The SA Journal Diabetes & Vascular Disease Vol 12 No 1 (July 2015)

VOLUME 12 NUMBER 1 • JULY 2015

RESEARCH ARTICLE

SA JOURNAL OF DIABETES & VASCULAR DISEASE

Agostinho Neto University, Luanda, Angola to be submitted to clinical

and laboratorial examinations to identify cardiovascular risk.

A total of 615 subjects with complete data were included in this

study. Details of the study design are described elsewhere.

26,27

The

study was conducted according to the tenets of the Declaration

of Helsinki and participants signed an informed consent form

approved by the Ethics Committee of the Faculty of Medicine,

Agostinho Neto University.

Clinical examinations were performed between 08:00 and noon

in temperature-controlled rooms (22–23°C) after a 12-hour fast.

Participants were asked to refrain from smoking, physical exercise

and caffeinated beverages for at least 12 hours before the visit.

Venous blood samples were obtained from the forearm by standard

techniques and processed immediately using commercially

available kits (BioSystems SA, Costa Brava 30, Barcelona, Spain)

for determination of levels of serum triglycerides, total cholesterol,

high-density lipoprotein cholesterol (HDL-C), glucose, creatinine

and uric acid.

Biochemical parameters were analysed using enzymatic methods

on a spectrophotometer (BioSystems BTS-310, Barcelona, Spain). In

subjects with triglyceride levels < 400 mg/dl, low-density lipoprotein

cholesterol (LDL-C) was calculated according to Friedewald’s

formula,

and very low-density lipoprotein cholesterol (VLDL-C)

was calculated as previously described.

Diabetes was defined as a fasting glucose level ≥ 126 mg/dl

or the use of antidiabetic drugs.

Dyslipidaemia was defined as

the presence of one or more of the following: total cholesterol ≥

200 mg/dl, triglycerides ≥ 150 mg/dl, LDL-C ≥ 160 mg/dl, or HDL-C

< 40 mg/dl (men), < 50 mg/dl (women).

Demographics including socio-economic level, educational data

and medical history were collected using a structured questionnaire.

Participants were classified as non-smokers (never and ex-smokers)

and current smokers (daily and occasional smokers).

Anthropometric measures included weight, height, WC and hip

circumference (HC), obtained from individuals wearing underwear

and no shoes. Weight was measured to the nearest 0.1 kg using a

previously calibrated mechanical scale (SECA GmbH & Co, Germany)

with a maximum capacity of 220 kg.

Height was measured with a precision of 0.5 cm using a

stadiometer fixed to the SECA scale. WC and HC were each

measured twice using an inextensible, 1-cm-wide tape measure.

The WC was measured at the end of normal expiration, at the

midpoint between the lower border of the rib cage and the top of

the iliac crest,

and recorded nearest to the 0.1 cm. The waist:hip

ratio (WHR) was calculated from the WC and HC.

BMI was calculated as the weight divided by the square of the

height (kg/m

). According to BMI values, individuals were classified

as normal (18.5–24.9 kg/m

), overweight (25.0–29.9 kg/m

) and

obese (≥ 30.0 kg /m

Socio-economic status was classified into quartiles according

to average monthly household income;

first quartile (low socio-

economic class), second quartile (middle class), third quartile

(upper middle class), and fourth quartile (upper class). Education

was classified into three levels based on the number of years of

education: low (≤ four years of education), middle (five to 12 years

of education), and high (≥ 13 years of education).

Blood pressure and heart rate were measured in triplicate in

the non-dominant arm after five minutes of resting in a seated

position with the arm at the level of the heart. These parameters

were measured using a validated, automated digital oscillometric

sphygmomanometer (Omron 705CP, Tokyo, Japan). The readings

were repeated at three-minute intervals. The mean of the last two

readings was recorded.

The pulse pressure (PP) was computed as the difference between

basal systolic blood pressure (SBP) and diastolic blood pressure

(DBP). Mean blood pressure (MBP) was computed as the DBP +

(PP/3). Hypertension was defined as SBP ≥ 140 mmHg, and/or DBP

≥ 90 mmHg, and/or the use of antihypertensive drugs.

