The skin is important to protect the body from various internal and external factors caused by chemical and biochemical stress [1]. The typical structural layers of skin are well known: the hypodermis, dermis, and epidermis [2]. Sebum glands, sweat glands, and collagen and elastic fibers are located in the dermis; skin pores and melanocyte are located in the epidermis. The changes in the body due to aging are influenced by many factors. Skin changes can be caused by external factors, such as air pollution, smoke, and photoaging, in addition to chronological aging, resulting in increased skin pigmentation and wrinkles, defective epidermal permeability barrier function, and reduced skin elasticity [3] [4]. Moreover, the skin disorders of atopic dermatitis, psoriasis, and ichthyosis result from decreased stratum corneum hydration and altered permeability barrier function [5] [6] [7] [8]. Furthermore, impaired skin barrier function is typically found in dry skin, which exhibits the increased values of transepidermal water loss and skin surface pH. This epidermal barrier insufficiency is reflected by a decrease in stratum corneum hydration and decreased amounts of natural moisturizing factor. Skin is influenced by internal factors, such as hormonal factors, which influence the secretory activity of human sebaceous glands [9]. The maximum sebum production of men occurs in their 20s, making them susceptible to skin diseases such as facial acne and dermatitis [10]. Studies show that large quantities of sebum and large pore can produce greasy skin and also cause adult diseases [11]. Recently, many male activities occur outside, such as physical activity, exposing them to sunlight [12] [13]. The ultraviolet (UV) radiation in sunlight has many positive influences on the human body, such as helping to release serotonin and playing an essential role in vitamin D synthesis [14] [15]. Among the different types of UV, ultraviolet B (UVA-B) sustains damage to the skin [16] [17]. So at this age, it is important for men to care for their skin [18]. And, normal physiological functions are still occurring in each part of the body, which can keep the skin healthy. In general, men have changed their skin care and grooming habits, and there is an increasing demand for cosmetic products for men [18]. The cosmetic product has a great effect on the skin [19]. Clinically, studies have shown that aloe, which is commonly used as a cosmetic product, affects collagen and fibroblast [20]. To date, however, very few studies have analyzed the skin function of adults in their 20s. Therefore, the objectives of this research were to analyze the skin in terms of the sebum content, moisture, pores, wrinkles, pigmentation, and elasticity in healthy South Korean men.

The sebum content and moisture of the skin’s surface varies with body part

The general characteristics were observed healthy Korean men (Table 1). We have summarized the segmentalized data of each body segment in supplementary data (Table S1), which enter the skin condition of each body segment. The sebum content of the men we assessed was relatively close except for the face and neck. The sebum content was high on the face (1306.8 ± 104.3 SAU) and slightly higher on the neck (173.6 ± 37.7 SAU) (Figure 1(a)). The sebum content of face was demonstrated to be significantly higher than other body parts (Figure 1(a)). The moisture on the face (53.0 ± 2.1 MAU), hand (52.9 ± 1.7 MAU), and foot (57.3 ± 1.5 MAU) was significantly higher than on the body (40.8 ± 1.4 MAU) (Figure 1(b)). However, there was no significant difference in moisture among the body parts. The moisture value among them at the foot was relatively higher than at other sites (Figure 1(b)).

The size of the pores on the skin’s surface varies with body part

The pore size on the face (6.0 ± 0.5 PAU) were significantly wider than at other parts, and the pores on the neck (2.5 ± 0.3 PAU) and lower limb (1.3 ± 0.3 PAU) were wider than at other parts (Figure 2). Furthermore, the value of pore size on the neck and lower limb were significantly increased compared with the ear, respectively (Figure 2).

The wrinkle and pigmentation of the skin’s surface varies with body part

The number of wrinkle of the face (3.9 ± 0.2 WAU) was significantly larger than at other sites, but not neck (3.7 ± 0.1 WAU) and hand (3.1 ± 0.2 WAU) (Figure 3(a) and Figure 3(b)). The number of wrinkle of the neck was significantly larger than at other sites, but not face and hand (Figure 3(a) and Figure 3(b)). Furthermore, the number of wrinkle of the upper limb (0.7 ± 0.2 WAU) was significantly smaller than at other sites, but not ear (2.0 ± 0.2 WAU) and lower limb (1.4 ± 0.2 WAU) (Figure 3(a) and Figure 3(b)). Meanwhile, the pigmentation of the face (3.7 ± 0.2 PiAU) was significantly higher than at other sites, but not neck (4.2 ± 0.3 PiAU) (Figure 3(a) and Figure 3(c)). The pigmentation of the neck was significantly higher than at other sites, but not the face (Figure 3(a) and Figure 3(c)). Furthermore, the pigmentation of the

upper limb (0.6 ± 0.1 PiAU) was significantly lower than at other sites, but not hand (0.9 ± 0.1 PiAU) and foot (0.3 ± 0.1 PiAU), respectively (Figure 3(a) and Figure 3(c)).

