All individuals were invited for interviews and medical examinations to the TLGS unit. Social workers first familiarized them at home with the study objectives and invited them to participate in the study at the second visit; they were asked to sign a written consent and bring it to the TLGS unit following the first visit. At TLGS unit they underwent:
Each interview was conducted by means of a structured questionnaire to collect demographic data such as personal, educational, occupational, medical, and residential details.
- Medical examination
In this stage, trained physicians collected data on the medical history, blood pressure, peripheral pulse, and thyroid exam. Trained technicians obtained anthropometrical data such as height, weight, hip, and waist sizes. ECG was taken from those aged 30 years and over.
- Blood sampling
Blood samples were drawn after 10-12 hours of fasting and the glucose tolerance test (2hPG) was performed in those aged 20 years and over.
After admission and documentation of personal characteristics and determination of a computer code, a 10-ml sample of venous blood was collected. The samples were kept for one and half hours in normal conditions of the lab. The samples were then centrifuged to separate the sera; all the tests were done daily and some samples (four micro-tubes) were stored in –70C temperature for future studies.