Table 2. Odds ratio (OR) and 95% confidence interval (CI) for risk of overweight and underweight relative to normal weight in boys.
|
Overweight |
Underweight |
|||
|---|---|---|---|---|
| Model 1 | Model 2 | Model 1 | Model 2 | |
| OR (95% CI) | OR (95% CI) | OR (95% CI) | OR (95% CI) | |
| Observations | 99,504 | 99,504 | 99,504 | 99,504 |
| Age (years) | 1.02 (1.01–1.04) | 1.02 (1.01–1.04) | 0.86 (0.85–0.87) | 0.86 (0.85–0.87) |
| Household income quartile before 2008 | ||||
| 1 (lowest) | 1.15 (1.02–1.30) | 0.92 (0.80–1.05) | 1.10 (1.01–1.20) | 1.11 (1.01–1.21) |
| 2 | 1.07 (0.95–1.21) | 0.95 (0.83–1.08) | 1.09 (1.00–1.18) | 1.09 (1.00–1.19) |
| 3 | 1.00 (0.89–1.14) | 0.95 (0.84–1.08) | 1.02 (0.94–1.11) | 1.02 (0.94–1.12) |
| 4 (highest) | 1.00 (ref) | 1.00 (ref) | 1.00 (ref) | 1.00 (ref) |
| >30% negative income change during economic crisis | ||||
| No | 1.00 (ref) | 1.00 (ref) | 1.00 (ref) | 1.00 (ref) |
| Yes | 1.14 (0.99–1.31) | 1.08 (0.93–1.24) | 1.06 (0.96–1.17) | 1.05 (0.95–1.16) |
| Step term | ||||
| Before September 2008 | 1.00 (ref) | 1.00 (ref) | 1.00 (ref) | 1.00 (ref) |
| After September 2008 | 1.52 (1.39–1.66) | 1.52 (1.39–1.67) | 1.51 (1.40–1.63) | 1.51 (1.40–1.63) |
| Interaction between income change and step term | ||||
| ⩽30% negative income change after September 2008 | 1.00 (ref) | 1.00 (ref) | 1.00 (ref) | 1.00 (ref) |
| >30% negative income change after September 2008 | 1.04 (0.93–1.17) | 1.05 (0.93–1.17) | 0.96 (0.87–1.06) | 0.96 (0.87–1.06) |
| Interaction between income quartile and step term | ||||
| Income quartile 1 after September 2008 | 1.12 (1.02–1.23) | 1.12 (1.02–1.24) | 1.04 (0.96–1.13) | 1.04 (0.96–1.13) |
| Income quartile 2 after September 2008 | 1.14 (1.04–1.26) | 1.15 (1.04–1.26) | 0.98 (0.91–1.07) | 0.98 (0.91–1.07) |
| Income quartile 3 after September 2008 | 0.99 (0.90–1.09) | 0.99 (0.90–1.09) | 1.07 (0.99–1.16) | 1.07 (0.99–1.16) |
| Income quartile 4 after September 2008 | 1.00 (ref) | 1.00 (ref) | 1.00 (ref) | 1.00 (ref) |
| Father's education | ||||
| Junior high school | 1.00 (ref) | 1.00 (ref) | ||
| High school | 0.92 (0.79–1.08) | 1.04 (0.91–1.19) | ||
| Vocational school | 0.87 (0.73–1.04) | 1.01 (0.87–1.17) | ||
| Higher education | 0.73 (0.62–0.87) | 1.03 (0.90–1.19) | ||
| Missing | 0.89 (0.62–1.30) | 0.97 (0.71–1.33) | ||
| Mother's education | ||||
| Junior high school | 1.00 (ref) | 1.00 (ref) | ||
| High school | 0.72 (0.58–0.88) | 0.97 (0.81–1.17) | ||
| Vocational school | 0.66 (0.54–0.82) | 0.95 (0.79–1.15) | ||
| Higher education | 0.62 (0.50–0.79) | 0.94 (0.77–1.15) | ||
| Missing | 0.80 (0.52–1.25) | 1.31 (0.90–1.9) | ||
| Single parent household | ||||
| No | 1.00 (ref) | 1.00 (ref) | ||
| Yes | 1.18 (0.88–1.59) | 0.89 (0.68–1.16) | ||
| Missing | 2.15 (0.45–10.23) | 0.40 (0.04–3.72) | ||
| Three generation household | ||||
| No | 1.00 (ref) | 1.00 (ref) | ||
| Yes | 1.39 (1.28–1.51) | 0.95 (0.88–1.01) | ||
| Residential area | ||||
| 20 designated cities | 1.00 (ref) | 1.00 (ref) | ||
| Other cities | 1.07 (0.98–1.17) | 0.93 (0.87–1.00) | ||
| Rural | 1.11 (0.97–1.27) | 0.98 (0.88–1.09) | ||
| Missing | 1.73 (0.96–3.14) | 0.96 (0.57–1.63) | ||
| Father's age | ||||
| <20 years | 1.00 (ref) | 1.00 (ref) | ||
| 21–25 years | 2.10 (0.91–4.85) | 0.77 (0.43–1.35) | ||
| 26–30 years | 1.77 (0.76–4.11) | 0.79 (0.44–1.39) | ||
| >30 years | 2.10 (0.91–4.88) | 0.79 (0.45–1.40) | ||
| Missing | 2.32 (0.93–5.81) | 0.98 (0.51–1.89) | ||
| Mother's age | ||||
| <20 years | 1.00 (ref) | 1.00 (ref) | ||
| 21–25 years | 1.08 (0.68–1.73) | 1.35 (0.89–2.05) | ||
| 26–30 years | 1.07 (0.67–1.72) | 1.24 (0.81–1.89) | ||
| >30 years | 1.14 (0.71–1.83) | 1.22 (0.80–1.86) | ||
A generalized estimating equation model,25 with an exchangeable correlation structure was used for the analysis.