Table 3.
Association between fiber, fruit and vegetable intake and the risk of kidney stone formation during participation in the Women's Health Initiative Observational Study, in separate adjusted regression models stratified by history of nephrolithiasis.
| No History of Nephrolithiasis n=80,451 | History of Nephrolithiasis n=3,471 | ||||
|---|---|---|---|---|---|
| Intake (quintile) | Intake Range | aHR** (95% CI) | p value | aHR** (95% CI) | p value |
| Fiber | (g/day)* | <0.001 | 0.93 | ||
| Lowest | 0-10.6 | Ref | Ref | ||
| Second | 10.6-14.0 | 0.94 (0.83-1.08) | 0.92 (0.76-1.12) | ||
| Third | 14.0-17.5 | 0.92 (0.81-1.05) | 0.94 (0.77-1.14) | ||
| Fourth | 17.5-21.9 | 0.74 (0.63-0.86) | 0.94 (0.75-1.18) | ||
| Highest | 21.9-99.4 | 0.78 (0.67-0.92) | 0.98 (0.77-1.26) | ||
| Fruit | (portions/day)* | <0.001 | 0.73 | ||
| Lowest | 0-1.0 | Ref | Ref | ||
| Second | 1.0-1.5 | 0.88 (0.77-0.99) | 0.87 (0.72-1.05) | ||
| Third | 1.5-2.1 | 0.82 (0.72-0.93) | 0.97 (0.79-1.18) | ||
| Fourth | 2.1-3.0 | 0.75 (0.66-0.86) | 0.92 (0.74-1.15) | ||
| Highest | 3.0-11 | 0.85 (0.74-0.98) | 0.93 (0.76-1.14) | ||
| Vegetable | (portions/day)* | 0.002 | 0.50 | ||
| Lowest | 0-1.2 | Ref | Ref | ||
| Second | 1.2-1.7 | 0.91 (0.80-1.03) | 0.90 (0.75-1.07) | ||
| Third | 1.7-2.4 | 0.85 (0.74-0.96) | 0.98 (0.81-1.18) | ||
| Fourth | 2.4-3.3 | 0.78 (0.69-0.90) | 0.86 (0.71-1.05) | ||
| Highest | 3.3-13.3 | 0.78 (0.68-0.91) | 0.85 (0.69-1.05) | ||
*
The ranges of intake for the quintile categories of fiber, fruit and vegetable intake are non-overlapping ranges.
**
Adjusted for age, race, region, diabetes mellitus, calcium supplementation, hormone therapy use categories, BMI categories, calibrated calorie intake, and quintiles of dietary water, sodium, animal protein, and calcium intake.