Table 1 Demographics and clinical characteristics of participants

Age (years)

47 (33, 61)

47 (33, 60)

63 (57, 72)

< 0.001

Gender, n (%)

Female

3,849 (51.5%)

3,724 (51.5%)

125 (51.6%)

Male

3,633 (48.5%)

3,488 (48.5%)

145 (48.4%)

0.984

Marital status, n (%)

Married

3,826 (53.9%)

3,703 (53.9%)

123 (55.0%)

Never

1,373 (18.5%)

1,355 (19.0%)

18 (5.0%)

Other

2,279 (27.6%)

2,151 (27.1%)

128 (40.0%)

< 0.001

Ethnicity, n (%)

Mexican American

1,116 (8.9%)

1,102 (9.2%)

14 (2.1%)

Non-Hispanic White

2,800 (63.9%)

2,617 (63.3%)

183 (80.6%)

Non-Hispanic Black

1,534 (11.1%)

1,499 (11.3%)

35 (5.7%)

Other Hispanic

800 (6.4%)

790 (6.5%)

10 (1.8%)

Other Race

1,232 (9.7%)

1,204 (9.7%)

28 (9.8%)

< 0.001

Educational attainment, n (%)

Middle school or lower

1,606 (13.6%)

1,527 (13.4%)

79 (20.9%)

High school

1,717 (23.6%)

1,635 (23.3%)

82 (32.1%)

College or more

4,153 (62.7%)

4,045 (63.3%)

108 (47.0%)

0.004

Serum cotinine (ng/mL)

0.03 (0.01, 3.57)

0.03 (0.01, 2.07)

3.96 (0.02, 258.20)

< 0.001

Past-year alcohol drinking, n (%)

Never

1,579 (19.8%)

1,550 (20.0%)

29 (12.2%)

1–3 drinks/day

3,408 (63.6%)

3,301 (63.4%)

107 (69.4%)

≥ 4 drinks/day

956 (16.7%)

925 (16.6%)

31 (18.4%)

0.171

BMI (kg/m²)

28.5 (24.7, 33.1)

28.4 (24.7, 33.1)

29.1 (25.5, 33.8)

0.223

Clinical manifestations, n (%)

Chronic bronchitis

425 (5.8%)

314 (4.5%)

111 (44.5%)

< 0.001

Emphysema

140 (1.6%)

44 (0.4%)

96 (37.1%)

< 0.001

Comorbidities, n (%)

Hypertension

721 (10.7%)

658 (10.2%)

63 (26.7%)

< 0.001

Diabetes mellitus

1,040 (10.4%)

969 (9.9%)

71 (24.9%)

< 0.001

Coronary heart disease

296 (3.6%)

235 (2.9%)

61 (23.8%)

< 0.001

Cancer or malignancy

721 (10.7%)

658 (10.2%)

63 (26.7%)

< 0.001

Blood furan, n (%)

Q1 group

6,219 (84.0%)

6,061 (84.7%)

158 (63.7%)

Q2 group

303 (4.0%)

287 (3.9%)

16 (5.2%)

Q3 group

322 (3.8%)

296 (3.7%)

26 (6.4%)

Q4 group

317 (3.9%)

289 (3.7%)

28 (7.0%)

Q5 group

321 (4.3%)

279 (3.8%)

42 (17.6%)

< 0.001