Table 4.
Odds ratios for overweight including obesity* in adolescence (15–20 years of age) overall and by sex. The Tromsø Study, Fit Futures 2010–11 and 2012–13†
| Overweight/obesity at 15–20 years of age | |||||||||||||
| All | Girls | Boys | |||||||||||
| Crude | Adjusted‡§ | Crude | Adjusted¶ | Crude | Adjusted¶ | ||||||||
| Birth | OR | 95 % CI | OR | 95 % CI | OR | 95 % CI | OR | 95 % CI | OR | 95 % CI | OR | 95 % CI | p Value** |
| Birth weight per SD | 1.22 | (1.06 to 1.41) | 1.25 | (1.06 to 1.48) | 1.39 | (1.10 to 1.74) | 1.37 | (1.05 to 1.77) | 1.08 | (0.90 to 1.29) | 1.15 | (0.93 to 1.43) | 0.090 |
| Birth weight SDS | 1.15 | (1.04 to 1.27) | 1.18 | (1.05 to 1.33) | 1.22 | (1.03 to 1.44) | 1.20 | (0.99 to 1.46) | 1.06 | (0.92 to 1.22) | 1.12 | (0.95 to 1.33) | |
| Ponderal index in tertiles: | |||||||||||||
| Low | 1.00 | Ref. | 1.0 | Ref. | 1.0 | Ref. | 1.0 | Ref. | 1.0 | Ref. | 1.0 | Ref. | 0.020/0.016†† |
| Medium | 1.30 | (0.90 to 1.89) | 1.34 | (0.91 to 1.96) | 1.67 | (0.94 to 2.97) | 1.65 | (0.92 to 2.95) | 1.08 | (0.67 to 1.75) | 1.13 | (0.69 to 1.87) | |
| High | 1.53 | (1.07 to 2.18) | 1.56 | (1.08 to 2.24) | 1.75 | (1.02 to 3.00) | 1.67 | (0.96 to 2.90) | 1.44 | (0.89 to 2.32) | 1.47 | (0.90 to 2.39) | |
| 2–4 Fyears of age | |||||||||||||
| BMI per SD | 1.66 | (1.41 to 1.95) | 1.66 | (1.40 to 1.96) | 1.96 | (1.55 to 2.47) | 2.03 | (1.60 to 2.58) | 1.42 | (1.12 to 1.80) | 1.39 | (1.08 to 1.77) | 0.062 |
| BMI SDS | 1.55 | (1.32 to 1.83) | 1.55 | (1.31 to 1.82) | 1.94 | (1.51 to 2.49) | 1.93 | (1.51 to 2.48) | 1.33 | (1.05 to 1.67) | 1.32 | (1.05 to1.67) | |
| Weight class at 2–4 years: | |||||||||||||
| Underweight | 0.42 | (0.24 to 0.73) | 0.42 | (0.24 to 0.73) | – | – | – | – | – | – | – | – | |
| Normal weight | 1.0 | Ref. | 1.0 | Ref. | – | – | – | – | – | – | – | – | |
| Overweight | 1.75 | (1.09 to 2.84) | 1.74 | (1.07 to 2.82) | – | – | – | – | – | – | – | – | |
| Obese | 5.49 | (1.44 to 20.98) | 5.35 | (1.42 to 20.09) | – | – | – | – | – | – | – | – | |
| 5–7 years of age | |||||||||||||
| BMI per SD | 3.10 | (2.47 to 3.88) | 3.23 | (2.56 to 4.07) | 3.72 | (2.57 to 5.37) | 3.72 | (2.59 to 5.34) | 2.73 | (2.02 to 3.70) | 2.88 | (2.10 to 3.95) | 0.215 |
| BMI SDS | 3.11 | (2.53 to 3.82) | 3.11 | (2.53 to 3.81) | 3.95 | (2.80 to 5.57) | 3.95 | (2.82 to 5.53) | 2.63 | (2.00 to 3.44) | 2.62 | (1.99 to3.44) | |
| Weight class at 5–7 years: | |||||||||||||
| Underweight | 0.23 | (0.08 to 0.61) | 0.22 | (0.08 to 0.61) | – | – | – | – | – | – | – | – | |
| Normal weight | 1.0 | Ref. | 1.0 | Ref. | – | – | – | – | – | – | – | – | |
| Overweight | 5.25 | (3.34 to 8.25) | 5.35 | (3.37 to 8.48) | – | – | – | – | – | – | – | – | |
| Obese | 15.68 | (6.54 to 37.62) | 15.59 | (6.60 to 36.85) | – | – | – | – | – | – | – | – | |
*Weight classes according to the International Obesity Taskforce (IOTF) age- and sex-specific cut-off values for children 2–18 years of age and the WHO index for adults from age 18–20.21 22
†Analysed in the dataset with 20 imputations (multiple imputation), n=961 (469 girls and 492 boys).
‡Variables at birth are adjusted for gestational age, maternal age and sex, except sex-specific SDS, which is adjusted for gestational age and maternal age.
§Variables at 2–4 and 5–7 years of age are adjusted for age, maternal age and sex, except age- and sex-specific weight class and SDS, which is adjusted only for maternal age.
¶Variables in sex specific analysis are adjusted for gestational age/age and maternal age, except age- and sex-specific SDS which is adjusted only for maternal age.
**p Value for sex difference (interaction term) in crude analysis.
††p for trend in all cases: 0.020 in crude analysis, 0.016 in adjusted analysis.
BMI, body mass index (kg/m2); GEE, generalised estimating equations; Ref, reference group; SDS, SD scores according to Norwegian reference data.
Numbers in italic type are significant (p<0.05).