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.

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.

Sun behaviour and personal UVR exposure among Europeans on short term holidays.

Solar ultraviolet radiation (UVR) is known to be the main cause of skin cancer, the incidence of which is rising with national differences across Europe. With this observation study we aimed to determine the impact of nationality on sun behaviour and personal UVR exposure on sun and ski holidays. 25 Danish and 20 Spanish sun-seekers were observed during a sun holiday in Spain, and 26 Danish and 27 Austrian skiers were observed during a ski holiday in Austria. The participants recorded their location and clothing in diaries. Personal time-logged UVR data were recorded as standard erythema doses (SEDs) by an electronic UVR dosimeter worn on the wrist. Danish sun-seekers were outdoors for significantly longer, received significant higher percentages of ambient UVR, and received greater accumulated UVR doses than Spanish sun-seekers. Danish skiers were also outdoors for significantly longer than Austrian skiers, but the behaviour of the Danish skiers did not result in significantly greater accumulated UVR doses. Both Danish and Spanish sun-seekers and Danish and Austrian skiers received substantial UVR doses. The behaviour's influence on the UVR doses received by the Danish participants may indicate an explanation of the higher skin cancer incidence among Scandinavians compared with other European populations.

Sun exposure patterns of urban, suburban, and rural children: a dosimetry and diary study of 150 children.

BACKGROUND: Sun exposure is the main etiology of skin cancer. Differences in skin cancer incidence have been observed between rural and urban populations. OBJECTIVES: As sun exposure begins in childhood, we examined summer UVR exposure doses and sun behavior in children resident in urban, suburban, and rural areas. METHODS: Personal, electronic UVR dosimeters and sun behavior diaries were used during a summer (3.5 months) by 150 children (4-19 years of age) resident in urban, suburban, and rural areas. RESULTS: On school/kindergarten days rural children spent more time outdoors and received higher UVR doses than urban and suburban children (rural: median 2.3 h per day, median 0.9 SED per day, urban: median 1.3 h per day, median 0.3 SED per day, suburban: median 1.5 h per day, median 0.4 SED per day) (p ≤ 0.007). Urban and suburban children exhibited a more intermittent sun exposure pattern than rural children. Differences in UVR exposure doses were from high exposure days (e.g. beach days) outside Denmark. Suburban children had a total UVR exposure similar to rural children (suburban: median 109.4 SED, rural: median 103.1 SED), with days spent abroad contributing greatly to the total UVR exposure dose (total UVR on days spent abroad: suburban: median 48.0 SED, rural: median 8.0 SED). CONCLUSIONS: Differences in sun exposure patterns exist between children from different areas and may be the background for higher skin cancer incidences in urban populations.

Sun and ski holidays improve vitamin D status, but are associated with high levels of DNA damage.

Skin cancer is caused by solar UVR, which is also essential for vitamin D production. DNA damage (thymine dimers: T-T dimers) and vitamin D (25(OH)D) synthesis are both initiated by solar UVB. We aimed to investigate the simultaneous adverse and beneficial effects of solar UVB exposure in holidaymakers. Sun-seekers and skiers (n=71) were observed over 6 days through on-site monitoring, personal diary entries, and recording of personal UVB exposure doses with electronic dosimeters. Urine and blood samples were analyzed for T-T dimers and 25(OH)D, respectively. The volunteers had a statistically significant increase in vitamin D. There were strong associations between UVB exposure and post-holiday levels of T-T dimers and vitamin D, as well as between post-holiday T-T dimers and vitamin D. We conclude that UVB-induced vitamin D synthesis is associated with considerable DNA damage in the skin. These data, on two major health predictors, provide a basis for further field studies that may result in better understanding of the risks and benefits of "real life" solar exposure. However, vitamin D status can be improved more safely through the use of vitamin D dietary supplements.

Sun exposure and protection behavior of Danish farm children: parental influence on their children.

