# Table 3 Univariate association of predictive variables with obesity

Variables Prevalence of obesity (%) P value Odds Ratio [OR]
Sex
Male 4.01 (N = 18,032) 0.003 Female vs Male 1.17 (1.06–1.30)
Female 4.66 (N = 17,402)
Age group
5.0 – < 5.5 2.50 (N = 80) 0.18 Per unit increase in age group: 0.96 (0.90–1.03)
5.5 – < 6.0 4.55 (N = 8,498)
6.0 – < 6.5 4.37 (N = 16,977)
6.5 – < 7.0 4.04 (N = 9,265)   Per unit increase in age: 1.00 (0.86–1.16)
7.0 – < 7.5 3.98 (N = 502)
7.5 – < 8.0 8.04 (N = 112)
Nationality
German 4.04 (N = 32,413) < 0.0001 Other than German vs German 1.95 (1.68 – 2.28)
Other than German 7.61 (N = 2,733)
Study region
East 3.88 (N = 23,998) < 0.0001 East vs West 0.73 (0.66–0.81)
West 5.26 (N = 11,436)
Study location
Urban 4.53 0.001 Urban vs Rural 1.24 (1.09–1.41)
Rural 3.69
Parental educational level
< 10 years of schooling 6.23 (N = 3,902) < 0.0001 *** Per unit increase in educational level 0.68 (0.63 – 0.73)
10 years of schooling 4.87 (N = 15,233)   0.77 (0.66 – 0.90)*
> 10 years of schooling 3.06 (N = 14,849)   0.48 (0.41 – 0.56)*
Living space
<= 75 m2 4.92 (N = 17,213)   > 75 m2 vs <= 75 m2 0.75 (0.67–0.83)
> 75 m2 3.73 (N = 16,882)
Number of persons in the child's living place   < 0.0001 *** Per unit increase in no of persons: 0.90 (0.86–0.95)
Single child
No 3.95 (N = 23,148) < 0.0001 Yes vs No: 1.30 (1.17–1.45)
Yes 5.08 (N = 11,849)
Attendance of day nursery
No 4.59 (N = 14,718) 0.01 Yes vs No: 0.88 (0.79–0.98)
Yes 4.05 (N = 19,108)
Smoking in the living place
No 3.65 (N = 18,266) < 0.0001 Yes vs No: 1.46 (1.32–1.63)
Yes 5.25 (N = 14,942)
Passive smoking during the first three years of life
No 3.92 (N = 23,609) < 0.0001 Yes vs No: 1.33 (1.19 – 1.48)
Yes 5.14 (N = 11,084)
Smoking during pregnancy
No 4.06 (N = 29,833) < 0.0001 Yes vs No: 1.47 (1.29 – 1.68)
Yes 5.86 (N = 4,745)
Breastfeeding for more than three months
No 4.48 (N = 22,634) < 0.0001 Yes vs No: 0.76 (0.68 – 0.86)
Yes 3.46 (N = 10,472)
Preterm delivery
No 4.42 (N = 32,313) < 0.001 Yes vs No: 0.64 (0.50 – 0.83)
yes 2.87 (N = 2,227)
Birth weight
< 2500 g 1.94 (N = 2,006) < 0.0001*** Per unit increase in birth weight category 1.35 (1.28 – 1.42)
2500 – < 3000 g 3.26 (N = 5,916)   1.70 (1.20 – 2.41)**
3000 – < 3500 g 3.91 (N = 13,340)   2.05 (1.48 – 2.85)**
3500 – < 4000 g 4.88 (N = 10,251)   2.59 (1.86 – 3.59)**
> 4000 g 7.62 (N = 3,296)   4.16 (2.95 – 5.85)**
1. *compared to educational level I (< 10 years of schooling)
2. **compared to low birth weight (< 2500 g)
3. ***Cochran-Armitage Trend Test