Cardiometabolic risk factors (RF) have been widely studied nowadays, with special focus on central obesity, excessive weight, dyslipidemia, Systemic Arterial Hypertension (SAH), insulin resistance and Diabetes Mellitus (DM).1^-4 Central obesity, especially visceral adipose tissue (VAT), represents a health risk due to its metabolic and endocrine capacity, contributing to the development of an atherogenic profile, in addition to being strongly associated with cardiovascular morbidity and mortality.5^,6

Roriz et al.,7 highlight that metabolic changes that promote the onset of chronic diseases are more related with visceral adipose tissue than with excessive weight, and that these conditions increase the need for drug treatment and interfere in the quality of life of individuals.

The individuals with high VAT levels tend to have insulin resistance, hyperglycemia, hypertriglyceridemia, increased low density lipoprotein (LDL) serum levels and reduced high density lipoprotein (HDL-C) concentration.8 HDL-C reduction in viscerally obese patients represents the main factor responsible for increased total cholesterol/HDL-C ratio, and this relationship is a strong risk predictor for cardiovascular disease.5^,6^,9

According to Piepoli et al.,10 age is the main cardiovascular risk factor and most individuals aged 65 years are already considered at high risk. Thus, it is of major relevance to determine the associations of metabolic RF with advanced age, especially among the population in the northeast of Brazil, where there are no studies in this context, due to its negative influence on functional capacity, as well as to the costs incurred to the Brazilian Unified Health System (SUS) for its treatment.11^-14

The objective of this study is to determine the association between central obesity and biochemical markers of cardiometabolic risk in elderly patients treated at a geriatric outpatient clinic in the city of Lagarto-SE.

This is a cross-sectional, primary data collection study, composed by a sample selected by convenience of 159 elderly individuals (aged ≥ 60 years), of both sexes, treated at a geriatric outpatient clinic in the city of Lagarto-SE.

The inclusion criteria used in the research were: patients aged ≥ 60 years, registered at the reference outpatient service and who accepted to participate voluntarily. The exclusion criteria were: patients with abdominal injury or tumors, hepatomegaly and/or splenomegaly, ascites and those who had undergone abdominal surgery recently which could compromise the verification of abdominal fat measures.

The data were collected using a standardized questionnaire, applied by duly trained individuals, following standardized procedures for data collection, such as quality control measures and consistency of information.

The selected covariables were: sex (male and female), age in complete years, self-referred skin color (black; non-black), education (uneducated/Incomplete middle school, complete middle school/Incomplete high school, complete high school or more), occupation (receiving assistance/Organic Law of Social Assistance - LOAS), retired, living on income or pension).

Central adiposity (the accumulation of adipose tissue in the abdominal region) was considered an independent variable, determined by waist circumference (WC) measurement, using an inelastic anthropometric tape (Cescorf, Brazil), in accordance with the measurement techniques proposed by Lohman et al.,15 and classified according to the International Diabetes Federation (IDF) criteria16 for South American individuals, when WC ≥ 80 cm and ≥ 90 cm for women and men, respectively.

Total cholesterol (TC), LDL-C, HDL-C, Non HDL-C, Triglycerides (TG), Glucose and Castelli's I and II risk indexes were considered dependent variables, obtained upon request and/or through analysis of data contained in the geriatric medical record, over a period of less than one month from data collection. To perform the classification, the criteria established by the V Brazilian Guidelines on Dyslipidemia and Atherosclerosis Prevention17 and by the Brazilian Diabetes Society Guidelines18 were used: TC < 200 mg/dL; LDL-C < 160 mg/dL; HDL-C > 40 mg/dl in men and > 50 mg/dl in women; non-HDL-C < 130 mg/dL, TG < 150 mg/dL and Glucose < 100 mg/dL.

Castelli risk index-I (CRI-I) is calculated as TC/HDLc and Castelli risk index-II (CRI-II), as LDLc/HDLc. TC/HDL-C ratio > 4.7 and LDL-C/HDL-C ratio > 3.1 indicate high metabolic risk.

The sample was characterized as individuals with or without central obesity. Thus, out of the 159 of the elderly assessed, central obesity was present in 43.2% of men and 56.8% of women (p = 0.002), with a higher prevalence among black patients (56.8%), uneducated/incomplete middle school (90.4%), retired (87.9%) and with excessive weight (51.2%) (p < 0.001) (Table 1).

The individuals' mean age was 70.9 ± 7.5 years. When the mean values of biochemical markers were assessed, no statistical significance was observed for individuals with or without central obesity (Table 2).

A significant statistical association was observed between the HDL-C (p = 0.019), Castelli's index I (p = 0.040) and central obesity among the elderly (Table 3). These and the non-HDL-C were included in the logistic regression model (Table 4), which showed a positive association between central obesity and low HDL-C (OR = 2.48; CI 95%: 1.15-5.37) and increased TC/HDL-C ratio (OR = 3.13; CI 95%: 1.01-9.76).

