Table 1.
Associations between exposures and nephrolithiasis, and evidence class reported in meta-analyses.
| Exposures | No. cases/total population | No. of study estimates | Study design | Effect metrics | Effect of largest study in meta-analysis | Random effect summary estimate (95% CI) | Random-effects P value | I2 (%) | 95% prediction interval | P value for Egger test | Excess significance bias P value | Large heterogeneity, small study effect, excess significance bias, P>0·05 of the largest study in meta-analysis | Evidence level |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Metabolic factors | |||||||||||||
| Waist circumference | 4282/256 502 | 3 studies, 5 cohort | cohort | RR | 1.18 (1.12, 1.25) | 1.16 (1.12, 1.19) | 1.63E-19 | 0 | (1.10, 1.20) | 0.136 | 0.731 | None | I |
| BMI | 10 368/459 860 | 5 studies, 8 cohorts | Cohorts/case-control | RR | 1.39 (1.26, 1.53) | 1.21 (1.12, 1.30) | 1.06E-06 | 77.3 | (1.02, 1.90) | 0.240 | 0.141 | Large heterogeneity | II |
| T2D | 21 676/738 222 | 12 studies, 12 cohorts | Cohort/case-control | RR | 1.11 (0.91, 1.34) | 1.18 (1.07, 1.29) | 1.84E-13 | 60.8 | (0.89, 1.57) | 0.705 | 0.401 | Large heterogeneity | II |
| Gout | At least 12 110 cases/NR | 3 studies, 3 cohorts | Cross-sectional | OR | 1.49 (1.04, 2.14) | 1.77 (1.43, 2.19) | 1.52E-07 | 0 | (0.44, 7.05) | 0.97 | 0.156 | None | II |
| NAFLD | NR/238 400 | 8 studies, 8 cohorts | Cohort/Cross-section | OR | 1.08 (0.90, 1.30) | 1.81 (1.29, 2.56) | 6.99E-04 | 92.1 | (0.58, 5.61) | 0.737 | 0.256 | Large heterogeneity, P>0·05 of the largest study in meta-analysis | III |
| Metabolic syndrome | At least 1396/64 867a | 6 studies, 6 cohorts | Cross-sectional | OR | 1.11 (1.03, 1.19) | 1.35 (1.16, 1.55) | 1.77E-04 | 81.9 | (0.80, 2.28) | 0.147 | 0.122 | Large heterogeneity | III |
| HDL-C (decreased) | 10 974/257 413 | 9 studies, 9cohorts | Cohort/Cross-section | OR | 0.97 (0.89, 1.06) | 1.17 (1.01, 1.36) | 0.031 | 81.2 | (0.74, 1.87) | 0.319 | 0.709 | Large heterogeneity, P>0·05 of the largest study in meta-analysis | IV |
| Triglycerides | 10 272/205 229 | 8 studies, 8 cohorts | Cohort/Cross-section | OR | 1.03 (0.97, 1.10) | 1.29 (1.07, 1.54) | 0.007 | 85.9 | (0.71, 2.33) | 0.098 | 0.949 | Large heterogeneity, small study effect. | IV |
| Hypertension | At least 18 023/544 713a | 11 studies, 13 cohorts | Cohort | RR | 0.95 (0.91, 1.01) | 1.30 (1.11, 1.52) | 0.002 | 92.3 | (0.72, 2.36) | 0.035 | 0.435 | Large heterogeneity, small study effect, P>0·05 of the largest study in meta-analysis | IV |
