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Associations between dietary carbohydrates and metabolic risk factors in Danish children and adolescents

Iben Kynde

Summary

Dietary quality and markers of metabolism and inflammation, identified by plasma cytokine concentrations, are associated with the development of cardiovascular diseases in adults (1,2).
The influence of dietary carbohydrates and plasma cytokine concentrations are so far only sparsely studied in children with regard to cardiometabolic risk factors. Danish children consume increasingly amounts of dietary added sugar and not enough fruit and vegetables according to national recommendations (3,4). Adverse plasma cytokine concentrations are found in young,
overweight children. It is possible that poor carbohydrate quality and adverse plasma cytokine concentrations can lead to increased risk of cardiometabolic diseases, including type 2 diabetes, in later life.
The aim was to study the associations between dietary carbohydrate components, plasma cytokine concentrations, insulin resistance, and the cardiometabolic risk profile in cross-sectional analyses and to study dietary carbohydrate components and plasma cytokine concentrations and their associations with insulin resistance and the cardiometabolic risk profile 6 years later in prospective analyses. The study population consisted of Danish children and adolescents from the European Youth Heart Studies in 1997/1998 and 2003/2004. At baseline, 1019 children (590 at 8–10 years old and 429 at 14–16 years old) took part in the study, and 6 years later, 384 of the 8–10-year olds from baseline were re-examined. Individual dietary intake was assessed using a 24h recall interview, and the carbohydrate quality was analysed as the following components: total sugar, added sugar, non-added sugar, starch, fibre and dietary glycaemic index. Among the 8–10-year olds, baseline plasma cytokines were quantified using an immuno-chemical method: adiponectin, leptin, interleukin-8 (IL-8) and hepatocyte growth factor (HGF). The degree of insulin resistance was calculated using the homeostasis model assessment, and standardized to the sample mean (Z-scores). A continuously distributed score of composite cardiometabolic risk derived from the sum of 6 risk factors (Z-scores): BMI, HOMA, total serum cholesterol to serum HDL-cholesterol ratio, total serum triglycerides, systolic blood pressure, and inverse cardiorespiratory fitness. Overweight was defined by BMI-cut-off points. Among 8–10 and 14–16-year-old Danish children, it seems that a fibre-rich diet with a low content of added sugar benefits cardiometabolic risk factors among girls whereas a high intake of non-added sugar benefits cardiometabolic risk factors among boys. The results are consistent with current recommendations of comsuming adequate amounts of fruit and vegetables, low-fat dairy products, and fibre-rich bread. Prospective results were all non-significant. No consistency was found in the association between carbohydrate quality and plasma cytokines. Hyperleptinaemia correlates with both insulin resistance and an adverse cardiometabolic risk profile in Danish children and hypo-adiponectinaemia among overweight children is associated with a high degree of insulin resistance and an adverse cardiometabolic risk profile in adolescence. In contrast, plasma IL-8 and HGF concentrations were not associated with cardiometabolic risk factors in childhood or adolescence. Future research is warranted using a more precise diet method and plasma cytokines should be analyzed in more complex statistical models. Dietary interventions, which may decrease cardiometabolic risk, should be considered for children and adolescents in terms of preventing cardiometabolic diseases, including type 2 diabetes, in later life. Hypo-adiponectinaemia and hyper-leptinaemia may be used — together with BMI measuring and dietary reporting — to identify high risk children and adolescents.