Physical measurements

Antropometric measurements: Height was measured without shoes using a metal scale fastened to the wall. Weight was measured using a heavy duty spring scale. It was calibrated by weights at the beginning of the examination on each research site. The examinee was weighed without shoes in light indoor clothing. In summer, 1 kg and in winter 2 kg were subtracted from the result. The body mass index was calculated as weight divided by height squared (Heliövaara and Aromaa 1981). The measurements were made by 10 nurses and 5 technicians working in turns.

Skinfold thickness (triceps and subscapular, Tanner 1959) was measured by the Harpenden skinfold caliper (British Indicators Ltd, John Bull) with a constant compression of 10 g/mm2 at skinfold thicknesses of 2 – 40 mm. Five technicians alternated and registered the results with a precision of 0,2 mm.

Blood pressure measurement: Prior to the blood pressure measurement the examinee was instructed to refrain from eating, drinking and smoking. Blood pressure was measured before drawing the blood samples and ingesting the glucose load. Blood pressure was measured once by a mercury manometer (Erkameter Original). The size of the rubber bag was 12.5 X 40 cm. The proper functioning of the manometer was checked each morning by raising the pressure to 250 mmHg and lowering it slowly. Systolic blood pressure was recorded at the appearance of the Korotkoff sounds and diastolic at the disappearance of the sounds. The recommended measurement technique (WHO 1962, WHO 1978, Aromaa 1978, Aromaa 1981) was used: Casual blood pressure was measured on the right arm while the person was sitting. The arm rested on the table so that the rubber bag was on heart level. The pressure was raised 30 mmHg above systolic pressure estimated based on the pulse. The observer listened to the Korotkoff sounds by stethoscope and recorded the appearance of sounds as systolic and their disappearance (phase V) as diastolic pressure. Four male technicians carried out the measurements. 

Resting ECG: A 12-lead ECG was recorded for all persons aged 30-59 during the previous examination. The recording was made using an Elema-Schönander Mingograf 34 device. Using an ECG simulator (ECG-Simulator EKS-70, Windsor Locks, Connecticut, USA) the galvanometers was checked daily. The ECG device was adjusted daily. Five male technicians made the recordings.

The ECG strips were classified according to the updated Minnesota code (Rose and Blackburn 1968, The Scandinavian Committee on ECG Classification 1968, Ristola et al. 1980, Reunanen et al. 1983) (Method folder 2.8). Trained observers carried out the ECG coding. Two cardiologists were responsible for the training and supervision. The observers worked in groups of 2 or 3 persons. Each observer independently coded the ECGs, the results were compared and if they differed the final code was agreed together by the group. The cardiologists checked and coded all ECGs where at least one observer had recorded Q- and QS-changes. To assess the reliability, every tenth ECG was reclassified. 

Miniature chest X-ray was taken of everyone except of pregnant women. The miniature X-ray pictures were a 100 x 100 mm shade picture. The device was Elema - Schönander DAT-154; X-ray tube Siemens PH 125/80; miniature picture camera Old Delft Odelca 100 XVIII; development device Kodak X - Omat M5. The x-ray photographing values were120 kV, 150 mA, tube distance 115 cm, focus 1.2 x 1.2 mm, filter 0.7 mm A1. Film was Agfa - Gevaert Scopix T2. 

A front and lateral picture were taken after the ingestion of Microtrast barium paste. The focal distance was 140 cm. To enhance the evaluation of the pictures a centimeter scale was placed in front of the shade plate. The pictures were taken by 5 technicians.
To assess changes of heart size or shape, two radiologists independently classified the pictures using 25 codes of x-ray findings (Aromaa et al. 1978).  A radiologist evaluated lung changes. Spondylosis and hyperostosis were evaluated and classified by an acquainted internist (Julkunen et al. 1975, 1981) (Method folder 1.13).