A comparison of the National Center for Health Statistics and new World Health Organization growth references for school-age children and adolescents with the use of data from 11 low-income countries.

BACKGROUND: In 2007 new World Health Organization (WHO) growth references for children aged 5-19 y were introduced to replace the National Center for Health Statistics (NCHS) references. OBJECTIVE: This study aimed to compare the prevalence of stunting, wasting, and thinness estimated by the NCHS and WHO growth references. DESIGN: NCHS and WHO height-for-age z scores were calculated with the use of cross-sectional data from 20,605 schoolchildren aged 5-17 y in 11 low-income countries. The differences in the percentage of stunted children were estimated for each year of age and sex. The z scores of body mass index-for-age and weight-for-height were calculated with the use of the WHO and NCHS references, respectively, to compare differences in the prevalence of thinness and wasting. RESULTS: No systematic differences in mean z scores of height-for-age were observed between the WHO and NCHS growth references. However, z scores of height-for-age varied by sex and age, particularly during early adolescence. In children for whom weight-for-height could be calculated, the estimated prevalence of thinness (WHO reference) was consistently higher than the prevalence of wasting (NCHS reference) by as much as 9% in girls and 18% in boys. CONCLUSIONS: In undernourished populations, the application of the WHO (2007) references may result in differences in the prevalence of stunting for each sex compared with results shown when the NCHS references are used as well as a higher estimated prevalence of thinness than of wasting. An awareness of these differences is important for comparative studies or the evaluation of programs. For school-age children and adolescents across all ranges of anthropometric status, the same growth references should be applied when such studies are undertaken.

A randomised trial in Mali of the effectiveness of weekly iron supplements given by teachers on the haemoglobin concentrations of schoolchildren.

OBJECTIVE: To assess the effect on the haemoglobin concentrations of schoolchildren of weekly iron tablets administered by teachers. DESIGN: Sixty schools were randomly assigned to two groups: in 30 schools children were given weekly for 10 weeks a tablet providing 65 mg of iron and 0.25 mg of folic acid; in the other 30 schools no iron tablets were given. All children were dewormed and given vitamin A before the study began. The haemoglobin concentration of up to 20 randomly selected children in each school was estimated before and 2 weeks after the end of treatment. SETTING: Rural community schools in Kolondieba district of Mali. SUBJECTS: Some 1113 schoolchildren aged 6-19 years with a mean of 11.4 years. RESULTS: The haemoglobin concentration of treated children rose on average by 1.8 g l(-1) and the prevalence of anaemia fell by 8.2%; in untreated children the haemoglobin concentration fell by an average of -2.7 g l(-1) and the prevalence of anaemia rose by 9.4%. The fall in haemoglobin concentration among untreated girls of -4.0 g l(-1) was greater than in untreated boys (-0.3 g l(-1) ). CONCLUSIONS: Weekly iron tablets given by teachers prevented a general fall in the haemoglobin concentrations of untreated children, and led to a small but statistically significant rise among treated children. Young children benefited more than children aged >or=12 years, and girls benefited more than boys.