Metabolic Syndrome and Carotid Intima-Media Thickness in Young Adults: Roles of Apolipoprotein B, Apolipoprotein A-I, C-Reactive Protein, and Secretory Phospholipase A2: The Cardiovascular Risk in Young Finns Study

OBJECTIVE: Aberrations in apolipoprotein (apo) metabolism and increased systemic inflammation associate with the metabolic syndrome (MetS) and may contribute to its atherogenicity. We examined whether the association between carotid atherosclerosis and MetS in a population of young adults is mediated by apoB and apoA-I and/or by inflammatory markers C-reactive protein and type II secretory phospholipase A2. METHODS AND RESULTS: We used cross-sectional and 6-year prospective data from the cardiovascular risk in young Finns study. In young adults (aged 24 to 39 years), apoB, C-reactive protein, and type II secretory phospholipase A2 enzyme activity were significantly higher and apoA-I lower in subjects with MetS (N=325) than in subjects without MetS (N=1858). In prospective analysis (N=1587), both MetS and high apoB predicted (P<0.0001) incident high carotid intima-media thickness, defined as carotid intima-media thickness >90th percentile and/or plaque. The association between MetS and incident high carotid intima-media thickness was attenuated by approximately 40% after adjustment with apoB. Adjustments with apoA-I, C-reactive protein, or type II secretory phospholipase A2 did not diminish the association. CONCLUSIONS: High levels of apoB, C-reactive protein, and type II secretory phospholipase A2 and low levels of apoA-I associate with MetS in young adults. The atherogenicity of MetS in this population assessed by incident high carotid intima-media thickness appears to be substantially mediated by elevated apoB but not inflammatory markers.