General characteristics of participants
| Characteristics | Total participants | ||
| Nephrolithiasis | Control | P value | |
| Age (years), n (%) | 1.000 | ||
| 40–44 | 1593 (8.3) | 6372 (8.3) | |
| 45–49 | 3659 (19.2) | 14 636 (19.2) | |
| 50–54 | 4570 (23.9) | 18 280 (23.9) | |
| 55–59 | 3525 (18.5) | 14 100 (18.5) | |
| 60–64 | 2570 (13.5) | 10 280 (13.5) | |
| 65–69 | 1709 (9.0) | 6836 (9.0) | |
| 70–74 | 955 (5.0) | 3820 (5.0) | |
| 75–79 | 402 (2.1) | 1608 (2.1) | |
| 80–84 | 102 (0.5) | 408 (0.5) | |
| 85+ | 18 (0.1) | 72 (0.1) | |
| Sex, n (%) | 1.000 | ||
| Male | 12 303 (64.4) | 49 212 (64.4) | |
| Female | 6800 (35.6) | 27 200 (35.6) | |
| Income, n (%) | 1.000 | ||
| 1 (lowest) | 2576 (13.5) | 10 304 (13.5) | |
| 2 | 2269 (11.9) | 9076 (11.9) | |
| 3 | 2893 (15.1) | 11 572 (15.1) | |
| 4 | 4108 (21.5) | 16 432 (21.5) | |
| 5 (highest) | 7257 (38.0) | 29 028 (38.0) | |
| Region of residence, n (%) | 1.000 | ||
| Urban | 8667 (45.4) | 34 668 (45.4) | |
| Rural | 10 436 (54.6) | 41 744 (54.6) | |
| CCI score, n (%) | 0.005* | ||
| 0 | 18 735 (98.1) | 74 671 (97.7) | |
| 1 | 58 (0.3) | 370 (0.5) | |
| 2 | 72 (0.4) | 336 (0.4) | |
| 3 | 53 (0.3) | 257 (0.3) | |
| ≥4 | 185 (1.0) | 778 (1.0) | |
| Obesity (BMI, kg/m2), n (%) | <0.001* | ||
| <18.5 (underweight) | 267 (1.4) | 1642 (2.2) | |
| ≥18.5 to <23 (normal) | 5546 (29.0) | 27 089 (35.5) | |
| ≥23 to <25 (overweight) | 5586 (29.2) | 21 246 (27.8) | |
| ≥25 to <30 (obese I) | 7069 (37.0) | 24 472 (32.0) | |
| ≥30 (obese II) | 635 (3.3) | 1963 (2.6) | |
| Smoking status, n (%) | <0.001* | ||
| Non-smoker | 12 434 (65.1) | 48 225 (63.1) | |
| Past smoker | 2490 (13.0) | 9512 (12.5) | |
| Current smoker | 4179 (21.9) | 18 675 (24.4) | |
| Alcohol consumption, n (%) | <0.001* | ||
| Non-drinker | 11 030 (57.7) | 40 219 (52.6) | |
| 1–3 times per month | 2985 (15.6) | 12 417 (16.3) | |
| ≥1 time per week | 5088 (26.6) | 23 776 (31.1) | |
| Total cholesterol (mg/dL), mean (SD) | 201.8 (37.2) | 199.4 (37.3) | <0.001† |
| Fasting blood glucose (mg/dL), mean (SD) | 99.8 (28.8) | 99.5 (29.9) | 0.186 |
| Stroke, n (%) | 1615 (8.5) | 5476 (7.2) | <0.001* |
| Ischaemic heart disease, n (%) | 1879 (9.8) | 5895 (7.7) | <0.001* |
*χ2 test. Significance at p<0.05.
†Independent t test. Significance at p<0.05.
BMI, body mass index; CCI, Charlson Comorbidity Index.