Both the ATP III

and JIS

criteria were used to define the metabolic

syndrome. The ATP III definition was based on the presence of

three or more of the following components: WC > 102 cm (men),

88 cm (women); SBP ≥ 130 mmHg and/or DBP ≥ 85 mmHg and/

or BP-lowering treatment; fasting triglyceride levels ≥ 150 mg/dl or

treatment for hypertriglyceridemia; HDL-C < 40 mg/dl (men), 50 mg/

dl (women), or treatment for dyslipidaemia; fasting glucose level ≥

110 mg/dl or on antidiabetic medication.

The JISdefinition was based on the presence of three or more of

the following components: WC ≥ 94 cm (men), 80 cm (women);

SBP ≥ 130 mmHg and/or DBP ≥ 85 mmHg and/or BP-lowering

treatment; fasting triglyceride levels ≥ 150 mg/dl or treatment for

hypertriglyceridaemia; HDL-C < 40 mg/dl (men), 50 mg/dl (women)

or treatment for dyslipidaemia; fasting glucose level ≥ 100 mg/dl or

on antidiabetic medication.

Statistical analysis

Data were analysed using SPSS software, version 13.0 (SPSS Inc,

Chicago, IL). Continuous variables are reported as mean ± standard

deviation, and compared by gender using the independent-

samples

test. Categorical variables were expressed as proportions

Table 1.

Characteristics of the participants according to gender

Characteristics

All

Men

Women

-value

Number (%)

615 (100)

294 (47.8)

321 (52.2)

0.392

Age (years)

44.5 ± 10.6

45.1 ± 11.1 44.0 ± 10.1 0.176

Weight (kg)

68.6 ± 15.3 68.0 ± 14.9 69.2 ± 15.7 0.349

Height (cm)

163.3 ± 7.9 167.4 ± 7.1 159.6 ± 6.6 < 0.001

WC (cm)

82.1 ± 13.3 80.1 ± 12.9 83.9 ± 13.5 < 0.001

HC (cm)

95.7 ± 11.3 91.5 ± 9.4 99.5 ± 11.4 < 0.001

WHR

0.86 ± 0.09 0.87 ± 0.08 0.84 ± 0.09 < 0.001

BMI (kg/m

)

25.7 ± 5.4 24.1 ± 4.3 27.1 ± 5.8 < 0.001

SBP (mmHg)

134.7 ± 24.9 136.5 ± 22.7 133.0 ± 26.6 0.087

DBP (mmHg)

82.6 ± 14 82.7 ± 14.2 82.5 ± 13.8 0.862

PP (mmHg)

52.1 ± 14.9 53.8 ± 13.2 50.5 ± 16.2 0.007

MBP (mmHg)

100.0 ± 16.9 100.6 ± 16.4 99.4 ± 17.5 0.351

Heart rate (bpm)

68 ± 10

67 ± 10

69 ± 10 0.003

Glucose (mg/dl)

94.0 ± 21 94.9 ± 20 93.2 ± 21.8 0.313

Creatinine (mg/dl)

1.1 ± 0.2

1.2 ± 0.2

1.0 ± 0.2 < 0.001

Uric acid (mg/dl)

5.4 ± 1.7

6.1 ± 1.7

4.8 ± 1.4 < 0.001

TC (mg/dl)

191.5 ± 38.9 189.5 ± 41.4 193. 2 ± 36.5 0.239

HDL-C (mg/dl)

46.0 ± 10.9 44.1 ± 10.3 47.6 ± 11.2 < 0.001

LDL-C (mg/dl)

125.5 ± 40.1 125.0 ± 41.8 125.9 ± 38.7 0.796

VLDL-C (mg/dl)

20.0 ± 8.0 20.4 ± 8.3 19.7 ± 7.7 0.339

TGL (mg/dl)

100.2 ± 40.0 101.8 ± 41.7 98.7 ± 38.4 0.339

Values are means ± standard deviation. WC, waist circumference; HC, hip

circumference; WHR, waist-to-hip ratio; BMI, body mass index; SBP, systolic

blood pressure; DBP, diastolic blood pressure; PP, pulse pressure; MBP, mean

blood pressure; TC, total cholesterol; HDL-C, high-density lipoprotein cho-

lesterol; LDL-C, low-density lipoprotein cholesterol; VLDL-C, very low-density

lipoprotein cholesterol; TGL, triglycerides.