comparison of age-related changes in facial wrinkles and sagging in the skin of japanese, chinese...

Comparison of age-related changes in facialwrinkles and sagging in the skin of Japanese,Chinese and Thai women

Kazue Tsukahara *, Keiichi Sugata, Osamu Osanai, Atsushi Ohuchi,Yuki Miyauchi, Minoru Takizawa, Mitsuyuki Hotta, Takashi Kitahara

Journal of Dermatological Science (2007) 47, 19—28

www.intl.elsevierhealth.com/journals/jods

Biological Science Laboratories, Kao Corporation, 2606, Akabane, Ichikai, Haga,Tochigi 321-3497, Japan

Received 2 November 2006; received in revised form 23 March 2007; accepted 26 March 2007

KEYWORDSSkin;Wrinkle;Sag;Face;Aging;Scale

Summary

Background: Differences in skin aging features between Asians and Caucasians arecommonly known, whereas little is known about such differences in various Asianpopulations.Objective: A survey was carried out in Tokyo, Shanghai and Bangkok to identifyspecific features of skin aging in each population and to evaluate whether ourconventional photo scale is an appropriate tool for this type of comparative study.Methods: Eighty-seven women residing in Tokyo, 100 women residing in Shanghai,and 90 women residing in Bangkok were examined by a specialist. Facial wrinkles(forehead, glabella, upper eyelid, crow’s feet, lower eyelid, cheek, nasolabial grooveand mouth corner) and cheek sagging were evaluated using photo scales previouslyobtained from Japanese subjects. Comparisons were made according to 10-year agegroups.Results: Women in Bangkok showed the most severe level of wrinkles, followed bythose in Shanghai in the three groups. Significant differences were observed betweenThai and Japanese women in the intensity of wrinkles at many facial sites. Chinesewomen had significantly more severe wrinkles in the area around the eyes comparedto Japanese women, while Thai women had significantly more severe wrinkles in thelower halves of their faces compared to Chinese women. In cheek sagging scores,significant differences were observed between Japanese and Thai women in their 30sand 50s, but not between Japanese and Chinese women or between Chinese and Thaiwomen in all age groups.

Abbreviations: %RH, % relative humidity; S.D., standard deviation* Corresponding author. Tel.: +81 285 68 7460; fax: +81 285 68 7469.E-mail address: tsukahara.kazue@kao.co.jp (K. Tsukahara).

0923-1811/$30.00 # 2007 Japanese Society for Investigative Dermatology. Published by Elsevier Ireland Ltd. All rights reserved.doi:10.1016/j.jdermsci.2007.03.007

20 K. Tsukahara et al.

Conclusion: These results indicate variations in skin aging features among womenfrom three Asian cities thereby suggesting the diversity of Asian skin. Our scalingmethod proved to be appropriate for facial wrinkles, but required modification tocompare cheek sagging among Asian populations.# 2007 Japanese Society for Investigative Dermatology. Published by Elsevier IrelandLtd. All rights reserved.

1. Introduction

It is commonly accepted that Europeans and Asianshave different skin aging features. This has beenproved through comparative studies between Amer-ican Caucasian and Japanese subjects [1] andbetween French and Chinese subjects [2]. In thoseand many other related studies, the term ‘‘Asianskin’’ is frequently used as a generic description forskin observed in a single Asian country (regardless ofthe intent, this is an over-generalization, unless themajority of Asians could be shown to have uniformskin characteristics). However, to date there hasbeen no such report detailing a comparison amongdifferent types of Asian skin.

We devised a skin research study in three Asiancities–—Bangkok, Shanghai and Tokyo. Shanghai andTokyo were chosen to detect a difference betweentwo cities with similar latitudes and temperatures,while Bangkok was chosen as a city closer to theEquator (see Table 1). The aims of this study were toidentify specific features of skin aging in each Asianpopulation, and to evaluate whether our conven-tional ‘‘photo scale’’ is an appropriate tool for thistype of comparative study.

