There are previous studies of ageing hair and scalp in Caucasians and some Asians, such as Koreans and Japanese. However, the characteristics of scalp and hair have not yet been studied in Chinese, the largest population in the world, especially in terms of ageing. The purpose of this study is to investigate ageing features in Chinese women’s hair and scalp. Methods: In total, 1343 women in China aged 20 to 65 participated in this research. Hair density and diameter were measured and analysed with Folliscope®. Hair color and scalp conditions such as dandruff and erythema were evaluated through microscopic images. Measuring equipment was also used to detect scalp water content, barrier function and sebum secretion. Results: Hair density decreased gradually with ageing, while hair diameter peaked at 40s. The color of hair became bright with ageing because of gray hair and color fading. The degree of scalp sebum and dandruff was higher at younger ages. Interestingly, scalp erythema became more severe with ageing. Conclusion: This study shows the physical and physiological changes of Chinese women ’ s hair and scalp. Most aging features (hair diameter, scalpsebum contents, dandruff and erythema) were noticeable in their 40s, but hair density began to decline in their 30s. This first study of aging hair and scalp in Chinese women would be helpful for understanding the ageing phenomenon and development of hair and scalp care products.
Ageing appears in various ways throughout the body. Like skin, hair undergoes physical and physiological changes over time. Hair loss [
The characteristics of ageing hair in Asian women have been studied previously. In Korean women, for example, the average hair diameter was highest in their 20s, maintained steadily until 50, and then decreased significantly [
Since China accounts for about 30% of the Asian population, it is important and necessary to study the ageing features of Chinese hair and scalp to understand those of Asians. Because of its enormous territory, there may be geological differences. For instance, androgenic alopecia was revealed differently among subjects from 6 cities in China [
In this study, we first investigated an ageing scalp which has been hardly known as well as hair of Chinese women by measuring their hair and scalp conditions with various instruments, evaluating by investigators and surveying subjects (
A total of 1343 Han Chinese women aged 20 to 65 living in 6 cities of Guangzhou, Shanghai, Beijing, Wuhan, Chengdu and Shenyang in China were enrolled for this study from 2011 to 2012. Those 6 cities were selected because they are China’s representative major cities and are distributed over various areas, from north to south and from coast to inland. Because all the subjects in 6 cities were
Han Chinese, there was no ethnic difference, but differences arise from climate and environment would be exist. The volunteers met the requirements of not having infectious skin disease, severe hair loss and surgical treatment on their scalp, chemical treatment on their hair such as dyeing and permanent waves for the 3 months preceding the measurements. The numbers of subjects in each group were shown in
Hair density and diameter were measured with Folliscope® (Lead M corp., Korea) [
Hair color was examined in two ways: the lightness value was measured using a Spectrophotometer® CM-2600D (Minolta, Osaka, Japan) and evaluated visually by the investigators. The criteria for evaluating gray hair were determined by the gray hair portion of the total hair: Grade 1: no gray hair, Grade 2: less than 20%, Grade 3: 20% - 40%, Grade 4: 40% - 60%, Grade 5: more than 60% of total hair. The grade of fading hair was determined by the uniformity of the entire hair color: Grade 1: even hair tone overall, Grade 2: generally even hair tone but with slightly uneven parts, Grade 3: many parts are slightly uneven, Grade 4: there is a part of distinctly different color, Grade 5: many parts are
Beijing | Shanghai | Chengdu | Guangzhou | Shenyang | Wuhan | Total | ||
---|---|---|---|---|---|---|---|---|
N | 20s | 90 | 37 | 68 | 74 | 101 | 79 | 449 |
30s | 27 | 86 | 56 | 49 | 22 | 30 | 270 | |
40s | 62 | 46 | 51 | 56 | 49 | 38 | 302 | |
50s | 40 | 39 | 46 | 33 | 53 | 52 | 263 | |
60s | 5 | 19 | 5 | 4 | 2 | 24 | 59 | |
Age (mean ± SD) | 20s | 24.8 ± 2.3 | 25.6 ± 2.1 | 25.9 ± 1.8 | 26.1 ± 2.0 | 26.0 ± 1.7 | 24.9 ± 1.9 | 25.6 ± 2.0 |
30s | 35.5 ± 2.7 | 34.2 ± 2.7 | 34.9 ± 2.9 | 35.1 ± 3.2 | 35.8 ± 3.4 | 33.3 ± 2.8 | 34.6 ± 2.8 | |
40s | 44.1 ± 3.1 | 44.7 ± 2.7 | 44.1 ± 2.5 | 44.5 ± 3.0 | 45.0 ± 3.0 | 45.8 ± 3.0 | 44.5 ± 2.9 | |
50s | 54.3 ± 2.7 | 55.0 ± 3.1 | 53.7 ± 2.8 | 53.7 ± 3.1 | 53.8 ± 2.3 | 54.4 ± 2.9 | 54.2 ± 2.8 | |
60s | 62.2 ± 2.3 | 62.6 ± 1.6 | 61.8 ± 2.2 | 62.3 ± 2.1 | 64.0 ± 1.4 | 62.1 ± 2.0 | 62.2 ± 1.8 |
distinctly different.
