Validation of brief questionnaire measures of sun exposure and skin pigmentation against detailed and objective measures including vitamin D status.
Self-reported sun exposure is commonly used in research, but how well this represents actual sun exposure is poorly understood. From February to July 2011, a volunteer sample (n = 47) of older adults (≥45 years) in Canberra, Australia, answered brief questions on time outdoors (weekdays and weekends) and natural skin color. They subsequently maintained a sun diary and wore an ultraviolet radiation (UVR) digital dosimeter for 7 days. Melanin density was estimated using reflectance spectrophotometry; lifetime sun damage was assessed using silicone casts of the back of the hand; and serum 25-hydroxyvitamin D (25(OH)D) concentration was assayed. Questionnaire-reported time outdoors correlated significantly with diary-recorded time outdoors (Spearman correlation r(s) = 0.66; 95% CI 0.46, 0.80; P < 0.001) and UVR dosimeter dose (r(s ) = 0.46; 95% CI 0.18, 0.68; P = 0.003), but not 25(OH)D concentration (r(s) = 0.24; 95% CI -0.05, 0.50; P = 0.10). Questionnaire-reported untanned skin color correlated significantly with measured melanin density at the inner upper arm (r(s) = 0.49; 95% CI 0.24, 0.68; P < 0.001). In a multiple linear regression model, statistically significant predictors of 25(OH)D concentration were self-reported frequency of physical activity, skin color and recent osteoporosis treatment (R(2) = 0.54). In this study, brief questionnaire items provided valid rankings of sun exposure and skin color, and enabled the development of a predictive model for 25(OH)D concentration.
National Centre for Epidemiology and Population Health, The Australian National University, Canberra, Australia.
Jessica
J
Cargill
Robyn M
RM
Lucas
Peter
P
Gies
Kerryn
K
King
Ashwin
A
Swaminathan
Martin W
MW
Allen
Emily
E
Banks
D000368:Aged; D050071:Bone Density Conservation Agents / Q000627:therapeutic use; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D008543:Melanins / Q000032:analysis; D008875:Middle Aged; D010024:Osteoporosis / Q000097:blood* / Q000188:drug therapy; D011829:Radiation Dosage; D011874:Radiometry / Q000295:instrumentation*; D012880:Skin Pigmentation / Q000528:radiation effects; D013053:Spectrophotometry; D013472:Sunlight; D011795:Surveys and Questionnaires / Q000592:standards*; D013997:Time Factors; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood
D050071:Bone Density Conservation Agents; D008543:Melanins; D014807:Vitamin D; C104450:25-hydroxyvitamin D