Photo scaling is a visual scoring method whichdepends on the visual impression of a specialist andthus is highly subjective. Griffiths et al. [3] devel-oped a reproducible visual scoring method by adapt-ing a technique of acne grading that usesphotography. However, Larnier et al. [4] reportedthat method was still inconsistent in grading, forexample, one individual with extensive wrinklingbut little pigmentation and another with mild wrink-ling but severe mottled pigmentation. To compen-sate for this, Larnier et al. revised the method ofGriffiths et al. by using three photographs in eachgrade. This revised method improved the gradingconsistency with white Caucasian subjects, but

Table 1 Climate and latitude information of Tokyo, Shang

Data period: 1971—2000 Tokyo

Latitude 358410NMean annual temperature (8C) 15.9Annual rainfall amount (mm) 1467

Data from homepage of the Japan Meteorological Agency.

Larnier et al. suggested the use of separate photo-graphic scales for non-white Caucasians.

With the aim of improving objectivity, we devel-oped a photo scale specialized for the evaluation offacial wrinkles [5]. We first obtained close-up photo-graphs of eight sites on the faces of 613 Japanesesubjects, graded them into five groups and thenchose one representative photo in each grade foreach facial site. Next, we evaluated the facialwrinkles of Japanese subjects using those represen-tative photos as a scale, and confirmed a highcorrelation with age. Furthermore, we applied thisscale obtained from Japanese women in a cross-ethnic comparison between Japanese women inTokyo and American Caucasian women in Cincinnatiand demonstrated the earlier incidence and devel-opment of wrinkles in Caucasian women comparedto Japanese women [1].

Combining this photo scale for facial wrinkleswith another scale for cheek sagging, which wassimilarly developed in an earlier study of Japanesesubjects [6], facial wrinkles and cheek sagging wereassessed in women from Shanghai, Bangkok andTokyo. The results were divided according to 10-year age groups and compared with age-matchedgroups to reveal characteristic features of skin agingin each population.

2. Materials and methods

2.1. Subjects and protocol

Volunteers were recruited in Tokyo, Shanghai andBangkok with no criteria for their ethnic origin.Ninety women residing in Bangkok, 100 residing inShanghai, and 87 residing in Tokyo were enrolled thisstudy. The populations in 10-year age groups andtheir mean ages are shown in Table 2.

hai and Bangkok

Shanghai Bangkok

318240N 138440N16.1 28.61155 529

Comparison of wrinkles and sagging in Asian skin 21

Table 2 Distribution of subject populations in 10-year age groups

Age group Number in group

Japanese (Tokyo) Chinese (Shanghai) Thai (Bangkok)

n Mean � S.D. age n Mean � S.D. age n Mean � S.D. age

10s 15 16.1 � 1.9 11 18.0 � 1.0 15 14.1 � 3.120s 15 23.3 � 3.6 25 23.8 � 3.2 15 24.7 � 3.030s 13 34.5 � 2.8 22 35.0 � 2.4 15 35.7 � 2.640s 15 44.4 � 2.6 19 44.4 � 2.2 14 45.3 � 2.750s 14 54.7 � 3.5 18 55.3 � 2.8 17 52.8 � 2.360s 15 64.6 � 2.9 5 61.6 � 1.5 14 63.3 � 2.3

Total 87 100 90

Table 3 The correlation coefficient between age andwrinkle and sagging scores

Tokyo Shanghai Bangkok

Wrinkle scoresForehead 0.799 ** 0.825 ** 0.860 **

Glabella 0.804 ** 0.879 ** 0.867 **

Upper eyelid 0.915 ** 0.911 ** 0.884 **

Crow’s feet 0.829 ** 0.866 ** 0.889 **

Lower eyelid 0.928 ** 0.899 ** 0.880 **

Cheek 0.852 ** 0.839 ** 0.924 **

Nasolabial groove 0.931 ** 0.910 ** 0.884 **

Mouth corner 0.920 ** 0.886 ** 0.920 **

Sagging score 0.929 ** 0.882 ** 0.930 **

** Represents p < 0.01.

2.2. Photography

After washing and then acclimating for 30 min, eachwoman was seated and her face was photographedwith eyes openboth frontally andobliquely (458)witha Nikon D100 camera and diffused flashing lights. Anydifferences in color, brightness or distance from thecamerawere adjusted by using Casmatch (Dai NipponPrinting, Tokyo). The photography was carried out inFebruary 2003 in Tokyo, in December 2004 in Bang-kok, and in February 2005 in Shanghai. In Tokyo, roomconditions during photography were maintained at20 8C and 50% RH, but were not similarly stabilized inBangkok or Shanghai. The mean (and range) in roomtemperatures/relative humidities were 23.6 8C (21—27 8C)/33% RH (30—37% RH) in Bangkok and 23.7 8C(17—27 8C)/44.4% RH (30—56% RH) in Shanghai.

