Gender differences in changes in metabolic syndrome status and its components and risk of cardiovascular disease: a longitudinal cohort study

BACKGROUND: We aimed to investigate the gender difference in the association between changes in metabolic syndrome (MetS) and its components with the risk of cardiovascular disease (CVD) and coronary heart disease (CHD) among adult participants in the Tehran lipid and glucose study cohort. METHODS: A total of 4624 adults (aged ≥ 30 years) who participated in two Phases 2 (2002-2005) and 3 (2005-2008) were included and followed up until 2018. Based on the status of MetS and its components in two phases, we divided participants into four groups: MetS-free, MetS-developed, MetS-recovery and MetS-stable groups, and similar categories were defined for MetS components. Multiple Cox regression models were used to estimate the adjusted hazard ratios (HRs) and 95% confidence intervals (95% CIs), and women-to-men ratios of HRs (RHRs). RESULTS: During a median follow-up of 11.6 years, 619 CVD events (292 women) and 512 CHD events (230 women) occurred. In both genders, the MetS-stable group had the highest risk of CVD and CHD, compared with the MetS-free group, but the associations were stronger in women than men: the HR (95% CI) were (2.76, 2.00-3.82) and (3.08, 2.15-4.40) for CVD and CHD, respectively, in women, and (1.60, 1.23-2.09) and (1.74, 1.30-2.31) for men. The multivariate adjusted women-to-men RHRs were (1.72, 1.16-2.56) for CVD and (1.77, 1.14-2.73) for CHD. Only among women, the risks for CVD in MetS-recovery group (1.67, 1.06-2.63) and MetS-developed group (1.89, 1.16-3.06|) were higher than MetS-free group. For CHD, women in MetS-developed group (1.86, 1.07-3.22) had higher risk than MetS-free group. However, no evidence of gender difference was observed in these associations. Among MetS components, persistent high blood pressure (BP) conferred greater risk for CVD and CHD in women than men; the women-to-men RHRs of CVD and CHD for high BP-stable groups were 1.54 (1.05-2.26) and 1.62 (1.07-2.47), respectively. For CHD events, persistent high fasting plasma glucose was associated with greater risk in women than men with women-to-men RHRs of 1.62 (1.09-2.40). CONCLUSION: Change in MetS and its key components were associated with different risks for CVD events in both genders, with generally stronger associations in women than men.