Effects of aging and sex on progression of carotid intima-media thickness: A retrospective 6-year follow-up study

Aim: We retrospectively examined the relationship of aging, sex and risk factors to increased carotid intima-media thickness (IMT) over a follow-up period of 6 years in patients with multiple risk factors. Methods: Subjects were comprised of 463 patients (287 men, 176 women) with a mean age of 64 +/- 0.4 years who had undergone carotid ultrasonography twice or more at intervals of 5 years or older. The mean follow-up period was 6.0 +/- 0.1 years. Results: Mean baseline IMT for all subjects was 1.40 +/- 0.02 mm, and no significant difference was seen between sexes. Mean IMT after 6 years for all subjects was 1.84 +/- 0.03 mm, and was significantly greater in men than in women. Mean annual increase in IMT (Delta IMT) for all subjects was 0.073 +/- 0.005 mm/year, with a significant positive correlation between baseline age and Delta IMT (r = 0.11, P < 0.05), and Delta IMT was significantly greater in men than in women (0.087 +/- 0.007 mm vs 0.050 +/- 0.007 mm, P < 0.001). IMT increased with age in both men and women, but Delta IMT increased with age only in men. Multivariate analysis showed baseline age and diabetes mellitus as significant risk factors with baseline IMT as the objective variable. Age and sex represented significant risk factors with Delta IMT as the objective variable. Conclusion: Sex differences exist in the relationship between increases in IMT and age. Age, sex and diabetes mellitus represented the main risk factors.