| Gallstones | 42 084/363 765 | 2 studies, 4 cohorts | Cohort | RR | 1.97 (1.81, 2.15) | 1.46 (1.15, 1.85) | 0.002 | 95.7 | (0.47, 4.57) | 0.424 | 0.255 | Large heterogeneity | IV |
| Impaired glucose tolerance | At least 1091/62041a | 4 studies, 4 cohorts | Cross-sectional | OR | 1.03 (0.96, 1.10) | 1.26 (0.94, 1.58) | 0.196 | 96.1 | (0.28, 5.41) | 0.971 | 0.919 | Large heterogeneity, P>0·05 of the largest study in meta-analysis | NS |
| Fluid and beverages intake | |||||||||||||
| Soda | 5031/221 728 | 3 studies, 5 cohorts | Cohorts/case-control | RR | 1.51 (1.37, 1.66) | 1.38 (1.26, 1.51) | 8.49E-12 | 35.8 | (1.08, 1.76) | 0.275 | 0.811 | None | I |
| Caffeine | 4982/217 883 | 1 study, 3 cohorts | Cohorts | HR | 0.69 (0.58, 0.82) | 0.71 (0.64, 0.79) | 8.03E-11 | 0 | (0.36, 1.39) | 0.874 | 0.362 | None | II |
| Fluid | 4765/273 954 | 9 studies, 9 cohorts | RCTs/Cohort/case-control | RR | 0.68 (0.56, 0.83) | 0.47 (0.33, 0.67) | 2.79E-05 | 90.6 | (0.14, 1.58) | 0.172 | 0.37 | Large heterogeneity | III |
| Alcohol | 4701/539 583 | 6 studies, 7cohorts | Cohort/Case-control | RR | 0.54 (0.47, 0.62) | 0.69 (0.56, 0.85) | 2.16E-04 | 71.9 | (0.36, 1.32) | 0.296 | 0.785 | Large heterogeneity | III |
| Beer | 6050/223 734 | 4 studies, 5 cohorts | Cohort/case-control | RR | 0.59 (0.46, 0.76) | 0.60 (0.49, 0.74) | 1.67E-06 | 35.7 | (0.35, 1.04) | 0.766 | 0.547 | None | III |
| Coffee | NR/170 544a | 6 studies, 10cohorts | Cohort/case-control | OR | 0.51 (0.36, 0.75) | 0.70 (0.60, 0.82) | 1.63E-05 | 42.7 | (0.46, 1.07) | 0.439 | 0.648 | None | III |
| Tea | 10 760/790 026 | 6 studies, 8 cohorts | Cohort/case-control | RR | 0.85 (0.78, 0.92) | 0.88 (0.79, 0.97) | 0.013 | 63.1 | (0.65, 1.19) | 0.722 | 0.697 | Large heterogeneity | IV |
| Milk | At least 6535/224 380a | 5 studies, 5 cohorts | Cohort/Case-control | RR | 1.00 (0.94, 1.07) | 0.95 (0.86, 1.05) | 0.325 | 52.9 | (0.71, 1.27) | 0.652 | 0.579 | Large heterogeneity, P>0·05 of the largest study in meta-analysis | NS |
| Juice | 5810/223 102 | 3 studies | Cohort/Case-control | RR | 0.95 (0.88, 1.03) | 1.00 (0.92, 1.09) | 0.951 | 33.5 | (0.46, 2.17) | 0.369 | 0.748 | P>0·05 of the largest study in meta-analysis | NS |
| Vitamin and calcium intake | |||||||||||||
| Calcium supplement | 2087/187 976 | 2 studies, 2 cohorts | Cohorts | RR | 1.13 (0.92, 1.36) | 1.16 (1.00, 1.35) | 0.047 | 0 | / (study number not enough) | / (study number not enough) | 0.811 | P>0·05 of the largest study in meta-analysis | III |
| Dietary calcium | 9695/41 4911 | 4 studies, 6 cohorts | Cohort | RR | 0.79 (0.69, 0.89) | 0.83 (0.76, 0.90) | 2.43E-05 | 20.4 | (0.69, 0.99) | 0.206 | 0.1425 | None | III |
