Cardiometabolic risk factor levels in Norwegian children compared to international reference values: The ASK study

Abstract

Objective: To investigate cardiometabolic risk factor levels in a group of Norwegian 10-year-old children compared to international values and examine the association between cardiorespiratory fitness (CRF) and the reference-standardized clustered risk score.

Methods: 913 children (49% girls) were included from the Active Smarter Kids (ASK) study. Body mass index (BMI), waist circumference (WC), systolic blood pressure (SBP), diastolic blood pressure (DBP), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), total cholesterol (TC) to HDL-C ratio, triglyceride (TG), glucose, insulin, homeostatic model assessment (HOMA) score and CRF, were standardized according to international age-and sex-specific reference values.

Results: The Norwegian children had significantly more favorable WC, DBP, glucose, HDL-C and CRF levels compared to the international reference values, but similar or less favorable levels of other cardiometabolic risk factors. CRF was the variable that differed the most from the international values (mean (95% CI) 1.20 (1.16 to 1.24) SD). The clustered risk score (excluding CRF) was higher in the Norwegian children, but decreased to below international levels when including CRF (mean (95% CI) - 0.08 (- 0.12 to -0.05) SD). CRF had a significant inverse association with the clustered risk score (excluding CRF) (β - 0.37 SD, 95% CI -0.43 to -0.31).

Conclusions: Norwegian children have substantially higher CRF levels than international standards, and including CRF in clustered risk scores reduces overall risk in Norwegian children below that of international levels. CRF is associated with improved cardiometabolic health in children.

Fig 1. Reference-standardized cardiometabolic risk factors.

Mean (95% CI) of the reference-standardized single risk factors and mean clustered risk scores excluding and including cardiorespiratory fitness (CRF) (inversed) in Norwegian children. Reference-standardized variable = $(\mathrm{x}+\overline{\mathrm{x}})/\mathrm{SD}\left(\overline{\mathrm{x}}\right)$, where age-predicted reference value was used as the mean ($\overline{\mathrm{x}}$) (10). The cardiometabolic clustered risk scores consisted of the following reference-standardized risk factors; WC, SBP, TG, TC:HDL-ratio, and HOMA score, excluding and including CRF (inversed).

Fig 2. Association between quartiles of cardiorespiratory fitness and the reference-standardized clustered risk score.

Mean (95% CI) of the reference-standardized clustered cardiometabolic risk score (excluding CRF) across quartiles of CRF. A higher clustered risk score indicates a less favorable cardiometabolic profile. Children in quartile 1 of CRF are the least fit and children in quartile 4 the fittest. P for trend < 0.001.