Patients and sample collection
This study randomly recruited 482 participants considered as controls
and 292 women with PCOS from the Center for Reproductive Medicine at the
Shengjing Hospital of China Medical University between May and October
2020. PCOS was diagnosed based on the new guidelines for the diagnosis
and treatment of PCOS,10 which specify that two of the
following three conditions should be satisfied: menstrual disturbance
(oligomenorrhea, amenorrhea, or anovulation), clinical or biochemical
signs of hyperandrogenism, and polycystic ovarian manifestations after
exclusion of other etiologies. The control group consisted of healthy
women and those with clinical infertility due to the involvement of the
fallopian tube.
The exclusion criteria were in accordance with our previous
publications.11 These involved excluding participants
with less than 3 years of menarche; smokers; pregnant women;
breastfeeding women; and those having hyperprolactinemia or any other
disease such as thyroid disease, diabetes, adrenal disease, or a history
of any known neoplastic, infectious, or inflammatory diseases. During
the 6 months prior to enrollment, none of the participants consumed
drugs that would affect reproductive or metabolic functions. The
characteristics of the study participants are listed in Table 1.
The basic information of the participants, including age and body mass
index (BMI), was recorded using the electronic health care record
databases of Shengjing Hospital, China Medical University. BMI was
calculated as body weight in kilograms divided by body height in meters
squared.12 Venous blood samples were collected from
the participants after 10 hours fasting between days 3 and 5 of
spontaneous menstruation or progesterone withdrawal bleeding. The blood
samples were centrifuged and divided into the following two parts: one
part was used as the basal blood sample for testing various biochemical
indicators at the laboratory of Shengjing Hospital, including the levels
of serum uric acid, luteinizing hormone (LH), follicle-stimulating
hormone (FSH), estradiol, total testosterone (TT), progesterone,
prolactin, thyroid-stimulating hormone (TSH), fasting plasma glucose
(FPG), fasting serum insulin (FSI), and lipids; the other part was
stored at -80 °C for further determination of serum fructose, free
testosterone, and dehydroepiandrosterone sulfate (DHEAS) levels.
Freezing and thawing was avoided for all the samples.