Epidemiological Study on the Incidence of Herpes Zoster in Nearby Cheonan

Abstract

Herpes Zoster is a disease that occurs after the virus is reactivated due to infection of the varicella virus in childhood. Risk factors are advanced age, malignant neoplasm, organ transplantation, immunosuppressive agents taking are known. The purpose of this study was to investigate the relationship between the seasonal effect and other risk factors on the incidence of herpes zoster.
The medical records of 1,105 patients admitted to the outpatient diagnosed with herpes zoster were retrospectively examined. The patients' sex, age, dermatome, onset, underlying disease, residential areas were collected.
The incidence of women outnumbered men and increased for those above the age of 50. The number of occurrences of herpes zoster patients was higher in the spring and summer than in winter. Unlike men, women had the most frequent outbreaks in March. The most common occurrence of dermatome is in the thoracic region. The number of occurrence was similar on the left as the right.
In this study, herpes zoster occurs more often in women than in men and more frequently occurs in women in the spring and summer.

Full text

Korean J Pain 2015 July; Vol. 28, No. 3: 193-197
pISSN 2005-9159 eISSN 2093-0569
http://dx.doi.org/10.3344/kjp.2015.28.3.193
| Original Article |
Epidemiological Study on the Incidence of
Herpes Zoster in Nearby Cheonan
Department of Anesthesia and Pain Medicine, Soonchunhyang University Cheonan Hospital,
Soonchunhyang University College of Medicine, Cheonan, Korea
Ho Soon Jung, Jin Ku Kang, and Sie Hyeon Yoo
Background: Herpes Zoster is a disease that occurs after the virus is reactivated due to infection of the
varicella virus in childhood. Risk factors are advanced age, malignant neoplasm, organ transplantation,
immunosuppressive agents taking are known. The purpose of this study was to investigate the relationship
between the seasonal effect and other risk factors on the incidence of herpes zoster.
Methods: The medical records of 1,105 patients admitted to the outpatient diagnosed with herpes zoster
were retrospectively examined. The patients' sex, age, dermatome, onset, underlying disease, residential areas
were collected.
Results: The incidence of women outnumbered men and increased for those above the age of 50. The
number of occurrences of herpes zoster patients was higher in the spring and summer than in winter. Unlike
men, women had the most frequent outbreaks in March. The most common occurrence of dermatome is in
the thoracic region. The number of occurrence was similar on the left as the right.
Conclusions: In this study, herpes zoster occurs more often in women than in men and more frequently
occurs in women in the spring and summer. (Korean J Pain 2015; 28: 193-197)
Key Words: Age; Epidemiology; Herpes zoster; Incidence; Seasons; Sex.
Received April 15, 2015. Revised May 29, 2015. Accepted June 2, 2015.
Correspondence to: Sie Hyeon Yoo
Department of Anesthesia and Pain Medicine, Soonchunhyang University Cheonan Hospital, Soonchunhyang University College of Medicine,
Soonchunhyang 2gil, Dongnam-gu, Cheonan 330-721, Korea
Tel: ＋82-41-570-2827, Fax: ＋82-41-573-3559, E-mail: doc0126@dreamwiz.com
This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://
creativecommons.org/licenses/by-nc/4.0/), which permits unrestricted non-commercial use, distribution, and reproduction in any medium,
provided the original work is properly cited.
Copyright ⓒ The Korean Pain Society, 2015
INTRODUCTION
Shingles is an infection caused by the Varicella-Zoster
virus, the same virus that causes chickenpox. Although
the virus lies dormant in individuals who have had chick-
enpox, it sometimes reactivates several years later, caus-
ing shingles. The infection is known to affect 1.5-3 in-
dividuals per 1,000 annually [1-3].
The known risk factors include old age, malignant ne-
oplasm, organ transplantation, and immunosuppressive
therapy. A higher incidence rate is also observed among
individuals with diabetes, women, and those being treated
for the human immunodeficiency virus (HIV) [4]. Dopico et
al. [5] reported that there is a change in immune function