The moisture content of the vertex site was measured with DermaLab® USB moisture (CORTEX Technology, Denmark) which measures the electrical conductivity of the scalp. The scalp barrier function was evaluated as TEWL (Transepidermal water loss) using a Vapometer (Delfin Technologies, Kuopio, Finland). Sebumeter® SM 815 (Courage + Khazaka Electronic GmbH, Cologen, Germany) was used to measure scalp sebum excretion.
Scalp condition was graded by evaluating 60× scalp photographs. The degree of dandruff and erythema were divided into five grades base on severity. The classification of dandruff was made in accordance with the Korea Food & Drug Administration (KFDA): Grade 1: clean and healthy scalp without dandruff, Grade 2: a little dandruff was discovered, Grade 3: dandruff exists around most of the hair follicles, Grade 4: dandruff partly covered the scalp, Grade 5: more than half of the scalp surface was covered with dandruff. In addition, the grade of scalp erythema was divided in a similar way; Grade 1: healthy scalp with light and even tone, Grade 2: partly mottled and irregular color of scalp, Grade 3: partly reddish scalp, Grade 4: scalp redness revealed in half of the scalp, Grade 5: scalp redness revealed overall.
Analysis between groups of subjects was performed using a Student’s t-test. In all cases, tests with p-values < 0.05 were considered statistically significant.
Commonly, hair density and diameter are considered as parameters of hair-loss. As shown in the photograph, hair density decreased and hair became thinner with ageing (
Our previous study showed that hair density decreased about 25% in Korean women in their 60s versus their 20s. In addition, the average hair diameter was the highest in their 20s in Korean and significantly decreased from the 50s to the 60s [
The hair lightness value (L value) increased exponentially especially after 40
years of age (
Transepidermal water loss (TEWL) was similar to subjects from 20s to 40s and significantly decreased in 50s. Interestingly, scalp water contents showed a similar degree over all ages, except for those in their 40s who had lower water contents (
Most subjects had dandruff with more than a few levels, but the severity weakened with advancing age. Approximately 50% of those in their 20s or 30s
Age | ||||||
---|---|---|---|---|---|---|
20s | 30s | 40s | 50s | 60s | ||
Hair | Hair density (N/cm2) | 159.6 ± 35.9 | 152.7 ± 31.0**,† | 146.4 ± 30.6*** | 141.1 ± 30.4***,† | 130.7 ± 38.4***,†† |
Hair diameter (µm) | 82.5 ± 17.9 | 86.8 ± 15.1*** | 89.0 ± 12.8*** | 85.8 ± 10.1***,††† | 83.7 ± 16.0† | |
Hair L value (AU) | 17.4 ± 4.2 | 18.1 ± 4.5*,††† | 20.5 ± 4.7*** | 23.3 ± 7.2***,††† | 29.4 ± 12.3***,††† | |
Gray hair ratio (grade 1 - 5) | 1.21 ± 0.7 | 1.40 ± 0.9**,††† | 1.80 ± 0.7*** | 2.34 ± 0.9***,††† | 3.20 ± 1.1***,††† | |
Hair color fadedness (grade 1 - 5) | 1.22 ± 0.4 | 1.31 ± 0.5*,††† | 1.55 ± 0.6*** | 1.91 ± 0.7***,††† | 2.41 ± 0.9***,††† | |
Scalp | Scalp water contents (µS(micro Siemens)) | 49.3 ± 18.7 | 47.2 ± 19.5†† | 41.8 ± 16.9*** | 49.1 ± 20.7††† | 54.5 ± 20.5††† |
Transepidermal water loss (g/m2h) | 21.3 ± 6.4 | 22.0 ± 5.4 | 22.1 ± 7.2 | 20.3 ± 6.7*,†† | 17.8 ± 6.2***,††† | |
Scalp sebum secretion (µg/cm2) | 69.1 ± 36.8 | 66.3 ± 36.4†† | 53.9 ± 29.4*** | 51.2 ± 30.5*** | 39.7 ± 23.5***,†† | |
