Individual Typology Angle and Fitzpatrick Skin Phototypes are Not Equivalent in Photodermatology

Osto, Muhammad; Hamzavi, Iltefat; Lim, Henry W.; Kohli, Indermeet

doi:10.1111/php.13562

Cited by 16 publications

(7 citation statements)

References 16 publications

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“…These ITA values (67 deg to

) are consistent with previous observations made in vivo using the Fitzpatrick skin type ( Table 1 ). 53 Reflectance at 685 nm was evaluated for each tissue model, giving a range of reflection coefficients from 0.20 to 0.72 over our simulated range of melanosome concentrations [ Fig. 1(c) , Table 1 ] again consistent with previous literature.…”

Section: Resultssupporting

confidence: 71%

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Effects of skin tone on photoacoustic imaging and oximetry

Else,

Hacker,

Gröhl

et al. 2023

J. Biomed. Opt.

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. Significance Photoacoustic imaging (PAI) provides contrast based on the concentration of optical absorbers in tissue, enabling the assessment of functional physiological parameters such as blood oxygen saturation ( ). Recent evidence suggests that variation in melanin levels in the epidermis leads to measurement biases in optical technologies, which could potentially limit the application of these biomarkers in diverse populations. Aim To examine the effects of skin melanin pigmentation on PAI and oximetry. Approach We evaluated the effects of skin tone in PAI using a computational skin model, two-layer melanin-containing tissue-mimicking phantoms, and mice of a consistent genetic background with varying pigmentations. The computational skin model was validated by simulating the diffuse reflectance spectrum using the adding-doubling method, allowing us to assign our simulation parameters to approximate Fitzpatrick skin types. Monte Carlo simulations and acoustic simulations were run to obtain idealized photoacoustic images of our skin model. Photoacoustic images of the phantoms and mice were acquired using a commercial instrument. Reconstructed images were processed with linear spectral unmixing to estimate blood oxygenation. Linear unmixing results were compared with a learned unmixing approach based on gradient-boosted regression. Results Our computational skin model was consistent with representative literature for in vivo skin reflectance measurements. We observed consistent spectral coloring effects across all model systems, with an overestimation of and more image artifacts observed with increasing melanin concentration. The learned unmixing approach reduced the measurement bias, but predictions made at lower blood still suffered from a skin tone-dependent effect. Conclusion PAI demonstrates measurement bias, including an overestimation of blood , in higher Fitzpatrick skin types. Future research should aim to characterize this effect in humans to ensure equitable application of the technology.

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“…These ITA values (67 deg to

Section: Resultssupporting

confidence: 71%

“…Parameters of the skin simulations (melanosome concentration, absorption coefficient) and quantities derived from adding-doubling simulations (reflectance, ITA, and HEX color value). The equivalent Fitzpatrick skin type was assigned based on literature values 53. …”

mentioning

confidence: 99%

Effects of skin tone on photoacoustic imaging and oximetry

Else,

Hacker,

Gröhl

et al. 2023

J. Biomed. Opt.

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“…ITA is used as an objective alternative to the subjective Fitzpatrick skin phototype ( 58 ), which is based on self-reported pigmentation and solar reactivity of the skin ( 50 ), and has been used as a measure of skin pigmentation in several studies ( 75 ). It should be noted that the ITA and the Fitzpatrick phototype (FT) classifications are not completely equivalent; whereas the FT is easier to use in a clinical setting, ITA is preferred for its objective classification of skin type in research ( 58 , 76 , 77 ). The analyses were performed using the base category of ‘light’, which was the most common in our study group.…”

Section: Discussionmentioning

confidence: 99%

Results of longitudinal Nutri-D study: factors influencing winter and summer vitamin D status in a Caucasian population

Hribar,

Pravst,

Pogačnik

et al. 2023

Front. Nutr.

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IntroductionInadequate vitamin D status is a worldwide public health issue. In humans, vitamin D status is affected by diet, and even more by exposure to ultraviolet B (UVB) light and consequential endogenous synthesis. Various personal and environmental factors influence endogenous synthesis. Factors affecting vitamin D status were investigated in a prospective longitudinal cohort study with a summer and winter observation period.MethodsThe final sample included 292 adults, of those 111 (38%) males and 181 (62%) females, with a mean age of 38.2 (±11.8) years from Slovenia who were not supplementing vitamin D. Serum 25-hydroxyvitamin D [25(OH)D] concentrations were measured in both periods; vitamin D intake, self-reported body mass index (BMI), and protective behaviors against sun were also recorded. Other measured parameters included measurements of constitutive skin color using the objective individual typology angle (ITA), and difference in the melanin index (ΔMI) for assessment of objective sun exposure.ResultsIn winter a high prevalence (63.4%) of insufficient vitamin D status (< 50 nmoL/L) was observed with higher odds ratios (OR) for insufficiency in those with a higher BMI and light ITA. During summer, insufficiency prevalence was low (5.5%), but half of the participants (50.0%) had suboptimal 25(OH)D concentration (< 75 nmol/L). In summer OR for suboptimal status were higher in those with obesity, lower ΔMI, light ITA, low vitamin D intake, and protective clothing behaviors.ConclusionUsing a series of measures, we showed that vitamin D status is hugely affected by several personal factors such as BMI, ITA, vitamin D intake, ΔMI, and protective behavior against the sun. This conclusion questions the usefulness of generalized population-level recommendations since personal factors are a major predictor of vitamin D status.

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“…ITA categorise skin colour into six groups (Del Bino & Bernerd, 2013). However, these are not equivalent to the six FST categories (Osto et al, 2022). Melanin indices and ITAs were shown to have a strong negative correlation; skin with a high melanin index had low ITA (Wilkes et al, 2015).…”

Section: Optimising Classification Of Skin Phototypesmentioning

confidence: 98%

Optimisation of skin phototype classification

Lim

Mohammad

Kohli

et al. 2023

Pigment Cell Melanoma Res

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Understanding individuals' skin pigmentation and photosensitivity is important in judging risk of skin cancer and response to certain treatment modalities. However, individuals with darkly pigmented skin are poorly represented in the widely used Fitzpatrick skin phototype (FST) system. Moreover, the FST system is prone to misuse, as it relies on subjective patient and clinician assessment of skin type, and does not clearly differentiate pigmentation from photosensitivity. By evaluating the key literature surrounding the FST system, its criticisms and proposed alternatives, this review serves to understand how skin phototype classification can be optimised.

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Individual Typology Angle and Fitzpatrick Skin Phototypes are Not Equivalent in Photodermatology

Cited by 16 publications

References 16 publications

Effects of skin tone on photoacoustic imaging and oximetry

Effects of skin tone on photoacoustic imaging and oximetry

Results of longitudinal Nutri-D study: factors influencing winter and summer vitamin D status in a Caucasian population

Optimisation of skin phototype classification

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