Low vitamin D in dark-skinned immigrants is mainly due to clothing habits and low UVR exposure: a Danish observational study.

Low 25-hydroxyvitamin D3 (25(OH)D) among dark-pigmented persons has been observed. To elucidate the reason for this we examined sun behaviour, sun-exposed body area, solar UVR exposure and 25(OH)D levels in immigrants with dark pigmented skin and Danes with light pigmented skin. Clothing, sun behaviour, and diet were recorded daily during a Danish summer season (93 analysed days). Erythema-weighted UVR doses were measured by personal electronic UVR dosimeters (with erythema response, measurement every 5th second) and 25(OH)D was measured in 72 participants (33 dark-skinned and 39 light-skinned). The immigrants exposed 28% less skin area, received 70% less UVR dose, and had 71% less 25(OH)D increase during the summer. The UVR reactivity (Δ25(OH)D per joule accumulated UVR dose) was similar (P = 0.62) among the immigrants (0.53 nmol l-1 J-1) and the Danes (0.63 nmol l-1 J-1). In the groups combined, 25(OH)D levels after summer were mainly influenced by UVR dose to exposed skin (28.8%) and 25(OH)D start level (27.9%). Height and measured constitutive skin pigmentation were of minor influence: 3.5% and 3.2%, respectively. Sun exposure and clothing habits were the main reasons for lower 25(OH)D level after summer in the darker immigrants, as both groups had similar UVR reactivity.

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.

Black light visualized solar lentigines on the shoulders and upper back are associated with objectively measured UVR exposure and cutaneous malignant melanoma.

Previous studies on the association of solar lentigines with ultraviolet radiation (UVR) exposure have been based on retrospective questionnaires about UVR exposure. We aimed to investigate the association between solar lentigines and UVR exposure in healthy individuals using objective measurements, and to investigate the association between solar lentigines and cutaneous malignant melanoma (CMM). Forty-eight patients with CMM and 48 controls that matched the patients individually by age, sex, constitutive skin type and occupation participated. Solar lentigines on the shoulders and upper back were counted and graded into 3 categories using black light photographs to show sun damage. Current UVR exposure in healthy controls was assessed by personal electronic UVR dosimeters that measured time-related UVR and by corresponding exposure diaries during a summer season. Sunburn history was assessed by interviews. Among controls, the number of solar lentigines was positively associated with daily hours spent outdoors between noon and 3 pm on holidays (P = 0.027), days at the beach (P = 0.048) and reported number of life sunburns (P < 0.001). Compared with matched controls CMM patients had a higher number of solar lentigines (P = 0.044). There was a positive association between CMM and higher solar lentigines grade; Category III versus Category I (P = 0.002) and Category II versus Category I (P = 0.014). Our findings indicate that solar lentigines in healthy individuals are associated with number of life sunburns, as well as time spent outdoors around noon on holidays and beach trips during a summer season, most likely reflecting past UVR exposure, and that solar lentigines are a risk factor for CMM.

A 3-year follow-up of sun behavior in patients with cutaneous malignant melanoma.

IMPORTANCE UV radiation (UVR) exposure is the primary environmental risk factor for developing cutaneous malignant melanoma (CMM). OBJECTIVE To measure changes in sun behavior from the first until the third summer after the diagnosis of CMM using matched controls as a reference. DESIGN, SETTING, AND PARTICIPANTS Three-year follow-up, observational, case-control study performed from May 7 to September 22, 2009, April 17 to September 15, 2010, and May 6 to July 31, 2011, at a university hospital in Denmark of 21 patients with CMM and 21 controls matched to patients by sex, age, occupation, and constitutive skin type participated in the study. Exposure to UVR was assessed the first and second summers (n=20) and the first and third summers (n=22) after diagnosis. Data from 40 participants were analyzed. MAIN OUTCOMES AND MEASURES Exposure to UVR was assessed by personal electronic UVR dosimeters that measured time-related UVR in standard erythema dose (SED) and corresponding sun diaries (mean, 74 days per participant each participation year). RESULTS Patients' daily UVR dose and UVR dose in connection with various behaviors increased during follow-up (quantified as an increase in daily UVR dose each year; all days: mean, 0.3 SED; 95% CI, 0.05-0.5 SED; days with body exposure: mean, 0.6 SED; 95% CI, 0.07-1.2 SED; holidays: mean, 1.2 SED; 95% CI, 0.3-2.1 SED; days abroad: 1.9 SED; 95% CI, 0.4-3.4 SED; and holidays with body exposure: mean, 2.3 SED; 95% CI, 1.1-3.4 SED). After the second year of follow-up, patients' UVR dose was higher than that of controls, who maintained a stable UVR dose. No difference was found between groups in the number of days with body exposure or the number of days using sunscreen in the second and third years of follow-up. CONCLUSIONS AND RELEVANCE Our findings suggest that patients with CMM do not maintain a cautious sun behavior in connection with an increase in UVR exposure, especially on days with body exposure, when abroad, and on holidays.

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.