2.3. Evaluation of wrinkles and sagging

Photographs of all subjects were assessed by a singlespecialist. The specialist assessed the intensity ofwrinkles at eight facial areas — forehead, glabella,upper eyelid, crow’s feet, lower eyelid, nasolabialgroove, cheek, and mouth corner — using a 5-point(1 = nowrinkle, 2 = slightwrinkles, 3 = mildwrinkles,4 = moderate wrinkles, 5 = severe wrinkles) photoscale previously based on Japanese skin. The inten-sity of cheek sagging was likewise assessed using a 6-point (0 = no sagging, l = slight sagging, 2 = mild sag-ging, 3 = moderate sagging, 4 = severe sagging,5 = very severe sagging) photo scale obtained fromJapanese skin at different intensities of sagging. Ourprevious reports providemore details on thosemeth-ods. Fig. 1a and b show a photo scale for crow’s feetand for cheek sagging, respectively [5,6].

2.4. Statistics

Differences among three groups were statisticallyanalyzed by Kruskal—Wallis test, a non-parametricequivalent of one-way ANOVA, followed by post hoc

Steel—Dwass non-parametric multiple comparisonprocedure using KyPlot (Kyenes Lab; Tokyo Japan).p values smaller than 0.05 were considered statis-tically significant.

3. Results

3.1. Age correlation

Positive correlation between age and each score wasdetermined in all groups. The correlation coeffi-cients were 0.799—0.931 as shown in Table 3.

3.2. Wrinkle intensity

The intensities of wrinkle/sagging scores werecompared among women from the three cities.Fig. 2a—h shows the mean intensities for wrinklescores at different facial sites according to each10-year age group.

3.3. Tokyo versus Shanghai

The Shanghai group showed significantly higherwrinkle scores than the Tokyo group in the glabella

22 K. Tsukahara et al.

Fig. 1 Referential photo scales. (a) A photo scale specialized for crow’s wrinkle, (b) a photo scale specialized for cheeksagging [5,6].

Comparison of wrinkles and sagging in Asian skin 23

Fig. 2 A comparison of wrinkle intensity among three Asian groups at eight facial sites. (a) Forehead, (b) glabella, (c)upper eyelid, (d) crow’s feet, (e) lower eyelid, (f) cheek, (g) nasolabial groove, (h) mouth corner. Results are expressed asmean � S.D. Statistical differences as analyzed by the Kruskal—Wallis test.

in all age groups except 20s and 60s, the crow’s feetfrom the 30s to the 40s, the upper eyelid in the 40sand the 60s, the cheeks in the 30s, and the mouthcorners in the 50s.

3.4. Tokyo versus Bangkok

The Bangkok group showed significantly higherscores than the Tokyo group in the cheek from the20s to 60s, the lower eyelid, crow’s feet and mouthcorner from the 20s to 50s, the nasolabial groovefrom the 20s to the 40s, the glabella from the 30s tothe 50s, the forehead from the 30s to the 50s, andthe upper eyelid in the 40s and the 60s.

3.5. Shanghai versus Bangkok

The Bangkok group showed significantly higherscores than the Shanghai group in the lower eyelidsin the 20s and 40s, the cheeks in the 20s, 40s and50s, the nasolabial groove in the 20s and 30s, andthe mouth corners in the 20s and 40s. In teenagers,the Shanghai group showed significantly higher scorethan the Bangkok group in the glabela.

3.6. Cheek sagging

Fig. 3 shows age-related deterioration assessed bythe 6-point photo scale for sagging. A significant

24 K. Tsukahara et al.

Fig. 3 A comparison of the cheek sagging score amongthree Asian groups. Results are expressed as mean � S.D.Statistical differences as analyzed by the Kruskal—Wallistest.

difference was observed between the Tokyo andBangkok groups in the 30s and 50s. No significantdifference was observed between the Tokyo andShanghai groups, or between the Shanghai andBangkok groups.