The association between central obesity and biochemical changes has been widely discussed nowadays19^-21, since visceral fat produces adipocytes which, in turn, are directly linked with inflammatory processes and cardiometabolic complications .22

In this sense, this study contributes with the scientific literature because it shows a positive correlation between central obesity and the biochemical markers HDL-C and Castelli's index I. A similar association was observed by several authors22^-24 who identified a positive correlation between WC and the lipid variables: TC, LDL-C, Non-HDL-C and TG. Roriz et al.,7 also observed an association between the visceral adipose tissue (VAT) area and Glucose, TG and uric acid. However, the biochemicals TC, LDL-C, HDL-C and VLDL-C did not present results with statistical significance.

Castelli's index I was adopted in this study because it is considered a major risk predictor for cardiovascular disease,5^,9 since HDL-C concentrations are inversely proportional to the incidence of atherosclerosis, due to its essential role in protecting the vascular bed, through cholesterol reverse transport.25 In this process, the HDL-C removes the oxidized lipids of LDL, inhibits the fixation of adhesion molecules and monocytes to the endothelium and stimulates the liberation of nitric oxide.26 In this context, the data presented are in line with the authors mentioned before, since in the logistic regression analysis we observed that the individuals with central obesity were 2.48 (p = 0.021) and 3.13 (p = 0.049) times more likely to develop changes in HDL-C and Castelli's I index, respectively. Similarly, Cabral et al.,27 when assessing the association between the phenotype hypertriglyceridemic-waist (HTW) and the cardiometabolic risk in women, also observed a prevalence ratio (PR) of 3.41 (CI 95%: 2.42-4.81) for the HDL-C.

These data corroborate the study conducted by Silva et al.,14 with older patients with type 2 diabetes, in which 55.6% of men and 76.6% of women (p = 0.024) presented increased cardiovascular risk according with Castelli's index I. However, few studies have used this relationship for predicting the cardimetabolic risk and/or its association with central obesity, which makes it difficult to compare the results with this variable.

The high prevalence of central obesity observed in this study was also seen in 51.9% of the individuals in a study carried out by Pinho et al.,28 Similar results were presented by Ding et al.,1 in a multicentric study performed with 12,607 Chinese adults. It is worth mentioning that, although this is applicable to both sexes, these results are more often found in women.4^,24 Corroborating this statement, in a study performed by Soar,4 the prevalence of abdominal adiposity was statistically higher in older women (76.16%) (p = 0.00). These data agree with those of Cabral,27 in whose study 67.4% of women also presented high WC. In a study carried out only with elderly patients, Souza29 observed that the majority of them (91.2%) also had central obesity.

This heterogeneity of abdominal fat distribution between the sexes may be due to the higher body-fat percentage in women as a result of hormonal differences, pregnancy, menopause and the climacteric period.30

Therefore, it is worth highlighting the importance of promoting healthy eating habits and lifestyle to reduce cardiometabolic risk factors in the population and, consequently, reduce hospitalization and mortality rates. As evidenced in a study developed in Canada, which assessed the association between adopting healthier lifestyle and decreased cardiovascular RF, for each increase of one healthy lifestyle habit, WC decreased by 4.0 cm and 4.8 cm for men and women, respectively. A decrease in TC of 0.2 mmol/L, in non-HDL-C of 0.2 mmol/L and in TG of 0.1 mmol/L was also observed.31

Piepoli et al.,10 contributing to these data, highlight that, in the last three decades, more than half of the decline in CVD mortality was attributed to changes in risk factor levels in the population, especially reduction in cholesterol levels, blood pressure and smoking.

The results of this study are added to others, thus aggregating scientific evidence of correlation between central obesity and changes in the biochemical markers of metabolic risk of older patients, which reinforces the adoption of WC measurements in clinical practice and in epidemiologic studies, due to its ease of application, practicality, accuracy and low cost. However, these results should be carefully analyzed, since this study used a cross-sectional design, which does not allow for causal inferences to be made. Besides, the biochemical data may have been affected by medication taken by the patients. Hence, more robust cohort studies are required to further investigate these parameters, including lifestyle, smoking and blood pressure assessments, as recommended by the European Society of Cardiology and other Societies on Cardiovascular Disease Prevention in Clinical Practice.10

We conclude that there was an association between central obesity and biochemical markers of cardiometabolic risk in the elderly patients who participated in the study. The findings suggest the need for better monitoring of these markers, as well as of VAT accumulation, even considering the use of more accurate measurement techniques, such as computed tomography and magnetic resonance, so that adequate health strategies can be provided in order to reduce the number of hospitalizations and deaths by these causes.