determine Factors of Bone Mineral Density in Korean Women.

Background: no studies have assessed the associations of nutrient intake, physical activity, age, and body mass index (BMI) with bone mineral density (BMD) using structural equation modelling (SEM) in Korean women. The aim of this study was to examine the effects of nutrient intakes, physical activity, and body mass index (BMI) on BMD in Korean premenopausal and postmenopausal women, with the SEM approach, based on the fourth and fifth Korea National Health and Nutrition Examination Surveys (KNHANES) 2008–2011. Methods: SEM analysis was performed with 4160 women (2863 premenopausal women and 1297 postmenopausal women) aged 30–75 years in order to investigate total, direct, or mediating effects of nutrient intake, physical activity, age, and BMI on BMD. Model sensitivity to external misspecification and statistical significance of SEM was determined by phantom variables and bootstrapping. Reliability assessment of the SEM was done by Cronbach’s alpha. Results: a direct effect of minerals (potassium, calcium, and phosphorus) on BMD (total femur, femoral neck, lumbar spine, and whole body) was observed in premenopausal and postmenopausal women (p = 0.045 and p = 0.048, respectively). Age and BMI showed a total effect on BMD in premenopausal and postmenopausal women (p = 0.002, respectively). Conclusions: our study suggests that mineral intake (potassium, calcium, and phosphorus), age, and BMI are major contributors to BMD in Korean premenopausal and postmenopausal women aged 30–75 years.

Characteristics of Vaginal Microbiome in Women with Pelvic Inflammatory Disease in Korea.

Human vaginal microorganisms play an important role in maintaining good health throughout the human life cycle. An imbalance in the vaginal microbiota is associated with an increased risk of pelvic inflammatory disease (PID). This study aimed to characterize and compare vaginal microbial profiles of premenopausal Korean women with and without PID. 74 Korean premenopausal female vaginal samples were obtained; 33 were from healthy women (a control group) and 41 from PID patients. Vaginal fluid samples were collected from the vaginal wall and posterior cervix and then analyzed by 16S ribosomal ribonucleic acid (rRNA) gene-based amplicon sequencing. Results showed a significant difference between the vaginal microbial communities of the two groups (Jensen-Shannon, p = 0.014; Bray-Curtis, p = 0.009; Generalized UniFrac, p = 0.007; UniFrac, p = 0.008). Lactobacillus accounted for the highest percentage (61.0%) of the control group but was significantly decreased (34.9%) in PID patients; this was the most significant difference among all bacterial communities (p = 0.028, LDA effect size = 5.129). In addition, in the PID patient group, species diversity significantly increased (Simpson, p = 0.07) as the proportion of various pathogens increased evenly, resulting in a polymicrobial infection. Similarly, lactate, which constituted the highest percentage of the organic acids in the control group, was significantly decreased in the PID patient group (p = 0.04). The present study’s findings will help understand PID from the microbiome perspective and are expected to contribute to the development of more efficient PID diagnosis and treatment modalities.

Relationship between Self-Reported Sleep Duration and Risk of Anemia: Data from the Korea National Health and Nutrition Examination Survey 2016-2017.

The importance of sleep has been gaining more and more attention nowadays. It has been widely studied that some major health issues, such as cardiovascular diseases or mortality, are closely related to the extreme ends of sleep durations. Anemia is one of the health problems in modern society. In this study, we aimed to find a relationship between anemia occurrence and sleep duration. Data of 11,131 Korean adults aged 19 years or older were recruited from the 2016–2017 Korea National Health and Nutrition Examination Survey and analyzed in this cross-sectional study. ‘Anemia’ was defined in this study by hemoglobin level of <13 g/dL in men and <12 g/dL in women. Selected data were sorted into five groups by sleep duration: <5 h, 5 h ~ <6 h, 6 h ~ <8 h, 8 h ~ <9 h, and ≥9 h per day. We performed multivariate logistic regression analysis to assess the relationship between sleep duration and risk of anemia after adjusting for covariates including age, gender, family income level, education level, physical activity, cigarette smoking, and alcohol usage. Other factors were assessed in the analysis, such as depression, hypertension, diabetes, dyslipidemia, stroke, coronary artery disease, malignancy, stress level, and body mass index (BMI). We found that sleep duration of <5 h was related to high risk of anemia (odds ratio = 1.87; 95% confidence interval = 1.01–3.49, sleep duration of 6 h ~ <8 h as the reference group). Also, sleep duration of ≥9 h was related to lower risk of anemia in most premenopausal women after adjusting for covariates (odds ratio = 0.61; 95% confidence interval = 0.38–0.96, sleep duration of 6 h ~ < 8 h as the reference group). Male individuals with sleep durations of <5 h (odds ratio = 2.01; 95% confidence interval =1.05–3.84) and of ≥9 h (odds ratio = 2.48; 95% confidence interval =1.63–3.81) had a significantly higher risk of anemia without covariate adjustment. Postmenopausal women with sleep durations of ≥9 h had a significantly higher risk of anemia (odds ratio =2.02; 95% confidence interval =1.33–3.08) without adjusting for covariates. However, the associations became statistically insignificant after adjusting for age and covariates in both men and postmenopausal women. In conclusion, we found significant associations between extreme ends of sleep duration and risk of anemia in premenopausal Korean women. However, we did not observe strong associations between self-reported sleep duration and anemia risk in men or postmenopausal women.

