| Risk factor | Early ARM vscontrols | Late ARM vscontrols |
| Facial wrinkling | ||
| <0.104 | 1 | 1 |
| 0.104–0.1314 | 1.4 (0.53 to 3.49) | 1.9 (0.54 to 6.56) |
| ⩾0.1314 | 2.5 (0.89 to 7.08) | 3.8 (1.01 to 13.97) |
| p Value for trend | 0.086 | 0.047 |
| Facial hyperpigmentation | ||
| <0.0264 | 1 | 1 |
| 0.0264–0.0342 | 0.6 (0.24 to 1.69) | 0.3 (0.08 to 0.92) |
| ⩾0.0342 | 0.6 (0.21 to 1.56) | 0.3 (0.08 to 0.92) |
| p Value for trend | 0.332 | 0.035 |
| Upper inner arm skin tone L* | ||
| <59.7 | 1 | 1 |
| 59.7–62.1 | 0.9 (0.30 to 2.57) | 0.5 (0.13 to 2.14) |
| ⩾62.1 | 0.9 (0.23 to 3.35) | 0.6 (0.10 to 2.94) |
| p Value for trend | 0.848 | 0.492 |
| Upper inner arm skin tone a* | ||
| <7.2 | 1 | 1 |
| 7.2–8.5 | 1.5 (0.51 to 4.37) | 1.5 (0.38 to 5.64) |
| ⩾8.5 | 2.1 (0.58 to 7.69) | 1.8 (0.37 to 9.17) |
| p Value for trend | 0.257 | 0.120 |
| Upper inner arm skin tone b* | ||
| <14.7 | 1 | 1 |
| 14.7–16.7 | 1.1 (0.38 to 2.97) | 0.7 (0.18 to 2.50) |
| ⩾16.7 | 1.2 (0.43 to 3.56) | 0.3 (0.08 to 1.34) |
| p Value for trend | 0.697 | 0.120 |
Values are OR (95% CI) obtained from the logistic model incorporating age, smoking, hypertension, facial wrinkling, facial hyperpigmentation and upper inner arm skin tone (L*, a* and b*).