Impact of cardiovascular risk factors on carotid intima-media thickness: sex differences

Abstract

Background and purpose: There has been growing interest in the sex-related differences in the impact of cardiovascular (CV) risk factors on carotid intima-media thickness (CIMT). Therefore, we aimed at examining the influence of CV risk factors on CIMT in men and women and identifying differences between males and females in the risk profiles affecting CIMT.

Patients and methods: The study group consisted of 256 patients (mean age 54.7 years), including 134 females (52%), with the following CV risk factors: arterial hypertension, type 2 diabetes mellitus, dyslipidemia, nicotine addiction, overweight, and obesity. Subjects with the history of any overt CV disease were excluded. CIMT was measured through B-mode ultrasound examination of the right common carotid artery. In the analysis of CIMT values at different ages, the patients were divided into three age groups: 1) <45 years, 2) 45-60 years, and 3) >60 years. Regression analysis was used to examine the influence of CV risk factors on CIMT in men and women.

Results: CIMT increased with age in both men and women. Women had lower values of CIMT than men (0.54 mm vs 0.60 mm, P=0.011). The analysis in three age subgroups revealed that CIMT values were comparable in men and women in group 1 (0.48 mm vs 0.48 mm, P=0.861), but over the age of 45 years, CIMT values became significantly lower in women compared to men (group 2: 0.51 mm vs 0.63 mm, P=0.005; group 3: 0.63 mm vs 0.72 mm, P=0.020). Significant differences were observed between the sexes in terms of risk factor impact on CIMT. In men, only three factors significantly affected CIMT: age (b=+0.009, P<0.0001), hypertension (b=+0.067, P<0.05), and type 2 diabetes (b=+0.073, P<0.05). In women, apart from age (b=+0.008, P<0.0001) and type 2 diabetes (b=+0.111, P<0.01), significant factors were pulse pressure (PP; b=+0.005, P<0.0001), body mass index (b=+0.007, P<0.05), increased waist circumference (b=+0.092, P<0.01), and metabolic syndrome (b=+0.071, P<0.05). In the multiple regression analysis, independent CIMT determinants for the entire group were age (β=0.497, P<0.001) and body mass index (β=0.195, P=0.006). For males, age was the only independent determinant of CIMT (β=0.669, P<0.001). For females, these were PP (β=0.317, P=0.014), age (β=0.242, P=0.03), and increased waist circumference (β=0.207, P=0.048).

Conclusion: CIMT values are lower in women than in men, which is most pronounced over the age of 45 years. There are sex-related differences in the profile of CV risk factors affecting CIMT: in males, CIMT is mostly determined by age, while in females, by age, PP, and increased waist circumference.

Keywords: carotid intima media thickness; risk factors; sex differences.

Figure 1

CIMT (median) changes with age in female and male patients. Abbreviation: CIMT, carotid intima–media thickness.

Figure 2

Correlation diagram of CIMT and age in male and female patients. Abbreviations: CIMT, carotid intima–media thickness; F, females; M, males.