Healthy sun habits acquired in childhood could reduce skin cancer incidence. We examined the sun exposure and protection behavior of an expected high-exposure group of children, and the association to their parents. Open, prospective cohort study. One hundred and thirty nine participants (40 families) kept daily sun behavior diaries (sun exposure, sunscreen use, sunburns) over a 4-month summer period (15,985 diary days). The Pigment Protection Factor (PPF), an objective measure of sun exposure, was measured at two body sites, before and after summer. All participants presented data from the same 115 days. Risk behavior (sun exposure of upper body) took place on 9.5 days (boys) and 15.6 days (girls). Sunburn and sunscreen use were infrequent. Boys' sun exposure resulted in an increased photo protection over the study period of 1.7 SED (upper arm) and 0.8 SED (shoulder) to elicit erythema. Corresponding values for girls were as follows: 0.9 SED (upper arm) and 0.5 SED (shoulder). Boys' sunscreen use correlated to their mothers' (r = 0.523, P = 0.02). Girls' number of risk days (r = 0.552, P = 0.005) and sun exposure (upper arm: r = 0.621, P < 0.001) correlated to their mothers'. The children's sun exposure was substantial. Only mothers influenced children's sun behavior and exposure. This may be of relevance in future sun protection campaigns.

A sun holiday is a sunburn holiday.

Many people take holidays in sunny locations with the express aim of sunbathing. This may result in sunburn, which is a risk factor for skin cancer. We investigated 25 Danish sun seekers during a week's holiday in the Canary Islands. The percentage of body surface area with sunburn was determined by daily skin examinations by the same observer. Erythemally effective ultraviolet radiation (UVR) exposure was assessed with time-stamped personal dosimeters worn on the wrist. Volunteers reported their clothing cover and sunscreen use in diaries, and this information was used to determine body site-specific UVR doses after adjustment for sun protection factor. Remarkably, we found that all volunteers sunburned at some point. The risk of sunburn correlated significantly with the adjusted body site-specific UVR dose. Furthermore, there was also a significant relationship between the daily UVR dose and percentage of body surface area with sunburn. Our study shows that holiday UVR exposure results in a high risk of sunburn, which potentially increases the risk of skin cancer. Possible protection by melanogenesis is insufficient to protect against sunburn during a 1-week sun holiday. Finally, our data clearly support a substantial skin cancer risk from sun holidays.

People maintain their sun exposure behaviour in a 5-7-year follow-up study using personal electronic UVR dosimeters.

The main purpose of this study was to investigate whether people change their sun behaviour over a period of 7 years. Thus 32 volunteers, who had all participated in earlier sun exposure studies in 1999-2001, were enrolled in a follow-up study in 2006. They were selected to represent a previous low, medium and high UVR exposure. They participated for mean 121 days (range 65-157 days) wearing a personal, electronic wrist-borne UVR dosimeter and completed sun exposure diaries. No statistically significant differences were seen from year to year in the estimated annual UVR dose, mean UVR dose per day or mean percentage of ambient UVR. However, there was a person effect showing that participants maintained a high or low UVR dose lifestyle over the years. In 2006 the 32 participants received an estimated annual mean UVR dose of 221 SED and a median dose of 154 SED (range 25-1337 SED), while they received a mean for the previous participation years (1999-2001) of 236 SED (median 153 SED, range 24-980 SED). The estimated annual UVR dose for each of the previous sun years and the estimated annual dose for 2006 correlated significantly (R(2) = 0.51; p < 0.0001). Sun risk behaviour, expressed as days sunbathing, did not change either. The participants thus seem to have maintained their sun exposure behaviour over a 5-7-year period.

Influence of having a home garden on personal UVR exposure behavior and risk of cutaneous malignant melanoma in Denmark.

There is a need for more knowledge concerning the association of higher socioeconomic status (SES) with cutaneous malignant melanoma (CMM). Having a home garden is associated with a higher SES. We aimed to study the influence of having a home garden on UVR exposure behavior and risk of CMM. Register study: We collected information from Danish national registers about gender, age, type of home and CMM among persons aged 16-75 in 2002-2006. A total of 5,118 CMM cases were identified. Risk of CMM of the trunk was increased by 46% (p < 0.001, 95% confidence interval (CI): 31-63) and risk of CMM of the extremities by 34% (p < 0.001, 95% CI: 20-49) among people with home gardens. Dosimeter study: During a summer season 194 participants living in the Capital area, Denmark, equally distributed in homes with and without a garden, wore personal electronic UVR dosimeters measuring time-stamped UVR doses continuously and filled in sun exposure diaries. While no difference was found in estimated yearly UVR dose between groups, participants with a home garden had more days exposing shoulders or upper body, and upper extremities outdoors than those without a garden (p = 0.026, age adjusted). People with a home garden are at increased risk of CMM of the trunk and extremities-body sites that seems to be exposed to a higher extent among people with home gardens. People with a higher SES are more likely to have a home garden. This may partly explain the well-known association of higher SES with CMM incidence.

Vitamin D production depends on ultraviolet-B dose but not on dose rate: a randomized controlled trial.

