For every patient included in the VaMIS cohort, a person from the community was invited to participate as a control subjects in the study. This person was randomly chosen from the Swedish National Population Register among the citizens of the same sex, age, and municipality as the VaMIS patient. If the invited person had a history of previous myocardial infarction, a second individual was invited (to be a control subject in the VaMIS study). However, not only the second but also the first control subject was examined according to the study protocol.
Initially, control subjects were included for all VaMIS patients. However, it soon became clear that older individuals often rejected the invitation. As a consequence, we decided to only invite control subjects for patients of ≤ 80 years of age. During the time between November 2005 and May 2011, a total of 855 individuals were included as control subjects.
The participants underwent extensive examinations including:
- A questionnaire regarding previous and current medical problems, medication, tobacco and alcohol habits, physical activity, heredity, quality of life, type D personality, etc.
- Measures of height, weight, waist, and hip. Blood pressures in arms and ankles
- Half of the control subjects (a randomized sample) underwent ambulatory 24-hour blood pressure monitoring
- Dynamic and static spirometry
- 12 lead resting ECG
- Ultrasonographic examinations of the heart (echocardiography) and arteries (carotid arteries, renal arteries, and abdominal aorta)
- Oral glucose tolerance test (measuring blood glucose in fasting state before and 120 minutes after intake of 75 g glucose)
- Blood analyses (including hemoglobin, leukocytes, creatinine, troponin I, HbA1c, total cholesterol and its fractions, triglycerides, apolipoproteins, CRP, cystatin C, NT-proBNP, insulin, proinsulin). In addition, blood samples are stored, aliquoted to microtubes, in freezers in the Ice hotel at the Uppsala Biobank, Uppsala, Sweden for future analyses.