Table 1 Baseline characteristics according to the α-klotho quartiles.

Age, years, mean (SD)

55.63 (10.16)

57.01 (10.47)

55.74 (9.91)

55.29 (10.27)

54.41 (9.84)

<0.001

Gender, n (%)

>0.9

 female

2030 (62.16)

497 (62.85)

485 (61.25)

524 (62.76)

524 (61.82)

 male

1299 (37.84)

336 (37.15)

347 (38.75)

308 (37.24)

308 (38.18)

Race, n (%)

0.001

 Mexican American

579 (7.76)

155 (8.17)

137 (6.58)

148 (8.46)

139 (7.91)

 Non-Hispanic White

1436 (70.73)

377 (71.09)

387 (73.90)

368 (71.39)

304 (66.01)

 Non-Hispanic Black

662 (10.53)

165 (11.08)

141 (8.19)

138 (8.46)

218 (14.89)

 Other Hispanic

440 (5.66)

92 (4.93)

104 (4.99)

117 (5.92)

127 (6.90)

 Other

212 (5.32)

44 (4.74)

63 (6.34)

61 (5.77)

44 (4.29)

PIR, mean (SD)

2.58 (1.58)

2.46 (1.58)

2.69 (1.59)

2.63 (1.61)

2.51 (1.53)

0.11

Education, n (%)

0.4

 Less than high school

1181 (23.59)

309 (24.48)

294 (21.63)

287 (21.98)

291 (26.66)

 High school graduate or GED

763 (24.57)

187 (25.05)

186 (25.83)

213 (25.99)

177 (21.10)

 Some college or above

1385 (51.84)

337 (50.48)

352 (52.53)

332 (52.02)

364 (52.25)

Marital status, n (%)

0.6

 Married and a partner

1788 (58.88)

439 (58.99)

449 (59.89)

449 (59.38)

451 (57.06)

 Widowed

344 (8.30)

92 (9.48)

78 (6.70)

89 (8.84)

85 (8.33)

 Divorced or separated

851 (24.21)

216 (24.29)

211 (23.79)

212 (22.35)

212 (26.60)

 Never married

346 (8.61)

86 (7.24)

94 (9.62)

82 (9.42)

84 (8.00)

BMI, kg/m², n (%)

0.047

 Normal (18.5 to <25)

615 (19.06)

132 (14.50)

171 (21.30)

144 (17.64)

168 (22.73)

 Obese (30 or greater)

1712 (49.21)

427 (48.10)

427 (49.70)

447 (53.29)

411 (45.40)

 Overweight (25 to <30)

955 (30.21)

265 (36.19)

220 (27.60)

233 (27.79)

237 (29.63)

 Underweight (<18.5)

47 (1.52)

9 (1.22)

14 (1.40)

8 (1.28)

16 (2.24)

Smoking status, n (%)

0.3

 Current smoker

935 (28.61)

259 (30.22)

241 (27.28)

223 (27.42)

212 (29.75)

 Former smoker

943 (29.15)

252 (31.90)

238 (30.09)

221 (29.26)

232 (25.11)

 Never smoker

1451 (42.24)

322 (37.88)

353 (42.63)

388 (43.33)

388 (45.14)

Alcohol, n (%)

2338 (76.87)

612 (77.94)

589 (77.02)

588 (77.80)

549 (74.60)

0.6

hypertension, n (%)

2045 (56.60)

547 (61.40)

493 (53.42)

504 (55.46)

501 (56.51)

0.059

Diabetes, n (%)

1064 (25.60)

279 (25.32)

246 (24.21)

258 (26.17)

281 (26.88)

0.8

CVD, n (%)

658 (16.52)

210 (20.62)

158 (14.51)

154 (16.36)

136 (14.77)

0.017

Sleep disorder, n (%)

527 (15.41)

134 (14.24)

138 (15.07)

143 (18.27)

112 (13.91)

0.2

Self-reported cancer, n (%)

412 (14.28)

105 (15.49)

99 (14.98)

116 (15.54)

92 (10.85)

0.2

Self-reported Liver diseases, n (%)

292 (7.39)

61 (5.89)

62 (6.10)

68 (6.75)

101 (11.14)

0.012

Antidepressant drug, n (%)

937 (33.56)

251 (35.09)

245 (33.23)

226 (36.58)

215 (29.08)

0.092

CKD, n (%)

374 (9.05)

150 (14.44)

99 (9.81)

68 (7.02)

57 (4.74)

<0.001

PHQ-9 score, mean (SD)

9.46 (4.98)

9.23 (5.16)

9.37 (4.73)

9.66 (5.03)

9.57 (5.00)

0.7

Symptomatic depression, n (%)

1313 (35.90)

315 (33.87)

326 (35.77)

335 (37.10)

337 (36.87)

0.7

Year cycles, n (%)

0.007

 2007–2008

734 (20.16)

189 (19.73)

176 (17.30)

181 (22.72)

188 (21.13)

 2009–2010

679 (17.54)

165 (17.09)

171 (18.04)

168 (17.13)

175 (17.85)

 2011–2012

560 (18.82)

116 (15.77)

121 (17.47)

156 (19.02)

167 (23.30)

 2013–2014

697 (21.83)

152 (19.30)

203 (23.64)

189 (23.99)

153 (20.05)

 2015–2016

659 (21.66)

211 (28.10)

161 (23.55)

138 (17.14)

149 (17.67)