Ultraviolet-B (UV-B) radiation increases serum vitamin D level expressed as 25-hydroxyvitamin D(3) (25(OH)D), but the dose-response relationship and the importance of dose rate is unclear. Of 172 fair-skinned persons screened for 25(OH)D, 55 with insufficient baseline 25(OH)D≤50 nm (mean 31.2 nm) were selected and randomized to one of 11 groups of five participants. Each group was exposed to one of four different UV-B doses: 0.375, 0.75, 1.5 or 3.0 standard erythema dose (SED) for 1, 5, 10 or 20 min. All participants had four UV-B sessions with 2- to 3-day interval with 24% of their skin exposed. Skin pigmentation and 25(OH)D were measured before and after the irradiations. The increase in 25(OH)D after UV-B exposure (adjusted for baseline 25(OH)D) was positively correlated with the UV-B dose (P=0.001; R(2) =0.176) but not to dose rate (1-20 min). 25(OH)D increased in response to four UV-B treatments of 3 SED with 24.8 nm on average and 14.2 nm after four UV-B treatments of just 0.375 SED. In conclusion, the increase in 25(OH)D after UV-B exposure depends on the dose but not on the dose rate (1-20 min). Further, a significant increase in 25(OH)D was achieved with a very low UV-B dose.

Vitamin D production after UVB exposure depends on baseline vitamin D and total cholesterol but not on skin pigmentation.

UVB radiation increases serum vitamin D level expressed as 25-hydroxyvitamin-D(3) (25(OH)D), but the influence of skin pigmentation, baseline 25(OH)D level, and total cholesterol has not been well characterized. To determine the importance of skin pigmentation, baseline 25(OH)D level, and total cholesterol on 25(OH)D production after UVB exposure, 182 persons were screened for 25(OH)D level. A total of 50 participants with a wide range in baseline 25(OH)D levels were selected to define the importance of baseline 25(OH)D level. Of these, 28 non-sun worshippers with limited past sun exposure were used to investigate the influence of skin pigmentation and baseline total cholesterol. The participants had 24% of their skin exposed to UVB (3 standard erythema doses) four times every second or third day. Skin pigmentation and 25(OH)D levels were measured before and after the irradiations. Total cholesterol was measured at baseline. The increase in 25(OH)D level after UVB exposure was negatively correlated with baseline 25(OH)D level (P<0.001) and positively correlated with baseline total cholesterol level (P=0.005), but no significant correlations were found with constitutive or facultative skin pigmentation. In addition, we paired a dark-skinned group with a fair-skinned group according to baseline 25(OH)D levels and found no differences in 25(OH)D increase after identical UVB exposure.

Vitamin D level in summer and winter related to measured UVR exposure and behavior.

The influence of the summer UVR exposure on serum-25-hydroxyvitamin D (25(OH)D) in late summer and winter was investigated in an open study on 25 healthy, adult volunteers. The UVR exposure dose in standard erythema dose (SED) was monitored continuously during a summer season with personal, electronic wristwatch UVR dosimeters and sun exposure diaries. Constitutive and facultative skin pigmentation was measured in September. 25(OH)D was measured in September and February and was in mean 82 nmol/L +/- 25 (mean +/- SD) in September and 56 nmol/L +/- 19 (mean +/- SD) in February. The received cumulative UVR dose measured during a mean of 121 days was 156 SED +/- 159 (mean +/- SD). The following UVR exposure parameters correlated with 25(OH)D in September and February, respectively: (1) The cumulative UVR dose (r = 0.53; P < 0.01) and (r = 0.43; P = 0.03); (2) Mean daily hours with UVR measurements monitored by the dosimeter (r = 0.64, P = 0.001) and (r = 0.53; P = 0.007); (3) Days "with sun-exposed upper body" (r = 0.58, P = 0.003) and (r = 0.50; P = 0.01); (4) Facultative pigmentation (r = 0.47; P < 0.02) and (r = 0.7; P < 0.001); (5) Constitutive pigmentation (r = 0.06, n.s.) and (r = 0.43, P = 0.03). Neither days "sunbathing" nor days with "sunscreen applied" correlated with 25(OH)D. The fall in 25(OH)D during winter was dependent on the entry value.

Sunbed radiation provokes cutaneous vitamin D synthesis in humans--a randomized controlled trial.