Dandruff (grade 1 - 5) | 2.57 ± 0.9 | 2.64 ± 0.9††† | 2.26 ± 0.8*** | 2.08 ± 0.8***,†† | 2.09 ± 0.9*** | |
Scalp erythema (grade 1 - 5) | 1.43 ± 0.7 | 1.48 ± 0.8††† | 2.08 ± 0.9*** | 2.33 ± 0.9***,††† | 2.38 ± 0.9***,† |
(Mean ± SD). *p < 0.05 vs. 20s group, **p < 0.01 vs. 20s group, ***p < 0.001 vs. 20s group. †p < 0.05 vs. 40s group, ††p < 0.01 vs. 40s group, †††p < 0.001 vs. 40s group.
had more than mid-level dandruff when evaluated with 5 levels of dandruff severities: none, slight, moderate, severe and highly severe (
Skin erythema is characterized as redness or rash. We found that about 70% of those in their 20s or 30s showed light and even-toned scalp. Surprisingly, it was even worse in elderly groups, with more than 70% of their 40s showing symptoms (
This is the first study of the features of Chinese women’s scalp and hair, especially focusing on ageing. More than 1300 Chinese women were enrolled to this study. We also covered 6 representative metropolises in China.
Chinese females undergo a reduction of hair density as a common feature of ageing hair. The decline in Chinese women’s hair diameter after reaching its peak in 40s is similar to other studies with Caucasian and Japanese people [
It was not just hair which changed as people got older, scalp did as well. First of all, the amount of scalp sebum and dandruff severity changed with ageing. It is well known that hormonal changes of females appear in their facial skin with the reduction of sebum secretion as they age [
In addition, scalp sebum is one of the important factors of dandruff. Sebaceous gland activity induces microfloral metabolism and makes flakes on the scalp [
Another scalp condition, erythema, was exacerbated in the elderly groups, with dramatic increase in those over 40s. It is well known that seborrheic dermatitis causes erythema and desquamations of the skin in sebaceous gland rich area [
It is well known that genetic background is the first determinant of skin characteristics [
Despite such superficial phenomenon, this study is meaningful in respect of the first research for Chinese women’s hair and scalp. It would be a good resource to understand the changes of hair and scalp by ageing. Furthermore, it is necessary to investigate the regional study about climate, water, pollution, food, life style and hair care behaviour for further understanding the characteristics of scalp and hair in Chinese.
Both hair and scalp changed with ageing, but there was a difference in time of beginning. The features of hair changed continuously from 20s. On the other hand, the ageing features of scalp appeared remarkably from 40s. We suppose that the mechanism of aging between hair and scalp is different or just hair changes earlier than scalp.
We thank H.G. Park1, J.Y. Han1, E.J. Kim1, Y. Gao2, J. Liu2 and Q. He2 for arranging and helping the clinical study.
None.
Amorepacific R&D funding.
Kim, S., Kim, S.N., An, S., Yeon, J.H., Wang, X.M., Li, L., Lai, W., Liang, H., Gao, X.H., Liu, W., Park, W.S. and Na, Y. (2017) Ageing-Related Features of Hair and Scalp in Chinese Women by Clinical Evaluation Study. Journal of Cosmetics, Dermatological Sciences and Applications, 7, 245-257. https://doi.org/10.4236/jcdsa.2017.73023