ABC | Volume 112, Nº3, March 2019

Original Article Eickemberg et al Abdominal adiposity and C-IMT in the ELSA-Brasil Arq Bras Cardiol. 2019; 112(3):220-227 as VAI 10 and the lipid accumulation product (LAP) 11 , need to be further explored. The conicity index (C index) stands out as a discriminator of high coronary risk in Brazilian studies, especially when a black population is being investigated. 12 On the other hand, there are no studies that investigated the effect of adiposity diagnosed by this index on CIMT. The aim of this study was to determine the magnitude of the association between abdominal adiposity, according to different diagnostic indicators (WC, WHR, C Index), and between indexes that reflect visceral adipose tissue dysfunction (LAP and VAI) and CIMT among the participants of ELSA-Brazil. Methods Study design and population The ELSA-Brasil study included in its baseline 15,105 civil servants, aged 35-74 years, connected to six teaching and research institutions in three Brazilian regions (South, Southeast and Northeast). More details on the study methodology can be found in an earlier publication. 13 Interviews and collection of anthropometric and biochemical measurements were carried out by a trained and certified team. A more detailed publication is available on the standardization and quality assurance procedures and the quality of uniformization regarding the conducts adopted in the ELSA-Brazil. 14 Exclusion Criteria In order to keep a healthy sample and to avoid biases related to CIMT, of the 10,943 participants with a valid image for both common carotid arteries, we excluded 569 patients who declared having cardiovascular disease, 36 with serum triglycerides > 800 mg/dL, 1,974 patients using lipid‑lowering medication, 144 with BMI > 40 kg/m 2 and 120 who underwent bariatric surgery. To avoid biases related to abdominal fat measurement, 32 participants with body dystrophies and abdominal hernias were excluded. We also excluded the participants who self-declared as having Asian and Native Brazilian ethnicity/skin color due to the small number (297 and 136, respectively), 150 participants who did not declare ethnicity/ skin color and 15 without information on indicators of abdominal adiposity. The final sample consisted of 8,449 participants (Figure 1). Some participants had more than one condition for exclusion. Carotid intima-media thickness (CIMT) All the research centers collected the CIMT measurement using a standardized method, utilizing an Aplio XG™, Toshiba equipment, with a 7.5 MHz linear transducer. The technique used in the study has been published elsewhere. 15,16 For this article, CIMT was defined as the mean of the mean values of the right and left carotid arteries. The 75 th percentile was used to dichotomize this variable according to gender (male: 0.69 mm, female: 0.64 mm). The 75 th percentile was based on technical consensuses and previous studies. 17 Indicators of abdominal adiposity Anthropometric measurements were obtained using standardized equipment and techniques. The WC was measured at midpoint between the inferior border of the costal arch and the iliac crest, at the median axillary line and at the hip circumference at the maximal protrusion of the gluteal muscles, over the trousers of the study clothing. These circumferences were used to calculate the WHR. The C index was calculated using the formula: WC(m)/0.109 x √Weight(kg)/Height(m). 18 The LAP 19 was calculated using gender-specific equations: Men: WC(cm) - 65 x triglycerides(mmol/L); Women: WC(cm) - 58 x triglycerides(mmol/L), as well as the VAI: 19 Men: (WC(cm)/39.68 + (1.88 x body mass index(kg/m 2 ))) x (triglycerides(mmol/L)/0.81) x (1.31/HDL cholesterol(mmol/L)); Women (WC(cm)/36.58 + 1.89 x body mass index(kg/m 2 )) x (triglycerides(mmol/L)/0.81) x (1.52/HDL cholesterol(mmol/L)). The indicators were categorized in the presence and absence of abdominal adiposity, according to the cut-off points defined by Eickemberg et al., 20 Respectively, the following values were used for white, brown and black individuals: WC: men 89.9 cm; 90.2 cm and 91.7 cm; women 80.4 cm; 82.7 cm and 85.4 cm; WHR: men 0.92; 0.92 and 0.90; women 0.82; 0.83 and 0.84; C index: men 1.24; 1.24 and 1.24; women 1,20; 1.22 and 1.19; LAP: men 29.81; 32.39 and 33.08; women 22,64; 30.27 and 27.12; VAI: men 1.74; 2.08 and 1.68; women 1.44; 2.16 and 1.65. We chose to use the term “adiposity” instead of obesity for the five indicators, considering that LAP and VAI reflect the function of visceral fat, and not only the accumulation of abdominal fat, such as WC, WHR and C index. 10,11 Covariates Ethnicity/skin color was self-attributed and categorized as white, brown and black. The level of schooling was categorized as complete college/university education, complete high school and incomplete and complete elementary school. Smoking was stratified as nonsmokers, ex-smokers, and current smokers. Weight and height were measured with participants wearing the study clothing, without shoes and accessories. A Toledo scale and a Seca stadiometer were used for the measurements of weight and height, respectively. These variables were used to calculate adiposity indexes. Blood samples were collected by venipuncture after 12 hours of fasting. Triglyceride and HDL-cholesterol tests were performed by colorimetric enzymatic and homogeneous enzymatic colorimetric methods without precipitation, respectively. LDL-cholesterol levels were obtained using Friedewald’s formula. Triglycerides and HDL-cholesterol were used to calculate the LAP and VAI. Arterial hypertension was defined with amean systolic blood pressure ≥ 140 mmHg and a mean diastolic ≥ 90 mmHg; or if the individual was undergoing antihypertensive treatment. Blood pressure was measured three times, considering the mean of the last two measurements for calcualtion. 15 221