Effects of Cardiorespiratory Fitness and Obesity on Salivary Secretory IgA and Alpha-Amylase in South African Children.

Dorota Starzak,Kristen Konkol,Andrew Mckune

doi:10.3390/children3030012

Abstract

This study examined whether cardiorespiratory fitness (CRF) and body composition are associated with salivary secretory immunoglobulin A (SIgA), a mucosal immunity marker, and salivary alpha-amylase (sAA), a marker of stress-related sympathetic nervous system (SNS) activity, in South African children. Morning (7:30–8:00 a.m.) saliva samples were collected from 132 children (10.05 ± 1.68 years old, 74 females, 58 males). Body composition, resting blood pressure, and predicted maximal aerobic capacity (VO2max) were determined, and SIgA and sAA were quantified. Obese children had significantly higher sAA compared with overweight and normal weight children (p < 0.01). SIgA secretion rate was significantly lower in obese and overweight vs. normal weight children (p < 0.01). Multiple-linear regression analysis revealed that body mass index (BMI) (p < 0.05) and diastolic blood pressure (DBP) (p < 0.05) were independent predictors of sAA with CRF acting as a mitigator. Age and BMI predicted SIgA secretion rate (p < 0.05) with BMI (p < 0.001) found to be an independent predictor of SIgA secretion rate. Obesity, based on BMI, was associated with elevated SNS activity and lowered mucosal immunity. CRF-mitigated sympathetic activation was not associated with mucosal immunity.

Highlights

Obesity and associated diseases, such as type 2 diabetes, have reached worldwide epidemic proportions [1]
The results demonstrated that obese children had significantly greater weight, body mass index (BMI),(pbody fat was found to be an independent predictor of percentage, diastolic blood pressure (DBP), and systolic blood pressure (SBP), compared to overweight and normal weight children
This study investigated the effect that body composition and cardiorespiratory fitness (CRF) have on salivary biomarkers of mucosal immunity as well as on sympathetic nervous system (SNS) activation in the paediatric population, and is the first such study conducted on South African children from a low socioeconomic area

Summary

Introduction

Obesity and associated diseases, such as type 2 diabetes, have reached worldwide epidemic proportions [1]. Childhood obesity is a focus of many public health efforts. Traditional and cultural perceptions regarding body size, urbanization, poor diet, low socioeconomic status, and lack of physical activity are a few of the suggested contributing factors [4,6]. The combination of obesity and lack of physical activity (PA) have been shown to have negative effects on immune and neuro-endocrine function [7,8]. Research examining the association between body composition, aerobic capacity, and immunity in children is still limited. From the studies available, it appears that both obesity and PA influence immunity. Frost, and Klentron [7]

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Conclusion