Objective: The increasing prevalence of overweight and obesity among children is now an important health problem. This fact, however, does not reflect the scale of the problem. The aim of the present study was to find how much the BMI threshold was exceeded in a population from Kraków. Design: The study was based on three cross-sectional surveys conducted in 1983, 2000 and 2010. The prevalence of overweight and obesity was estimated based on the International Obesity Task Force cut-off points. In addition to these, an extent of overweight (EOW) index was calculated. Setting: Poland. Subjects: Children aged 3-18 years (n 14 534) from Kraków. Results: Between the populations examined in 1983 and 2010, the EOW index in boys rose by almost 10 %, and the prevalence of overweight and obesity by 39 %. In girls, however, the EOW index decreased by 45 %, while the prevalence of overweight and obesity remained at similar levels. Analyses in separate age groups showed that the EOW index increased only among early adolescents (150 % for boys, 94 % for girls) and late adolescents (390 % and 64 %, respectively). Conclusions: The observed increased prevalence of overweight and obesity mainly concerned boys and was accompanied by an increase in the amount by which the BMI threshold values were exceeded.
Keywords
BMI Extent of overweight Obesity Economic transformationIn the 1960s, Western nations, especially the USA (1,2) and Western Europe (3) , saw a dramatic increase in the frequency of overweight and obesity. In 1998, the WHO (4) declared obesity a major public health epidemic, both in developed and developing countries, and estimated that by 2025 obesity would concern more than half the adult population in the USA, UK and Australia (4) . A similar trend was found among children and adolescents (5,6) . In the period 1963-1991 in the USA the prevalence of overweight among 6-11-year-old children increased from 15 % to 22·5 %, while the frequency of obesity rose from 5 % to 11 %. In the UK in the period 1989-1998 the prevalence of overweight among children under 4 years of age increased from 14·7 % to 23·6 %, and obesity from 5·4 % to 9·2 %. Between the years 1975 and 1995 in Germany, the frequency of overweight among boys (7-14 years of age) increased from 10·0 % to 16·3 %, and among girls from 11·7 % to 20·7 % (7) . However, relatively recent reports from