Differentiating effects of socio-economic factors on relative weight and nutritional status in Polish schoolchildren across intergenerational changes

Objective: The aim of this study was an assessment of the effects of urbanisation level, family size and parental education on body mass index (BMI) and mid-upper arm circumference (MUAC) among Polish schoolchildren in cross-sectional surveys conducted between 1966 and 2012. Design: The analysis involved schoolchildren measured in four Polish Anthropological Surveys (1966, 1978, 1988 and 2012). Socio-economic factors involved: urbanisation level (city, town and village), family size (one child, two children, three children, four or more children), and father's and mother's education (lower and higher education). Setting: Regions in Poland - cities: Warsaw, Lodz and Wroclaw; towns: Bystrzyca Klodzka, Pinczow, Siemiatycze, Wolsztyn and their rural surroundings. Participants: A total sample consisted of 63 757 children (31 774 boys and 31 983 girls) aged 7-18 years. Results: Between 1966 and 1988, both BMI and MUAC had significantly higher values in children from cities, in families with one child and with higher parental education (P< 0 center dot 05). However, MUAC revealed significant differences between particular socio-economic groups more frequently than BMI. In 2012, urbanisation level and parental education ceased to show a differentiating effect on both indicators, while family size remained a significant social factor for both measures (BMI:P< 0 center dot 05; MUAC:P< 0 center dot 01). Conclusions: Since MUAC reflected socio-economic differences more frequently than BMI, it could be a more sensitive and reliable anthropometric measure revealing the effects of socio-economic factors on children's nutritional status.