Table 2.
Descriptive statistics of the study population
| n (%)a | Median (range) | |
|---|---|---|
| Age at examination (years) | ||
| < 44 | 333 (24·8) | 55·6 (19·1–87·2) |
| 44–54 | 319 (23·8) | |
| 55–65 | 361 (26·9) | |
| > 65 | 328 (24·5) | |
| Sex | ||
| Female | 810 (60·4) | – |
| Male | 531 (39·6) | |
| Highest educational level | ||
| Primary/secondary school | 465 (35·2) | – |
| Sixth form/vocational training | 561 (42·5) | |
| University/postgraduate | 295 (22·3) | |
| Sun-sensitive phenotype | ||
| No | 670 (50·8) | – |
| Yes | 608 (49·2) | |
| MC1R genotype | ||
| −/− (wild-type) | 226 (20·0) | – |
| r/− | 259 (22·9) | |
| r/r | 96 (8·5) | |
| R/− | 269 (23·8) | |
| R/r | 186 (16·5) | |
| R/R | 94 (8·3) | |
| BMI | ||
| < 25 | 571 (43·3) | 25·8 (15·6–68·4) |
| 25–30 | 508 (38·5) | |
| > 30 | 240 (18·2) | |
| Smoking | ||
| Never | 410 (52·8) | – |
| Ever | 366 (47·2) | |
| Pack-yearsb | ||
| 0 | 412 (55·3) | 0 (0–120) |
| 0–15 | 164 (22·0) | |
| > 15 | 169 (22·7) | |
| Average alcohol intake (units per week)c | ||
| ≤ 1 | 195 (25·3) | 6 (0–99) |
| 2–6 | 205 (26·6) | |
| 7–13 | 181 (23·5) | |
| > 14 | 190 (24·6) | |
| Sunburn – no. before age 20 years | ||
| 0 | 941 (72·8) | 0 (0–152) |
| 1–12 | 216 (16·7) | |
| > 12 | 136 (10·5) | |
| Sunburn – no. at or after age 20 years | ||
| 0 | 849 (66·4) | 0 (0–240) |
| 1–10 | 292 (22·9) | |
| > 10 | 137 (10·7) | |
| Sunburn – average no. in life | ||
| 0 | 647 (50·4) | 0 (0–360) |
| 1–26 | 318 (24·8) | |
| > 26 | 318 (24·8) | |
| Sunbed – ever vs. never | ||
| Never | 714 (54·2) | – |
| Ever | 603 (45·8) | |
| Sunbed – no. of sessions in life | ||
| 0 | 714 (55·1) | 0 (0–5000) |
| 1–20 | 308 (23·8) | |
| > 20 | 273 (21·1) | |
| Sunscreen – used to avoid sunburn | ||
| Never or hardly ever | 496 (37·0) | – |
| Not often | 447 (33·3) | |
| Often | 398 (29·7) | |
| Sunscreen – used to stay in the sun longer | ||
| Never or hardly ever | 865 (64·5) | – |
| Not often | 224 (16·7) | |
| Often | 252 (18·8) | |
| Sunscreen – SPF level | ||
| Never or hardly ever | 512 (38·2) | – |
| SPF < 10 | 469 (35·0) | |
| SPF ≥ 10 | 360 (26·8) | |
| Wrinkle scored | ||
| Grades 0 and 1 | 177 (13·2) | – |
| Grade 2 | 351 (26·3) | |
| Grade 3 | 415 (31·0) | |
| Grade 4 | 212 (15·9) | |
| Grades 5–7 | 182 (13·6) | |
| Vascularity scored | ||
| Grades 0 and 1 | 306 (23·0) | – |
| Grade 2 | 432 (32·4) | |
| Grade 3 | 409 (30·7) | |
| Grade 4 | 185 (13·9) | |
| Pigmentation scored | ||
| Grades 0 and 1 | 112 (8·4) | – |
| Grade 2 | 427 (32·1) | |
| Grade 3 | 471 (35·3) | |
| Grades 4 and 5 | 322 (24·2) | |
BMI, body mass index; SPF, sun-protection factor.
a
Numbers do not always total 1341 due to missing data.
b
A ‘pack-year’ is defined by the formula: number of daily cigarettes × years smoked/20.
c
In the U.K., an ‘alcohol unit’ is defined as 10 mL of pure alcohol (ethanol).
d
Grades 0 and 1 were grouped in the three skin ageing scales as well as grades 5–7 and 4 and 5 in the wrinkle and the pigmentation scales, respectively, due to low numbers.