Table 1.
Population characteristics
| Eligible population(n = 18 913) | Case-cohort population (n = 312) | ||||
|---|---|---|---|---|---|
| Non-CKD (n = 159) | CKD (n = 153) | ||||
| Cohort (n = 111) | Cases (n = 48) | Cohort (n = 112) | Cases (n = 48) | ||
| Demography | |||||
| Age, years | 53 (48-61)a | 53 (46-60) | 57 (51-63)b | 64 (59-67) | 60 (55-66)b |
| Sex, female | 9587 (50.7) | 51 (45.9) | 35 (69.2)b | 48 (42.9) | 31 (64.6)b |
| White ethnicity | 16937 (89.6) | 103 (92.8) | 44 (91.7) | 104 (92.9) | 45 (93.8) |
| Clinical parameters | |||||
| eGFR (mL/min/1.73 m2) | 90 (78-99)a | 90 (79-100) | 91 (81-99) | 56 (50-59) | 52 (46-56)b |
| Body mass index (kg/m2) | 27 ± 5 | 28 ± 5 | 28 ± 6 | 30 ± 6 | 29 ± 6 |
| Active smoking | 3593 (19.0) | 20 (18.0) | 4 (8.3) | 14 (12.5) | 16 (33.3)b |
| Weekly alcohol servings | 2 (0-6)a | 3 (1-7) | 1 (0-5)b | 1 (0-3) | 1 (0-5) |
| Prior fracture | 655 (3.5) | 3 (2.7) | 4 (8.3) | 2 (1.8) | 5 (10.4)b |
| Secondary osteoporosis | 2888 (15.3) | 18 (16.2) | 13 (27.1)b | 27 (24.1) | 15 (31.3) |
| Diabetes | 1876 (9.9)a | 10 (9.0) | 4 (8.3) | 25 (22.3) | 8 (16.7) |
| Cardiovascular disease | 1304 (6.9)a | 8 (7.2) | 2 (4.2) | 21 (18.8) | 9 (18.8) |
| Calcaneal QUS stiffness index | 103 ± 19 | 104 ± 17 | 94 ± 20b | 102 ± 19 | 94 ± 20b |
| Medication | |||||
| Glucocorticoids | 136 (0.7)a | 0 (0) | 0 (0) | 3 (2.7) | 3 (6.3) |
| Bisphosphonates | 683 (3.6) | 2 (1.8) | 7 (14.6)b | 9 (8.0) | 7 (14.6) |
| Hormonal replacement therapy | 1351 (3.6) | 8 (7.2) | 8 (16.7) | 7 (6.3) | 3 (6.3) |
| Oral contraceptives | 268 (1.4) | 0 (0) | 1 (2.1) | 0 (0) | 0 (0) |
| Mineral parameters | |||||
| cFGF23, RU/mL | 80 (73-91) | 79 (73-98) | 88 (79-105) | 92 (79-114) | |
| α-Klotho, pg/mL | 677 (565-877) | 713 (583-862) | 662 (543-831) | 651 (498-783) | |
| PTH, ng/L | 17.3 (11.6-23.1) | 14.9 (8.9-23.7) | 19.7 (11.3-27.5) | 20.8 (13.0-28.3) | |
| Phosphate, mmol/L | 1.10 ± 0.21 | 1.07 ± 0.20 | 1.08 ± 0.22 | 1.15 ± 0.28 | |
| Calcium, mmol/L | 2.38 ± 0.10 | 2.38 ± 0.09 | 2.36 ± 0.11 | 2.37 ± 0.13 | |
Continuous variables are presented as means (SD) or medians (interquartile range) according to their distribution. Categorical variables are presented as counts (percentages). Abbreviations: CKD, chronic kidney disease; eGFR, estimated glomerular filtration rate; PTH, parathyroid hormone. QUS, quantitative ultrasound.
aIndicates a P value < 0.05 for non-CKD vs CKD comparison.
bIndicates a P value < 0.05 for cases vs cohort patients in a given CKD status.