Differences of Minimum Erythema Dose (MED) in Fitzpatrick IV

Skin Type Adults and Elderly with an Exposure of Narrowband

Ultraviolet B (NB-UVB)

Arini Astasari Widodo

, Tjut Nurul Alam Jacoeb

, Aria Kekalih

, Endi Novianto

Dermato-venereology Department, Faculty of Medicine, Universitas Indonesia/Dr. Cipto Mangukusumo National General

Hospital, Jakarta

Community Medicine Department, Faculty of Medicine, Universitas Indonesia

Keywords: Minimal Erythema Dose, Fitzpatrick Skin Type IV, Narrowband Ultraviolet B, elderly

Abstract: The skin of the elderly is different compared to that of an adult due to aging, where such changes could

influence the skin's response to ultraviolet exposure, including erythemal response. This difference could lead

to MED change, which in turn affects the effectiveness of treatment modalities for skin diseases. This study

aims to determine the difference between average MED in the elderly and adults with Fitzpatrick IV skin

type, as well as the difference between 24 hours-MED and 48 hours-MED. MED calculations were based on

skin erythemal responses relative to six different exposure doses of NB-UVB in elderly people aged over 60

years and adults aged 18-45 years. The irradiation is done with a Waldmann UV109 lamp with dosages

starting from 300, 500, 700, 900, 1100, and 1300 mJ/cm

. Responses were examined at 24 hours and 48 hours

post-irradiation by three different assessors. In the adult group, the mean of 24 hours-MED was 554 ± 182

mJ/cm

and 48 hours-MED was increased to 606 ± 167 mJ/cm

. In the elderly group, the mean of 24 hours-

MED was 702 ± 340 mJ/cm

and 48 hours-MED was increased to 836 ± 341 mJ/cm

. The 24 hours-MED in

the elderly group is higher compared to that of the adult group; however, the difference is not statistically

significant (p=0.158). There is a statistically significant difference between 24 hours-MED and 48 hours-

MED was found (<0.001) in the elderly group. The mean of 24 hours-MED in elderly and adults in this study

could be applied clinically.

1 INTRODUCTION

Elderly is defined as a person who has reached the age

of 60 (sixty) years old or above, while adult age is

defined as 18-45 years old and 45-59 years old is

defined as pre-geriatrics age (Peraturan Menteri

Kesehatan Republik Indonesia, 2016). According to a

report detailing visits to the Geriatric Division of

Dermatovenereology Department of Dr. Cipto

Mangunkusumo General Hospital, psoriasis vulgaris

and atopic dermatitis are included in the top 10

diagnoses (Legiawati et al., 2016), and these diseases

frequently require phototherapy modalities, including

phototherapy using NB-UVB.

The assessment of initial dose for phototherapy

may be approximated based on skin types or on MED

irradiation test (Taylor and Stern, 1991). MED refers

to a radiation dose used to produce just perceptible

erythema (JPE) or the minimum energy required to

produce a pink erythema response with clearly-

defined border (Cafardi et al., 2012; Morrison W,

2005).

The skin of the elderly is different compared to

that of an adult due to aging. These changes may

affect the skin’s response to ultraviolet light exposure

(Gilchrest et al, 1982), and may include changes in

inflammatory response and its mediators, changes in

the immune system (immunosenescense), changes in

the morphology of keratinocytes, and changes in the

size of blood vessels. These may lead to a reduced

erythema response triggered by UV exposure

(Raschke and Elsner, 2010). Changes in erythema

response due to aging is expected to affect MED in

the elderly group.

Studies on MEDs in the elderly yield varying

results. This may be due to difference of light source

and measurement in differing phases, resulting in the

difficulties to conclude the erythematous effect of

NB-UVB exposure in the elderly (Thomas and

Bergoend, 1977).

Studies on MED in the elderly with

Widodo, A., Jacoeb, T., Kekalih, A. and Novianto, E.

Differences of Minimum Erythema Dose (MED) in Fitzpatrick IV Skin Type Adults and Elderly with an Exposure of Narrowband Ultraviolet B (NB-UVB).

DOI: 10.5220/0008151100730077

In Proceedings of the 23rd Regional Conference of Dermatology (RCD 2018), pages 73-77

ISBN: 978-989-758-494-7

the most frequent skin types in Indonesian population

has never been conducted and it is deemed necessary

to study the MED with the exposure of NB-UVB in

the elderly, compared to adult population with the

same skin type (Fitzpatrick IV and V being the most

frequent in Indonesians) (Bernadette et al., 2002).

This study aims to determine the difference of

MED in adults and elderly with Fitzpatrick IV skin

type, to determine the average MED for Fitzpatrick

IV skin type for both adults and elderly, and to

determine the difference of 24 hours- and 48-hour-

MEDs in the elderly.

