Profiles of body mass index and the nutritional status among children and adolescents categorized by waist-to-height ratio cut-offs.

BACKGROUND: Waist-to-height ratio (WHtR) is proposed as a simple, valid and convenient measure of abdominal obesity and health risks in practice. The present study examined the distribution of nutritional status among children and adolescents categorized by WHtR cut-offs.

METHODS: A total of 30,459 students (15,249 boys and 15,210 girls) aged 7-18years participated in the study. Height, weight and waist circumference (WC) of all subjects were measured, body mass index (BMI) and WHtR were calculated. The grades of nutritional status (thinness, normal weight, overweight and obesity) was defined by the international BMI cut-offs. All subjects were divided into three groups (low, moderate and high) according to their WHtR, BMI level and the distribution of nutritional status among the three groups were compared.

RESULTS: In both boys and girls, significant differences in BMI level and the nutritional status were observed among the three groups. Children and adolescents aged 7-18years in the 'high WHtR group' (≥0.5) had higher BMI than those in the 'low WHtR group' (<0.4) by 6.00-10.15kg/m(2) for boys and 5.24-9.51kg/m(2) for girls. 'low WHtR group' had higher prevalence of thinness, and 'high WHtR group' had higher prevalence of overweight and obesity. The optimal distribution of nutritional status is found in the 'moderate WHtR group' (between 0.4 and 0.5) with the highest proportion of normal weight and low prevalence of thinness and obesity.

CONCLUSION: WHtR is associated with nutritional status, which could be an indicator of nutritional status and early health risk. It is necessary to develop optimal boundary values in the future.