This chapter summarizes some of the current available scientific information on aging in Asian skin.
It is clear that Asians and Caucasians manifest different phenotypes of aging. Asians are more prone to changes in pigment with age, with wrinkles developing later in life.
In comparison, Caucasians develop wrinkling earlier and more extensively. External influences, such as differences in diet, exposure to sunlight, and culture undoubtedly play a role in this. Biologically, differences between Caucasians and Asians are due to the melanocytic pathways operating in either skin type, although the data seem to suggest that the number of melanocytes and melanin production is only marginally different.
More dramatic differences are observed suprabasally with melanosomes distribution and size. With the greater protection from the increased melanin levels and differences in melanosomes, Asian skin additionally demonstrates differences in the way it responds to UV exposure compared to Caucasian skin. Notably there are better and more efficient mechanisms for coping with damage caused by UV-exposure.
Helen Knaggs, in Skin Aging Handbook, 2009
9.3 How is Asian Skin Different?
Skin type is typically classified by the Fitzpatrick score on the predicted reaction of skin to sunlight and ultraviolet radiation (6).
The majority of the Asian population has relatively darker skin, usually type IV and above (Table 9.1), compared to Westerners. Furthermore, there are distinct differences between different ethnic groups in Asia. Asians can be subdivided into North East Asians (Chinese, Japanese, Koreans), Southeast Asians (Indonesians, Malaysians, Singaporeans, Thais, Cambodians, Vietnamese) and South or Central Asians (Indians, Pakistanis, Sri Lankans, Bangladeshis).
The skin of people from Northeast Asia tend to be lighter and exhibit more seasonal variation compared with Southeast Asians who inhabit countries receiving more sunlight all year round since they are geographically closer to the equator.
For example, people with skin type II, commonly associated with Caucasians, have been reported in Korea (7) and even in Thailand (8).
Table 9.1. Table of Fitzpatrick Score and Natural SPF
|Fitzpatrick Assigned Score||Definition||Natural SPF|
|2||Peaches and cream||2.5|
In fact, this diversity only originates from two different skin types. Indians and inhabitants of Central Asia are Caucasian in origin, while Japanese, Koreans, Chinese, and South East Asians are primarily of Mongolian descent, with typical Mongol features.
Thus, at the very basic level, differences in skeletal structure exist which could affect the progress of intrinsic aging. Along with this, Asian skin is reported to have a thicker dermis containing more collagen (9) and epidermally, there is an increased pigmentation in skin providing greater protection against UV exposure (4).
Conversely, Asian faces are subjected to greater gravitational force due to the weaker skeletal support and heavier soft tissue which could make this group more prone to skin sagging during aging (9). Although Caucasian skin is firmer, the better photoprotective property of Asian skin, owing to the high pigment content, preserves Asian skin, with it showing fewer signs of wrinkling and less sagging.
Ethnic differences have also been found in the stratum corneum and the barrier properties it provides to skin, between blacks, Asians and Caucasians, although the data are contradictory.
Some scientists find Asian skin to have a thinner stratum corneum (10, 11), indicating that as a consequence it can be compromised more easily and is more susceptible to barrier damage (12). Others, however, report finding no ethnic differences in Japanese compared with German women (13) or a better barrier function in Asians (14) related to the higher ceramide content.
Article from Sciencedirect.com