4. Discussion

Differences of skin aging features among Asianpopulations have been considered negligible for along time. However, our results indicate that thesedifferences are not negligible but highly informativefor understanding of mechanisms involved in skinaging. Here we discuss our findings in comparisonwith those of previous studies.

4.1. Mechanism involved in skin wrinkling

It is commonly believed that exposure to the sun is amajor cause of extrinsic skin aging. Previous studiesdetermined that elastic fibers become disorganizedin the sun-exposed sites of skin [7—9]. This alterationis considered to be a major cause of skin-aging phe-nomena including wrinkling [9—17]. Our researchrevealed a higher prevalence and greater severityof wrinkles in the Bangkok group as compared to age-matched women in the Tokyo and Shanghai groups.The lower latitude and the higher temperatures inBangkok suggest the higher levels of UV exposure inBangkok. The severe levels ofwrinkles in theBangkokgroup might have caused by UV exposure; however,questions remain to what extent UV exposure con-tributes to the wrinkle formation.

Skin tones are reported to be closely related toethnic skin types, UV sensitivity and other physio-logical functions of skin [18—22]. Results of ourprevious study that assessed the brightness of skintone (L* value) in women (age: 10—66) living inTokyo (n = 174), Shanghai (n = 100) and Bangkok(n = 90) indicate that the L* value of Japanese

women (64.03) is similar to that of Chinese(63.31) but significantly different from Thai women(58.81). Thus we consider the difference in skin tonemay also have an effect on the difference in wrinkleintensities between Thai women and other women(Japanese/Chinese).

Smoking and daily skin care are known to havean impact on wrinkle development [23,24]. Areport (The tobacco Atlas, # World Health Orga-nization 2002) stated that the percentage offemale smokers aged over fifteen years is below10% in China and Thailand but 10—19% in Japan.Due to this low percentage of female smokers, thehigher intensity of wrinkles determined in Thaiwomen is unlikely to be caused by smoking. Asto the daily skin care, regrettably, this study didnot collect data about the daily use of cosmeticsfrom these subjects; however, a previous question-naire obtained from women residing in Japan,China and Thailand showed that Japanese womenuse cosmetics more frequently than Chinese orThai women (data not shown). Thus, daily skincare may be one of the factors explain the differ-ence among three groups.

In our comparison between Thai and Chinesewomen, significant differences were mainlyobserved in the lower halves of their faces (lowereyelid, cheek, mouth corner, and nasolabial groove,see representative photographs Fig. 4a), and less soon other facial sites. Likewise, in the comparisonbetween Chinese and Japanese women, significantdifferences were mainly observed in the areaaround the eyes (glabella and crow’s feet, seerepresentative photographs Fig. 4b and c). Thesesite-dependent differences suggest that a factorother than sun-exposure, genetics, skin tone or dailyskincare underlies wrinkle development.

In a previous animal experiment with threegroups of hairless mice, we pinched and bondedtwo folds of dorsal skin in a continuous line parallelto the backbone from neck to tail in two groups, butthen irradiated only one group with UVB. The thirdgroup of hairless mice was irradiated with UVB butwithout underdoing the bonded folding of the firsttwo groups. After unbonding the skin folds, wefound wrinkles that ran parallel to the backboneon the skin surface of the folding/UVB group. Thisindicates that it was the combination of the bondedskin folding and UVB irradiation which togetherresulted in the embossing of wrinkles on the dorsalskin surface of hairless mice [25].

Based on this folding effect in the animal study,we assumed that the folds of the temporal wrinkleswhich appear from the facial muscle movements inspeech, mastication and emotional expressionssuch as smiling and laughing [26,27] become,

Comparison of wrinkles and sagging in Asian skin 25

Fig. 4 Representative photographs. (a) Nasolabial grooves of women in their 40s: (A) Japanese, age 43, (B) Chinese, age45, (C) Thai, age 42. (b) Glabella area of women in their 50s: (A) Japanese, age 56, (B) Chinese, age 56, (C) Thai, age 52.(c) Crow’s feet of women in their 40s: (A) Japanese, age 46, (B) Chinese, age 42, (C) Thai, age 46. The more severe levelsof wrinkles of Thai women were mainly observed in their lower halves of their face, while those of Chinese women weremainly observed around their eyes.

