Table 4.
Predictors of the three skin ageing measures from proportional odds regression models including the significant predictors in Table 3, age, sex, highest educational level attained and melanoma status
| Vascularitya | Pigmentationb | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Wrinkles n=1317 | Model 1 n=1241 | Model 2 n=1045 | Model 3 n=630 | Model 1 n=1257 | Model 2 n=1058 | |||||||
| OR (95% CI) | P-valuec | OR (95% CI) | P-valuec | OR (95% CI) | P-valuec | OR (95% CI) | P-valuec | OR (95% CI) | P-valuec | OR (95% CI) | P-valuec | |
| Age at examination | 2·39 (2·16–2·65) | < 0·001 | 1·25 (1·13–1·38) | < 0·001 | 1·18 (1·06–1·32) | 0·002 | 1·14 (1·00–1·30) | 0·05 | 1·11 (1·01–1·23) | 0·03 | 1·08 (0·97–1·20) | 0·15 |
| Sex (male vs. female) | 1·13 (0·91–1·39) | 0·27 | 6·75 (5·27–8·65) | < 0·001 | 6·47 (4·95–8·45) | < 0·001 | 6·63 (4·65–9·49) | < 0·001 | 1·23 (0·99–1·52) | 0·06 | 1·28 (1·01–1·62) | 0·04 |
| Highest educational level | ||||||||||||
| Primary/secondary school | 1 | 1 | 1 | 1 | 1 | 1 | ||||||
| Sixth form/vocational training | 0·96 (0·76–1·20) | 0·72 | 0·83 (0·65–1·05) | 0·13 | 0·79 (0·60–1·02) | 0·07 | 0·76 (0·55–1·07) | 0·12 | 1·43 (1·13–1·81) | 0·003 | 1·46 (1·13–1·89) | 0·004 |
| University/postgraduate | 0·85 (0·65–1·12) | 0·24 | 1·00 (0·75–1·34) | 0·99 | 0·96 (0·70–1·31) | 0·79 | 1·00 (0·66–1·52) | 0·99 | 1·73 (1·30–2·29) | < 0·001 | 1·57 (1·16–2·13) | 0·004 |
| MC1R genotype – groupedd | ||||||||||||
| Wild-type | 1 | 1 | 1 | |||||||||
| ‘r’ without ‘R’ | 1·53 (1·11–2·12) | 0·01 | 1·20 (0·78–1·87) | 0·41 | 0·71 (0·52–0·97) | 0·03 | ||||||
| ‘R’ | 1·44 (1·06–1·95) | 0·02 | 1·13 (0·76–1·67) | 0·54 | 0·61 (0·46–0·82) | 0·001 | ||||||
| BMI | 1·20 (1·04–1·38) | 0·01 | 1·26 (1·08–1·47) | 0·003 | 1·25 (1·02–1·52) | 0·03 | ||||||
| Pack-years | 1·25 (1·04–1·50) | 0·02 | ||||||||||
| Average daily sun exposuree | 1·13 (1·02–1·24) | 0·02 | 1·10 (0·99–1·23) | 0·07 | 1·08 (0·94–1·24) | 0·26 | ||||||
| Average weekday sun exposure – warmer months | 1·11 (1·01–1·22) | 0·03 | 1·10 (0·99–1·22) | 0·07 | ||||||||
| Sunscreen – used to stay in the sun longer | 0·85 (0·74–0·97) | 0·02 | 0·85 (0·73–0·98) | 0·03 | ||||||||
| Sunscreen – SPF level | 0·84 (0·74–0·96) | 0·01 | ||||||||||
Findings significant at the 5% level are highlighted in bold. n, number of observations in each model; OR, odds ratio; CI, confidence interval; BMI, body mass index; SPF, sun-protection factor.
Model 1 excludes MC1R and smoking data, model 2 includes MC1R but not smoking, model 3 includes both MC1R and smoking.
Model 1 excludes MC1R, model 2 includes MC1R.
P-values for trend are presented, as displayed in Table 2, except for highest educational level and MC1R genotype.
Models including MC1R genotype nongrouped rather than grouped displayed similar results.
Models including average weekday (overall and cooler months) rather than daily sun exposure displayed similar results.