2 METHODS

This study is a clinical trial that compares the MED

of adults and the elderly. The subject of the study are

geriatric residents of Tresna Werdha Nursing Home

(Cilandak, South Jakarta, Indonesia) with Fitzpatrick

IV skin type who consented to participate in the

study, as well as Nursing Home workers aging 18-45

years old with no history of diseases affected by UV

lights or causing photosensitivity. Thirty-eight

subjects from the adult group and 36 subjects from

the elderly group was exposed with narrowband

ultraviolet light on their backs using Waldmann

UV109 lamp on the opened window with dosages

starting from 300, 500, 700, 900, 1100, and 1300

mJ/cm

. This study has been approved by the Health

Research Ethical Committee of the Faculty of

Medicine, Universitas Indonesia.

Responses were examined at 24 hours and 48

hours post-irradiation by 3 individuals, namely the

principal investigators and 2 dermatovenereologist

with ICC approaching 1.00 (0.98).

Data analyses were conducted in two phases, i.e.

descriptive phase and inferential phase. The

descriptive phase was performed to compare MED of

adults and elderly population using Mann-Whitney

due to abnormal distribution. A Wilcoxon test was

conducted to compare the 24 hours- and 48 hours-

MED in both adults and elderly. All analyses were

performed using SPSS program version 20.

3 RESULTS

Of 36 elderly subjects, 17 (47.2%) were male, and 19

(52.9%) were female. In the adult group, 14 (42.4%)

were male, and 19 (57.6%) were female. There is no

significant difference in the number of male between

the adult and elderly groups. Although the percentage

of female is higher in both groups, this is not

significant; thus, both groups can be considered

homogenous in terms of gender. Based on the data

from 69 subjects included in the analysis, other than

gender, there are no significant difference in terms of

ethnicity and level of dependency.

In the adult population, the median of 24 hours-

and 48 hours-MED are 500 mJ/cm

(300 – 900

mJ/cm

) and 700 mJ/cm

(300 – 900 mJ/cm

respectively; while the mean 24 hours-MED and 48-

hours MED are 554 ± 182 mJ/cm

and 606 ± 167

mJ/cm

, respectively. The 24 hours-MED in the

elderly group is higher compared to that of the adult

group; however, the difference is not statistically

significant (p=0.158). Table 1 presents the

comparison of 24 hours- and 48 hours-MED in the

adult and elderly groups. Figure 1 presents the

distribution of 24 hours- and 48 hours-MED in both

adults and elderly.

In terms of the 24 hours-MED, we failed to reject

null hypothesis despite the fact that our sample size

indicates adequate power.

Table 1. Comparison of 24 hours- and 48 hours-MED in the adult and elderly groups

Variable Adult Elderly p

24 hours-MED

(mJ/cm

)

Median (min – max)

Mean

500 (300-900)

554  182

550 (300-1300)

702  340

0.158

48 hours-MED

(mJ/cm

)

Median (min – max)

Mean

700 (300-900)

606  167

700 (400-1300)

836  341

0.026

*Due to the abnormal distribution of MED data in this study, a non-parametric test, i.e. Mann-Whitney Test was

used in data analysis.

RCD 2018 - The 23rd Regional Conference of Dermatology 2018

Figure 1. Distribution of 24 hours- and 48 hours-MED in the adult and elderly groups

In the elderly group, the median of 24 hours-MED

and 48 hours-MED are 550 (300 – 1300) mJ/cm

and

700 (400 – 1300) mJ/cm

, respectively; while the

mean 24 hours-MED and 48 hours-MED are 702 

340 mJ/cm

and 836  341 mJ/cm

, respectively.

Based on the Wilcoxon test, there is a statistically

significant difference between 24 hours- and 48

hours-MED in the elderly group (p <0.001). Table 2

presents the comparison of median 24 hours- and 48

hours-MED in the elderly group.

Table 2. Comparison of median 24 hours- and 48 hours-MED in the elderly groups

Variable Elderly p

24 hours-MED (mJ/cm

)

Median (min-max)

Mean

550 (300-1300)

702  340

<0.001

48 hours-MED (mJ/cm

)

Median (min-max)

Mean

700 (400-1300)

836  341

* Due to the abnormal distribution of MED data in this study, Wilcoxon Test was used in data analysis

4 DISCUSSION

This study found a higher percentage of female

compared to male in both groups. However, the

difference is not significant; thus, both groups can be

considered homogenous in terms of gender. This is

likely due to the fact that there is more female elderly

compared to male in the location where the study was

conducted. This is also consistent with the female to

male elderly ratio in Indonesia, which is 9:8, and with

the higher life expectancy for female elderly

compared to male elderly (Pusat Data dan Informasi

Kementerian Kesehatan Republik Indonesia, 2016).

This study found a difference in 24 hours-MED

between adult and elderly groups. However, this

difference is not statistically significant (p=0.158).

Some literatures have found that the erythema

response in the elderly differs from that of adult

population (Gilchrest at al., 1982; Gloor and

Scherotzke, 2002; Guerrera, 1989).

