Table 1 Characteristics of the CARDIA-MRI sample by smoking status at Year 25

From: Cigarette smoking and gray matter brain volumes in middle age adults: the CARDIA Brain MRI sub-study

  Mean (SD) or n (%)
Never-smoker n = 362 Former-smokers n = 219 Current smokers n = 117
Age at MRI 50.18 (3.61) 50.82 (3.27) 49.63 (3.57)*
Gender (Women) 189 (52.2%) 120 (54.8%) 57 (48.7%)
Race (Black) 143 (39.5%) 68 (31.1%) 68 (58.1%)*
Educational attainment ( ≤ high school) 48 (13.3%) 52 (23.7%) 49 (41.9%)*
Self-reported history of vascular disease 42 (11.6%) 28 (12.8%) 19 (16.2%)
Hypertension 97 (26.8%) 76 (34.7%) 56 (47.9%)*
Diabetes 35 (9.7%) 22 (10.0%) 16 (13.9%)
Body mass index 28.68 (5.59) 28.86 (5.97) 29.28 (5.80)
High cholesterol 72 (19.9%) 49 (22.4%) 25 (21.4%)
History of respiratory illnesses 51 (14.1%) 42 (19.2%) 33 (28.2%)*
Forced expiratory volume (FEV1)a 3.12 (0.79) 3.15 (0.77) 2.96 (0.73)
Alcohol consumption
Non-user 159 (43.1%) 92 (41.6%) 38 (33.0%)
Low-risk alcohol use 167 (46.1%) 85 (38.8%) 42 (35.9%)
High-risk alcohol use 39 (10.77%) 42 (19.2%) 37 (31.6%)*
History of illicit drug use 223 (61.60%) 196 (89.5%) 100 (85.5%)*
Depressive symptoms (CES-D) 8.01 (6.80) 8.73 (6.90) 11.41 (8.36)*
  1. *p < 0.01; p-values obtained using chi-square tests for comparing categorical variables and ANOVA tests for comparing continuous tests across smoking groups
  2. aForces expiratory volume measured at Year 20 and for n = 643 subjects, all other covariate measures at Year 25 and for n = 698 subjects