[Updated growth standards for Chinese children under 7 years of age]

Objective: To construct growth standards for Chinese children under 7 years of age. Methods: Cross-sectional study design based on national representative data on children's growth and development in 2015 was used. Stratified cluster sampling method was used. A total of 83 628 healthy children aged 0-<7 years from 9 cities, including Beijing, Harbin, Xi'an, Shanghai, Nanjing, Wuhan, Guangzhou, Fuzhou, and Kunming, were investigated from June to November 2015, excluding those with adverse conditions that may impact the establishment of the growth standards. Weight, length (height) and head circumference were measured using unified measurement tools and measurement methods. The Lambda-Mu-Sigma method was employed to establish percentile and standard deviation score reference values of weight-for-age, length (height)-for-age, head circumference-for-age, weight-for-length (height) and body mass index (BMI)-for-age of the study population. The standard deviation score curves of the new-established growth standards were compared with the 2009 reference standards. Results: Reference values of percentile (P₃, P₁₀, P₂₅, P₅₀, P₇₅, P₉₀, P₉₇) and standard deviation score (-3, -2, -1, 0,+1,+2,+3) of weight-for-age, length (height)-for-age, head circumference-for-age, weight-for-length (height) and BMI-for-age were obtained. Compared with the 2009 growth standards, the difference of weight at P₅₀ was -0.1-0.4 kg, the difference of length (height) at P₅₀ was 0.1-1.3 cm, the difference of head circumference at P₅₀ was -0.2-0.2 cm, the difference of weight for length (height) at P₅₀ was -0.2-0.5 kg, and the difference of BMI at P₅₀ was -0.2-0.2 kg/m². The main differences were as follows: weight for girls aged 5.0-<7.0 years was 0.4-0.6 kg higher at +2 s, height for boys and girls aged 2.0-<7.0 years was 0.4-1.4 cm higher at -2 s, and BMI for boys and girls aged 5.0-<7.0 years was 0.1-0.3 kg/m² higher at +2 s than the 2009 reference standards. Conclusion: The newly established growth standards for Chinese children under 7 years of age that have achieved a minor revision to the 2009 reference standards, are recommended for nationwide use in growth monitoring and nutritional assessment.