194 Korean J Pain Vol. 28, No. 3, 2015
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Fig. 1. Number of cases of herpes zoster each age during
2012 and 2013.
Ta b l e 1 .
Seasonal Cases of Herpes Zoster by Gender
Season Male Female Total %
Spring (Mar
−
May)
Summer (Jun
−
Aug)
Autumn (Sep
−
Nov)
Winter (Dec
−
Feb)
Subtotal
126
131
122
77
456
184
183
146
136
649
310
314
268
213
1105
28.0
28.4
24.3
19.3
Fig. 2. Number of cases of herpes zoster each month.
according to the season. According to Miller et al. [6],
chickenpox most frequently occurs in the spring and winter
months, but cases of shingles do not vary by season.
However, Toyama and Shiraki [7] reported that a surge of
the cases was noted in the summer, which dropped in the
winter.
The present study was designed based on the hypoth-
esis that the occurrence of shingles in the rural commun-
ities of Cheonan might be affected by seasonal factors.
MATERIALS AND METHODS
Of the individuals who visited the Soonchunhyang
University Cheonan Hospital between January 1, 2012 and
December 31, 2013, a total of 1,498 patients diagnosed
with shingles were selected for a retrospective inves-
tigation of clinical records. Approval was obtained from the
hospital
’
s Institutional Review Board prior to the start of
the investigation. Based on the following criteria, 393 pa-
tients were excluded: (1) individuals who contracted the ill-
ness before the investigation period; (2) individual exhibits
no blisters, but complains of pain; (3) individual diagnosed
with suspected shingles; and (4) insufficient clinical record.
Data on the final 1,105 patients, pertaining to gender, age,
time of occurrence, affected site (dermatome, left/right of
body), underlying diseases, and place of residence, were
collected. The subjects were classified into groups based
on age (in increments of 5 years, beginning at 0 years),
location of dermatome (trigeminal ganglion, cervical verte-
bra, thoracic vertebra, lumbar, or sacrum), time of occur-
rence (month in which rash appeared), underlying diseases
(hypertension, diabetes, cerebropathy, cardiovascular dis-
eases, respiratory diseases, renal diseases, musculos-
keletal disorders, liver diseases, endocrinal diseases, can-
cers, exhaustion and stress, pregnancy, and miscella-
neous), and by place of residence (as recorded at the time
of the initial hospital visit).
RESULTS
1. Age and gender
Of the 1,105 study subjects, 41.2% (456 subjects) were
male and 58.8% (659 subjects) were female. The mean age
was 56 years (± 19.1; range, 4-97 years). In both 2012
and 2013, a higher incidence rate was observed in the sub-
jects 50 years of age and older, which dropped in the sub-
jects 80 years and older (Fig. 1).
2. Time of occurrence
In female subjects, March showed the highest in-
cidence rate, and February and December exhibited the
lowest. In male subjects, no notable variation was found

Jung, et al / Epidemiological Study on the Incidence of HZ 195
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Fig. 3. Underlying disease of herpes zoster.
Fig. 5. Dermatomal distribution of herpes zoster each age.Fig. 4. Dermatomal distribution of herpes zoster.
between the months of the year. The overall monthly in-
cidence rate showed a pattern that was similar to the
monthly incidence rate observed in the female subjects
(Fig. 2). In terms of seasonal incidence rates, which were
obtained after grouping the months by seasons, spring and
summer exhibited higher incidence rates than winter (Table 1).
3. Underlying diseases
Of the 1,105 patients, 131 (11.9%) had diabetes, 46
(4.2%) had cancer, 276 (25.0%) had hypertension, 46
(4.2%) had cardiovascular diseases, 32 (2.9%) were preg-
nant, 29 (2.6%) reported exhaustion and stress, and 89
(8.1%) had other diseases (cerebropathy, endocrinal dis-
eases, respiratory diseases, renal diseases, musculos-
keletal disorders, liver diseases, infection, etc.). 606
(55.0%) patients reported not having any disease other
than shingles (Fig. 3).
4. Affected site
The most commonly affected site was the thoracic
vertebra, reported by 530 subjects (47.9%), followed by the
trigeminal ganglion reported by 237 subjects (21.4%)
[ophthalmic nerve, 164 subjects (69.2%), maxillary nerve,
57 subjects (24.0%), and mandibular nerve, 16 subjects
(6.8%)] (Fig. 4). No significant differences were found in
the left and right trunk orientation of the rash (Left
：
Right
= 1
：
1.04). Among the subjects aged 50 and older, the
thoracic vertebra was the most commonly affected site
(Fig. 5).
5. Place of residence
Because 76% of the study subjects resided in the
neighboring area, and not enough cases were reported
from elsewhere, the potential association between place of
residence and season could not be traced. The number of
occurrences during the study period did not appear to be
affected by the trends in temperature, daily temperature
range, humidity, duration of daylight, etc.
DISCUSSION
Through a retrospective analysis of clinical records,
the present study was conducted to examine the associa-
tion between shingles and seasonal factors.

