Lifetime UVR Dose and Skin Cancer Risk, Determined by Their Common Relation to Solar Lentigines.

BACKGROUND/AIM: Ultraviolet radiation (UVR) causes solar lentigines (SL) and skin cancer (SC) in humans. The association between measured lifetime UVR dose and SC has not been investigated. This study investigated this relation through their common relationship to SL. MATERIALS AND METHODS: First we investigated the association between lifetime UVR dose and SL for 16,897 days in 38 healthy participants, and secondly, the relation between SL and SC was investigated in 2,898 participants, including 149 with SC. By combining both studies, SC risk related to lifetime UVR dose and skin phototype was estimated. RESULTS: A positive association was found between SL and lifetime UVR dose (p=0.060). Skin phototype (p=0.001) and SL (p<0.001) were associated with SC. Combined SC risk increased 1.23 by doubling the average lifetime UVR dose and was 34.9 times higher for those with very fair skin compared to dark Mediterranean skin. CONCLUSION: The estimate of SC risk shows that skin phototype is of greater relative importance than lifetime UVR dose.

Measurements of sun sensitivity in five European countries confirm the relative nature of Fitzpatrick skin phototype scale.

BACKGROUND/PURPOSE: Skin colour and sun sensitivity are highly related to the distance to the equator: people in southern latitudes are usually darker and less sensitive to sun than in northern latitudes. Whether differences in sun sensitivity can be found in a relatively homogenous European population is unclear. We aimed to objectively measure sun sensitivity (assessed as pigment protection factor (PPF)) in five European countries, relate it to self-assessed Fitzpatrick skin phototype (FST) and to determine whether PPF levels in the different FST categories are dependent on the investigated countries. METHODS: Volunteers (n = 569) were recruited in Copenhagen (Denmark), Dublin (Ireland), London (England), Münster (Germany) and Ioannina (Greece). Skin phototype was self-assessed using the FST scale. PPF was measured at both sun-protected buttocks and five sun-exposed skin sites by a skin reflectance spectrophotometer. RESULTS: Overall, there were statistically significant differences in PPF of the buttocks, inner arm, outer arm, forehead, chest and back between the five countries (P ≤ .031). Generally, PPF level was lower in northern than in southern latitudes. PPF of the buttocks was similar in all countries for those who identified as FST I (P = .723). However, it was statistically significantly different (P ≤ 2.913*10-4 ) and country-dependent for those who identified as FST II-IV. CONCLUSION: Objectively measured sun sensitivity is higher (lower PPF) in northern compared with southern latitudes. The choice of self-identified FST category is influenced by a person's immediate environment. Therefore, we confirmed the relative nature of the FST scale and the need to standardise the skin phototype assessment procedure.

Adult UVR exposure changes with life stage - a 14-year follow-up study using personal electronic UVR dosimeters.

Over a period spanning 14 years (1999-2001, 2006 and 2012), 31 volunteers participated in sun behaviour studies with the same protocol wearing a personal, electronic wrist-borne UVR dosimeter and completed sun exposure diaries resulting in a total of 15 946 measurements days (126 days per person per year). The participants individually maintained their UVR dose level and behaviour over the years. No statistically significant differences were seen from year to year in the "estimated annual UVR dose", the "mean UVR dose per day", the "mean percentage of ambient UVR", "days sunbathing to get a tan", "days with intermittent exposure" or in "sunburn episodes". The 20 participants still active in the labour market used sunscreen on more days in 2012 than in 1999 (p = 0.019) and with a significantly higher SPF (sun protecting factor (p < 0.001)) resulting in significantly fewer days with risk behaviour without sunscreen applied in 2012 than in 2006 (p < 0.001) and 1999 (p < 0.003). This was in contrast to the 11 participants who retired during the study period. The retired group received a non-significant 45% higher UV dose in 2012 than in 1999 (p = 0.054). In an additional study, nine 30-year-old indoor workers (high school students in the 1999 study) had changed their sun exposure pattern and had fewer days sunbathing (p = 0.008) and fewer risk behaviour days without sunscreen applied in 2012 than in 1999 (p = 0.002). Conclusion: The participants still active in the labour market maintained their sun exposure behaviour over a 14-year period. The retirees had a higher UVR dose and riskier exposure behaviour after retirement, while the high school students had changed to less risky sun behaviour on becoming indoor workers.

Skin cancer phototype: A new classification directly related to skin cancer and based on responses from 2869 individuals.

BACKGROUND/PURPOSE: Fitzpatrick phototype (FST) classification (based on ability to tan and tendency to burn) is widely used for evaluating skin cancer risk; however, it was not developed for that purpose and has been criticised scientifically. The purpose of the present study was a first approach in establishing a new skin cancer phototype (SCP) classification with direct relation to skin cancer risk, based on the questions originally proposed by Fitzpatrick. However, contrary to Fitzpatrick, the questions are in the present study kept separate. METHODS: Validated information on skin cancer and answers about participants' tendency to burn (4 answers) and ability to tan (4 answers) were obtained from 2869 Danes. The 16 (4 × 4 answers) possible answers formed a matrix, on which a logistic regression was carried out. Successively, the matrix neighbours which were insignificantly different were identified; of which the neighbours with the mutual lowest difference were merged. The merging resulted in four different SCP classes. RESULTS: There was a linear relationship between SCP classes and skin cancer risk. Further, SCP was as good a predictor of skin cancer as objectively measured skin phototype. CONCLUSION: As skin phototype is an important factor in skin cancer research, SCP has great potential in investigative studies of skin cancer risk.