The relationship between ambient ultraviolet radiation (UVR) and objectively measured personal UVR exposure dose is modified by season and latitude

Abstract

Despite the widespread use of ambient ultraviolet radiation (UVR) as a proxy measure of personal exposure to UVR, the relationship between the two is not well-defined. This paper examines the effects of season and latitude on the relationship between ambient UVR and personal UVR exposure. We used data from the AusD Study, a multi-centre cross-sectional study among Australian adults (18-75 years), where personal UVR exposure was objectively measured using polysulphone dosimeters. Data were analysed for 991 participants from 4 Australian cities of different latitude: Townsville (19.3°S), Brisbane (27.5°S), Canberra (35.3°S) and Hobart (42.8°S). Daily personal UVR exposure varied from 0.01 to 21 Standard Erythemal Doses (median = 1.1, IQR: 0.5-2.1), on average accounting for 5% of the total available ambient dose. There was an overall positive correlation between ambient UVR and personal UVR exposure (r = 0.23, p < 0.001). However, the correlations varied according to season and study location: from strong correlations in winter (r = 0.50) and at high latitudes (Hobart, r = 0.50; Canberra, r = 0.39), to null or even slightly negative correlations, in summer (r = 0.01) and at low latitudes (Townsville, r = -0.06; Brisbane, r = -0.16). Multiple regression models showed significant effect modification by season and location. Personal exposure fraction of total available ambient dose was highest in winter (7%) and amongst Hobart participants (7%) and lowest in summer (1%) and in Townsville (4%). These results suggest season and latitude modify the relationship between ambient UVR and personal UVR exposure. Ambient UVR may not be a good indicator for personal exposure dose under some circumstances.

The validated sun exposure questionnaire: association of objective and subjective measures of sun exposure in a Danish population‐based sample

“…Other measures may be more applicable in other climates. 41 The questionnaire developed and validated can be applied in short-or long-term studies that need to assess the UVR exposure in a study group or population, e.g. studies of skin cancer, sun protection, vitamin D 23 or even outdoor behaviour.…”

Investigating the patterns and determinants of seasonal variation in vitamin D status in Australian adults: the Seasonal D Cohort Study

“…But there are moderating effects, particularly the amount of time spent outdoors, clothing cover, and use of sun protection. For example, in very hot locations (typically low latitude), people may spend more time indoors during summer, while in cool locations, the warmer weather of summer leads people to spend more time outdoors [5, 6]. In addition, more skin is typically covered by clothing in the winter and this is particularly apparent at higher latitudes.…”

Review on Nonoccupational Personal Solar UV Exposure Measurements

“…This analysis expanded that of Sun et al . (*) where it was shown, as many times before, that ERTA changes with season and with latitude. Both may be influenced by weather.…”