26 K. Tsukahara et al.

through repetition over time and sun-exposure,embossed permanently into facial skin. Thisassumption would explain the site-dependentdifferences observed between the three nationalgroups in our present study. The cultural differ-ences in facial expression, language articulation,and dietary habit can result in different typesof temporal wrinkles, which in turn becomeembossed as permanent wrinkles on differing facialsites. Further studies are warranted to investi-gate the impact of facial movements in wrinkleformation.

4.2. Interest of photo scoring methods

One trend in the field of evaluation of skin agingfeatures is quantitative analysis; one such approachis to analyze the topography of skin surface [28—32],and another is to measure the displacement rate ofskin surface in response to changes in body position[33,34]. The former method evaluates a limited partand thus is considered inadequate for detecting the

Fig. 5 Representative photographs of the cheek areas of womand (C) Thai, age 50. Upper row: color photographs; lower row:matched Japanese and Chinese women, Thai women showedmarea 1 (indicated by arrows).

overall characteristics of skin aging features in thisstudy. While the latter method is considered to beinadequate for evaluating lower levels of sagging inyounger generations.

On the other hand, a photo scoring method iswidely accepted in studies of various skin phenom-ena in the field of plastic surgery, dermatology andcosmetology [2—4,27]. It scores the degree of skinphenomena such as acne scar, pigmentation, wrin-kles or sagging by using a set of photos (a photoscale) obtained from people at different magnifica-tions of the phenomena. The result of this methodreflects visual impression of people, and thus it issubjective.

To improve its objectivity, we developed a photoscale specialized for evaluating facial wrinkles.Assuming that bias may occur in grading, for exam-ple, a subject with extensive crow’s feet but noother wrinkles and another subject with mild wrink-ling all over the face, we developed a method thatevaluates wrinkles at eight facial sites using close-up photographs of each site [5, see Fig. 1a and b].

en in their 50s. (A) Japanese, age 52, (B) Chinese, age 53black and white photographs. In comparison with the age-ore fine lines in areas 2 and 3, but less nasolabial grooves in

Comparison of wrinkles and sagging in Asian skin 27

The usefulness and objectivity of our method hasbeen confirmed in a cross-ethnic comparisonbetween Japanese women in Tokyo and AmericanCaucasian women in Cincinnati [1] and among Asianpopulations in this study.

Although our results of cheek sag scoring revealedan age-dependent increase in each group, andthough significant differences were observedbetween Thai and Japanese women in their 30sand 50s, we suspect that these results do not fullydepict a characteristic variation, as shown in repre-sentative photographs (Fig. 5a—c). In our previousstudy of Japanese subjects, cheek sagging firstappeared as grooves in area 1, followed by linesin area 2. As more tissues in these areas slid down-ward, the cheeks hollowed and concomitant wrin-kles appeared in area 3 [6]. Based on thisinformation, Fig. 5a (a Japanese woman) andFig. 5b (a Chinese woman) were both scored asgrade 2, while Fig. 5c (a Thai woman) was scoredas grade 3. The higher score of the Thai womandepended largely upon the lines in areas 2 and 3,which are regarded as more advanced level. How-ever, the grading criteria failed to consider thatgrooves in area 1, which will droop over the mouthcorners with age, were less visible in Thai women ascompared to Japanese and Chinese women. Toreveal characteristic variations of cheek saggingamong Asians, this method needs to be modifiedbased on the information about site-dependent dif-ference between Thai women and Chinese/Japa-nese women.

In conclusion, this study determined differences inskin aging features amongwomen in Bangkok, Shang-hai and Tokyo, thereby warranting extensive studiesin other Asian cities. The photo scale is a simplemethod that requires no measuring instrument otherthan a camera and is thus appropriate for multi-centered skin surveys. The high consistency of thephoto scale was proved during the facial wrinkleevaluation performed in this study. However, mod-ifications or even newapproacheswill be required fora comparison of cheek sagging and for the detectionof the causes underlying the differences in skin agingfeatures among Asian populations.

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