We wanted to investigate whether the use of sunbeds with sunlamps emitting mainly UVA and only 0.5% or 1.4% UVB will increase the level of serum 25-hydroxyvitamin D (25(OH)D). In a randomized, controlled, open study on healthy, Caucasian females (> 50 years) sunbed radiation was given as follows: four 6-min sunbed sessions (days 0, 2, 4 and 7) and four 12-min sunbed sessions (days 9, 11, 14 and 16 ) with sunlamps emitting 0.5% UVB (n = 20) or with sunlamps emitting 1.4% UVB (n = 15). The controls (n = 21) had no intervention. Serum levels of 25(OH)D were measured on days 0, 9 and 18 in all three groups. The average increase in serum 25(OH)D from day 0 to day 9 was 12 nmol L(-1) (SD 11 nmol L(-1), P = 0.0002) in the 0.5% UVB group and 27 nmol L(-1) (SD 9 nmol L(-1), P < 0.0001) in the 1.4% UVB group. From day 9 to day 18 a further but not significant increase in serum 25(OH)D of 3 nmol L(-1) (SD 9 nmol L(-1), P = 0.2) in the 0.5% UVB group and 0.6 nmol L(-1) (SD 18 nmol L(-1), P = 0.9) in the 1.4% UVB group was seen. No significant changes were found in the control group. Increasing with UVB dose and exposure time, 37-64% of the sunbed sessions resulted in side effects such as erythema or polymorphic light eruption. The results showed that sunbeds emitting 0.5% and 1.4% UVB increased 25(OH)D serum levels. The increases were dose dependent but reached a plateau after few sessions. Sunbed use as vitamin D source is, however, not generally recommendable due to the well-known carcinogenicity and high frequency of acute side effects.

Sun exposure behaviour among subgroups of the Danish population. Based on personal electronic UVR dosimetry and corresponding exposure diaries.

Solar ultraviolet radiation (UVR) is known to be the most important etiological factor in skin cancer development. The main objective of this thesis was to achieve an objective, basic knowledge of the individual UVR exposure dose pattern and to reveal the factors and with which power they influence on the UVR dose among the Danes. Eight open prospective, observational studies and one study analyzing the compliance and reliability of data were performed in healthy Danish volunteers with an age range of 4-68 years. The subjects were chosen to cover an age span group of children, adolescents, and indoor workers and in addition, groups with expected high UVR exposure, sun worshippers, golfers, and gardeners. We developed a personal, electronic UVR dosimeter in a wristwatch (SunSaver). The subjects wore the UVR dosimeter that measured time-stamped UVR doses in standard erythema doses (SED) and completed diaries with data on their sun exposure behaviour. This resulted in corresponding UVR dosimeter and diary data from 346 sun-years where one sun-year is one person participating in one summer half-year (median 119 days). The annual UVR doses were calculated based on the personal and ambient measured UVR doses. We found a huge variation in annual UVR exposure dose within the total population sample, median 173 SED (range, 17-980 SED). The inter-group variation in annual UVR dose was from median 132 SED among indoor workers to median 224 SED among gardeners. No significant correlation was found between annual UVR dose and age either within the total population or among the adults. But the subjects below 20 years of age had an increase in annual UVR dose of 5 SED per year. Young people before the age of 20 years did not get a higher proportion of the lifetime UVR dose than expected (25%) when assuming a life expectancy of 80 years. There was no significant difference in annual UVR dose between males and females in the total population sample. But, among children, girls received a significantly higher UVR dose than boys due to more days with risk behaviour (sunbathing or exposing shoulders outdoors). This exposure pattern, with females having more risk behaviour than males, was also found among adolescents and adults. Sunbathing or exposing shoulders (risk behaviour) outside the beach resulted in a median of 2.5 SED per day in northern Europe and 3.2 SED per day in southern Europe, while the corresponding values were 4.6 SED and 6.9 SED per day at the beach. UVR doses above 10 SED per day were connected with risk behaviour. The subjects had a median of 13 days with risk behaviour (range, 0-93 days). The subjects used sunscreen on a median of five days (range, 0-130 days), but have a median of seven days with risk behaviour without sunscreen applied (range, 0-47 days). They had a median of one sunburn per sun-year (range 0-10). Fifty percent of the UVR dose was received between 12.00 and 15.00. Only the gardeners received the main part of their UVR dose on workdays. Conclusions : - High UVR doses are connected with risk behaviour. Reduction of cumulative lifetime UVR dose could be obtained by minimizing risk behaviour. - Sunburns were highly correlated to risk behaviour. - Use of sunscreen correlated with days "sunbathing with the intention to tan", indicating that sunscreens were used to avoid sunburn during risk behaviour. - Scheduling lunch breaks and other breaks indoors at noon, where ambient UVR peaks, could reduce the occupational UVR exposure significantly. - In the winter-half-year in Denmark. the UVR dose received from solar exposure is negligible and no UVR precautions are needed. This study documented that high subject compliance rate and data reliability could be obtained in long-time UVR dosimeter study as ours by being service minded but persistent, offering dosimeter maintenance service within 24 hours and scrutinizing data for errors and mistakes just after data collection.

