Table 1.
Association of Cataract with Plasma Vitamin C
| Any Cataract or Operated Cataract | North India |
South India |
Both Centers |
|||
|---|---|---|---|---|---|---|
| Model 1⁎ | Model 2† | Model 1⁎ | Model 2† | Model 1⁎ | Model 2† | |
| Vitamin C (μmol/L) | ||||||
| Q1: All < 2 | 1 | 1 | 1 | 1 | 1 | 1 |
| Q2: 4.4 (3.1–5.7)† | ||||||
| OR | 0.70 | 0.74 | 0.84 | 0.84 | 0.74 | 0.76 |
| 95% CI | 0.53–0.94 | 0.56–0.99 | 0.63–1.13 | 0.63–1.12 | 0.60–0.91 | 0.62–0.94 |
| Q3: 12.7 (9.9–16.2)‡ | ||||||
| OR | 0.56 | 0.62 | 0.81 | 0.86 | 0.66 | 0.72 |
| 95% CI | 0.42–0.75 | 0.45–0.84 | 0.64–1.04 | 0.67–1.10 | 0.54–0.80 | 0.59–0.87 |
| Q4: 38.4 (28.2–52.5)‡ | ||||||
| OR | 0.48 | 0.55 | 0.63 | 0.71 | 0.54 | 0.61 |
| 95% CI | 0.36–0.65 | 0.41–0.74 | 0.50–0.80 | 0.57–0.89 | 0.45–0.65 | 0.51–0.74 |
| P trend§ | 3.2×10−7 | 0.00003 | 0.00003 | 0.004 | 2.2×10−10 | 1.1×10−6 |
| P interaction∥ | 0.3 | 0.4 | ||||
CI = confidence interval; OR = odds ratio.
⁎
Adjusted for age and sex.
†
Adjusted for age, sex, tobacco use, current fuels, BMI mid-upper arm circumference, diastolic blood pressure, outdoor exposure, diabetes, and socioeconomic status.
‡
Median (interquartile range).
§
Test for trend by design-adjusted Wald test with 4 ordered categories of vitamin C entered as independent continuous variable.
∥
Test for interaction by center and vitamin C by design-adjusted chi-square test.