Measurement and determination of risk factors

The measurement of the risk factors was carried out following all the guidelines and recommendations of the STEPS method (44).

3.14.1. Step 1

Through the application of the STEPS questionnaire, the field implementation teams investigated exposure to four behavioural risk factors: tobacco consumption, alcohol consumption, low consumption of fruits and vegetables, and physical inactivity.

3.14.1.1. Tobacco use

Current and daily consumption, the age of onset of daily consumption, time of cessation of daily consumption and exposure to second-hand smoke in the home and other spaces were investigated.

3.14.1.2. Consumption of alcohol

The consumption of alcohol is established according to periodicity (in the previous year and month) and the number of drinks consumed. The participants were classified as:

● non- or exdrinker: absence of alcoholic beverages during the previous 12 months;

● all respondents drinking at a high level: ≥ 60 g pure alcohol on average per occasion among men and ≥ 40 g among women;

● all respondents drinking at an intermediate level: 40–59.9 g pure alcohol on average per occasion among men and 20–39.9 g pure alcohol among women; and

● all respondents drinking at a lower level: < 40 g pure alcohol on average per occasion among men and

< 20 g pure alcohol among women) (44).

3.14.1.3. Consumption of fruits and vegetables

Teams asked participants about their consumption of fruits and vegetables in a typical week (number of days of consumption and daily portions consumed). To establish risk behaviour, they took account of the current recommendation of daily consumption of at least five servings of fruits or vegetables (44).

3.14.1.4. Physical activity

The STEPS questions on physical activity were adapted from the WHO Global Physical Activity Questionnaire, version 2, which assesses behaviour in three domains: at work (which includes paid and unpaid work, in and outside the home), for transport and during leisure time. To establish the total and the level of physical activity of each participant, metabolic equivalents (METs) per minute were calculated for one week; for this, the weekly minutes of vigorous physical activity were multiplied by 8 METs and the minutes of moderate physical activity and displacements, by 4 METs. (By definition, the movements are considered as moderate-intensity physical activity.) The physical activity of the surveyed population was described using continuous indicators (MET-minutes per week and minutes per week) and category indicators using the following cut-off points to establish the level of physical activity (44).

Participants’ physical activity was said to be high if they met one of the following criteria:

● vigorous-intensity activity for at least three days, reaching a minimum of 1500 MET-minutes per week; or

● ≥ 7 days of physical activity in any domain and intensity, reaching a minimum of 3000 MET-minutes per week.

Participants’ physical activity was said to be moderate if they did not meet the criteria for the high level, but met any of the following three criteria:

● vigorous-intensity physical activity for ≥ 3 days for at least 20 minutes a day;

● moderate-intensity physical activity for ≥ 5 days for at least 30 minutes a day; or

● physical activity of any intensity and domain for ≥ 5 days, reaching a minimum of 600 MET-minutes per week.

Participants’ physical activity was said to be low if they did not meet the criteria stated for the high or moderate levels.

3.14.2. Step 2

Physical measurements of blood pressure, height, weight, and waist and hip circumference were made to evaluate the exposure to biological risk factors: hypertension, overweight and obesity.

3.14.2.1. Blood pressure

Blood pressure (BP) was measured three times, with 15 minutes’ rest after the first measurement and three minutes between the second and third. To establish the alteration of the BP, the following cut-off points were taken into account:

● high: systolic blood pressure (SBP) ≥ 140 mmHg or diastolic blood pressure (DBP) ≥ 90 mmHg; and

● very high: SBP ≥ 160 mmHg or DBP ≥ 100 mmHg.

Teams also inquired about any history of hypertension diagnosis made by a doctor or other health professional To establish the total prevalence of hypertension, teams took account of the figure for high BP and the reported current use of drugs for the control of arterial hypertension (question asked to the participants with a background report of diagnosis). In addition, they determined the prevalence of high BP with and without antihypertensive treatment, and normal blood pressure with antihypertensive treatment.

3.14.2.2. BMI

The calculation of BMI is based on measurements of height and weight in the survey population. The height measurement is made with acrylic height 2 m long, fixed with adhesive tape on surfaces perpendicular to the floor, such as walls or doors, asking the participant to stand without shoes, with his or her body touching the stadiometer. For the measurement of weight, an electronic scale was used, placed on a flat, horizontal and firm surface such as the floor; the participants had to stand in front of the scale screen, at the centre of the scale surface, standing with the heels together, the arms at the sides and chin parallel to the floor.

Before the measurement, the team verified that the participant was not wearing excess clothes, so as not to overestimate the weight.

With the height and weight averages, teams calculated participants’ BMI, classifying them using the following categories (44):

Category BMI (kg/m²)

Underweight < 18.5

Normal weight 18.5–24.9

Overweight 25–29.9

Obesity > 30

3.14.2.3. Waist and hip circumference

For the measurement of the waist and hip circumference, the participant remained standing, with feet together and hands on each side of the body. A 6-mm wide fibreglass retractable tape measure, graduated in centimetres, was placed directly on the participant’s skin at the midpoint between the last rib and the iliac crest to measure the circumference of the waist and in the most prominent part of the waist.

