Abstract: Background Sitting height/leg length ratio (SH/LL) and Sitting height/height ratio (SH/H) are the important indicators of body proportion assessment. Their scientific assessment will supply valuable information in clinical practices, but the detailed data on their growth reference standards have not been reported. Objective To construct the SH/LL and SH/H growth charts for Chinese children and adolescents from birth to 18 years. Design A cross-sectional survey. Methods Stature and sitting height of 92 494 healthy urban children aged 0-18 years were measured in two national surveys in 2005 in China, which named The National Survey on the Physical Growth and Development of Children in the Nine Cities of China and The Chinese National Survey on Student's Constitution and Health. Leg length was calculated by height minus sitting height and the SH/LL ratio and SH/H ratio were calculated. Growth reference standards of SH/LL and SH/H were constructed using the LMS method. Main outcome measures Reference values of SH/LL and SH/H. Results The Z-scores growth charts of SH/LL and SH/H (-3SD, -2SD, -1SD, Median, +1SD, +2SD, +3SD) were constructed. The median of SH/LL declined from birth (2.00) to 13 years in boys (111) and to 11 years in girls (1.13), then increased slightly to the age of 18 (1.16 in boys and 1.18 in girls). A similar growth pattern was found in the SH/H, that is, the median of SH/H was 0.67 at birth and declined to the lowest point (0.53) with age, then increased slightly to 0.54 at 18 years old. Conclusions The growth charts of SH/LL and SH/H are used in assessing body proportions for Chinese children and adolescent individuals, and they could be used in conjunction with the growth charts of height, weight for Chinese children aged 0-18 years.

Key words: Children and adolescents, body proportions, Sitting-height/Leg length ratio, Sitting-height/height ratio, Growth charts