Age and Sex Differences in Carotid Intima-Media Thickness: A Systematic Review and Meta-Analysis

Ageing is a significant risk factor for carotid atherosclerosis, affecting over a billion people worldwide. Carotid intima-media thickness (cIMT) is a surrogate marker for cardiovascular disease (CVD) risk, with age- and sex-related differences in levels and progression. The onset of clinical manifestations of CVD in women is delayed by about 10 years compared to men. The present study aims to evaluate whether subclinical atherosclerosis is the same disease in men and women or two pathologies with a possible different etiology. For this purpose, we analyzed the differences in cIMT, the impact of patient characteristics, and the influence of age on cIMT in men and women.

A systematic search related to cIMT measured by an ultrasound and gender-specific differences was conducted according to the PRISMA 2020 guidelines. Ninety studies, enrolling 165,551 subjects (76,955 men and 88,553 women), were included in the quantitative synthesis.

We found that men compared to women had greater common cIMT, (standardized mean difference (SMD) = 0.506, p < 0.03; I²: 98.2, p < 0.0001), greater bifurcation IMT (SMD = 1.056, p = 0.022; I²: 99.9%, p < 0.001), and higher internal cIMT (SMD = 1.124, p = 0.017; I²: 99.9%, p < 0.001). The study did not reveal any association between cardiovascular risk factors and differences in cIMT between men and women. A virtual analysis revealed that age-related cIMT is equal between sexes but postponed by 10 years in women.

This study showed that classical risk factors for CVD have a comparable effect on cIMT in men and women. While subclinical atherosclerotic disease, as assessed by cIMT, is essentially identical in the two sexes, it manifests itself by about 10 years later in women.