Familial aggregation of carotid intima media thickness is better appreciable in young generational pairs

AIM: Carotid intima media thickness (C-IMT) aggregates at family level. It has been reported that the amount of offspring C-IMT variability explained by parents' C-IMT ranges from 20 to 92%. To assess whether this wide range of association is related to the age of generational pairs studied, we compared the amount of offspring C-IMT variability explained by parents’ C-IMT detected in “young generational pairs” (offspring in paediatric age) with that of “old generational pairs” (parent in geriatric age). METHODS: We studied 201 individuals from 67 families, each consisting of a grandchildren, a parent and a grandparent. Each of them had C-IMTmean and C-IMTmax measured. The amount of offspring C-IMT variability explained by C-IMT of parents was expressed in terms of squared correlation coefficients (r2). The r2 of young and old generational pairs were then compared. RESULTS: The mean age (±SD) of grandparents, parents and children was 70±8.3, 44±9.1 and 14±8.7, respectively. The corresponding figures for C-IMTmean was 1.17±0.19 mm, 1.11±0.35 mm and 1.06±0.28 mm, respectively. C-IMT variables of parents correlated with C-IMT of their offspring just in the young generational pairs (C-IMTmean: r2=0.34 p<0.0001; C-IMTmax: r2=0.21, p=0.001) but not in the old generational pairs. Analogous results were obtained when the analyses were repeated in groups homogeneous for gender (father Vs. son, mother Vs. daughter, etc). CONCLUSIONS: Familial aggregation of C-IMT is appreciable only in young generational pairs. This might be due to the fact that in older generational pairs, familial aggregation is masked by a higher prevalence of environmental confounders.