Table 1.
Cross-sectional characteristics of participants, NHANES 1999–2008
| No. of available cases | Overall (n = 11,180) | Emmetropes (n = 5909) | Mild myopia (n = 3961) | Moderate myopia (n = 1034) | High myopia (n = 276) | P value | |
|---|---|---|---|---|---|---|---|
| Weighted proportion (%) | 11,180 | 51.84 (0.87) | 34.16 (0.74) | 10.74 (0.58) | 3.27 (0.31) | ||
| SE (D) | 11,180 | -1.13 (0.04) | 0.02 (0.01) | -1.30 (0.02) | -4.14 (0.04) | -7.84 (0.16) | < 0.001 |
| Age (year) | 11,180 | 18.32 (0.07) | 18.12 (0.09) | 18.32 (0.11) | 18.83 (0.19) | 19.97 (0.28) | < 0.001 |
| Sex (%) | 11,180 | < 0.001 | |||||
| Male | 5542 | 50.82 (0.58) | 53.33 (0.87) | 51.06 (1.15) | 40.80 (2.12) | 41.45 (3.94) | |
| Female | 5638 | 49.18 (0.58) | 46.67 (0.87) | 48.94 (1.15) | 59.20 (2.12) | 58.55 (3.94) | |
| Ethnicity (%) | 11,180 | < 0.001 | |||||
| Mexican American | 3636 | 12.01 (0.94) | 11.99 (0.90) | 13.61 (1.22) | 8.35 (1.21) | 7.57 (1.51) | |
| Other Hispanic | 607 | 6.63 (0.82) | 6.90 (1.20) | 6.61 (0.88) | 5.95 (1.10) | 4.86 (1.85) | |
| Non-Hispanic White | 3230 | 61.27 (1.53) | 61.73 (1.64) | 58.98 (1.76) | 65.09 (2.50) | 65.37 (3.73) | |
| Non-Hispanic Black | 3221 | 13.81 (1.02) | 14.11 (1.08) | 14.51 (1.19) | 11.50 (1.37) | 9.51 (1.70) | |
| Other Race | 486 | 6.27 (0.54) | 5.27 (0.66) | 6.28 (0.67) | 9.11 (1.53) | 12.70 (3.27) | |
| Education level (%) | 11,176 | < 0.001 | |||||
| < 9th Grade | 4187 | 27.34 (0.69) | 29.28 (0.98) | 27.98 (1.07) | 21.50 (1.75) | 9.21 (1.79) | |
| 9–12th Grade | 4101 | 30.04 (0.76) | 31.43 (1.07) | 28.79 (1.00) | 28.61 (1.98) | 25.78 (3.56) | |
| High School Grade | 1358 | 16.08 (0.70) | 15.95 (0.93) | 16.53 (1.01) | 14.81 (1.81) | 17.54 (2.79) | |
| College or above | 1530 | 26.54 (0.99) | 23.35 (1.25) | 26.70 (1.31) | 35.07 (2.34) | 47.46 (3.60) | |
| BMI (kg/m2) | 11,180 | 24.65 (0.11) | 24.50 (0.14) | 24.83 (0.15) | 24.89 (0.28) | 24.60 (0.41) | 0.042 |
| WC (cm) | 11,180 | 84.81 (0.30) | 85.41 (0.78) | 85.19 (0.41) | 84.47 (0.38) | 84.15 (1.05) | 0.068 |
| WWI (cm/√kg) | 11,180 | 10.22 (0.02) | 10.24 (0.03) | 10.22 (0.02) | 10.21 (0.02) | 10.13 (0.05) | 0.084 |
| PIR | 10,329 | 2.42 (0.04) | 2.38 (0.05) | 2.41 (0.05) | 2.68 (0.09) | 2.42 (0.18) | < 0.001 |
| TV and computer use (hours per day) | 7074 | 4.13 (0.04) | 3.87 (0.15) | 4.07 (0.06) | 4.08 (0.09) | 4.19 (0.05) | < 0.001 |
| Vitamin D level, nmol/La | 7910 | 62.95 (0.78) | 63.43 (0.83) | 61.98 (0.94) | 63.90 (1.35) | 62.29 (2.78) | 0.036 |
Data were weighted estimates and expressed as the mean (standard error) or percentage (%)
aThe serum vitamin D level was measured only in NHANES 2001–2006
SE: Spherical equivalent, BMI: body mass index, WC: waist circumference, WWI: weight-adjusted-waist index, PIR: poverty income ratio