Background and aims: Postmenopausal status is correlated with increased metabolic syndrome (MetS) and cardiovascular risks. However, the vital roles of age and MetS-associated risk factors in sex-specific arterial stiffness remain unclear. Methods: In this population-based cross-sectional study of the general population, we enrolled in our Health Examination Program 9812 adult participants who were measured for brachial-ankle pulse wave velocity (baPWV) to assess arterial stiffness. Piecewise linear regression models were used to survey pre-defined ages associated with menopause and andropause in relation to arterial stiffness. Multivariate linear regression analyses were used to evaluate independent determinants. Results: Across gender, stepwise increases in baPWV corresponded to increased MetS-associated risk scores (MetSRS) and aging (all p for trend < 0.001), while a turning point was found at 50 years of age (50age). The incremental ratios of baPWV presented inverse U curves with aging, whereas the highest R-2 values and incremental ratios of baPWV were found at 50age across gender. Comparing men with women, a 1.4-fold higher incremental ratio of baPWV was observed before 50age, compared to a 1.3-fold after 50age, respectively. MetS risk group and over 50age were associated with stepwise increased baPWV across gender (both p for trend < 0.001). Before 50age, the determinants did not include hs-CRP for women compared with men, while MetSRS was lost as a determinant across gender. In contrast with men, in women after 50age, HDL-C was an additional determinant and triglyceride was not, while MetSRS remained a determinant across gender. Conclusions: Arterial stiffness increased with aging across nearly lifelong ages more in women than in men. While menopause and andropause may both play a role, 50age was the most critical factor across gender. The sex-specific differences in determinants of arterial stiffness may remind us of sex-specific targets for further interventional studies associated with arterial stiffness. (C) 2017 Elsevier B.V. All rights reserved.