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Table 1 Baseline characteristics of participants without diabetes mellitus and number of events during follow-up of included cohort studies

From: HbA1c levels in non-diabetic older adults – No J-shaped associations with primary cardiovascular events, cardiovascular and all-cause mortality after adjustment for confounders in a meta-analysis of individual participant data from six cohort studies

Baseline characteristic

Unit

ESTHER

SHIP

ELSA

Tromsø

KORA

NHANES

Baseline years for this analysis

 

2000–2002

1997–2001

2004–2005

1994–1995

1999–2001

1988–1994

Total sample size

 

7,982

1,777

5,262

6,045

1,850

5,778

 Age

Years

61.8 (6.6)

63.4 (8.3)

65.8 (9.7)

61.6 (7.0)

61.7 (7.1)

67.9 (11.0)

  Age ≥65 years

%

2,481 (31.1)

733 (41.3)

2,410 (45.8)

1,958 (32.4)

645 (34.9)

3,157 (54.6)

 Male sex

%

3,476 (43.6)

905 (50.9)

2,334 (44.4)

2,550 (42.2)

929 (50.2)

2,774 (48.0)

 Race/ethnicity

       

  Non-Hispanic white

%

N/A

N/A

N/A

N/A

N/A

3,428 (60.3)

  Non-Hispanic black

%

N/A

N/A

N/A

N/A

N/A

1,088 (18.8)

  Mexican-American

%

N/A

N/A

N/A

N/A

N/A

997 (17.3)

  Other

%

N/A

N/A

N/A

N/A

N/A

211 (3.7)

 School education

       

  ≤9 years

%

5,743 (73.5)

975 (55.2)

968 (19.0)

3,228 (53.8)

322 (17.5)

2,238 (39.1)

  10–12 years

%

1,671 (21.4)

443 (25.1)

3,137 (61.6)

1,773 (29.5)

1,156 (62.7)

2,147 (37.5)

  ≥13 years

%

398 (5.1)

348 (19.7)

992 (19.5)

1,005 (16.7)

367 (19.9)

1,343 (23.5)

 BMI

kg/m2

27.3 (4.2)

28.2 (4.4)

27.5 (4.6)

25.9 (3.8)

28.1 (4.2)

26.8 (5.2)

 BMI category

       

  Underweight

%

146 (1.8)

29 (1.6)

141 (2.8)

239 (4.0)

21 (1.1)

361 (6.3)

  Optimal weight

%

2,249 (28.2)

389 (21.9)

1,356 (26.9)

2,360 (39.1)

389 (21.2)

1,835 (31.9)

  Overweight

%

3,816 (47.9)

832 (46.9)

2,247 (44.6)

2,603 (43.2)

907 (49.3)

2,251 (39.2)

  Obese

%

1.763 (22.1)

525 (29.6)

1,296 (25.7)

831 (13.8)

522 (28.4)

1,303 (22.7)

 Smoking

       

  Never

%

3,974 (51.1)

942 (54.6)

2,390 (45.8)

1,949 (32.3)

969 (53.4)

2,583 (44.7)

  Former

%

2,479 (31.9)

486 (28.2)

1,922 (36.8)

2,184 (36.2)

568 (31.3)

1,956 (33.9)

  Current

%

1,319 (17.0)

298 (17.3)

905 (17.4)

1,907 (31.6)

279 (15.4)

1,239 (21.4)

 Relative alcohol consumption

       

  Abstainer or low

%

3,851 (53.2)

848 (50.5)

2,537 (50.1)

2,394 (51.7)

1,005 (54.6)

3,410 (64.2)

  Moderate

%

2,650 (36.6)

655 (39.0)

2,024 (39.9)

1,745 (37.7)

638 (34.6)

1,325 (24.9)

  High

%

741 (10.2)

177 (10.5)

508 (10.0)

490 (10.6)

199 (10.8)

580 (10.9)

 Vigorous physical activity

%

3,452 (43.4)

905 (51.5)

2,232 (42.4)

2,043 (34.2)

819 (44.5)

2,204 (38.2)

 Total cholesterol

mmol/L

5.7 (1.3)

6.1 (1.2)

6.0 (1.2)

6.8 (1.3)

6.3 (1.1)

5.7 (1.1)

 HDL cholesterol

mmol/L

1.4 (0.4)

1.5 (0.4)

1.5 (0.4)

1.6 (0.4)

1.5 (0.4)

1.4 (0.4)

 Subclinical inflammation

%

2,786 (35.5)

492 (28.8)

1,827 (35.0)

1,079 (20.8)

520 (28.4)

2,187 (38.9)

 Serum creatinine

nmol/L

79.8 (28.1)

87.1 (18.5)

N/A

67.6 (16.0)

