The contribution of physical fitness to individual and ethnic differences in risk markers for type 2 diabetes in children: The Child Heart and Health Study in England (CHASE).

Claire M Nightingale,Derek G Cook,Christopher G Owen,Peter H Whincup,Angela S Donin,Soren Brage,Alicja R Rudnicka,Sarah R Kerry-Barnard,Kate L Westgate,Ulf Ekelund

doi:10.1111/pedi.12637

Abstract

BackgroundThe relationship between physical fitness and risk markers for type 2 diabetes (T2D) in children and the contribution to ethnic differences in these risk markers have been little studied. We examined associations between physical fitness and early risk markers for T2D and cardiovascular disease in 9‐ to 10‐year‐old UK children.MethodsCross‐sectional study of 1445 9‐ to 10‐year‐old UK children of South Asian, black African‐Caribbean and white European origin. A fasting blood sample was used for measurement of insulin, glucose (from which homeostasis model assessment [HOMA]‐insulin resistance [IR] was derived), glycated hemoglobin (HbA1c), urate, C‐reactive protein (CRP), and lipids. Measurements of blood pressure (BP) and fat mass index (FMI) were made; physical activity was measured by accelerometry. Estimated VO2 max was derived from a submaximal fitness step test. Associations were estimated using multilevel linear regression.ResultsHigher VO2 max was associated with lower FMI, insulin, HOMA‐IR, HbA1c, glucose, urate, CRP, triglycerides, LDL‐cholesterol, BP and higher HDL‐cholesterol. Associations were reduced by adjustment for FMI, but those for insulin, HOMA‐IR, glucose, urate, CRP, triglycerides and BP remained statistically significant. Higher levels of insulin and HOMA‐IR in South Asian children were partially explained by lower levels of VO2max compared to white Europeans, accounting for 11% of the difference.ConclusionsPhysical fitness is associated with risk markers for T2D and CVD in children, which persist after adjustment for adiposity. Higher levels of IR in South Asians are partially explained by lower physical fitness levels compared to white Europeans. Improving physical fitness may provide scope for reducing risks of T2D.

Highlights

Evidence suggests that ethnic differences in risk markers for type 2 diabetes (T2D) are apparent in prepubertal children with higher levels of T2D risk markers in South Asian children compared to white Europeans.[7]
Boys had higher estimated levels of VO2 max than girls; South Asians had lower levels and black African-Caribbeans had higher levels of estimated VO2 max compared to white Europeans
This study provides strong evidence that low levels of physical fitness are associated with risk markers for T2D and cardiovascular disease (CVD) in this multi-ethnic population of school children

Summary

| INTRODUCTION

Higher levels of physical fitness in adults are associated with a lower risk of developing type 2 diabetes (T2D)[1,2] and lower rates of cardiovascular disease (CVD) mortality and all-cause mortality.[3,4] South Asian adults are at higher risk of developing T2D, stroke and coronary heart disease compared to white Europeans in the UK and other western countries.[5,6] Evidence suggests that ethnic differences in risk markers for T2D ( insulin resistance) are apparent in prepubertal children with higher levels of T2D risk markers in South Asian children compared to white Europeans.[7] Ethnic differences in physical fitness are apparent in childhood; we have shown in a. Given the complex relationship between physical activity and fitness, we examine the independent associations between physical activity, physical fitness, and risk for T2D and CVD

| METHODS

| Statistical methods

| RESULTS

| DISCUSSION

| Strengths and limitations

Conflict of interest