196 Korean J Pain Vol. 28, No. 3, 2015
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It is known that older individuals and those undergoing
immunotherapy for HIV infection, malignant neoplasm, or-
gan transplantation, and steroid treatment are at a higher
risk of developing shingles because of the increased like-
lihood of the virus reactivating. Additionally, psychological
and physical stress has been reported to have an impact
[8].
In general, shingles are known to affect 1.5-3 in-
dividuals per 1,000 annually [1-3]. However, shingles af-
fect 15-16 individuals per 1,000 in the U.S. each year,
which is attributed to the fact that most have had chick-
enpox as a child [8]. In Korea, shingles are known to affect
0.88-4.8 individuals per 1,000 annually [9-11].
Hope-Simpson [12] reported that the rate of occur-
rence among individuals under the age of 10 is extremely
low at 0.74 per 1,000 individuals, in contrast to 7.8 per
1,000 among individuals over the age of 60. Donahue et
al. [1] reported an even higher rate of occurrence among
individuals 75 years and older, at 18.4 per 1,000. In the
present study, the highest incidence was observed in the
50-64 years age group, and the incidence among in-
dividuals aged 50 years and older (770 cases) was more
than twice that of their younger counterparts (335 cases).
In our study, the incidence was lower in the group of in-
dividuals 75 years and older. However, this appears to be
due to the demographic characteristics of the study area,
namely, the decline in the number of individuals in the age
group (Fig. 1).
In terms of shingles and gender, Gialloreti et al. [13]
reported the most significant risk factors of shingles in-
cluded being female, being 55 years of age or older, and
possessing a weak immune system. However, the influence
of gender was not so clear [14]. A study supports the po-
tential association between the female gender and elevated
risk of shingles [15]. The study, which analyzed a total of
14,532 subjects, found a significantly higher rate of in-
cidence among female subjects, which was attributed to
differences in the immune systems between the genders.
Due to the biological differences between the genders, the
virus is more likely to reactivate in the female body than
in the male body. The study also cited the higher exposure
rate of females to children with chickenpox as one of the
reasons behind the higher incidence rate [15-18]. The
present study also found a higher proportion of female pa-
tients with shingles (M
：
F = 1
：
1.42). Higher rates of shin-
gles were observed in the spring and summer months
among female subjects.
Dopico et al. [5] reported that interleukin-6 (IL-6) re-
ceptor and C-reactive protein - risk biomarkers for car-
diovascular, psychiatric and autoimmune diseases - have
peak incidences in winter. Nelson [19] reported that ex-
posure to short day lengths affects several parameters of
the immune system. Toyama and Shiraki [7] analyzed a to-
tal of 48,388 shingles cases and found that occurrence of
shingles increased in the summer and decreased in the
winter. The study also reported a higher rate of occurrence
among females and individuals in the 50-70 years age
group. On the other hand, Hope-Simpson [12] reported
high rates of occurrence in the summer and fall.
Zak-Prelich et al. [20] reported that exposure to UV rays
increased the rates of shingles affecting the face among
the male subjects. Other studies, however, found no corre-
lation between shingles and seasons [2,21,22]. The present
study found that shingles had a higher rate of occurrence
in the spring and summer months among female subjects
than in male subjects.
In terms of the affected site and time of occurrence,
no correlation was found, with the exception of the thoracic
vertebrae, which showed a greater incidence in the spring
and summer, similar to the overall trend. Similar incidence
rates were observed in the left and right sides of the body
throughout the seasons.
The places of residence of the study subjects were
mostly in Cheonan and neighboring areas, such as Asan,
and the incidence during the study period was not affected
by weather conditions such as temperature, daily temper-
ature range, humidity, or duration of daylight.
Based on these findings, it is plausible that immuniza-
tion in the winter months may reduce the incidence of
shingles in Cheonan and neighboring areas.
This study has several limitations. Since the study
subjects were limited to the patients diagnosed with shin-
gles at the hospital, the area incidence rate could not be
identified. As a retrospective study, only data regarding the
places of residence could be incorporated, and therefore,
the findings do not reflect the potential influence of socio-
economic factors on shingles, such as occupation and res-
idential environment. Finally, data collection regarding un-
derlying diseases may have been inadequate as it relied
only on the existing clinical record. For a more detailed in-
vestigation of the influence of seasons on the occurrence
of shingles, changes in the natural, living, and occupa-

Jung, et al / Epidemiological Study on the Incidence of HZ 197
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tional environment need to be examined.
In the present study, a higher incidence rate was ob-
served in females than in males, and the rate was higher
in the spring and summer. Based on our findings, shingles
immunization in the winter months could be beneficial for
residents in the neighboring area.
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