Defining "intermittent UVR exposure".

BACKGROUND: Cutaneous malignant melanoma (CMM) has been associated with "intermittent UVR exposure", which in previous studies has mainly been assessed by retrospective questionnaire data. Further, there is no uniform definition of the term "intermittent UVR exposure". OBJECTIVES: We aimed to define and quantify "intermittent UVR exposure" by an objective measure. METHODS: A broad study population of adults and children had data collected during a summer period. Data were personal UVR dosimetry measurements, from which the number of "intermittent days" was derived, sun behaviour diaries and retrospective questionnaires. Two definitions of intermittent UVR exposure were tested: (1) days when UVR dose exceeded 3 times individual average daily UVR dose, and (2) days when UVR dose exceeded individual constitutive skin type. Measures of nevi and lentigines were used as surrogates for CMM. RESULTS: Using the first definition based solely on UVR dosimetry data we found 1241 "intermittent days" out of a total of 17 277 days (7.2%) among 148 participants. The numbers for nevi and lentigo density were significantly predicted by the number of intermittent days (R(2) = 0.15 and R(2) = 0.40, p < 0.001). The corresponding numbers for prediction of nevi and lentigo density by retrospective questionnaire data was lower (R(2) = 0.11, R(2) = 0.26, p < 0.001). CONCLUSIONS: We introduce a well-defined objective measure of intermittent UVR exposure. This measure may provide a better prediction of solar skin damage and CMM than retrospective questionnaire data.

Personal UVR exposure of farming families in four European countries.

BACKGROUND: The main risk factor for skin cancer is ultraviolet radiation (UVR). Farming families living in rural areas with easy outdoor access may experience excessive UVR exposure. Differences between countries in latitude, altitude and sun behaviour could result in different personal UVR exposures. However, no studies have examined this until now. OBJECTIVES: To determine personal UVR exposure in work and leisure situations among farming families in Europe. METHODS: Prospective cohort study of farmers, their partners (spouses) and children in Denmark (DK), Poland (PL), Austria (AT), and Spain (ES) from 2009 to 2011. Personal UVR exposure and sun behaviour were recorded by dosimetry and diaries. RESULTS: Farmers' average daily UVR exposure on working days ranged from 1.4 SED (DK, AT) to 2.7 SED (ES). Corresponding figures for partners were: 0.6 SED (DK) to 1.9 SED (PL), and for children (day-care/school days): 0.7 SED (ES) to 1.3 SED (PL). DISCUSSION AND CONCLUSIONS: Farmers' UVR exposure was comparable to that of outdoor workers in previous studies and exceeded the recommended UVR exposure limits on 36% (DK, AT), 29% (PL) and 56% (ES) of their working days. Attention to sun protection for outdoor workers across Europe in preventing UVR-induced skin cancer is still needed.

UVR exposure and vitamin D in a rural population. A study of outdoor working farmers, their spouses and children.

BACKGROUND: Living and working in the countryside may result in excessive UVR exposure, with increased risk of skin cancer. Some sun exposure is, however, recommended, since vitamin D production is UVB-dependent. OBJECTIVES: To examine UVR exposure and vitamin D levels in a rural population of outdoor working male farmers, their indoor working spouses and their children, expected to receive high UVR exposure. METHODS: Prospective, cohort study. During the summer 2009 daily, personal UVR exposure and sun behaviour were recorded by dosimetry and diaries (17 403 days). Vitamin D was measured at the end of summer and the following winter. RESULTS: Risk behaviour (= exposure of shoulders/upper body to the sun), beach days, sunscreen use and sunburns were infrequent. Farmers and boys had the highest daily UVR exposure (both 1.5 SED per day), likewise on work days. On non-work days the UVR exposure was even higher (up to 2.0 SED per day). Farmers, girls and boys had a higher chronic UVR exposure than the spouses, who had more intermittent high UVR exposure. Vitamin D levels did not differ between family members. At the end of summer 16% of the participants were vitamin D insufficient, the following winter, 61%. Some UVR exposure variables correlated positively, but weakly, with vitamin D levels. CONCLUSIONS: UVR exposure was generally high among this study population, however, vitamin D levels still dropped below the recommended level during winter for most participants. Differences in UVR exposure between the groups did not result in differences in vitamin D levels.