Establishing international optimal cut-offs of waist-to-height ratio for predicting cardiometabolic risk in children and adolescents aged 6-18 years.

BACKGROUND: Waist-to-height ratio (WHtR) has been proposed as a simple and effective screening tool for assessing central obesity and cardiometabolic risk in both adult and pediatric populations. However, evidence suggests that the use of a uniform WHtR cut-off of 0.50 may not be universally optimal for pediatric populations globally. We aimed to determine the optimal cut-offs of WHtR in children and adolescents with increased cardiometabolic risk across different countries worldwide. METHODS: We used ten population-based cross-sectional data on 24,605 children and adolescents aged 6-18 years from Brazil, China, Greece, Iran, Italy, Korea, South Africa, Spain, the UK, and the USA for establishing optimal WHtR cut-offs. We performed an external independent test (9,619 children and adolescents aged 6-18 years who came from other six countries) to validate the optimal WHtR cut-offs based on the predicting performance for at least two or three cardiometabolic risk factors. RESULTS: Based on receiver operator characteristic curve analyses of various WHtR cut-offs to discriminate those with ≥ 2 cardiometabolic risk factors, the relatively optimal percentile cut-offs of WHtR in the normal weight subsample population in each country did not always coincide with a single fixed percentile, but varied from the 75th to 95th percentiles across the ten countries. However, these relatively optimal percentile values tended to cluster irrespective of sex, metabolic syndrome (MetS) criteria used, and WC measurement position. In general, using ≥ 2 cardiometabolic risk factors as the predictive outcome, the relatively optimal WHtR cut-off was around 0.50 in European and the US youths but was lower, around 0.46, in Asian, African, and South American youths. Secondary analyses that directly tested WHtR values ranging from 0.42 to 0.56 at 0.01 increments largely confirmed the results of the main analyses. In addition, the proposed cut-offs of 0.50 and 0.46 for two specific pediatric populations, respectively, showed a good performance in predicting ≥ 2 or ≥ 3 cardiometabolic risk factors in external independent test populations from six countries (Brazil, China, Germany, Italy, Korea, and the USA). CONCLUSIONS: The proposed international WHtR cut-offs are easy and useful to identify central obesity and cardiometabolic risk in children and adolescents globally, thus allowing international comparison across populations.

The correlation between anthropometric measurements and biochemical cardiovascular risk markers in the hypertensive elderly.

OBJECTIVES: This study was aimed at correlating anthropometric markers indicating additional cardiovascular risk in a hypertensive elderly population enrolled in the HIPERDIA programme in Campina Grande, Paraíba, Brazil, South America. METHODS: The sample consisted of 131 hypertensive elderly people aged60 to 92 (25.9 % males and 74.1 % females). A socioeconomic, demographic, life-style questionnaire was used in the assessment. Information about anthropometry measurements and pathology frequency were also recorded via this questionnaire. Pearson's correlation, descriptive statistics, comparison between anthropometric variables by gender using Student's t-test and one-way ANOVA were used in the analysis for comparing groups by age(60 to 69, 70 to 79 and > 80 years). RESULTS: 14.7 % of men and 24.7 % of women were overweight and 11.8 % of men and 21.6 % of women were obese. 57.0 % of women and 26.5 % of men had inadequate values in waist-to-hip ratio analysis. 95.9 % of women and 52.9 % of men had high risk and 95.9 % of women and 38.2 % of men had high abdominal circumference values regarding waistline measurement. After selection (n=40) for correcting potential confounders, it was found that 27 subjects had high C-reactive protein values, an additional cardiovascular risk factor. CONCLUSIONS: The results suggested that additional cardiovascular risk could be demonstrated by the high prevalence of being overweight and central obesity presented by the population and the presence of subclinical inflammation amongst hypertensive ones.