Study design and participants
Healthy peri- and postmenopausal women aged at least 40 years old (defined by STRAW+10 stage of reproductive aging ) who attended an annual health check-up at check-up clinic, or a visit at menopause clinic at a university hospital, were recruited during January – December 2020. The participants who had history of stroke, cardiovascular disease, cancer, polycystic ovary syndrome, diagnosed with any inflammatory diseases (SLE, autoimmune disease, rheumatoid arthritis, etc.), on immunosuppressive therapy, steroid or NSAIDs, and chronic kidney disease were excluded. The study was conducted in accordance with the ethical principles of the Declaration of Helsinki, and the study protocol was approved by the Vajira Institutional Review Board. The informed consents were obtained from all subjects.
All participants were undergone a clinical and biochemical evaluations. The anthropometric measurements (waist circumference, hip circumference, and height) were carried out according to the World Health Organization recommendations . Weight was measured in kilograms. The waist-hip ratio (WHR) was calculated and stratified into android (WHR ≥ 0.85) and gynoid (WHR < 0.85) body fat distribution pattern. The body mass index (BMI) was calculated and stratified into normal (BMI < 23.0kg/m2), overweight (BMI 23.0–29.9 kg/m2), and obese (BMI ≥ 30.0 kg/m2). Height was measured while standing in light clothes without footwear. The standard sphygmomanometer was placed at the same level with the participants’ chest for blood pressure measurement.
Afterward, a two-part questionnaire was self-administered. The first part comprised of demographic data including age, lifestyle (alcohol consumption, eating habits, and smoking), menstrual history, marital status, parity, education, occupation, and family history of metabolic diseases. The second part was the Thai version of MENQOL questionnaire. The MENQOL was translated and validated at our institution, with Cronbach’s alpha = 0.8940. The MENQOL questionnaire consists of 29 items within four domains, vasomotor (3 items), psychosocial (7 items), physical (16 items), and sexual (3 items). The participants were demanded to rate their experience of each of the items within the previous month and to score the bothersome of each symptom in a Likert scale ranging from 0 (not disturbed at all) to 6 (extremely disturbed). The investigators supervised the self-administered questionnaire or interviewed and completed the questionnaire for illiterate participants.
After overnight fast, the blood specimen was drawn for bio-chemical evaluations including complete blood count (CBC), fasting blood glucose (FBG), triglyceride (TG), total cholesterol, high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C). The biochemical assays were conducted in an ISO 15189 certified biochemical laboratory at the department of clinical pathology. The FBG, total cholesterol, HDL-C, and TG were analyzed with auto-analyzer (SIEMENS Dimension® EXL™ 200, USA) and reported as mg/dL. LDL-C was calculated using the Friedewald equation and reported as mg/dL.
Urine adiponectin was measured by ultrasensitive human adiponectin ELISA kit (Invitrogen, Thermo Fisher Scientific, Austria)  with auto-analyzer (TECAN® SUNRISE, Austria). Urine samples were collected and transferred to pyrogen/endotoxin-free tubes, and then snap frozen at -20˚C for further analysis according to the manufacturer recommendation. Each sample was assayed in duplicate with 10-fold dilution using quantitative sandwich enzyme immunoassay technique. The range of measured concentrations is 0–32 ng/mL using diluted reconstituted standard human adiponectin according to the manufacturer protocol. The coefficient variation (%CV) of intra- and inter-assay were less than 8.31% and 9.69%, respectively.
Criteria for diagnosis of MetS
The diagnosis of MetS was made following the Joint Interim Statement 2009 (JIS 2009) criteria  where the participants had at least three of the following criteria: 1) abdominal obesity defined as waist circumference ≥ 80 cm for Asian women; 2) elevated TG ≥ 150 mg/dl or drug treatment for elevated triglycerides; 3) reduced HDL-C < 50 mg/dl or drug treatment for reduced HDL-C; 4) elevated blood pressure defined as systolic ≥ 130 mmHg and/or diastolic ≥ 85 mmHg or antihypertensive drug treatment; and 5) elevated fasting glucose ≥ 100 mg/dl or drug treatment of elevated glucose.
From our previous study , we found that prevalence of metabolic syndrome in peri- and postmenopausal women was 21.4%. We required 290 participants in this study with α = 0.05, and 80% power.
All data were analyzed using IBM SPSS statistics version 22.0 (SPSS Inc., USA). Data were presented as mean±SD, number (%), or percentage (95% confidence interval – CI), as appropriate. Urinary adiponectin was analyzed and compared among participants with and without MetS using independent sample t-test or one-way ANOVA as appropriate. Pearson’s correlation coefficient was determined for the correlation between urinary adiponectin and MetS components. The area under the curve (AUC) of receiver operating characteristic (ROC) curve analysis for diagnosing MetS was performed to obtain the diagnostic performance and cutoff of urinary adiponectin for diagnosis of MetS by Yuden index. The p-value of < 0.05 was considered statistically significant.