Table 1. .
Mean Macular Pigment Optical Density (MPOD) by Level of Various Potential Predictors
|
Variable |
N
of Subjects |
Adjusting for Dietary L and Z* |
Additional Adjustment* for Waist Circumference, Diabetes Status, Fiber Intake, and Serum L and Z and 13 SNPs Associated with MPOD |
||
|
Mean MPOD |
% Diff. from Ref. |
Mean MPOD |
% Diff. from Ref. |
||
| Demographics, anthropometrics, and medical history | |||||
| Age group, y | |||||
| ≤69 | 801 | 0.36 | Ref. | 0.36 | Ref. |
| 70 to 74 | 386 | 0.38 | 5 | 0.39 | 7 |
| ≥75 | 398 | 0.34 | −5 | 0.34 | −5 |
| P value† | 0.81 | 0.81 | |||
| Waist circumference, cm, quartile (median) | |||||
| 1 (73.7) | 440 | 0.40 | Ref. | 0.39 | Ref. |
| 2 (83.8) | 378 | 0.39 | −4 | 0.37 | −3 |
| 3 (91.4) | 361 | 0.34 | −14 | 0.35 | −10 |
| 4 (104.1) | 406 | 0.31 | −22 | 0.34 | −12 |
| P value† | <.0001 | <.0001 | |||
| Presence of diabetes | |||||
| No | 1482 | 0.37 | Ref. | 0.37 | Ref. |
| Yes | 103 | 0.28 | −24 | 0.30 | −17 |
| P value† | <.0001 | 0.003 | |||
| Study visit site | |||||
| Iowa | 535 | 0.38 | Ref. | 0.38 | Ref. |
| Oregon | 515 | 0.39 | 2 | 0.38 | 0 |
| Wisconsin | 535 | 0.32 | −15 | 0.32 | −16 |
| P value† | <.0001 | <.0001 | |||
| Education, WHI baseline | |||||
| High school | 355 | 0.34 | Ref | 0.35 | Ref. |
| College | 776 | 0.36 | 5 | 0.36 | 4 |
| Postcollege | 454 | 0.38 | 10 | 0.36 | 3 |
| P value† | 0.02 | 0.48 | |||
| Diet and lifestyle | |||||
| Dietary L+Z, μg, quintile (median) | |||||
| 1 (797.9) | 317 | 0.31 | Ref. | 0.33 | Ref. |
| 2 (1383.1) | 317 | 0.33 | 8 | 0.34 | 2 |
| 3 (2120.5) | 317 | 0.38 | 24 | 0.38 | 14 |
| 4 (3121) | 317 | 0.39 | 27 | 0.37 | 12 |
| 5 (5330.9) | 317 | 0.41 | 32 | 0.38 | 14 |
| P value† | <.0001 | 0.18 | |||
| Physical activity, MetHrs/wk‡ | |||||
| <3 | 369 | 0.34 | Ref. | 0.37 | Ref. |
| 3 to 10 | 348 | 0.36 | 5 | 0.37 | 0 |
| 10 to 21 | 440 | 0.36 | 4 | 0.35 | −5 |
| ≥21 | 417 | 0.39 | 12 | 0.36 | −3 |
| P value† | 0.14 | 0.09 | |||
| Dietary fiber, g/d, quintile (median) | |||||
| 1 (7.9) | 316 | 0.31 | Ref. | 0.33 | Ref. |
| 2 (12.1) | 317 | 0.36 | 14 | 0.36 | 10 |
| 3 (16.0) | 316 | 0.36 | 15 | 0.35 | 7 |
| 4 (20.1) | 317 | 0.39 | 25 | 0.38 | 16 |
| 5 (27.0) | 316 | 0.39 | 26 | 0.38 | 15 |
| P value† | <.0001 | 0.004 | |||
| Dietary saturated fat, % of energy, quintile (median) | |||||
| 1 (7.6) | 316 | 0.38 | Ref. | 0.35 | Ref. |
| 2 (9.8) | 317 | 0.38 | 0 | 0.37 | 5 |
| 3 (11.5) | 316 | 0.36 | −6 | 0.36 | 4 |
| 4 (13.6) | 317 | 0.36 | −6 | 0.36 | 3 |
| 5 (16.6) | 316 | 0.35 | −9 | 0.37 | 5 |
| P value† | 0.01 | 0.82 | |||
| Dietary polyunsaturated fat, % of energy, quintile (median) | |||||
| 1 (4.34) | 316 | 0.34 | Ref. | 0.33 | Ref. |
| 2 (5.66) | 317 | 0.37 | 11 | 0.37 | 13 |
| 3 (6.67) | 316 | 0.37 | 11 | 0.37 | 13 |
| 4 (7.82) | 317 | 0.37 | 11 | 0.38 | 15 |
| 5 (9.78) | 316 | 0.36 | 9 | 0.37 | 12 |
| P value† | 0.21 | 0.03 | |||
| Dietary total n-3 fatty acids, g/d, quintile (median) | |||||
| 1 (0.61) | 316 | 0.34 | Ref. | 0.35 | Ref. |
| 2 (0.91) | 317 | 0.36 | 5 | 0.36 | 5 |
| 3 (1.16) | 316 | 0.37 | 10 | 0.36 | 5 |
| 4 (1.49) | 317 | 0.37 | 8 | 0.36 | 4 |
| 5 (2.10) | 316 | 0.38 | 11 | 0.37 | 8 |
| P value† | 0.05 | 0.23 | |||
| Dietary retinol, μg/d, quintile (median) | |||||
| 1 (196.2) | 316 | 0.37 | Ref. | 0.37 | Ref. |