| Total vitamin D | 6905/220 552 | 2 studies, 4 cohorts | Cohorts | RR | 1.18 (0.94, 1.48) | 1.07 (0.93, 1.23) | 0.358 | 0 | (0.79, 1.46) | 0.101 | 0.715 | P>0·05 of the largest study in meta-analysis | NS |
| Vitamin D supplement | 7815/210 199 | 10 studies, 12 cohorts | RCTs/Cohorts/case-control | RR | 1.38 (1.03, 1.85) | 1.07 (0.92, 1.26) | 0.381 | 0 | (0.90, 1.28) | 0.359 | 0.348 | None | NS |
| Total vitamin C | 6574/224 272 | 2 studies, 3 cohorts | Cohorts | RR | 0.99 (0.90, 1.09) | 1.15 (0.95, 1.26) | 0.268 | 78.0 | (0.06, 21.46) | 0.491 | 0.678 | Large heterogeneity, P>0·05 of the largest study in meta-analysis | NS |
| Vitamin C supplement | 11 917/385 747 | 5 studies, 8 cohorts | Cohorts/case-control | RR | 0.90 (0.79, 1.04) | 1.10 (0.95, 1.26) | 0.204 | 64.8 | (0.73, 1.66) | 0.208 | 0.583 | Large heterogeneity, P>0·05 of the largest study in meta-analysis | NS |
| Total vitamin B6 | 6905/220 677 | 2 studies, 4 cohorts | Cohorts | RR | 1.06 (0.91, 1.24) | 1.01 (0.91, 1.12) | 0.881 | 0 | (0.83, 1.27) | 0.092 | 0.681 | None | NS |
| Dietary intake | |||||||||||||
| Dietary sodium | 5172/660 412 | 4 studies, 4 cohorts | cohort | RR | 1.33 (1.12, 1.58) | 1.38 (1.21, 1.56) | 7.42E-07 | 23.2 | (0.93, 2.05) | 0.513 | 0.449 | None | II |
| Fructose intake | 4902/241 538 | 1 study, 3 cohorts | Cohort | RR | 1.27 (1.04, 1.54) | 1.33 (1.19, 1.49) | 8.65E-07 | 0 | (0.65, 2.74) | 0.795 | 0.194 | None | II |
| Meat | 3820/507 780 | 4 studies, 5 cohorts | Cohorts/case-control | RR | 1.21 (1.05, 1.39) | 1.24 (1.12, 1.39) | 8.49E-05 | 0 | (1.05, 1.46) | 0.256 | 0.131 | None | III |
| Spinach | 1473/45 619 | 1 study, 3 cohorts | Cohort | RR | 1.34 (1.10, 1.64) | 1.21 (1.01, 1.44) | 0.035 | 56.7 | (0.18, 8.07) | 0.390 | 0.266 | Large heterogeneity | IV |
| Fiber | 4750/570 859 | 3 studies, 3 cohorts | Cohort | RR | 0.67 (0.60, 0.75) | 0.71 (0.64, 0.79) | 4.11E-11 | 15.9 | (0.31, 1.63) | 0.727 | 0.223 | None | II |
| DASH-diet | 6449/192 126 | 1 study, 3 cohort | Cohort | RR | 0.65 (0.56, 0.76) | 0.69 (0.64, 0.75) | 6.83E-17 | 0 | (0.42, 1.12) | 0.403 | 0.367 | None | II |
| Dietary potassium | 6637/220 677 | 2 studies, 4 cohorts | Cohort | RR | 0.67 (0.57, 0.78) | 0.59 (0.46, 0.75) | 8.59E-06 | 75.4 | (0.21, 1.65) | 0.990 | 0.725 | Large heterogeneity | III |
| Dietary magnesium | 2105/123 956 | 3 cohorts | Cohort | RR | 0.62 (0.43, 0.89) | 0.56 (0.46, 0.75) | 5.90E-06 | 0 | (0.20, 2.15) | 0.06 | 0.102 | None | III |
