Table 1. Linear regression analysis of factors studied with the body mass index of a national sample of Iranian children and adolescents aged 6–18 years (n = 21 111).
| Sex | Regression coefficient | Standard error | P-value |
|---|---|---|---|
| Boys (n = 10 253) | |||
| (Constant) | 15.6 | 0.4 | < 0.0001 |
| History of breastfeeding | –0.4 | 0.1 | < 0.0001 |
| Mother’s education | 0.2 | 0.1 | 0.02 |
| Father’s education | 0.2 | 0.09 | 0.04 |
| Plant protein (times/week) | –0.08 | 0.02 | 0.001 |
| Vegetablesa (times/week) | –0.05 | 0.02 | 0.005 |
| Positive family history of obesityb | 0.2 | 0.05 | 0.03 |
| Rural residence | –0.9 | 0.1 | < 0.0001 |
| Girls (n = 10 858) | |||
| (Constant) | 13.3 | 0.5 | < 0.0001 |
| History of breastfeeding | –0.5 | 0.1 | < 0.0001 |
| Mothers’ education | 0.2 | 0.07 | 0.001 |
| Positive family history of obesity | 0.2 | 0.04 | < 0.0001 |
| Fruitsc (times/week) | –0.06 | 0.01 | < 0.0001 |
| High physical activity leveld | –0.3 | 0.1 | 0.002 |
| Dairy product (times/week) | –0.03 | 0.01 | 0.007 |
| Birth weight | 0.3 | 0.1 | 0.04 |
a Potatoes and chips not included. b Parents, grandparents, aunts, uncles. c Fresh, dried, juice. d 3rd tertile of physical activity.