Compliance and data reliability in sun exposure studies with diaries and personal, electronic UV dosimeters.

BACKGROUND/PURPOSE: Skin cancer risk estimations are based on sun exposure data. However, the reliability of collected data in personal ultraviolet (UV) dosimeters studies has not previously been validated. We aimed at investigating the data reliability and subject compliance in a study of sun exposure behaviour among 407 subjects (age range, 4-68 years) during 54 943 days based on time-stamped personal UV dosimeter readings and diary records. METHODS: By comparing diary records and UV dosimeter readings on a daily basis, we investigated subject compliance, total sun exposure record, reasons for non-responding along with rates of diary completing errors. Efforts to improve compliance were described. RESULTS: The subject compliance rate was median 93.5% (percent days where the diary was completed and the UV dosimeter was worn). The total sun exposure record rate was median 84.1% (percent of participation days with both UV dosimeter and diary records and where the UV dosimeter was worn). Children, adolescents and golfers had lower sun exposure record rates than the rest of the groups (P<0.05). No significant difference was found between males and females (P=0.15). The 17 non-responders were 10 children, three adolescents, one sun worshipper, two golfers and one gardener. Correctable diary completing mistakes were found in 3.1% of the days. Children made more completing mistakes than adults (P=0.001). The average estimated error rate was 3.3% and was higher for children (6.3%) and adolescents (3.6%) than the adult groups (2.4%). CONCLUSION: High subject compliance rate and data reliability were obtained because the investigators were service minded but persistent, offering dosimeter maintenance service within 24 h and scrutinized data for errors and mistakes.

Sunscreen use related to UV exposure, age, sex, and occupation based on personal dosimeter readings and sun-exposure behavior diaries.

OBJECTIVES: To examine during what behaviors people apply sunscreen and to assess the relationship to UV exposure monitored by personal dosimetry and diaries. DESIGN: Open prospective observational study. SETTING: University hospital. PARTICIPANTS: A convenience sample of 340 Danish volunteers: children, adolescents, indoor workers, sun worshippers, golfers, and gardeners (age range, 4-68 years). Intervention Subjects recorded sunscreen use and sun-exposure behavior in diaries and carried personal, electronic UV dosimeters, measuring time-stamped UV doses continuously, during a median of 119 days covering 346 sun-years (1 sun-year equals 1 subject participating during 1 summer season). MAIN OUTCOME MEASURES: Associations between sunscreen use and age, sex, skin type, occupation, sunburn, UV exposure doses, and behavior; and adequate application density and sun protection factor required to prevent sunburn. RESULTS: There were great variations in sunscreen use, which was highly correlated with risk behavior (sunbathing or exposing the upper body) (r = 0.39; P<.001). Sunscreens were used on a median of 5 days per sun-year (range, 1 day for gardeners to 16 days for sun worshippers). Ten percent of females and 41% of males never used sunscreens. Females used sunscreens more but also had more unprotected risk behavior than males (8 days vs 4 days; P<.001). Sunscreen use was not correlated with age, and children had as much unprotected risk behavior as adults. Sunscreens were used on 86% of the days with risk behavior in southern Europe vs 20% in northern Europe (P<.001). The UV doses were significantly higher on days with sunscreen (P< or = .03) and on sunburn days (P<.001). The median sun protection factor was 10.5. The sun-protecting effect corresponded to an application density of 0.5 mg/cm2. CONCLUSION: Days with sunscreen correlated not with days without risk behavior, but with days "sunbathing with the intention to tan," indicating that sunscreens were used as tanning aids to avoid sunburn.

Sunburn related to UV radiation exposure, age, sex, occupation, and sun bed use based on time-stamped personal dosimetry and sun behavior diaries.