| Fruit | 6504/588 959 | 5 studies, 6 cohorts | Cohorts/case-control | RR | 0.79 (0.71, 0.89) | 0.79 (0.71, 0.89) | 1.09E-04 | 30.1 | (0.61, 1.03) | 0.527 | 0.135 | None | III |
| Vegetable | 5485/586 953 | 4 studies, 4 cohorts | Cohorts | RR | 0.90 (0.81, 1.00) | 0.84 (0.75, 0.94) | 0.002 | 42.7 | (0.55, 1.26) | 0.695 | 0.164 | None | IV |
| Energy | 8050/350 694 | 3 studies, 5 cohorts | Cohort | RR | 1.01 (0.85, 1.18) | 1.12 (0.99, 1.27) | 0.075 | 42.0 | (0.26, 4.65) | 0.022 | 0.234 | Large heterogeneity, P>0·05 of the largest study in meta-analysis, small study effect. | NS |
| Other factors | |||||||||||||
| Higher temperatures | At least 490 057 cases/NRa | 4 studies, 8 cohorts | Cohort/case-control | OR | 1.30 (1.20, 1.41) | 1.32 (1.24, 1.39) | 2.54E-21 | 0 | (1.22, 1.43) | 0.175 | 0.044 | Excess significance bias | II |
| Polycystic kidney disease | 128/1368 | 6 studies, 6 cohorts | Case-controls | RR | 1.75 (0.98, 2.64) | 1.85 (1.29, 2.64) | 6.99E-04 | 0 | (1.11, 3.08) | 0.177 | 0.724 | P>0·05 of the largest study in meta-analysis | III |
| Inflammatory bowel disease | 222/1624 | 5 studies, 5 cohorts | Cohort/case-control | RR | 5.62 (4.37, 7.24) | 3.86 (1.14, 13.03) | 0.030 | 88.4 | (0.08, 197.67) | 0.835 | 0.629 | Large heterogeneity | IV |
| Cadmium exposure | NR/88 045a | 6 studies, 6 cohorts | Cohort/ Cross-sectional study | OR | 1.29 (1.01, 1.61) | 1.32 (1.08, 1.62) | 0.007 | 58.1 | (0.74, 2.35) | 0.001 | 0.114 | Large heterogeneity, small study effect. | IV |
| Pulp Stones | 147/284 | 2 studies, 2 cohorts | Case-control | OR | 1.71 (0.90, 3.5) | 1.97 (1.22, 3.18) | 0.006 | 0 | / (study number not enough) | / (study number not enough) | 0.495 | None | IV |
| Physical activity | 7747/299 358 | 2 studies, 4 cohorts | Cohort | RR | 1.02 (0.85, 1.21) | 0.91 (0.73, 1.12) | 0.379 | 89.4 | (0.33, 2.54) | 0.204 | 0.884 | Large heterogeneity, P>0·05 of the largest study in meta-analysis | NS |
| Bariatric surgery | NR/11 348a | 4 studies, 4 cohorts. | RCTs/cohorts | RR | 1.71 (1.44, 2.04) | 1.22 (0.63, 2.35) | 0.551 | 82.8 | (0.07, 20.20) | 0.443 | 0.077 | Large heterogeneity | NS |
| Postmenopausal hormone | NR/71101a | 3 studies, 7 cohorts | RCTs/cohorts/case-control | RR | 1.08 (0.87, 1.34) | 0.91 (0.72, 1.14) | 0.397 | 74.1 | (0.46, 1.81) | 0.007 | 0.274 | Large heterogeneity, P>0·05 of the largest study in meta-analysis, small study effect | NS |
DASH-diet, dietary approaches to stop hypertension-diet; HDL-C, high-density lipoprotein cholesterol; NAFLD, non-alcoholic fatty liver disease; OR, odds ratio; RR, risk ratio; T2D, type 2 diabetes.
a
Some original studies did not offer detailed number of participants.