Table 1

 Characteristics of men and women in the 1966 Northern Finland Birth Cohort study

CharacteristicsMen(n = 2684)Women(n = 2706)
FEV1, forced expiratory volume in 1 s; FVC, forced vital capacity; BMI, body mass index.
Data presented as mean (SD) for all continuous variables.
*Measured between the 10th and 14th months; data available for 2262 men and 2295 women.
†Parental social class (III = unskilled/others, IV = farmers).
‡Hospital diagnosis of acute respiratory infection or pneumonia between 0 and 7 years.
§Physician diagnosis.
¶Participation in brisk activity of at least 20 minutes was less than twice a week.
**Adult social class (III = vocational, IV = no education beyond elementary school/unknown).
Early life factors
    Birth weight (g)3592 (512)3467 (474)
    Weight gain during first year (kg)*7.0 (1.1)6.5 (1.1)
    Gestational age at birth (weeks)40.2 (1.5)40.3 (1.5)
    % Parental social class III and IV at birth†47.5 (n = 222)40.9 (n = 220)
    % Mothers smoking during pregnancy13.3 (n = 349)12.3 (n = 324)
    % Childhood respiratory infection‡6.7 (n = 181)5.0 (n = 135)
Factors at age 31 years
    FEV1 (l)4.54 (0.62)3.41 (0.47)
    FVC (l)5.48 (0.75)4.02 (0.55)
    FEV1:FVC ratio (%)83.1 (6.4)85.0 (6.5)
    FEV1 (% predicted)99.2 (11.7)101.8 (11.7)
    Height (m)1.78 (0.8)1.65 (0.6)
    Weight (kg)80.2 (12.7)65.6 (12.5)
    BMI (kg/m2)25.2 (3.6)24.2 (4.7)
    % Current cigarette smokers32.7 (n = 878)23.0 (n = 622)
    % Known asthma at 14 or 31 years§8.3 (n = 223)10.5 (n = 284)
    % Known emphysema or chronic bronchitis§5.4 (n = 144)5.9 (n = 160)
    % Low physical activity level¶42.9 (n = 1151)41.7 (n = 1129)
    % Social class III and IV**66.0 (n = 308)50.7 (n = 249)