Background: In individuals whose relatives have experienced heart disease, levels of classic risk factors may have been underestimated because of life style changes after serious family disease or inaccurate disease reports.
Methods: To overcome pitfalls noted in previous research, risk factors were measured at a screening of the general population aged 20-52 years in four Norwegian municipalities. After 12 years of follow-up, a first myocardial infarction was evident in 51 of 753 sibships and in 68 of 1518 spouse pairs.
Results: Multiple adjusted means were higher in men with than in men without a brother or sister who became affected: 7.17 versus 6.84 mmol/l (P=0.07) for serum total cholesterol, 140.8 versus 135.6 mmHg (P=0.02) and 85.7 versus 82.5 mmHg (P=0.04) for systolic and diastolic blood pressure. Total cholesterol readings were higher the younger (P < 0.01 ) the sibling who experienced heart disease. Elevations were less pronounced in women, but smoking was more frequent among wives of affected than wives of unaffected husbands (58.3% versus 41.2%, P<0.01).
Conclusions: The markedly adverse levels of modifiable risk factors found in individuals whose brothers or sisters developed heart disease offer a potential for prevention in families with heart disease.