Cytokines and clustered cardiovascular risk factors in children.

The aim was to evaluate the possible role of tumor necrosis factor alpha (TNF-alpha), interleukin-6 (IL-6), C-reactive protein (CRP), low fitness, and fatness in the early development of clustering of cardiovascular disease (CVD) risk factors and insulin resistance. Subjects for this cross-sectional study were obtained from 18 schools near Copenhagen, Denmark. Two hundred ten 9-year-old children were selected for cytokine analysis from 434 third-grade children with complete CVD risk profiles. The subgroup was selected according to the CVD risk factor profile (upper and lower quartile of a composite CVD risk score). All the CVD risk factors and CRP differed between the high- and low-risk groups; but plasma glucose, TNF-alpha, and IL-6 had small and inconsistent differences. Strong associations were found between CVD risk scores and fitness (VO(2peak)) or fatness. No associations were found between CVD risk scores and TNF-alpha and IL-6. C-reactive protein was associated with fitness, fatness, and CVD risk score. This study does not support an association between plasma IL-6 or TNF-alpha and low insulin sensitivity or clustering of CVD risk factors in a young cohort. Inflammation was more pronounced in fat and unfit children based on the association with CRP levels. The association between fitness and fatness variables, insulin resistance, and clustered risk could be caused by other mechanisms related to these exposures. The role of IL-6 remains unclear.