76.5 (21.3)

101.6 (29.4)

 Albuminuria

%

760 (9.6)

331 (21.0)

N/A

675 (12.8)

N/A

1,166 (22.0)

 Hemoglobin

g/dL

N/A

13.6 (1.2)

14.3 (1.4)

14.1 (1.1)

14.4 (1.2)

13.9 (1.4)

 Biomarkers of iron deficiency

       

  Ferritin

μg/L

N/A

N/A

N/A

N/A

N/A

157 (168)

  Transferrin saturation

%

N/A

N/A

N/A

N/A

N/A

25.2 (10.6)

  Erythrocyte protoporphyrin

μmol/L

N/A

N/A

N/A

N/A

N/A

0.95 (0.56)

 Hypertension

       

  No hypertension

%

3,270 (41.0)

807 (45.5)

2,526 (48.0)

2,584 (42.8)

849 (46.1)

2,553 (44.2)

  Known hypertension or systolic blood pressure ≥140 to <160 mmHg

%

3,915 (49.1)

593 (33.4)

2,313 (44.0)

2,044 (33.8)

778 (42.2)

2,545 (44.1)

  Systolic blood pressure ≥160 mmHg

%

796 (10.0)

375 (21.1)

423 (8.0)

1,417 (23.4)

216 (11.7)

679 (11.8)

 History of MI or stroke

%

511 (6.5)

140 (7.9)

398 (7.6)

438 (7.3)

97 (5.2)

738 (12.8)

 Biomarkers of liver function

       

  GGT

U/L

N/A

N/A

N/A

N/A

N/A

31.6 (45.5)

  AST

U/L

N/A

N/A

N/A

N/A

N/A

21.9 (11.8)

  ALT

U/L

N/A

N/A

N/A

N/A

N/A

14.7 (10.6)

 HbA1c

%

5.5 (0.4)

5.4 (0.5)

5.4 (0.3)

5.4 (0.4)

5.6 (0.3)

5.5 (0.5)

  Very low (<5.0 % (<31 mmol/mol))

%

476 (6.0)

336 (18.9)

345 (6.6)

626 (10.4)

63 (3.4)

678 (11.7)

  Low (5.0 to <5.5 % (31 to <37 mmol/mol))

%

2,747 (34.4)

546 (30.7)

2,344 (44.6)

2,719 (45.0)

603 (32.6)

1,994 (34.5)

  Intermediate (5.5 to <6.0 % (37 to <42 mmol/mol))

%

3,726 (46.7)

583 (32.8)

2,201 (41.8)

2,323 (38.4)

937 (50.7)

2,272 (39.3)

  Increased (6.0 to <6.5 % (42 to <48 mmol/mol))

%

1,033 (12.9)

312 (17.6)

372 (7.1)

377 (6.2)

247 (13.4)

834 (14.4)

Follow-up

       

 All-cause mortality

       

  Total sample size

 

7,981

1,777

5,253

6,045

1,850

5,775

  Cases (%)

 

1,069 (13.4)

298 (16.8)

645 (12.3)

1,704 (28.2)

180 (9.7)

2,873 (49.8)

  Mean FUP (SD)

Years

11.1 (2.1)

9.4 (2.1)

7.0 (1.3)

14.0 (3.8)

8.5 (1.3)

11.4 (4.9)

 Cardiovascular mortality

       

  Total sample size

 

7,943

1,761

5,113

5,987

1,843

5,721

  Cases (%)

 

263 (3.3)

90 (5.1)

174 (3.0)

707 (11.8)

69 (3.7)

1,345 (23.5)

  Mean FUP (SD)

Years

11.1 (2.0)

9.4 (2.1)

7.0 (1.3)

14.1 (3.8)

8.6 (1.3)

11.4 (4.9)

 Cardiovascular events

       

  Total sample size

 

7,233

1,637

4,462

5,602

1,556

N/A

  Cases (%)

 

595 (8.2)

65 (4.0)

315 (7.1)

1,386 (24.7)

132 (8.5)

N/A

  Mean FUP (SD)

Years

7.1 (2.3)

9.5 (2.0)

5.3 (1.4)

12.6 (4.8)

8.2 (1.7)

N/A

  1. Unless indicated otherwise, the table shows proportions (%) for categorical and means (SD) for continuous variables. Numbers shown were drawn from the unimputed data set. Therefore, numbers do not always add up to the total because of missing values (see Additional file 1: Table S2 for number of missing values for each variable). ALT, alanine transferase; AST, aspartate transferase; BMI, body mass index; FUP, follow-up; GGT, gamma-glutamyl transferase; HbA1c, glycated hemoglobin; HDL, high-density lipoprotein; MI, myocardial infarction; N/A, not assessed; SD, standard deviation