Association of metabolic risk factor clustering and all-cause mortality in adults with non-metabolic syndrome: the rural Chinese cohort study

Abstract

Studies demonstrated an increased risk of death with aggregation of metabolic syndrome (MetS) components in the general population; however, the association is unclear in people with non-MetS. We aimed to explore the effect of aggregated metabolic risk factors on all-cause mortality in the non-MetS population. Questionnaire interviews and physical and blood biochemical factors for 13,749 adult participants were analyzed at baseline between July–August 2007 and July–August 2008. We followed up 11,604 participants (84.4%) between July–August 2013 and July–October 2014. Cox proportional-hazards regression produced multivariate adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) to evaluate metabolic risk factor clustering at baseline for all-cause mortality at follow-up. During a mean of 5.93 years of follow-up, 742 deaths (508 males) occurred. With aggregated metabolic risk factors, mortality rate increased overall for male and female participants (p < 0.001). For all participants, adjusted HRs for death increased from 1.29 to 1.91 with increased number of metabolic risk factors; risk of death was increased with elevated blood pressure (BP), low high-density lipoprotein cholesterol (HDL-C) level, and high glucose level (HR 1.43 [95% CI 1.23–1.67], 1.17 [1.01–1.37], and 1.24 [1.06–1.45], respectively). A similar association was observed in males but not females, except for elevated BP. Mortality risk increases with aggregated metabolic risk factors except for females, and might be attributed to high BP, low HDL-C levels, and high glucose levels in the non-MetS Chinese population.