Table 1.
Selected characteristics of AMD cases and controls in Physicians’ Health Study II.
| AMD Cases (n=146) | No AMD (n=146) | P value | |
|---|---|---|---|
| Age (mean [SD], y) | 73.6 (6.3) | 72.8 (6.0) | Matched |
| Cigarette smoking, % | Matched | ||
| Current | 1.4 | 1.4 | |
| Past | 59.6 | 59.6 | |
| Never | 39.0 | 39.0 | |
| Alcohol intake, % | 0.57 | ||
| Rarely/never | 18.5 | 21.2 | |
| ≥1 drink/month | 81.5 | 78.8 | |
| Body mass index (kg/m2) (mean [SD]) | 25.5 (3.2) | 25.5 (3.3) | 0.97 |
| Current exercise ≥1 time/wk, % | 65.8 | 65.8 | 1.00 |
| Reported history, % | |||
| High cholesterol* | 32.9 | 44.5 | 0.04 |
| Diabetes | 6.9 | 7.5 | 0.82 |
| Plasma homocysteine, μmol/L (median [IQR]) | 14.0 ( 12.7–17.1) | 14.0 (12.2–16.2) | 0.67 |
| Total dietary folate, μg/d (median [IQR]) | 401.7 (334.2–597.6) | 462.4 (344.8–698.5) | 0.027 |
| Total dietary vitamin B6, mg/d (median [IQR]) | 2.0 (1.7–2.9) | 2.2 (1.8–3.5) | 0.99 |
| Total dietary vitamin B12, μg/d (median [IQR]) | 5.8 (4.2–10.6) | 6.3 (4.4–12.7) | 0.30 |
| Total dietary choline, mg/d (median [IQR]) | 301.6 (264.5–327.8) | 306.0 (268.3–336.7) | 0.40 |
| water soluble | 134.2 (116.0–152.1) | 135.8 (116.9–162.0) | 0.17 |
| lipid soluble | 162.4 (132.6–191.0) | 160.2 (130.0–193.5) | 0.84 |
| Total dietary betaine, mg/d (median [IQR]) | 89.8 (68.0–123.5) | 105.8 (71.5–144.3) | 0.04 |
Abbreviations: AMD, age-related macular degeneration; SD, standard deviation; IQR, interquartile range.
*
History of high cholesterol was defined as self-reported total cholesterol level of at least 240 mg/dL or past or current treatment for high cholesterol.