1.2. Marco teórico
1.2.1.4. Beneficios tributarios
1.2.1.4.3. Equidad
The multi- centre study was conducted in 2009 and took place in 150 PHHC’s in Riyadh, Saudi Arabia.
6.5.
Ethical approval for the Biomarkers Screening in
Riyadh Survey (2009)
Ethical approval was obtained from the Ethics Committee of the College of Medicine Research Centre, King Saud University, Riyadh, KSA (available in Appendix 4).
6.6.
Participant selection of the Biomarkers Screening in
Riyadh Survey
(2009)
A total of 14060 Saudis aged ≥ 6 years old were randomly selected from the roster of 150 PHCC’s of Riyadh city. For each PHCC, a physician invited participants from randomly selected households (alternate houses). The number of subjects collected from each PHCC was dependent on the total population assigned to the respective PHCC.
Chapter 6: The biomarkers screening in Riyadh (2009) survey methods
6.7.
Data collection of the Biomarkers Screening in Riyadh
Survey
(2009)
Consenting participants were requested to arrive at their local PHCC’s in an overnight fasting state. Physicians and trained research nurses collected socio-demographic, anthropometric, dietary, and biochemical data.
6.8.
Socio-demographic measurements and medical history
Physicians and research nurses completed a questionnaire (available in Appendix 1) which assessed age, sex, marital status, consanguinity, occupation, annual income, education level, medical family history (diabetes, hypertension, hyperlipidemia, obesity, coronary heart disease, cancer, asthma and other diseases), participants medical history (diabetes, hypertension, renal disease, liver disease, dyslipidemia, coronary heart disease, cancer, asthma and other diseases) and smoking habits (cigarette smoker, shisha smoker, ex-smoker, non-smoker, number of packs/shisha per day, duration of smoking/quitting).
6.9.
Anthropometric measurements
Trained research nurses recorded anthropometric measurements. Measurements included body weight (kg), height (cm), waist circumference (cm), hip circumference (cm), and sagittal abdominal diameter (cm). Body weight was measured to the nearest 0.1 kg using a Standardized Detecto Balance Beam scale, with participants wearing light clothing. A Standardized Stadiometer was used for height measurements.
Chapter 6: The biomarkers screening in Riyadh (2009) survey methods
Participants were required to stand upright on a flat surface with no shoes on and the back of their heels on the Stadiometer, height was measured to the nearest 0.5 cm. Waist and hip circumference was measured using a standardized measuring tape to the nearest centimeter. Participants were required to stand upright, feet together, arms to the side and relax their abdomen. Waist circumference measurements were taken midway between the lowest rib and iliac crest. Female’s hip measurements were taken at the level of greater trochanters, whist male’s measurements were taken 2-3 inches below the navel.
The research nurse measured the sagittal abdominal diameter (cm) using an abdominal caliper. Participants were in a supine position, and were requested to bend their knees to a 45° angle and to keep their feet flat on the examination table. Sagittal abdominal
diameter was recorded as the distance between the blades of the caliper at the end of normal expiration. Body mass index (BMI) was calculated to define overweight and obesity; weight (kg) divided by height (m2) in squared meters (WHO 2004).
6.10.
Dietary measurements
Dietary intake was assessed using a semi quantitative food frequency questionnaire (FFQ) which was specifically developed for the survey (available in Appendix 2). The FFQ was completed by physicians, and trained research nurses. The FFQ measured the intake (quantity) of various food groups on a daily, weekly and monthly basis. The type and quantity of food groups were assessed. The type of dietary intake was assessed on the basis of fat content, sugar intake, type of food (e.g. grains), and cooking methods. Portion size was reported as grams, litres, and servings (e.g. cups, teaspoons, pieces). The included food groups in the FFQ were bread (e.g. white bread, brown bread),
Chapter 6: The biomarkers screening in Riyadh (2009) survey methods
cereals (e.g. corn flakes, bran flakes, porridge), meat (e.g. beef, sausage, kebab), seafood (e.g. white fish, canned fish, shrimps), vegetables (e.g. potatoes, peas, green leafy vegetables), fruits (e.g. apples, watermelon, canned fruits), traditional meals (e.g. gereesh, humus, falafel), fast food meals (e.g. pizza, burgers), bakery items (e.g. biscuits, sweets, cake), eggs and dairy products (e.g. eggs, milk, yogurt, cream) , fat and oils (e.g. animal fat, vegetable fat), soups and dressings (vegetable soup, lentil soup, curry sauce), beverages (e.g. tea, coffee, soft drinks, juice) and water intake (e.g. tap water, bottled water).
6.11.
Biochemical and physiological measurements
Consenting participants were invited to their PHCC in a 10-hour overnight fasted state. Biochemical measurements were assessed using standard laboratory procedures. Blood was drawn by trained nurses, centrifuged and processed on the same day. Whole blood and serum were placed in plain polystyrene tubes and stored in freezers at -20° C. The
lipid profile (triglycerides – TG, total cholesterol - TC, high density lipoprotein cholesterol - HDL-C, and low-density lipoprotein cholesterol - LDL-C) and fasting blood glucose (FBG) were assessed and quantified using routine laboratory analysis (Konelab, Espoo, Finland). LDL-C concentrations were measured using Friedewald’s formula. The biochemical analyser was calibrated routinely prior to the analysis of all serum samples using quality control samples provided by the manufacturer (ThermoFisher Scientific, Espoo, Finland). For validation purposes, randomized samples were sent to King Faisal Specialist Hospital and Research Centre, Riyadh, KSA which served as a reference laboratory. Research nurses measured blood pressure using a clinical mercury manometer. Systolic and diastolic blood pressures were taken twice and the average of both readings was recorded.
Chapter 6: The biomarkers screening in Riyadh (2009) survey methods
6.12.
Clinical diagnosis of chronic conditions
The diagnostic criteria for type 2 diabetes mellitus (T2DM) and impaired fasting glucose (IFG) were based on the World Health Organization (WHO) proposed cut-off values for the newly diagnosed (FPG levels of ≥ 7.0 mmol/L (126 mg/dL); IFG with a FPG between 6.1-6.9 mmol/L (110-125 mg/dL); non-diabetics with a FPG of < 6.1 mmol/L (110 mg/dL) (WHO 2006), along with self-report of physician diagnosis and/or intake of anti-diabetes medications.
Participants were considered as having abnormal lipid levels if they self-reported dyslipidaemia or intake of lipid lowering drugs or had lipid levels in the following ranges TC ≥ 5.2 mmol/L and/or TG ≥ 1.7 mmol/L and/or LDL-C ≥ 2.6 mmol/L and/or HDL-C < 1.03 (Expert Panel on Detection 2001). Hypertension diagnosis was based on the recommendations of the Seventh Joint National Committee on Pre vention, Detection, Evaluation, and Treatment of High Blood Pressure (Chobanian et al. 2003). Participants were diagnosed with hypertension if systolic blood pressure was > 140 mmHg and/or diastolic blood pressure of > 90 mmHg, or if participants were on anti- hypertensive mediations. Participants were classified as being underweight if BMI < 18 kg/m2, normal weight if BMI 18.5-24.9, overweight if BMI 25-29.9 kg/m2, and obese if
BMI ≥ 30 kg/m2 based on WHO classifications (WHO 2004).