In multiple situational light settings, visual observation for skin colour assessment is comparable with colorimeter measurement.
BACKGROUND
Finding inexpensive and reliable techniques for assessing skin colour is important, given that it is related to several adverse human health outcomes. Visual observation is considered a subjective approach assessment and, even when made by trained assessor, concern has been raised about the need for controlled lighting in the study venue. The aim of this study is to determine whether visual skin colour assessments correlate with objective skin colour measurements in study venues with different lighting types and configurations.


METHODS
Two trained investigators, with confirmed visual acuity, visually classified the inner, upper arm skin colour of 556 adults using Munsell(®) colour classifications converted to Individual Typology Angle (°ITA) values based on published data. Skin colour at the same anatomic site was also measured using a colorimeter. Each participant was assessed in one of 10 different buildings, each with a different study day. Munsell(®) -derived °ITA values were compared to colorimeter °ITA values for the full sample and by building/day.


RESULTS
We found a strong positive, monotonic correlation between Munsell(®) derived °ITA values and colorimeter °ITA values for all participants (Spearman ρ = 0.8585, P < 0.001). Similar relationships were found when Munsell(®) and colorimeter °ITA values were compared for participants assessed in the same building for all 10 buildings (Spearman ρ values ranged from 0.797 to 0.934, all correlations were statistically significant at P < 0.001).


CONCLUSIONS
It is possible to visually assess individual skin colour in multiple situational lighting settings and retrieve results that are comparable with objective measurements of skin colour. This was true for individuals of varying population groups and skin pigmentation.
Environment & Health Research Unit, South African Medical Research Council, Department of Geography, Meteorology and Geoinformatics, University of Pretoria, Pretoria, South Africa.
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Wright
Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY, USA.
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Wilkes
Occupational Hygiene and Health Research Initiative, North-West University, Potchefstroom, South Africa.
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du Plessis
Cancer Society of New Zealand Social and Behavioural Research Unit, Department of Preventive and Social Medicine, University of Otago Medical School, Dunedin, New Zealand.
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Reeder
Environment & Health Research Unit, South African Medical Research Council, Pretoria, South Africa.
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Albers
D000293:Adolescent; D000328:Adult; D002983:Clinical Competence; D003118:Color Perception / Q000502:physiology*; D003124:Colorimetry / Q000379:methods*; D005260:Female; D006801:Humans; D008029:Lighting / Q000379:methods*; D008297:Male; D015588:Observer Variation; D010808:Physical Examination / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012880:Skin Pigmentation / Q000502:physiology*; D055815:Young Adult
Individual Typology Angle; Munsell® colour charts; colorimeter; lighting; skin colour