Family burden of cardiovascular mortality: risk implications for offspring in a national register linkage study based upon the Malmö Preventive Project

OBJECTIVE: To investigate the adjusted relative risk of cardiovascular disease (CVD) events in offspring of parents with cardiovascular mortality before 75 years. SETTING: The city of Malmö, Sweden. DESIGN: A follow-up study based on register linkage analyses. SUBJECTS AND METHODS: In the Malmö Preventive Project (MPP), a total of 22,444 men and 10,902 women attended the screening programme between 1974 and 1992. At the screening conventional risk factors for CVD were measured (blood pressure, lipids, glucose, smoking and social class). MAIN OUTCOME MEASURES: Parental CVD mortality was determined via register linkage analysis between the Multiple-Generation Register and the National Mortality Register (NMR). CVD events (morbidity and mortality) in offspring were collected from national registers. The relative risk for CVD events in offspring, in relation to parental CVD mortality, was adjusted for age and risk factors at screening. RESULTS: The age-adjusted relative risk (RR; 95%CI) for a son to experience a CVD event was increased in relation to a maternal positive family history of CVD mortality before 75 years when compared with no maternal history, RR 1.74 (1.43-2.11). This RR decreased to 1.51 (1.23-1.84; P < 0.001) after full adjustment for risk factors. The corresponding fully adjusted RRs for father-son heritage was RR 1.22 (1.02-1.47; P < 0.05), mother-daughter RR 0.87 (0.54-1.41), and father-daughter RR 1.20 (0.83-1.73). CONCLUSION: The existence of maternal CVD mortality before the age of 75 years implies a substantial risk increase for CVD morbidity and mortality in sons that cannot be explained by social background, lifestyle, or conventional cardiovascular risk factors in the adult offspring.