| 2 (338.8) | 317 | 0.37 | 1 | 0.37 | 0 |
| 3 (479.0) | 316 | 0.36 | −1 | 0.36 | −4 |
| 4 (641.4) | 317 | 0.36 | −2 | 0.36 | −4 |
| 5 (919.1) | 316 | 0.35 | −4 | 0.35 | −7 |
| P value† | 0.15 | 0.07 | |||
| Total HEI-2005 score, quintile (median) | |||||
| 1 (61.4) | 317 | 0.34 | Ref. | 0.37 | Ref. |
| 2 (67.0) | 317 | 0.36 | 4 | 0.36 | −2 |
| 3 (70.5) | 317 | 0.36 | 4 | 0.36 | −2 |
| 4 (73.5) | 317 | 0.37 | 7 | 0.36 | −2 |
| 5 (77.7) | 317 | 0.39 | 15 | 0.37 | 1 |
| P value† | 0.001 | 0.70 | |||
| Healthy lifestyle score | |||||
| 0 to 2 | 415 | 0.34 | Ref. | 0.37 | Ref. |
| 3 | 426 | 0.36 | 7 | 0.36 | −2 |
| 4 | 368 | 0.37 | 8 | 0.36 | −3 |
| 5 | 287 | 0.38 | 13 | 0.36 | −3 |
| 6 | 89 | 0.40 | 18 | 0.35 | −4 |
| P value† | 0.001 | 0.44 | |||
| Serum analytes | |||||
| L+Z, trans, μmol/L, quintile (median) | |||||
| 1 (0.15) | 313 | 0.25 | Ref. | 0.28 | Ref. |
| 2 (0.22) | 314 | 0.35 | 36 | 0.35 | 27 |
| 3 (0.29) | 313 | 0.37 | 46 | 0.37 | 32 |
| 4 (0.37) | 313 | 0.41 | 59 | 0.39 | 40 |
| 5 (0.50) | 314 | 0.44 | 71 | 0.42 | 51 |
| P value† | <.0001 | <.0001 | |||
| Retinol, μmol/L, quintile (median) | |||||
| 1 (1.84) | 313 | 0.36 | Ref. | 0.36 | Ref. |
| 2 (2.20) | 314 | 0.35 | −2 | 0.35 | −4 |
| 3 (2.50) | 313 | 0.38 | 8 | 0.39 | 7 |
| 4 (2.80) | 314 | 0.37 | 4 | 0.36 | −1 |
| 5 (3.31) | 313 | 0.36 | 0 | 0.36 | −1 |
| P value† | 0.96 | 0.70 | |||
| Retinyl palmitate, μmol/L, quintile (median) | |||||
| 1 (0.0004) | 195 | 0.37 | Ref. | 0.37 | Ref. |
| 2 (0.0010) | 193 | 0.36 | −3 | 0.36 | −2 |
| 3 (0.0019) | 191 | 0.38 | 3 | 0.38 | 2 |
| 4 (0.0032) | 194 | 0.40 | 8 | 0.40 | 7 |
| 5 (0.0070) | 193 | 0.34 | −7 | 0.33 | −10 |
| P value† | 0.13 | 0.03 | |||
| Beta-carotene, all trans, μmol/L, quintile (median) | |||||
| 1 (0.23) | 313 | 0.29 | Ref. | 0.34 | Ref. |
| 2 (0.40) | 314 | 0.36 | 21 | 0.37 | 9 |
| 3 (0.60) | 313 | 0.38 | 30 | 0.37 | 11 |
| 4 (0.90) | 314 | 0.39 | 31 | 0.36 | 8 |
| 5 (1.52) | 313 | 0.40 | 37 | 0.37 | 12 |
| P value† | <.0001 | 0.31 | |||
| Triglyceride, μmol/L, quintile (median) | |||||
| 1 (0.90) | 316 | 0.36 | Ref. | 0.34 | Ref. |
| 2 (1.25) | 315 | 0.39 | 8 | 0.38 | 12 |
| 3 (1.57) | 305 | 0.37 | 3 | 0.36 | 8 |
| 4 (2.07) | 319 | 0.38 | 7 | 0.39 | 17 |
| 5 (2.96) | 310 | 0.32 | −12 | 0.34 | 0 |
| P value† | 0.003 | 0.48 | |||
| Vitamin D, adjusted for blood drawn month, nmol/L, quintile (median) | |||||
| 1 (30.4) | 235 | 0.35 | Ref. | 0.37 | Ref. |
| 2 (44.5) | 236 | 0.36 | 2 | 0.37 | 0 |
| 3 (55.7) | 235 | 0.36 | 3 | 0.36 | −2 |
| 4 (67.2) | 236 | 0.38 | 9 | 0.37 | 1 |
| 5 (84.9) | 235 | 0.38 | 7 | 0.35 | −6 |
| P value† | 0.07 | 0.52 | |||
| C-reactive protein, mg/L, quintile (median) | |||||
| 1 (0.7) | 221 | 0.38 | Ref. | 0.35 | Ref. |
| 2 (1.5) | 219 | 0.38 | −1 | 0.35 | 0 |
| 3 (2.7) | 216 | 0.36 | −6 | 0.36 | 3 |
| 4 (4.8) | 225 | 0.36 | −5 | 0.37 | 5 |
| 5 (9.9) | 221 | 0.35 | −8 | 0.38 | 8 |
| P value† | 0.03 | 0.35 | |||
Diff., different.
*
Exception to adjustment variables are when the respective variable is that being tested.
†
P values are for trend of MPOD across continuous variable or categorical, where appropriate.
‡
MetHrs/Week is h/wk spent doing an activity by the intensity (the fold increase the activity is estimated to increase metabolic activity [oxygen consumption] relative to the resting state).