Association between Irritable Bowel Syndrome and Risk of Osteoporosis in Korean Premenopausal Women

Objective: The objective of this study is to evaluate irritable bowel syndrome (IBS) as a risk factor for osteoporosis and osteoporotic fracture in Korean women after controlling for basic confounding factors and considering detailed demographic and clinical information. Subjects and Methods: We performed a nationwide population-based retrospective cohort analysis and matched every IBS case with a non-IBS case at a 1:4 frequency ratio based on age. The population consisted of female patients with data in the Health Insurance Review and Assessment (HIRA) database from 2002 to 2010. To determine the risk of osteoporosis and osteoporotic fracture in IBS and non-IBS patients, hazard ratios (HRs) with 95% confidence intervals (CI) were estimated using Cox proportional hazards regression models, adjusting for confounding variables, such as the area of residence, health insurance type, and economic status. Results: We identified 1,017,468 patients in the HIRA database with data from 2002 to 2010 who could potentially be included in the cohort. Among these, we identified 1,545 (11.4%) women (age >19 years) with newly diagnosed IBS (IBS group). Additionally, 6,180 patients without IBS and age-matched to the IBS group were selected. Cox modeling revealed that the crude HRs for osteoporosis and osteoporotic fractures in patients with IBS were 1.476 (95% CI, 1.241–1.754) and 1.427 (95% CI, 1.086–1.876), respectively. Conclusion: Our data showed an increased incidence of osteoporosis and osteoporotic fractures in women with IBS compared with age-matched controls.

Association between menstrual cycle irregularity and tinnitus: a nationwide population-based study

This population-based cross-sectional study investigated the association between menstrual cycle irregularity and tinnitus in premenopausal Korean women. We used data from the 5th Korea National Health and Nutrition Examination Survey (2010–2012). A total of 4633 premenopausal women were included. Hierarchical multivariable logistic regression analysis was performed. Individuals with tinnitus accounted for 21.6%. Women with tinnitus or menstrual irregularity had significantly higher rates of stress, depressive mood, and suicidal ideation than those without. The proportion of individuals with irregular menstrual cycles with duration of longer than 3 months increased as the severity of tinnitus increased (P = 0.01). After adjusting for confounding variables, the odds of tinnitus increased in individuals with irregular menstrual cycles compared to those with regular menstrual cycles. The odds ratios (ORs) of tinnitus tended to increase as the duration of menstrual irregularity became longer (1.37, 95% confidence interval: 1.06–1.78 for duration of up to 3 months; 1.71, 1.03–2.85 for duration of longer than 3 months, P for trend = 0.002). Our study found a positive association between menstrual cycle irregularity and tinnitus. Menstrual cycle irregularity may be a related factor of tinnitus in women with childbearing age.

The Association between Low Vitamin D Status and Autoimmune Thyroid Disease in Korean Premenopausal Women: The 6th Korea National Health and Nutrition Examination Survey, 2013-2014.

BackgroundThis study aimed to analyze the association of low vitamin D status with thyroid autoimmunity and dysfunction in the Korean population according to sex and menopausal status in women.MethodsThis study was based on the data acquired from the 6th Korea National Health and Nutrition Examination Survey. We enrolled 4,356 subjects who had data of thyroid function, antithyroid peroxidase antibody (TPOAb), and serum 25-hydroxyvitamin D (25[OH]D) levels. We excluded subjects who were pregnant and who had a history of thyroid disease or thyroid cancer, and those with transient thyroid dysfunction who tested negative for TPOAb (TPOAb[-]).ResultsTPOAb positivity (TPOAb[+]) with thyroid dysfunction (subclinical and overt hypothyroidism) was more prevalent in the vitamin D deficient group than in the vitamin D insufficient and sufficient groups including premenopausal (P=0.046) and postmenopausal women (P=0.032), although no significant differences were observed in men. The mean serum 25(OH)D level was significantly lower in the TPOAb(+) with thyroid dysfunction group than in the TPOAb(+) with euthyroidism and TPOAb(-) groups of premenopausal women (P=0.001), although no significant differences were observed in men and postmenopausal women. Multivariate binary logistic regression analysis, adjusted for age, body mass index, and current smoking status, showed that vitamin D insufficiency and deficiency were significantly associated with TPOAb(+) with thyroid dysfunction in premenopausal women (P<0.001), although no significant associations were observed in men and postmenopausal women.ConclusionLow vitamin D status was significantly associated with thyroid autoimmunity and dysfunction in the Korean population, especially in premenopausal women.