Table 1 Characteristics of the study population by combinations of dietary sodium and β-carotene intakes (n = 6725).

n

1513

1847

1851

1514

Age, years

59.0 ± 16.2

54.1 ± 17.9

52.2 ± 16.9^a

47.4 ± 16.6

<0.0001

Men, n (%)

430 (28.4)

631 (34.2)

1104 (59.6)

954 (63.0)

<0.0001

Ethnicity, n (%)

<0.0001

Hispanic

403 (26.6)

573 (31.0)

394 (21.3)^a

349 (23.1)

White

808 (53.4)

855 (46.3)

1092 (59.0)^a

805 (53.2)

Black

254 (16.8)

370 (20.0)

258 (13.9)^a

297 (19.6)

Others

48 (3.2)

49 (2.7)

107 (5.8)^a

63 (4.2)

Education, n (%)

<0.0001

Less than high school

377 (24.9)

669 (36.2)

346 (18.7)^a

351 (23.2)

High school

351 (23.2)

461 (25.0)

329 (17.8)^a

400 (26.4)

More than high school

785 (51.9)

717 (38.8)

1176 (63.5)^a

763 (50.4)

Family monthly poverty levels

<0.0001

≤1.30

406 (26.8)

697 (37.7)

414 (22.4)^a

473 (31.2)

1.31–1.85

279 (18.4)

404 (21.9)

270 (14.6)^a

267 (17.6)

>1.85

828 (54.7)

746 (40.4)

1167 (63.1)^a

774 (51.1)

Smoking status, n (%)

<0.0001

Current

143 (9.5)

356 (19.3)

224 (12.1)^a

317 (20.9)

Former

400 (26.4)

462 (25.0)

582 (31.4)^a

385 (25.4)

Never

970 (64.1)

1029 (55.7)

1045 (56.5)^a

812 (53.6)

Drinker, n (%)

829 (54.8)

1009 (54.6)

1352 (73.0)^a

1030 (68.0)

<0.0001

Hypertension, n (%)

718 (47.5)

819 (44.3)

686 (37.1)

530 (35.0)

<0.0001

Diabetes, n (%)

223 (14.7)

282 (15.3)

237 (12.8)

204 (13.5)

0.1298

Sedentary time, h/day

5.1 ± 3.2

5.0 ± 3.2

5.8 ± 3.5^a

5.4 ± 3.2

<0.0001

Dietary inflammatory index

0.5 ± 1.3

1.5 ± 1.1

−0.9 ± 1.4^a

0.1 ± 1.3

<0.0001

Total energy, kcal

1527 ± 402

1479 ± 423

2433 ± 741

2428 ± 689

<0.0001

Body mass index, kg/m²

28.5 ± 6.1

29.3 ± 6.6

29.0 ± 6.6^a

29.9 ± 7.2

<0.0001

Log-transformed c-reactive protein, mg/dL

−1.7 ± 1.2

−1.5 ± 1.2

−1.8 ± 1.3^a

−1.7 ± 1.3

<0.0001

Log-transformed red cell distribution width, %

2.6 ± 0.1

2.6 ± 0.1

2.5 ± 0.1

2.6 ± 0.1

<0.0001