TABLE 2.
Age- and multivariable-adjusted HRs for the risk of incident kidney stones by aMED categories in HPFS, NHS I, and NHS II, and pooled using random-effect meta-analysis
| aMED categories | P value for trend | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8–9 | ||
| HPFS | ||||||||||
| Cases | 41 | 142 | 253 | 349 | 373 | 319 | 263 | 158 | 65 | — |
| Person-years | 10,488 | 39,519 | 77,518 | 108,484 | 122,113 | 118,260 | 96,456 | 63,280 | 33,339 | — |
| Age-adjusted HR | 1.00 | 0.88 | 0.83 | 0.85 | 0.80 | 0.71 | 0.73 | 0.66 | 0.55 | <0.001 |
| 95% CI | ref | 0.62, 1.25 | 0.59, 1.15 | 0.61, 1.17 | 0.58, 1.11 | 0.51, 0.99 | 0.52, 1.01 | 0.47, 0.94 | 0.37, 0.81 | |
| Multivariable HR | 1.00 | 0.88 | 0.83 | 0.85 | 0.82 | 0.73 | 0.74 | 0.69 | 0.57 | <0.001 |
| 95% CI | ref | 0.62, 1.25 | 0.59, 1.16 | 0.61, 1.18 | 0.59, 1.13 | 0.52, 1.02 | 0.53, 1.04 | 0.48, 0.97 | 0.38, 0.85 | — |
| NHS I | ||||||||||
| Cases | 33 | 125 | 208 | 302 | 316 | 258 | 202 | 105 | 50 | — |
| Person-years | 18,971 | 77,770 | 150,463 | 204,619 | 227,969 | 214,621 | 169,765 | 106,184 | 48,451 | — |
| Age-adjusted HR | 1.00 | 0.95 | 0.80 | 0.85 | 0.79 | 0.69 | 0.67 | 0.56 | 0.59 | <0.001 |
| 95% CI | ref | 0.64, 1.39 | 0.55, 1.16 | 0.59, 1.22 | 0.55, 1.14 | 0.48, 1.00 | 0.46, 0.97 | 0.38, 0.83 | 0.38, 0.91 | — |
| Multivariable HR | 1.00 | 0.97 | 0.83 | 0.89 | 0.85 | 0.76 | 0.75 | 0.65 | 0.71 | 0.001 |
| 95% CI | ref | 0.65, 1.42 | 0.57, 1.20 | 0.62, 1.28 | 0.59, 1.23 | 0.53, 1.10 | 0.51, 1.10 | 0.43, 0.96 | 0.45, 1.10 | — |
| NHS II | ||||||||||
| Cases | 74 | 269 | 477 | 515 | 535 | 458 | 370 | 214 | 102 | — |
| Person-years | 26,321 | 106,978 | 189,458 | 241,233 | 256,746 | 237,592 | 188,673 | 121,780 | 59,582 | — |
| Age-adjusted HR | 1.00 | 0.90 | 0.90 | 0.76 | 0.75 | 0.70 | 0.70 | 0.63 | 0.61 | <0.001 |
| 95% CI | ref | 0.69, 1.16 | 0.70, 1.15 | 0.60, 0.97 | 0.59, 0.96 | 0.54, 0.89 | 0.54, 0.90 | 0.48, 0.82 | 0.45, 0.82 | — |
| Multivariable HR | 1.00 | 0.94 | 0.96 | 0.84 | 0.85 | 0.81 | 0.84 | 0.78 | 0.80 | 0.003 |
| 95% CI | ref | 0.72, 1.21 | 0.75, 1.23 | 0.66, 1.07 | 0.67, 1.09 | 0.63, 1.04 | 0.65, 1.08 | 0.59, 1.01 | 0.59, 1.08 | — |
| Pooled | ||||||||||
| Cases | 148 | 536 | 938 | 1166 | 1224 | 1035 | 835 | 477 | 217 | — |
| Person-years | 55,780 | 224,267 | 417,439 | 554,336 | 606,828 | 570,473 | 454,894 | 291,244 | 141,372 | — |
| Age-adjusted HR | 1.00 | 0.90 | 0.86 | 0.80 | 0.77 | 0.70 | 0.70 | 0.62 | 0.58 | <0.001 |
| 95% CI | ref | 0.72, 1.08 | 0.68, 1.02 | 0.65, 0.95 | 0.59, 0.92 | 0.59, 0.83 | 0.52, 0.83 | 0.47, 0.75 | 0.37, 0.72 | — |
| Multivariable HR | 1.00 | 0.94 | 0.93 | 0.89 | 0.86 | 0.84 | 0.78 | 0.79 | 0.72 | <0.001 |
| 95% CI | ref | 0.93, 0.95 | 0.77, 1.11 | 0.75, 1.06 | 0.72, 1.02 | 0.71, 1.00 | 0.65, 0.93 | 0.66, 0.94 | 0.59, 0.87 | — |
Multivariable models were adjusted for age, BMI, history of high blood pressure, history of diabetes, use of thiazides, intake of supplemental calcium, supplemental vitamin C, total vitamin D, fluid, and caffeine. aMED: alternate Mediterranean Diet Score; HPFS, Health Professionals Follow-up Study; NHS I, Nurses’ Health Study I; NHS II, Nurses’ Health Study II; Ref, reference group.