Open AccessAssessing skin pigmentation in epidemiological studies: The reliability of measurements under different conditions
Author(s) -
Uter W.,
Benz M.,
Mayr A.,
Gefeller O.,
Pfahlberg A.
Publication year - 2013
Publication title -
skin research and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.521
H-Index - 69
eISSN - 1600-0846
pISSN - 0909-752X
DOI - 10.1111/srt.12013
Subject(s) - reproducibility , intraclass correlation , reflectivity , mathematics , repeatability , optics , statistics , materials science , biomedical engineering , medicine , physics
Background/purpose Different devices are used for the non‐invasive measurement of (constitutive) skin pigmentation in (epidemiological) studies. Reproducibility of measurements with the Chromameter ( CM , model CR 300, Minolta, Osaka) and the Reflectometer ( RM , Courage & Khazaka, Cologne) has not yet been examined in detail and was addressed in a set of four experiments and studies respectively. Methods Regarding the CM , the Y value of the Yxy CIE 1931 colour system was utilized, representing lightness in this colour space, while the RM measured reflectance at 660 nm with a small bandwidth of 20 nm. Both devices measure reflectance on a scale from 0 to 100%, however, in different wavelength ranges. Between 3 and 20 repetitions were performed on standard grey scales and different sets of human volunteers, including RM measurements in a large epidemiological field study. Results While the coefficient of variation ( V ) increases and the intraclass correlation coefficient decreases from controlled laboratory to field conditions, reproducibility remained in a range considered acceptable, if adequate study conditions were maintained. In a direct comparison on human skin, V of the RM was significantly smaller than that of the CM . Conclusion Both devices can be used confidently in field studies; however, based on considerations of skin optics and in view of slightly lesser variability, the RM may be preferable.