This is due to various factors, including

differences in anatomical and physiological aspects,

vascular response, immune response, and so on.

Previous studies also found varying results. Cox

found that in the 24 hours after irradiation, no

statistically significant difference was observed in the

mean MED of adult group compared to elderly.

However, this study used different UVB source,

leading to difficulties in comparing the dosages

received by subjects. The study also included subjects

with Fitzpatrick I-V skin types (Cox et al., 1989).

Amblard performed an analysis of 2 quantitative

variable, namely age and MED, and found a good

correlation (r=0.78, P<0.001) in 303 patients aged 5-

89 years old. The study found that the MED lowers

with the increase of age. However, the study was

conducted on patients with lighter skin, which may

confound the result. Differ to the current study,

Amblard exposed their subjects to UVB using

different light source and measure the erythema

response using different methods as well. These

differences may contribute to the different results

yielded by that study and the current study (Amblard

et al., 1982).

Gloor conducted a study on 20 subjects aged 20-

40 years old and 20 subjects aged 70 and above with

Fitzpatrick I – IV skin types, where the MED was

Differences of Minimum Erythema Dose (MED) in Fitzpatrick IV Skin Type Adults and Elderly with an Exposure of Narrowband

Ultraviolet B (NB-UVB)

measured 48 hours after irradiation using narrowband

UVB. The study found no statistically significant

difference in 48 hours-MED between both groups

(Gloor and Scherotzke, 2002). All differences in

erythema response in the elderly descibed above

explains the finding of higher MED in the elderly

group compared to the adult group. However,

considering that the difference of 24 hour-MED is not

statistically significant, one can interpret that in

practice, the initial dose of phototherapy does not

need to be different between adults and the elderly.

Despite previous literatures showing various

evidences that the biological and physiological

erythema response are different in adults and in the

elderly, this alone does not affect the MED for NB-

UVB which may be useful to determine the initial

dose of phototherapy.

This study is also the first to compare the MED

between adults and elderly population in Indonesia,

where the majority of skin type is Fitzpatrick IV.

Even with the same skin type, considering the wide

range of minimum and maximum value as presented

in Table 2, determining initial dose for phototherapy

based on skin type might not always lead to a uniform

result; therefore, it is more recommended to use MED

as a reference for initial dose for phototherapy.

When a comparison is made between 24 hours-

and 48 hours-MED in the elderly, we found a

statistically significant difference with a p value of

<0.001). This indicates that significant erythematous

changes occur over time in the elderly. From this

finding, it can be interpreted that exposure to NB-

UVB with a mean radiation dose of 836  341 mJ/cm

will result in an erythema with a higher intensity than

MED definition at 24 hours, and result in clinical

features of erythema consistent with the definition of

MED at 48 hours.

In clinical application, the lowest dose to produce

a pink erythema response with clearly-defined border

should be used in determining MED. Based on the

findings of the current study, the lowest dose for

MED is obtained at 24 hours; therefore, 24 hours-

MED should be used in determining the initial dose

for phototherapy.

This study is the first study that compares 24

hours- and 48-hour MED in the elderly. Gloor were

the first to observe the 48 hours-MED in the elderly.

This observation was conducted in the 48th hour

following irradiation due to a theory stating that

erythema response in the elderly is expected to be

delayed, as confirmed in the findings of a previous

study (Gloor and Scherotzke, 2002; Guerrera, 1989).

Gloor’s study did not compare the 24 hours- and 48-

hour MED; however, despite finding that there are no

significant difference in terms of 48-hour MED

between adults and elderly populations, they found a

higher erythema intensity in the elderly population at

48 hours after irradiation.

Considering that this study is performed on

subjects with Fitzpatrick IV skin type, it is also

important to remember that the photoprotection effect

of melanin might also be a contributing factor to the

differences between the current study and previous

studies conducted on subjects with lighter skin. It

remains possible that the findings of this study are due

to the photoprotection effect of melanin, which is a

stronger determinant factor compared to age. In

darker skin, erythema resulting from UVB exposure

will subside after 1-3 days, while in individuals with

lighter skin, the response may persist for 1-2 weeks

(Weichenthal and Schwarz T., 2005).

5 CONCLUSION

The mean 24 hours-MED in the adult group with

Fitzpatrick IV skin type is 554 ± 182 mJ/cm

and the

mean 24 hours-MED in the elderly group with

Fitzpatrick IV skin type is 702  340 mJ/cm

. The 24

hours-MED of the elderly group is higher compared

to that of the adult group; however, this difference is

not statistically significant. There is significant

difference between 24 hours-MED and 48 hours-

MED in the elderly group with Fitzpatrick IV skin

type. The mean of 24 hours-MED in elderly and

adults in this study could be applied clinically.

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Differences of Minimum Erythema Dose (MED) in Fitzpatrick IV Skin Type Adults and Elderly with an Exposure of Narrowband

Ultraviolet B (NB-UVB)