Validation of Questionnaire and Diary Measures of Time Outdoors Against an Objective Measure of Personal Ultraviolet Radiation Exposure

Abstract

Self-reported sun exposure is commonly measured using questionnaires or diaries, but there are limited data on their validity, particularly for population subgroups. This research aimed to compare self-reported sun exposure, measured as (1) habitual time outdoors over the past month on weekends and weekdays and (2) a 4-day diary measure, against objective measurement of personal ultraviolet radiation using polysulfone film dosimeters. From November 2015 to January 2016, 94 people (22-69 years and living in New South Wales, Australia) completed a questionnaire, 4-day diary and 4-day dosimeter measures of overall, weekday and weekend sun exposure. Spearman correlations and Bland-Altman plots were used to measure agreement. The overall weekly correlation was 0.57 (95% confidence interval [CI] 0.44, 0.68) between standard erythemal doses (SEDs) measured by dosimeter and time spent outdoors measured by questionnaire, 0.74 (95% CI 0.66-0.81) between dosimeter and diary, and 0.59 (95% CI 0.48-0.68) between questionnaire and diary measures. Validity was lower for younger people and weekend sun exposure. There was strong correlation between dosimeter and sun diary measures and moderate correlation between dosimeter and questionnaire measures. Daily measurement over a longer period may be required to accurately capture weeklong sun exposure in all population subgroups.

Influence of physical activity on serum vitamin D levels in people with multiple sclerosis

“…In some studies, higher vitamin D levels were attributed to activity during sunlight exposure, however, in most of these investigations physical activity independent of sunlight exposure was not accounted for. In the present study, pwMS documented 1.2 hours of sunlight exposure per day on average, which is similar to another study reporting 1.4 hours, also using a diary [19].…”

Influence of physical activity on serum vitamin D levels in people with multiple sclerosis

“…In some studies, higher vitamin D levels were attributed to activity during sunlight exposure, however, in most of these studies physical activity independent of sunlight exposure was not accounted for. In the present study, pwMS documented 1.2 hours of sunlight exposure per day on average, which is similar to another study reporting 1.4 hours, also using a diary (15).…”

Daily Minutes of Unprotected Sun Exposure (MUSE) Inventory: Measure description and comparisons to UVR sensor and sun protection survey data

“…Analyses indicated moderate correspondence between the Daily MUSE Inventory and both UVR sensors and the widely-used Sun Habits Survey. For estimates of time outdoors, discrepancies were identified which warrant further investigation, but overall agreement was comparable to past studies ( Cust et al, 2018 ; Cargill et al, 2013 ; Glanz et al, 2010 ).…”

“…Currently, the most widely used self-report measure of personal sun protection and exposure in the US is the Sun Habits Survey, which assesses the frequency of sun-protection behaviors on warm summer days ( Glanz et al, 2008 ). Diary measures have also been developed to capture daily-level sun behavior and have taken various forms, including asking about outdoor time during specific windows of time ( Cust et al, 2018 ; O'Riordan et al, 2009 ; Cargill et al, 2013 ; Chodick et al, 2008 ) or asking the length of time participants were engaged in specific sun-protection behaviors ( Hillhouse et al, 2012 ).…”