From: Relationship between sleep and obesity among U.S. and South Korean college students
 | All IRR (95% CI)a | Men IRR (95% CI)a | Women IRR (95% CI)a | Whites IRR (95% CI)a | Blacks IRR (95% CI)a | Koreans IRR (95% CI)a |
---|---|---|---|---|---|---|
Race/nationality | ||||||
 Whites | Reference | Reference | Reference | – | – | – |
 Blacks | 0.89 (0.81, 0.98)* | 0.85 (0.75, 0.96)** | 0.99 (0.84, 1.15) | – | – | – |
 Koreans | 0.79 (0.73, 0.86)*** | 0.77 (0.70, 0.85)*** | 0.82 (0.70, 0.95)* | – | – | – |
Gender | ||||||
 Men | Reference | – | – | Reference | Reference | Reference |
 Women | 0.92 (0.86, 0.99)* | – | – | 0.79 (0.68, 0.91)** | 1.00 (0.90, 1.12) | 0.91 (0.82, 1.02) |
BMI | ||||||
 Underweight | 0.88 (0.71, 1.09) | 0.92 (0.62, 1.35) | 0.92 (0.70, 1.20) | 0.98 (0.48, 1.97) | 1.06 (0.67, 1.67) | 0.92 (0.68, 1.12) |
 Normal weight | Reference | Reference | Reference | Reference | Reference | Reference |
 Overweight | 0.96 (0.89, 1.03) | 0.95 (0.87, 1.03) | 0.95 (0.83, 1.08) | 0.92 (0.79, 1.08) | 0.99 (0.87, 1.12) | 0.97 (0.87, 1.08) |
 Obesity | 0.92 (0.85, 0.99)* | 0.91 (0.82, 1.01) | 0.90 (0.79, 1.03) | 0.86 (0.70, 1.06) | 0.90 (0.78, 1.04) | 0.97 (0.86, 1.09) |