Table 2.
Multivariable adjusted estimates of association between modifiable risk factors and incidence of kidney stones
| HPFS | NHS I | NHS II | ||||
|---|---|---|---|---|---|---|
|
| ||||||
| IRR | 95% CI | IRR | 95% CI | IRR | 95% CI | |
|
| ||||||
| BMI | ||||||
| - < 25 kg/m2 | 1.00 | 1.00 | 1.00 | |||
| - 25–29 kg/m2 | 1.26 | 1.14, 1.39 | 1.40 | 1.25, 1.57 | 1.34 | 1.23, 1.47 |
| - ≥ 30 kg/m2 | 1.44 | 1.23, 1.67 | 1.80 | 1.57, 2.05 | 1.71 | 1.56, 1.88 |
|
| ||||||
| Fluid intake | ||||||
| - ≥ 2 liters/day | 1.00 | 1.00 | 1.00 | |||
| - 1.9–1 liters/day | 1.53 | 1.37, 1.69 | 1.29 | 1.15, 1.44 | 1.30 | 1.20, 1.41 |
| - < 1 liter/day | 1.86 | 1.58, 2.14 | 1.86 | 1.58, 2.18 | 1.75 | 1.56, 1.97 |
|
| ||||||
| DASH-style diet | ||||||
| - Fifth quintile | 1.00 | 1.00 | 1.00 | |||
| - Fourth quintile | 1.06 | 0.90, 1.25 | 0.98 | 0.82, 1.17 | 1.18 | 1.04, 1.34 |
| - Third quintile | 1.21 | 1.04, 1.42 | 1.22 | 1.03, 1.44 | 1.09 | 0.96, 1.24 |
| - Second quintile | 1.36 | 1.17, 1.59 | 1.32 | 1.12, 1.56 | 1.33 | 1.18, 1.51 |
| - First quintile | 1.53 | 1.31, 1.78 | 1.47 | 1.25, 1.73 | 1.37 | 1.21, 1.55 |
|
| ||||||
| Dietary calcium intake | ||||||
| - Fifth quintile | 1.00 | 1.00 | 1.00 | |||
| - Fourth quintile | 1.09 | 0.94, 1.27 | 1.16 | 0.98, 1.37 | 1.06 | 0.93, 1.20 |
| - Third quintile | 1.02 | 0.87, 1.19 | 1.07 | 0.90, 1.27 | 1.13 | 1.00, 1.27 |
| - Second quintile | 1.14 | 0.98, 1.32 | 1.17 | 0.99, 1.39 | 1.18 | 1.04, 1.33 |
| - First quintile | 1.18 | 1.01, 1.37 | 1.21 | 1.02, 1.44 | 1.27 | 1.12, 1.44 |
|
| ||||||
| SSB intake | ||||||
| - <4 servings/week | 1.00 | 1.00 | 1.00 | |||
| - 4–6 servings/week | 1.23 | 1.09, 1.38 | 1.18 | 1.03, 1.37 | 1.19 | 1.07, 1.32 |
| - ≥7 servings/week | 1.41 | 1.23, 1.62 | 1.31 | 1.10, 1.56 | 1.51 | 1.37, 1.66 |
Models adjusted for age, race, geographic area, use of thiazide diuretics, history of diabetes, history of hypertension and all the other risk factors (DASH-score was not adjusted for dietary calcium and SSB intake). BMI, body mass index; CI, confidence interval; HPFS, Health Professionals Follow-up Study; IRR, incidence rate ratio; NHS, Nurses’ Health Study; SSB, sugar-sweetened beverages