Dynamic Changes of Metabolic Syndrome Alter the Risks of Cardiovascular Diseases and All-Cause Mortality: Evidence From a Prospective Cohort Study

Background: Metabolic syndrome (MetS) at baseline increases the risks of cardiovascular diseases (CVD) and all-cause mortality. However, MetS status is changeable during follow-up. The associations of dynamic changes of MetS with CVD and all-cause mortality remain unclear. Methods: Thirty-one thousand four hundred eighty-one eligible subjects were included from the Kailuan cohort. Dynamic changes of MetS were divided into four patterns as MetS-free, MetS-developed, MetS-recovery and MetS-stable. The outcomes were CVD, all-cause mortality, and the subtypes of CVD as myocardial infarction (MI), stroke and heart failure. Multiple Cox regression models were used to calculate the adjusted hazard ratios (HRs) and confidence intervals (95% CIs). Results: Altered risks of CVD, the subtypes of CVD, and all-cause mortality were observed among different dynamic patterns of MetS. Compared with the MetS-free group, MetS-developed group increased the risks of CVD (HR = 1.78, 95% CI = 1.51-2.11), MI (HR = 1.54, 95% CI = 1.01-2.34), stroke (HR = 1.78, 95% CI = 1.45-2.18), and heart failure (HR = 1.63, 95% CI = 1.11-2.39). MetS-recovery group decreased these risks with the HRs of 0.59 (95% CI = 0.48-0.72) for CVD, 0.62 (95% CI = 0.41-0.96) for MI, 0.59 (95% CI = 0.46-0.75) for stroke, and 0.56 (95% CI = 0.34-0.91) for heart failure compared with the MetS-stable group. However, the increased risk in the MetS-developed group and the decreased risk in the MetS-recovery group were not significant for all-cause mortality. When stratified by the onset age of MetS status change, early development of MetS (<50 years) had higher risks of CVD (HR = 2.20, 95% CI = 1.58-3.05), MI (HR = 2.35, 95% CI = 1.00-5.50), stroke (HR = 2.05, 95% CI = 1.38-3.05), heart failure (HR = 2.63, 95% CI = 1.15-6.04), and all-cause mortality (HR = 1.61, 95% CI = 1.13-2.30) than late development (≥50 years). Early recovery of MetS had lower risks with the HRs of 0.38 (95% CI = 0.24-0.59) for CVD, 0.43 (95% CI = 0.18-1.06) for MI, 0.37 (95% CI = 0.21-0.64) for stroke, 0.30 (95% CI = 0.09-1.04) for heart failure, and 0.68 (95% CI = 0.43-1.06) for all-cause mortality than late recovery. Conclusion: Dynamic changes of MetS altered the risks of CVD and all-cause mortality, especially in individuals with an early onset age. These findings highlight the importance of dynamic changes of MetS and onset age on the prevention and control for CVD.