background: the main objective of this study was to assess the malnutrition and some socio-economic related factors based on three ethnic groups among primary school children in north of iran in 2010 . methods: this cross-sectional study was carried out through multistage cluster random sampling on 5698 subjects (2505 fars-native, 2154 turkman, and 1039 sistani) in 112 schools. well-trained sta...