747 autoanalyzer

Subjects aged 18–85 years old with type 2 diabetes mellitus (T2DM), according to American Diabetes Association criteria [22 (link)], were recruited from the diabetes center and podiatry departments at Hamad Medical Corporation in Doha, Qatar. Age, gender, duration of diabetes, height, weight, and BMI were recorded. The systolic (SBP) and diastolic (DBP) blood pressure were assessed in the left arm using a standard zero mercury sphygmomanometer after the subject had been seated for at least 10–15 min, and the average of two readings was obtained. Through venipuncture, 10 mL of blood was collected into vacutainer tubes containing EDTA. The samples were kept at room temperature and transported within 2 h to a central certified laboratory at Hamad General Hospital, HMC, Doha, Qatar. Glycated hemoglobin (HbA_1c), total cholesterol, LDL, triglycerides, and creatinine were measured by an autoanalyzer (Hitachi 747 Autoanalyzer, Chiyoda, Japan).
Participants with known ophthalmic pathology, auto-immune disease, and peripheral neuropathy (other than diabetic neuropathy), lower limb ischemia, and osteomyelitis were excluded from the study.

We collected information on sociodemographic characteristics (e.g., age, gender, birth date, and education level), lifestyle factors (e.g., smoking, alcohol intake, salt intake, and physical activity), medical history (e.g., CVD, hypertension, diabetes mellitus, family history of CVD), and active treatments such as hypoglycemic, antihypertensive, and lipid-lowering medications through the self-reported questionnaire in the Kailuan Study since the baseline survey, as detailed previously (13 (link)). Education was classified as less than high school and high school or above. Drinking status was stratified into two levels: current or never/former. Weight and height were measured, and BMI was calculated as weight (kg)/height (m)². Moreover, BP was measured on the left arm using an appropriate cuff size after the participant had a rest in a chair for at least 5 min. The average values of at least two readings each of systolic and diastolic BPs were used for further analysis.
The blood sample of each participant was collected on the morning of the survey after at least a 12-h fast. All samples were measured by a Hitachi 747 autoanalyzer at the central laboratory of the Kailuan General Hospital. The estimated glomerular filtration rate (eGFR) was calculated using the Chronic Kidney Disease Epidemiology Collaboration creatinine equation (15 (link)).

Biochemical blood tests of all patients were analyzed. Blood samples were taken from the patients, then they were analyzed in the same laboratory. Plasma glucose by the enzymatic test method, glycosylated hemoglobin by high-performance liquid chromatography method, calcium, phosphate, alanine transaminase, aspartate transaminase, high-density lipoprotein cholesterol, total cholesterol, and triglyceride concentration by enzymatic colorimetric test (Hitachi 747 autoanalyzer, German), creatinine by Jaffe` method, blood urea nitrogen by spectrophotometer, potassium, sodium, and chlorine level with ion-selective electrode analysis was measured with Architect plus device. The serum sample taken to measure the VD levels of the patients was centrifuged at 3500 rpm for 15 min and then measured by the electrochemiluminescence method. VD was measured using the Elecsys 2010, Roche Diagnostics, GmbH, Mannheim, Germany device with an intra and inter test coefficient of variation of 3.0% and 3.3%, respectively. The serum VD detection limit was 2 ng/ml. We know that VD level is affected by seasonal factors. Therefore, the study was carried out in January, February, and March. Patients were grouped according to their VD measurement levels as deficient (0–19.9 ng/ml), insufficient (20–29.9 ng/ml), and normal (30 ng/ml) [13 (link)].