OBJECTIVE: To assess when sunburn occurs and who experiences sunburn by personal UV dosimetry and diaries. DESIGN: Open prospective observational study. SETTING: University hospital. PARTICIPANTS: A convenience sample of 340 Danish volunteers: children, adolescents, indoor workers, sun worshippers, golfers, and gardeners (age range, 4-68 years). MAIN OUTCOME MEASURES: Subjects recorded sunburn and sun-exposure behavior in diaries and carried personal, electronic, wristwatch UV radiation (UVR) dosimeters that measured time-stamped UVR doses continuously for a median of 119 days covering 346 sun-years (1 sun-year equals 1 subject participating during 1 summer half-year). RESULTS: A typical sunburn day was a day off work (91%; odds ratio, 4.1) with risk behavior (sunbathing/exposing shoulders) (79%; odds ratio, 15.9) in May, June, or July (90%) for 6.4 exposure hours (interquartile range, 5-7.7 hours), of which 2.8 hours fell between noon and 3 pm. Subjects had a median of 1 sunburn per sun-year; adolescents, sun worshippers, and indoor workers had more than children, golfers, and gardeners (P<.05). Sunburn peaked at age 20 years, and female subjects had more sunburns than male subjects (P<.01). Skin type IV had fewer sunburns than types I through III (P<.01). Sunburned persons had more risk-behavior days and lower skin type (P<.01) than nonsunburned persons. The median UVR doses received were significantly higher on sunburn days than on nonsunburn days with risk behavior (P<.01). There was a significant correlation between sunburn size and severity; sunburn and sunscreen use; and sunburn and sun-bed use (P<.01 for all 3 comparisons). CONCLUSIONS: Sunburn was highly correlated with risk behavior. Reduction of risk-behavior days and/or exposure hours around noon can reduce sunburn. Sunburn was not found during breaks on normal full-time indoor work or school days.

Proportion of lifetime UV dose received by children, teenagers and adults based on time-stamped personal dosimetry.

Ultraviolet (UV) reduction campaigns since 1986 were based on the estimation that individuals get 80% of their cumulative lifetime UV dose by the age of 18. To investigate if this estimation is true, we compared annual UV doses received during life in 164 Danish volunteers: children, teenagers, indoor workers, and golfers (age range 4-67 y) who recorded sun exposure behavior in diaries and carried personal UV dosimeters, measuring time-stamped UV doses. The annual UV dose did not significantly correlate with age but the variation in annual UV dose was high (median 166 SED (standard erythema dose), 95% range: 37-551 SED). The annual UV dose did correlate with days with risk behavior (sunbathing/exposing upper body) (r=0.51, p<0.001) and in adults also with hours performing outdoor sports (r=0.39, p<0.001), gardening, and sun-bed sessions (r=0.26, p=0.02). Teenagers had significantly more days with risk behavior than adults (21 vs 13 d, p=0.006) but not than children (15 d). No differences in UV dose among the age groups were found on workdays. Only 25% of the lifetime UV dose was received before the age of 20 and the annual UV dose was thus independent of age. Reduction of cumulative lifetime UV dose could be obtained by minimizing risk behavior.

Dermal echogenicity: a biological indicator of individual cumulative UVR exposure?

Dermal alterations due to chronic UVR exposure may influence dermal ultrasound echogenicity, and a subepidermal low-echogenic band has been proposed as a marker of photoaging. The aim of this study was to determine whether dermal echogenicity could be used as a biological UVR dosimeter. We included 201 subjects (138 healthy volunteers, 31 patients with basal cell carcinoma, and 32 patients with cutaneous malignant melanoma). The number of low-echogenic pixels in the upper dermis relative to the lower dermis (LEP(u/l)) was determined in sun-exposed and sun-protected skin. Individual UVR exposure data were collected retrospectively and prospectively using a questionnaire and electronic personal UVR dosimeters. Age, but not sex, skin type, constitutive pigmentation or smoking, correlated significantly with LEP(u/l) at all body sites. Different measures of individual UVR exposure were significantly positively correlated with LEP(u/l) (together r(2)=0.39, dorsal forearm), but separately the correlations were poor ( r(2)=0.04-0.19). LEP(u/l) was higher in the dorsal forearm in a group with high UVR exposure compared to a low-exposure group ( P=0.007). Skin cancer patients in general had a lower LEP(u/l) than healthy subjects. The results indicate that the age-related increase in LEP(u/l) might be attributed mainly to UVR exposure, and that the methods used to obtain the UVR exposure data might not be sufficiently sensitive or specific. Genetic factors might also influence LEP(u/l). We consider LEP(u/l) to be a sensitive and specific marker for UVR exposure at the dorsal aspect of the forearm in healthy subjects.