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Updated: Dec 30, 2025
Precision Implementation of Minimal Erythema Dose MED Testing to Assess Individual Variation in Human Inflammatory Response
Published on: October 3, 2019
Identification of factors associated with minimal erythema dose variations in a large-scale population study of
1Department of Skin & Cosmetic Research, Shanghai Skin Disease Hospital, Shanghai, China.
Background:
Minimal erythema dose (MED) has substantial inter- and intraindividual variations, reflecting the influence of very diverse factors. However, related studies showed little consistency probably because of their limited sample size.
Objective:
To identify the factors associated with MED variations in a large-scale population study.
Methods:
The MED test was performed by following the international standard procedure on 22 146 subjects. The results were analysed in adjusted multivariable linear and logistic regression models.
Results:
This large-scale study revealed that lower MED was consistently associated with lighter skin [β-coefficient = -0.33, 95% confidence interval (CI) -0.36 to 0.30, P = 6.41 × 10-84 ]. Females had significantly higher MED than male (β = 0.91, 0.32-1.50, P = 2.93 × 10-3 ). Stratified analyses showed that MED was not associated with age [female: odds ratio (OR) = 0.99, 0.98-1.01; male: OR = 0.99, 0.97-1.00]. MED was lower in summer than in other seasons (spring: OR = 1.08, 1.06-1.11; autumn: OR = 1.11, 1.08-1.13; winter: OR = 1.20, 1.18-1.22). Furthermore, MED was associated with air temperature (β = -0.36, -0.49 to 0.23, P = 4.81 × 10-8 ) and air pressure (β = -0.64, -0.82 to 0.46, P = 8.01 × 10-12 ) in summer only while not in other seasons.
Conclusions:
This study provides unprecedented evidence that MED is associated with skin colour, sex, season and meteorological factors, but not with age.
