BMC Public Health 2008, 8:171 http://www.biomedcentral.com/1471-2458/8/171 Table 1: Characteristics of the study population (N = 35,434) Characteristic Age [years] Weight [kg] Height [cm] BMI [kg/m2] No of persons in the child's living place (N = 34,997) Overweight Obese Male sex Age group 5.0 – < 5.5 years 5.5 – < 6.0 years 6.0 – < 6.5 years 6.5 – < 7.0 years 7.0 – < 7.5 years 7.5 – < 8.0 years German nationality Study region: East Study location: Urban Parental educational level: < 10 years of schooling 10 years of schooling > 10 years of schooling Living space > 75 m2 Single child Attendance of day nursery Smoking in the living place Passive smoking during the first 3 years of life Smoking during pregnancy Breastfeeding > 3 months Preterm delivery Birth weight < 2500 g 2500 – < 3000 3000 – < 3500 3500 – < 4000 > 4000 Mean 6.28 22.85 120.05 15.77 3.91 N 35,434 35,434 35,434 35,434 35,146 35,434 35,434 33,984 34,095 34,997 33,826 33,208 34,693 34,578 33,106 34,540 34,809 SD 0.34 4.11 5.53 2.03 1.06 % 15.48 4.33 50.89 0.23 23.98 47.91 26.15 1.42 0.32 92.22 67.73 76.14 11.48 44.82 43.69 49.51 33.86 56.49 45.00 31.95 13.72 31.63 6.45 5.76 17.00 38.32 29.45 9.47 Univariate associations In univariate analyses (Table 2), female sex, increasing age group, other than German nationality, living in an urban area, single child, smoking in the living place, passive smoking during the first three years of life, smoking dur- ing pregnancy and increasing birth weight were found to increase the odds of overweight. Living in the East of Ger- many, increasing parental educational level, living space > 75 m2, increasing number of persons living in the child's place, attendance of a day nursery, breastfeeding for more than three months and preterm delivery were found to be inversely associated with overweight. All exposure varia- bles were significantly associated with overweight (p < 0.05). There was a significantly decreasing trend in preva- lence with increasing parental education and increasing number of persons in the household. There was also a sig- nificantly increasing trend in prevalence with increasing birth weight category. Univariate analyses for obesity (Table 3) revealed the same picture as the analyses for overweight with the exception that age group was not significantly related to obesity. Multivariable models for overweight and obesity In multivariable analyses (Table 4), female sex, other than German nationality, being a single child, smoking in the child's living place, smoking during pregnancy, preterm delivery, increasing birth weight and increasing year of study were found to be independent risk factors for over- weight. Of these factors, only female sex, other than Ger- man nationality, smoking in the living place and Page 4 of 10 (page number not for citation purposes)