Table 1. Weighted characteristics of the analyzed sample by age-related macular degeneration (AMD) severity, NHANES 2005–2006.
| Variable | No AMD | Early AMD | Late AMD | P | η2 |
|---|---|---|---|---|---|
| Age in years, mean (95% CI) | 55.6 (54.1–57.0) | 68.3 (66.1–70.6) | 79.2 (76.1–82.3) | <0.001 | 0.93 |
| Gender, % (95% CI) | |||||
| Male | 48.1 (46.1–50.1) | 50.4 (37.4–63.4) | 31.2 (6.3–56.1) | ||
| Female | 51.8 (49.8–53.8) | 49.5 (36.5–62.5) | 68.7 (43.8–93.6) | 0.42 | 0.05 |
| Race-Ethnicity, % (95% CI) | |||||
| non-Hispanic white | 79.1 (73.8–84.3) | 85.6 (78.9–92.4) | 100 | ||
| Other | 20.8 (15.6–26.1) | 14.3 (7.5–21.0) | 0 | 0.09 | 0.15 |
| BMI, mean kg/m2 (95% CI) | 28.8 (28.2–29.4) | 29.5 (28.3–30.7) | 27.4 (25.0–29.8) | 0.25 | 0.08 |
| Mean arterial pressure, mean mmHg (95% CI) | 90.0 (89.3–90.7) | 90.1 (86.1–94.1) | 93.3 (85.3–101.3) | 0.82 | 0.05 |
| Cotinine, mean ng/mL (95% CI) | 58.5 (46.8–70.3) | 34.3 (25.4–43.2) | 15.4 (0.0–40.1) | 0.005 | 0.41 |
| Coronary heart disease, % (95% CI) | |||||
| No | 95.1 (93.7–96.4) | 89.7 (83.6–95.8) | 93.8 (82.2–100.0) | ||
| Yes | 4.8 (3.5–6.2) | 10.2 (4.1–16.3) | 6.1 (0.0–17.7) | 0.06 | 0.17 |
| Stroke, % (95% CI) | |||||
| No | 96.9 (96.2–97.7) | 90.4 (83.4–97.4) | 80.9 (59.9–100.0) | ||
| Yes | 3.0 (2.2–3.7) | 9.5 (2.5–16.5) | 19.0 (0.0–40.0) | 0.003 | 0.31 |
| Diabetes, % (95% CI) | |||||
| No | 87.9 (85.2–90.6) | 82.5 (72.6–92.3) | 93.8 (82.2–100.0) | ||
| Yes | 12.0 (9.3–14.7) | 17.4 (7.6–27.3) | 6.1 (0.0–17.7) | 0.21 | 0.09 |
| Sedentary behavior (min/day) | 494.7 (487.4–502.0) | 527.8 (496.1–559.5) | 573.7 (500.0–647.5) | 0.04 | 0.25 |
| Light-intensity physical activity (min/day) | 348.1 (341.6–354.6) | 317.8 (284.2–351.4) | 252.6 (212.9–292.2) | <0.001 | 0.62 |
| Moderate-to-vigorous physical activity (min/day) | 21.4 (19.8–23.0) | 14.2 (8.8–19.6) | 3.9 (1.3–6.5) | <0.001 | 0.92 |
| Daily movement patterns,% † | 0.004 | 0.80 | |||
| Group 1 | 12.2 (9.7–14.8) | 10.5 (1.6–19.3) | 0 | ||
| Group 2 | 27.0 (23.2–30.9) | 10.5 (1.6–19.4) | 0 | ||
| Group 3 | 9.0 (7.1–10.9) | 5.7 (0.8–10.7) | 6.7 (0.0–75.0) | ||
| Group 4 | 51.5 (47.2–55.8) | 73.1 (57.7–88.5) | 93.2 (24.9–100.0) | ||
| Accelerometer wear time, hr | 14.4 (14.2–14.5) | 14.3 (13.7–14.9) | 13.8 (12.9–14.7) | 0.20 | 0.10 |
| Valid accelerometer days, % | |||||
| 4 days | 8.7 (7.2–10.4) | 9.2 (1.8–16.5) | 11.2 (0.0–27.7) | ||
| 5 days | 17.9 (14.6–21.3) | 10.0 (1.7–18.2) | 3.7 (0.0–11.5) | ||
| 6 days | 24.7 (22.0–27.4) | 24.6 (16.6–32.6) | 32.4 (5.6–59.2) | ||
| 7 days | 48.4 (43.2–53.6) | 56.1 (45.9–66.2) | 52.6 (26.6–78.7) | 0.24 | 0.08 |
| Presenting better-eye visual acuity, mean logMAR (95% CI) | 0.06 (0.05–0.07) | 0.12 (0.09–0.15) | 0.43 (0.28–0.57) | <0.001 | 0.64 |
† 4 daily movement patterns were assessed: Group 1) sufficiently active (see methods section) light-intensity physical activity (LPA) ≥ sedentary behavior (SED); Group 2) sufficiently active and but LPA < SED; Group 3) not sufficiently active but LPA ≥ SED; and Group 4) not sufficiently active and LPA < SED.
A Wald test was used to make comparisons between no AMD and late AMD across continuous variables (e.g., age). A chi-square test (design-based likelihood ratio test) was used for categorical variables (e.g., education). The design-based likelihood ratio test converts the chi-square value into an F-statistic. Beyond probability testing, the magnitude of each Wald test F-statistic and design-based likelihood ratio F-statistic was estimated using eta-squared (η 2), with values ≥ 0.1, 0.3, and 0.5, respectively, thought to be small, medium, and large (Lau & Kuk, 2011).Eta-squared (η2) calculated using the formula: (df1*F)/((df1*F)+df2). BMI = Body mass index. The 95% confidence intervals represent the 95% confidence interval for the observed mean/proportion. No AMD, n = 1533. Early AMD, n = 107. Late AMD, n = 16. AMD, age-related macular degeneration.