Prevalence thresholds for wasting, overweight and stunting in children under 5 years.

Objective: Prevalence ranges to classify levels of wasting and stunting have been used since the 1990s for global monitoring of malnutrition. Recent developments prompted a re-examination of existing ranges and development of new ones for childhood overweight. The present paper reports from the WHO-UNICEF Technical Expert Advisory Group on Nutrition Monitoring. Design: Thresholds were developed in relation to SD of the normative WHO Child Growth Standards. The international definition of 'normal' (2 SD below/above the WHO standards median) defines the first threshold, which includes 2.3% of the area under the normalized distribution. Multipliers of this 'very low level (rounded to 2.5%) set the basis to establish subsequent thresholds. Country groupings using the thresholds were produced using the most recent set of national surveys. Setting: One hundred and thirty-four countries. Subjects: Children under 5 years. Results: For wasting and overweight, thresholds are: 'very low (<2.5%), 'low' (approximate to 1-2 times 2.5%), 'medium' (approximate to 2-4 times 2.5%), 'high' (approximate to 4-6 times 2.5%) and 'very high' (> approximate to 6 times 2.5%). For stunting, thresholds are: 'very low' (<2.5%), 'low' (approximate to 1-4 times 2.5%), 'medium' (approximate to 4-8 times 2.5%), 'high' (approximate to 8-12 times 2.5%) and 'very high' (> approximate to 12 times 2.5 %). Conclusions: The proposed thresholds minimize changes and keep coherence across anthropometric indicators. They can be used for descriptive purposes to map countries according to severity levels; by donors and global actors to identify priority countries for action; and by governments to trigger action and target programmes aimed at achieving 'low' or 'very low' levels. Harmonized terminology will help avoid confusion and promote appropriate interventions.