Table 2.
Selected age-adjusted baseline characteristics among U.S. adults aged ≥20 years, by quintiles of serum vitamin A concentration, National Health and Nutrition Examination Survey 2001–2006
| Characteristics | Vitamin A quintiles (μmol/L)
|
||||||
|---|---|---|---|---|---|---|---|
| ≤1.6439
|
1.6440–1.9337
|
1.9340–2.2143
|
2.2147–2.5798
|
≥2.5800
|
P for trend | P for trend | |
| Mean or % (95% CI) | Mean or % (95% CI) | Mean or % (95% CI) | Mean or % (95% CI) | Mean or % (95% CI) | |||
| N, unweighted | 2461 | 2179 | 2133 | 2073 | 2047 | – | – |
| Age (years) | 40.8 (40.0, 41.7) | 43.7 (42.6, 44.7) | 45.9 (44.9, 47.0) | 48.3 (47.2, 49.3) | 51.6 (50.6, 52.5) | < .001 | .001 |
| Men, % | 29.7 (27.6, 31.9) | 43.5 (40.7, 46.3) | 52.8 (50.6, 55.1) | 59.1 (56.4, 61.7) | 62.4 (60.0, 64.8) | < .001 | < .001 |
| Whites, % | 59.5 (54.1, 64.8) | 71.0 (66.6, 75.0) | 74.6 (70.7, 78.0) | 79.4 (75.3, 82.9) | 84.8 (82.3, 87.0) | < .001 | < .001 |
| >High school, % | 49.8 (47.3, 52.2) | 55.6 (52.8, 58.4) | 57.1 (53.9, 60.2) | 57.0 (54.5, 59.4) | 62.3 (59.1, 65.5) | < .001 | .021 |
| Cotinine (ng/ml) | 69.1 (60.9, 77.2) | 67.1 (60.7, 73.4) | 66.8 (58.4, 75.3) | 63.1 (55.1, 71.0) | 65.6 (56.5, 74.7) | .340 | .111 |
| Alcohol intake (g/d) | 5.8 (5.1, 6.6) | 9.0 (7.5, 10.5) | 12.5 (10.6, 14.4) | 16.1 (13.9, 18.3) | 22.6 (19.8, 25.4) | < .001 | .001 |
| Leisure-time physical activity (MET-h/month) | 59.7 (53.0, 66.5) | 71.0 (64.1, 77.8) | 76.4 (68.5, 84.3) | 88.9 (79.6, 98.2) | 95.3 (82.2, 108.3) | < .001 | .264 |
| Energy intake (kcals/d) | 2009 (1957, 2062) | 2174 (2116, 2233) | 2308 (2259, 2358) | 2350 (2288, 2413) | 2416 (2346, 2486) | .001 | .589 |
| Hypertension, % | 26.0 (23.7, 28.4) | 27.7 (25.8, 29.6) | 28.8 (26.6, 31.0) | 30.8 (28.5, 33.2) | 35.2 (33.4, 37.1) | < .001 | .001 |
| Body mass index (kg/m2) | 28.7 (28.3, 29.1) | 28.3 (27.9, 28.6) | 28.1 (27.8, 28.5) | 27.9 (27.6, 28.3) | 27.3 (27.0, 27.6) | < .001 | .831 |
| High-density lipoprotein cholesterol (mmol/L) | 1.39 (1.37, 1.41) | 1.38 (1.35, 1.40) | 1.37 (1.35, 1.39) | 1.38 (1.36, 1.40) | 1.40 (1.37, 1.42) | .478 | .230 |
| Non-high-density lipoprotein cholesterol (mmol/L) | 3.47 (3.42, 3.52) | 3.70 (3.64, 3.76) | 3.87 (3.81, 3.92) | 3.94 (3.89, 4.00) | 4.10 (4.00, 4.20) | < .001 | .032 |
| C-reactive protein (mg/L) | 6.8 (6.2, 7.5) | 4.3 (3.8, 4.7) | 3.3 (3.1, 3.5) | 3.3 (3.0, 3.5) | 3.0 (2.8, 3.2) | < .001 | .208 |
| Estimated glomerular filtration rate (mL/min per 1.73 m2) | 99.9 (99.2, 100.6) | 95.8 (94.8, 96.7) | 93.6 (92.7, 94.5) | 91.6 (90.7, 92.4) | 86.7 (85.5, 87.9) | < .001 | < .001 |
| Beta-carotene (μmol/L) | 0.3 (0.3, 0.3) | 0.4 (0.3, 0.4) | 0.4 (0.3, 0.4) | 0.4 (0.4, 0.4) | 0.4 (0.3, 0.4) | .016 | .072 |
| Uric acid (μmol/L) | 286 (282, 290) | 309 (305, 313) | 323 (318, 327) | 334 (330, 338) | 352 (348, 356) | < .001 | < .001 |
*
P-values for differences adjusted for all other covariates in table.