Table 2.
HRs (95% CIs) for associations between tea, alcohol, and fruit consumption and risk of kidney stones (n = 502,621).
| Cases | Cases/PYs (/10,000) |
Model 1 | Model 2 | Model 3 | |
|---|---|---|---|---|---|
| Tea consumption | |||||
| Never | 2676 | 13.99 | 1.00 | 1.00 | 1.00 |
| Less than daily | 5240 | 25.29 | 0.99 (0.94, 1.04) | 0.98 (0.93, 1.03) | 0.99 (0.94, 1.04) |
| Daily (cups/day) | |||||
| 1–2 | 1471 | 43.59 | 1.01 (0.94, 1.09) | 1.01 (0.94, 1.08) | 1.02 (0.95, 1.10) |
| 3–4 | 2010 | 40.47 | 0.90 (0.84, 0.96) | 0.89 (0.83, 0.96) | 0.91 (0.85, 0.98) |
| 5–6 | 660 | 20.66 | 0.88 (0.80, 0.96) | 0.86 (0.79, 0.94) | 0.89 (0.81, 0.98) |
| ≥7 | 350 | 14.12 | 0.72 (0.64, 0.80) | 0.71 (0.63, 0.79) | 0.73 (0.65, 0.83) |
| p for trend a | <0.001 | <0.001 | <0.001 | ||
| Alcohol consumption | |||||
| Never | 6146 | 24.03 | 1.00 | 1.00 | 1.00 |
| Less than daily | 5000 | 21.29 | 0.97 (0.93, 1.01) | 0.97 (0.93, 1.02) | 0.98 (0.94, 1.02) |
| Daily (grams/day) | |||||
| <30.0 | 319 | 21.60 | 0.94 (0.83, 1.05) | 0.94 (0.84, 1.06) | 0.95 (0.85, 1.07) |
| 30.0–59.9 | 529 | 26.42 | 0.79 (0.72, 0.87) | 0.78 (0.71, 0.86) | 0.79 (0.72, 0.87) |
| 60.0–89.9 | 177 | 28.80 | 0.78 (0.67, 0.91) | 0.76 (0.65, 0.89) | 0.77 (0.66, 0.90) |
| ≥90.0 | 236 | 33.23 | 0.77 (0.67, 0.88) | 0.75 (0.66, 0.86) | 0.77 (0.67, 0.88) |
| p for trend a | 0.609 | 0.328 | 0.346 | ||
| Fruit consumption | |||||
| Less than weekly | 5533 | 25.65 | 1.00 | 1.00 | 1.00 |
| 1–3 d/w | 4556 | 26.82 | 0.95 (0.92, 0.99) | 0.96 (0.93, 1.01) | 0.96 (0.92, 1.00) |
| 4–6 d/w | 1028 | 20.10 | 0.89 (0.83, 0.95) | 0.90 (0.84, 0.97) | 0.89 (0.83, 0.96) |
| 7 d/w | 1290 | 12.66 | 0.77 (0.72, 0.83) | 0.81 (0.75, 0.87) | 0.81 (0.75, 0.87) |
| p for trend b | <0.001 | <0.001 | <0.001 |
Abbreviations: HR, hazard ratio; CI, confidence interval; PYs, person years. Model 1 was adjusted for sex (male, female); model 2: further adjusted for education (no formal school, primary school, middle school, high school, college, or university or above), occupation (agriculture, industrial, administrative or managerial, professional or technical, sales or service, retired, house wife or husband, self-employed, unemployed, or other), household income (<2500, 2500–4999, 5000–9999, 10,000–19,999, 20,000–34,999, or ≥35,000 CNY/year), smoking status (never or occasional, former, daily smoking 1–14, 15–24, or ≥ 25 cigarettes or equivalent tobacco; former smokers who had stopped smoking because of illness were included in the current daily smokers), physical activity (MET-h/day), intake of red meat, dairy products, and vegetables (variables were assigned according to the midpoint value of intake frequency: never or rarely = 0, monthly = 0.5, 1–3 days/week = 2, 4–6 days/week = 5, or daily = 7; and were adjusted as continuous variables), dietary supplement use of vitamin, calcium, iron or zinc for at least one month (yes or no), BMI (kg/m2), waist-to-hip ratio, prevalent hypertension (presence or absence), and prevalent diabetes (presence or absence); model 3: further mutually adjusted for tea, alcohol, and fruit consumption. a Tests for linear trend were conducted in daily tea or alcohol consumers by assigning the median value of tea (in cups per day) or alcohol (in grams per day) drinking to each of the categories. b Test for linear trend were conducted in all participants by assigning the midpoint value of fruit intake frequency to each of the categories.