Study design and participants
The current cross-sectional study assessed 476 patients undergoing angiography who were referred to Afshar Hospital in Yazd, Iran, from September 2020 to October 2021. Participants ranged in age from 30 to 76 and were of both sexes. Out of all participants provided written consent to be included in the study. Subjects were excluded if they had: a history of cancer, chronic heart failure (CHF), history of myocardial infarction (MI), percutaneous coronary intervention (PCI), coronary artery bypass grafting (CABG), chronic kidney disease stage 3 or higher, liver disease or was receiving medication for liver disease, certain perceptual or psychological disorders, immune system failure, an acquired immunodeficiency syndrome (AIDS), or extreme obesity (BMI > 40). Pregnant and lactating women and those with restrictions on oral intake were also excluded. The present study was approved by the Ethics Committee of Shahid Sadoughi University (SSU) of Medical Sciences Yazd, Iran (IR.SSU.SPH.REC.1400.079).
Dna Extraction And Genotyping
Genome DNA was extracted from white blood cells in 100 µL peripheral whole blood according to the Kit described protocol (SIMBIOLAB, IRAN). Extracted DNA was kept at --20°C until analysis. The CETP-TaqIB variant was amplified by the polymerase chain reaction (PCR) method, its solution had a 20 µL volume consisting of 2 µL genomic DAN, 6 µL water, 10 µL Master Mix (Amplicon, Denmark), and 1 µL of each primer 5’-ACTAGCCCAGAGAGAGGAGTG-3’ and 5’-CAGCCGCACACTAACCCTA-3’ that synthesized by SinaClon, Iran. Amplification was applied with 1 cycle denaturation in 5 minutes at 95°C, followed by 40 cycles in 30 seconds at 95°C, annealing at 66°C for 30 seconds, and primary extension at 72°C for 30 seconds. The final extension was for 1 cycle at 72°C in 5 minutes. The PCR products were electrophoresed on 2% agarose gel (SinaClon, Iran) and then digested after incubating at 37°C overnight by endonuclease of the Taq1 (Fermentase, Lithuania), which contained 30 µL (10 µL PCR product, 2 µL buffer, 0.5 µL Taq1 enzymes, and 17.5 µL water). Digested fragments of the 708272-CETP were electrophoresed using 2% agarose gel with a voltage of 100 for 1 hour. Finally, three genotypes were identified on the gel by ultraviolet transillumination based on fragment length, which was homozygous B1B1 containing 2 bands with 175 and 345 base pair (bp) and heterozygous B1B2 with 3 bands: 520 and 175, and 345 (bp), as well as homozygous B2B2 with 1 band: 520 (bp) Fig. 1. Genotyping was confirmed by sequencing the PCR products.
Anthropometric Assessment
Weight and height were measured based on the standard protocols utilizing Omron BF-511 portable digital scales (with an accuracy of 100 gr) and a tape measure (with an accuracy of 0.1 cm). WC was measured with an accuracy of 0.5 cm using a non-stretch tape at the middle of the iliac crown and lowest rib in the standing position. Based on Cholesterol Education Program Adult Treatment Panel III (NCEP ATP III), WC > 102 and > 88 cm were considered as abdominal obesity for men and women, respectively (55). Body mass index (BMI) was calculated through rate weight (kg) to the square of height (m2). All those were measured by nutrition-trained students.
Physical Activity Assessment
Daily physical activity was evaluated using the International Physical Activity Questionnaire (IPAQ) (56). Activity levels were considered as metabolic equivalent (MET) hours per week and categorized as sedentary, moderate, or intense based on a list of usual activities per day, over the previous week.
Laboratory Measurements
Venous blood samples (4 ml) were drawn from participants after overnight fasting. The samples were poured into tubes containing EDTA and then centrifuged at 5000 rpm for 5 min. Biomarkers such as TG, HDL-C, LDL-C, TC, and FBS were measured according to a standard laboratory protocol using Pars Azmun kits (Tehran, Iran). Hypertriglyceridemia was considered as TG ≥ 150 mg/dl, FBS ≥ 110 mg/ dl; HDL-C < 40 mg dl for men, and HDL-C < 50 mg/ dl for women and TC > 200 mg/dl (55). LDL-C > 100 mg/dl were considered abnormal levels of serum cholesterol (57).
Calculation Syntax And Gensini Scores
The severity of coronary artery stenosis in participants undergoing angiography was determined based on two scoring criteria: Syntax and Gensini. Atherosclerotic lesions scored according to Gensini, were the percentage of lumen obstruction: 1 point for ≤ 25% obstruction, 2 points for 26–50% obstruction, 4 points for 51–75% obstruction, 8 points for 76–90% obstruction, 16 points for 91–99% obstruction, and 32 points for full obstruction. Scores were multiplied by coefficients 1 to 5 depending on the coronary arteries and obstructed sections. A coefficient of 5 was used for the main left coronary artery, 2.5 for the anterior descending and proximal of the left coronary artery, 1.5 for the mid-segment of the left anterior descending coronary artery, 1 for the proximal right section and 0.5 for other segments. Total Gensini scores were calculated from the sum of scores for stenosis and coefficients for each duct (58, 59). GS ≥ 20 were considered as intermediate - high-risk CAD and < 20 low-risk (60).
According to an online calculator version 2.0, the SYNTAX score was calculated (http://syntaxscore.org/calculator/syntaxscore/frameset.htm). List questions SYNTAX score were regarding functional and anatomical parameters of the obstruction ≥ 50% stenosis of arteries with a diameter of ≥ 1.5 mm. Finally, the SYNTAX score was calculated to sum of all obstruction scores. (Scores < 23 were considered low intensity and ≥ 23 moderate to severe (61, 62). The coronary angiograms were explained by experienced cardiologists who were blinded for some variables except for age and sex.
Assessment Of Other Variables
Demographic data including age, gender, smoking status, jobs, educational levels, menstrual status and intake history of drugs, and other related information to socioeconomic was collected by trained interviewers using a general questionnaire. Blood pressure (BP) was measured before angiography by hospital-experienced nurses according to standard protocol. Subjects with BP ≥ 130 and ≥ 85 mm HG are categorized into systolic and diastolic BP, respectively (55).
Statistical analysis
One-way ANOVA analysis for continuous variables and the chi-square test for categorical variables were used throughout the TaqIB genotypes to compare risk factors of CVDs. Odds ratios with a 95% confidence interval (OR [95%CIs]) of CVD risk factors across genotypes were estimated by binary logistic regressions in crude and multivariable-adjusted models. Hardy–Weinberg equilibrium (HWE) was assessed using the goodness-of-fit test. A p-value < 0.05 was considered significant. All analyses were conducted using SPSS software version 24 (IBM Corporation, USA).