Use of UV dosimeters and diaries may influence sun exposure

May 13, 2016

Highlights

Personal UV dosimeters and diaries were previously applied in studies of UV radiation.
Effects of using UV dosimeters and diaries on participants' behavior were not previously examined.
Correlation between objective and subjective measures of outdoor exposure time was shown.
Their correlation coefficient depends on length of recall (bias).
The use of dosimeters and diaries increases attention towards the examined behavior.

Abstract

Dosimeters and diaries have previously been used to evaluate sun-related behavior and UV exposure in local samples. However, wearing a dosimeter or filling in a diary may cause a behavioral change. The aim of this study was to examine possible confounding factors for a questionnaire validation study. We examined the effects of wearing dosimeters and filling out diaries, measurement period and recall effect on the sun-related behavior in Denmark in 2012.

Our sample included 240 participants eligible by smartphone status and who took a vacation during weeks 26–32 in 2012, randomized by gender, age, education and skin type to six groups: 1) Control + diary, 2) Control, 3) 1-week dosimetry measurement, 4) 1-week dosimetry measurement + diary, 5) 3-week dosimetry measurement and 6) 1-week dosimetry measurement with 4 week delayed questionnaire.

Correlation coefficients between reported outdoor time and registered outdoor time for groups 3–6 were 0.39, 0.45, 0.43 and 0.09, respectively. Group 6 was the only group not significantly correlated. Questionnaire reported outdoor exposure time was shorter in the dosimeter measurement groups (3–6) than in their respective controls.

We showed that using a dosimeter or keeping a diary seems to increase attention towards the behavior examined and therefore may influence this behavior. Receiving the questionnaire with 4 week delay had a significant negative influence on correlation and recall of sunburn. When planning future UV behavior questionnaire validations, we suggest to use a 1-week interval for dosimetry measurements, no diary, and to minimize the time from end of measurement to filling out questionnaires.

Køstera, B, et al. Effects of smartphone diaries and personal dosimeters on behavior in a randomized study of methods to document sunlight exposure. Preventive Medicine Reports. 2016;3:367-372. doi:10.1016/j.pmedr.2016.04.002. http://www.sciencedirect.com/s...