The count of family histories of vascular diseases is an independent de-terminant of susbclinical atherosclerosis

BACKGROUND: The individual cardiovascular risk increases with the numbers of relatives affected by cardiovascular (CV) diseases and with the genealogical proximity of relatives affected. These findings document the importance of genetic/environmental factors, nested in the family, for the development of atherosclerosis or cardiovascular diseases. Several FH items have been associated with an increased risk of CV disease, among these: FH of coronary heart disease (FHCHD), FH of cerebrovascular disease (FHCVD), and FH of peripheral vascular disease (FHPVD). Most of the studies published so far, however, were carried out by considering these FH items one at a time, completely neglecting that a single individuals may be simultaneously exposed to more than one FH items and that these may increase the individual atherosclerosis with an additive or even synergistic effects. In this study we have addressed this issue by investigating whether multiple FH items associates with carotid artery intima media thickness (C-IMT) independently by the personal presence of vascular risk factors and whether these items act with an additive/synergistic effect or not. METHODS: To reach the study objective we have take advantage of the dataset of the IMPROVE project, a European, multicenter, longitudinal, observational study specifically designed to assess whether C-IMT and its change over time associate with vascular events (VEs). The data set includes 3711 individuals free of vascular events (median age 64.4 years; 48% men) followed up for three years. The subject’s FH profile was determined by a face-to-face interviews. The presence of at least one first-degree family member (father, mother, brothers or sisters) affected by CHD, CVD or PVD identified the patient as positive for a specific FH. The total count of FH items (FHcount) was calculated on individual basis. RESULTS: The 21.5% of subjects were free of any family history of vascular diseases, the 50.8% was exposed to one FH item, the 23.8% to two, and the 3.9% to three. In a multivariable general linear model, adjusted for those vascular risk factors which may aggregate at the family level; (i.e. dyslipidemia, hypertension and diabetes), FHCHD, FHPVD but not FHCVD associated with a greater IMT value (both p<0.05) when compared to subjects free of any family history. Regardless of the type of FH item considered, the average value of IMTmean-max increased, step by step, of about 1.02% (95% C.I. 1.00-1.03), moving from subjects without any FH item, to subjects with one, two or three types of family history of vascular diseases (ptrend=0.003). This trend was confirmed also after adjustment for confounders and for the personal history of VRFs (ptrend=0.011), thus suggesting an independent and additive effect of the three FH items in determining the individual atherosclerotic profile. CONCLUSIONS: Regardless the type of items included, the simple count of FH items, may be considered as a new risk factor for carotid IMT which adds over and above each single FH item.