Table 3 Relationship between percent body fat and mortality, and between body mass index and mortality after controlling for percent body fat, using cox regression analysis and stratified by frailty levels (N =5309)

≤0.1

1

Percent body fat (%)

− 0.012

0.015

0.99 (0.96,1.02)

0.437

2

Percent body fat (%)

0.008

0.022

1.01 (0.97,1.05)

0.708

Body mass index (kg/m²)

18.5–24.9 (reference)

25.0–29.9

− 0.272

0.205

0.76 (0.51,1.14)

0.185

30.0–34.9

− 0.532

0.306

0.59 (0.32,1.07)

0.083

≥35.0

− 0.223

0.454

0.80 (0.33,1.95)

0.623

0.1–0.2

3

Percent body fat (%)

− 0.007

0.010

0.99 (0.97,1.01)

0.521

4

Percent body fat (%)

− 0.014

0.013

0.99 (0.96,1.01)

0.308

Body mass index (kg/m²)

18.5–24.9 (reference)

25.0–29.9

− 0.004

0.139

1.00 (0.76,1.31)

0.977

30.0–34.9

0.028

0.197

1.03 (0.70,1.51)

0.887

≥35.0

0.328

0.257

1.39 (0.84,2.30)

0.201

0.2–0.3

5

Percent body fat (%)

− 0.024

0.010

0.98 (0.96,0.99)

0.019

6

Percent body fat (%)

− 0.015

0.015

0.99 (0.96,1.01)

0.298

Body mass index (kg/m²)

18.5–24.9 (reference)

25.0–29.9

− 0.228

0.145

0.80 (0.60,1.06)

0.116

30.0–34.9

− 0.260

0.197

0.77 (0.52,1.14)

0.188

≥35.0

− 0.125

0.269

0.88 (0.52,1.50)

0.642

>0.3

7

Percent body fat (%)

− 0.011

0.009

0.99 (0.97,1.01)

0.221

8

Percent body fat (%)

− 0.010

0.013

0.99 (0.97,1.02)

0.459

Body mass index (kg/m²)

18.5–24.9 (reference)

25.0–29.9

− 0.183

0.140

0.83 (0.63,1.10)

0.189

30.0–34.9

0.007

0.180

1.01 (0.72,1.44)

0.967

≥35.0

− 0.095

0.226

0.91 (0.58,1.42)

0.673