Implications of using World Health Organization growth reference (2007) for identifying growth problems in Hong Kong children aged 6 to 18 years.

OBJECTIVE To evaluate the implications of replacing Hong Kong's 1993 growth references (HK1993) with the World Health Organization's 2007 references (WHO2007) for children aged 6 to 18 years. DESIGN Cross-sectional study. SETTING Thirty-six randomly selected primary and secondary schools in Hong Kong. PARTICIPANTS A total of 14 842 children and adolescents aged 6 to 18 years in Hong Kong during 2005/06. MAIN OUTCOME MEASURES Creation of age-specific z-scores for height, weight, and body mass index relative to HK1993 and WHO2007 references. RESULTS Use of WHO2007 instead of HK1993 could classify an additional 1.4% children aged 6 to 10 years and 2.8% children aged 11 to 18 years as having a short stature. Using WHO2007, respective proportions that could be classified as underweight and obese increased by 3.5% and 2.1% among children aged 6 to 10 years, and 5.5% and 1.6% among children aged 11 to 18 years. CONCLUSIONS Use of WHO2007 could increase clinical workload and patient and parent anxiety by 'over-diagnosing' short stature and underweight. Although WHO2007 may have a role in international comparative research, retention of HK1993 would seem appropriate from a clinical perspective.