Association between serum leptin concentration and asthma in study participants stratified by age (NHANES III, 1988–1994)
| Leptin quartiles* | Men | Women | ||
|---|---|---|---|---|
| OR (95% CI) | p value Wald χ2 | OR (95% CI) | p value Wald χ2 | |
| *For men, quartile 1 is ⩽2.6, quartile 2 is >2.6–⩽4.4, quartile 3 is >4.4–⩽7.3, and quartile 4 is >7.3 μg/l serum leptin. For women, quartile 1 is ⩽7.7, quartile 2 is >7.7–⩽13.2, quartile 3 is >13.2–⩽21.9, and quartile 4 is >21.9 μg/l serum leptin. | ||||
| †Adjusted for age, race/ethnicity, educational status, smoking status, cotinine concentration, triceps skinfold thickness, physical activity, and atopy. | ||||
| Age 20–49 years | ||||
| N | 1584 | 0.37 | 1871 | 0.01 |
| Quartile 1 (reference)† | 1.00 | 1.00 | ||
| Quartile 2 | 0.99 (0.35 to 2.76) | 1.84 (0.55 to 6.17) | ||
| Quartile 3 | 0.48 (0.14 to 1.60) | 2.21 (0.71 to 6.88) | ||
| Quartile 4 | 1.48 (0.36 to 6.01) | 6.34 (2.01 to19.92) | ||
| Age ⩾50 years | ||||
| N | 1169 | 0.24 | 1252 | 0.47 |
| Quartile 1 (reference)† | 1.00 | 1.00 | ||
| Quartile 2 | 3.04 (0.97 to 9.55) | 0.61 (0.20 to 1.91) | ||
| Quartile 3 | 1.82 (0.45 to 7.37) | 0.64 (0.20 to 1.97) | ||
| Quartile 4 | 2.93 (0.60 to 14.31) | 1.11 (0.34 to 3.59) | ||
| p value Wald χ2 for sex-specific interaction between age and quartiles of leptin concentration on asthma status | 0.12 | 0.74 | ||