The cut-off points given in Table 8 were used in the measurement of waist circumference to establish the prevalence of waist obesity and to classify the risk of CVD and metabolic alterations related to obesity, according to waist measurement, by sex.

Table 8. WHO cut-off points and risk of metabolic complications

Indicator Cut-off points (cm)

Risk of metabolic complications

Men Women

Waist circumference > 94 > 80 Increased

Waist circumference > 102 > 88 Substantially increased

Waist–hip ratio ≥ 0.90 ≥ 0.85 Substantially increased

3.14.3. Step 3

Step 3 of the STEPS survey included urine and blood testing. Due to fasting requirements for glucose and triglycerides measurements, blood testing was done in the morning of the day after steps 1 and 2 were done.

Participants were asked to fast for 24 hours before blood samples were taken. Fasting venous capillary blood samples were taken to assess blood glucose, HbA1c, triglyceride and cholesterol levels and determine the presence of hyperglycaemia and hypercholesterolemia. These biochemical measurements were performed by dry method using the devices listed in Table 7, including automated instruments for the biochemical sampling by dry method recommended by WHO (44) for this study. The biochemical measurements in step 3 included the following:

● glucose

● cholesterol

● triglycerides

● HDL cholesterol

● HbA1c

● urinary sodium and urinary creatinine

During the STEPS 3 implementation, measurement of BP was repeated three times, with 15 minutes’ rest after the first measurement and three minutes between the second and third.

3.14.3.1. Glycaemia

To determine the prevalence of raised blood glucose, the teams took into account the value of the fasting blood glucose or the current consumption of insulin or other medications to control diabetes (a question asked of participants who reported a history of diagnosis of diabetes by a health professional). In addition, the prevalence of high blood sugar with and without treatment, and normal glycaemia with treatment, was determined. The following cut-off points were used for detecting glycaemia (44):

● impaired fasting glycaemia: plasma venous value ≥ 110 mg/dl and < 126 mg/dl; and

● raised fasting blood glucose: plasma venous value ≥ 126 mg/dl or currently on medication for raised blood glucose.

3.14.3.2. HbA1c

The NHHST also included measurement of HbA1c in step 3 of the survey. The following cut-off point was used for diagnosing glycaemia:

● raised fasting blood glucose: HbA1c ≥ 6.5%.

The study also combined fasting blood glucose and HbA1c and used the following cut-off: raised fasting blood glucose:

● fasting plasma venous glucose ≥ 126 mg/dl or HbA1c ≥ 6.5% or currently on medication for raised blood glucose.

3.14.3.3. Total cholesterol

To determine the prevalence of hypercholesterolemia, the total fasting cholesterol value or the current use of medications or special diet for control was considered, based on a question asked to participants who reported a diagnosis of hypercholesterolemia by a health professional. The cut-off points established in the STEPS manual (44) were used to classify total cholesterol levels, using the dry method:

● raised total cholesterol: ≥ 190 mg/dl or currently on medication for raised cholesterol.

3.14.3.4. Triglycerides

Fasting triglycerides were also measured following the recommended procedure in STEPS and using the cut-off recommended by WHO (44):

● raised triglycerides: fasting triglycerides ≥ 180 mg/dl.

3.14.3.5. HDL cholesterol

To examine low-cholesterol prevalence in the study population, the teams measured HDL cholesterol in STEPS 3 using the cut-off point recommended by WHO (44):

● suboptimal HDL cholesterol: HDL < 40 mg/dl for men and < 50 mg/dl for women.

3.14.3.6. Urinary sodium and creatinine

Urinary sodium and creatinine were measured to determine population levels of high salt intake, a risk factor mainly for hypertension and CVD. Urine samples were sent to the Central Laboratory of Hacettepe University Faculty of Medicine in Ankara in cold chain. The samples were analysed by laboratory technicians, who recorded the results on a tablet PC and uploaded them to the database on the server, to have each participant’s data complete. The identification number of each participant played a crucial role here, since it was the variable used for matching the data.

Levels of sodium and creatinine in spot urine samples are used in STEPS to estimate population 24-hour salt intake, using the following formulas (provided by the WHO Regional Office for Europe):

● estimated 24-hour sodium intake for males: [39.58 + (0.45*urinary sodium (mmol/L)] – [3.09*urinary creatinine (mmol/L)*88.4/1000) + (4.16*BMI) + (0.22*age)]; and

● estimated 24-hour sodium intake for females: [17.02+ (0.33*urinary sodium (mmol/L)] – [2.44*urinary creatinine (mmol/L)*88.4/1000) + (2.42*BMI) + (2.34*age) – (0.03*age)].

The 24-hour sodium values in mmol are divided by 17.1 in order to get grams of salt. As mentioned, WHO recommends an intake of < 5 g salt or < 2 g sodium per person per day.

SURVEY