Parental education, body mass index and prevalence of obesity among 14-year-old boys between 1987 and 1997 in Wroclaw, Poland

The main aim of this study was to examine changes in relative weight and pr evalence of obesity across a ten-year period among 14-year-old boys accordi ng to parental education level. Data from two surveys, carried out in 1987 and 1997, of boys attending the 7th grade of primary schools in Wroclaw wer e used in the analysis. The heights and weights of 3165 boys aged 14 years selected from cohort of 6969 7th and 8th grade boys from all primary school s of the city Wroclaw were used. The data of the second sample of 14-year-o ld boys (n = 1014) were obtained from a health examination study carried ou t in the Silesian Centre for Preventive Medicine, 'DOLMED', in Wroclaw in 1 997. All boys attended the 7th grade of 34 randomly selected primary school s from a total of 129 schools in the city of Wroclaw. Social status was ass essed on the basis of parental education level scored to four categories: u niversity, secondary school, trade school, and elementary school. The preva lence of overweight and obesity was defined as the percentage of children a bove the 85th and 95th percentiles of the body mass index (BMI), the means of which were 21.27 and 23.75 kg/m(2) respectively. Prevalence of overweigh t among boys is slightly lower in the 1997 sample, whereas the prevalence o f obesity shows the opposite trend and is higher by more than one percent i n comparison with the 1987 sample. Similar trends of declining medians and increasing variance are observed in all educational groups. The differences in medians between the two samples within educational groups did not achie ve statistical significance for the groups with parents with education at e lementary level and fathers with university education. There is a trend tow ard increasing prevalence of obesity across the decade considered, accordin g to father's education level. With respect to mother's education levels, t he most dramatic changes in BMI and obesity occurred in the elementary educ ation group, where the percentage of obese subjects increased more than two fold. A significant increase is also observed in the group with parents att aining university education.