Estimated difference in respiratory function, assessed at age 31 years, for every 500 g higher birth weight in 5390 men and women in the 1966 Northern Finland Birth Cohort study
| Covariates adjusted for in regression models | FEV1 (ml) | FVC (ml) | FEV1:FVC ratio (%) |
|---|---|---|---|
| β (95% CI) | β (95% CI) | β (95% CI) | |
| FEV1, forced expiratory volume in 1 s; FVC, forced vital capacity. | |||
| *At birth. | |||
| †Excludes height as covariate for regression models for predicted FEV1. | |||
| ‡Adult factors: height, weight, cigarette smoking (never, former and current) and physical activity level (high versus low) at 31 years. | |||
| ¶Gestational age at birth, maternal smoking during pregnancy, aforementioned adult factors as well as hospital diagnosis of respiratory infection between 0 and 7 years, other respiratory illnesses (physician diagnoses of asthma at age 14 or 31 years or emphysema/chronic bronchitis at 31 years), social class at birth (I, II, III and IV) and at age 31 years (I, II, III and IV). | |||
| §Excludes those with hospital diagnosis of respiratory infection between 0 and 7 years, whose mothers smoked during pregnancy and had physician-diagnosed asthma (at 14 or 31 years) or emphysema/chronic bronchitis at 31 years, and adjusted for gestational age at birth, aforementioned factors at 31 years and social class at birth (I, II, III and IV) and at age 31 years (I, II, III and IV). | |||
| Men (n = 2684) | |||
| Unadjusted | 127.7 (105.4 to 150.1) | 160.4 (133.4 to 187.5) | –0.11 (–0.35 to 0.12) |
| Height† at 31 years | 47.0 (26.6 to 67.4) | 49.6 (26.0 to 73.2) | 0.09 (–0.16 to 0.33) |
| Gestational age* and height† at 31 years | 57.4 (35.1 to 79.7) | 59.4 (33.5 to 85.2) | 0.13 (–0.14 to 0.39) |
| Gestational age,* maternal smoking during pregnancy and height† at 31 years | 54.6 (32.1 to 77.2) | 57.8 (31.6 to 84.0) | 0.10 (–0.17 to 0.37) |
| Gestational age,* maternal smoking during pregnancy and adult factors†‡ | 57.8 (35.1 to 80.4) | 61.6 (35.3 to 88.0) | 0.11 (–0.16 to 0.38) |
| Life course factors¶ | 57.5 (34.9 to 80.1) | 61.4 (35.1 to 87.7) | 0.11 (–0.16 to 0.38) |
| Subgroup of men†§ (n = 1893) | 56.3 (30.4 to 82.3) | 56.6 (25.7 to 87.5) | 0.16 (–0.14 to 0.45) |
| Women (n = 2706) | |||
| Unadjusted | 105.8 (87.7 to 123.9) | 119.9 (98.3 to 141.4) | 0.12 (–0.14 to 0.38) |
| Adjusted for height† at 31 years | 39.6 (23.2 to 56.1) | 33.6 (14.5 to 52.6) | 0.27 (0.07 to 0.54) |
| Adjusted for gestational age* and height† at 31 years | 45.5 (27.8 to 63.2) | 41.0 (20.7 to 61.3) | 0.26 (–0.03 to 0.54) |
| Gestational age,* maternal smoking during pregnancy and height† at 31 years | 44.8 (26.8 to 62.9) | 41.9 (21.2 to 62.6) | 0.22 (–0.07 to 0.51) |
| Gestational age,* maternal smoking during pregnancy and adult factors†‡ | 48.2 (30.0 to 66.4) | 42.3 (21.3 to 63.2) | 0.30 (0.01 to 0.60) |
| Life course factors¶ | 48.8 (30.3 to 66.6) | 42.3 (21.3 to 63.2) | 0.31 (0.01 to 0.60) |
| Subgroup of women†§ (n = 1880) | 52.7 (31.2 to 74.3) | 43.7 (19.1 to 68.2) | 0.41 (0.04 to 0.77) |