The elasticity of the skin’s surface varies with body part

The elasticity of the face (52.3 ± 1.1 EAU) was significantly higher than at other sites, but not ear (52.4 ± 1.3 EAU), hand (62.4 ± 1.2 EAU), and foot (59.5 ± 1.2 EAU), respectively (Figure 4(a) and Figure 4(d)). Furthermore, the elasticity of the upper limb (35.0 ± 1.7 EAU) was significantly lower than at other sites, but not body (36.3 ± 1.5 EAU) (Figure 4(a) and Figure 4(d)). To confirm the measured data, we used the integral formula. As a result, given the measured elasticity data, the highest value obtained from the hand (Figure 4(b) and Figure 4(c)), and the highest values was similarly seen at the hands in the value using integral formula (Figure S3). We obtained the matching results from the measured values and values using the integral formula.

The correlation of skin conditions among variables

The Pearson’s correlation coefficients among components are shown in Table 2. In this study, the variables; sebum, moisture, pore, wrinkle, pigmentation and elasticity, were classified. All variables input to continuous data. In the correlation analysis results, sebum and pore (r = 0.390, p < 0.05) were positively correlated, but sebum and moisture(r = −0.524, p < 0.01) and wrinkle and elasticity (r = −0.402, p < 0.05) were negatively correlated (Table 2).

The correlation between sebum and moisture

The Pearson’s correlation coefficients between sebum and moisture on face are shown in Figure 5(a). There were significant correlation between sebum and moisture on face. Among the parts of the body, sebum-moisture values of the face (r = −0.492, p < 0.01) were negatively correlated (Figure 5(a)).

The correlation between sebum and pore

The Pearson’s correlation coefficients between sebum and pore on face are shown in Figure 5(b). There were significant correlation between sebum and

Data presented as Pearson’s correlation coefficients. *p < 0.05, **p < 0.01

pore on face. Among the parts of the body, sebum-pore values of the face (r = 0.760, p < 0.01) were positively correlated (Figure 5(b)).

The correlation between wrinkle and elasticity

The Pearson’s correlation coefficients between wrinkle and elasticity on foot are shown in Figure 5(c). There were significant correlation between wrinkle and elasticity on foot. Among the parts of the body, wrinkle-elasticity values of the foot (r = −0.773, p < 0.01) were negatively correlated (Figure 5(c)).

The skin has various factors that protect it from internal factors, such as hormones and temperature, and external irritation, such as tiny particles of dust, air and water pollution, human contact, and ultraviolet radiation, which can be influenced by the change in the skin’s biophysical properties [1] [2] [4]. This study found that the average values of sebum for the ear, body, upper limb, hand, lower limb, and foot range from 0 to 14.83, and sebum values are higher at the face and then the neck. This was also reported by mechanism studies of sebum. The sebocyte was affected by both testosterone and 5α-DHT, and testosterone controls the sebaceous glands on the face more than those on the upper and lower limb [27]. Moreover, dehydroepiandrosterone levels proceed to a maximum at about 20 years of age in men. Therefore, peak sebum content occurs in the 20 year age group in men [28]. In another study, Pochi reported that the development and secretory activity of men’s sebaceous glands is influenced by hormonal factors [10]. Sato reported that androgenic steroids, particularly of gonadal origin, are the hormones principally responsible for these effects and the only ones shown to have a direct stimulatory effect on glandular activity [29]. Therefore, face sebum content is higher than at other sites. This means that men in their 20 s are greatly influenced by hormones, so sebum values are higher in the face and neck. As a result, men should pay attention to skin care and use appropriate skin products thoughtfully. The present study demonstrates that the average values of skin moisture for the face, ear, neck, body, upper limb, and lower limb range from 34.73 to 46.91. Moisture values are higher in the hand and foot. Previous studies have demonstrated that higher water evaporation in the hand is caused [9]. As the parts of the body that move the most, muscular contraction during activity elevates the temperature of the skin and the sweat rate [34]. Because eccrine glands is known that are found mainly on the palm, soles, and maxillary region [35]. On the other hand, as negative effects are caused by external factors, the depletion or disturbance of the major lipids in the SC that can be caused by dry air is thought to be one of the etiological factors producing dryness and barrier disruption in skin conditions [2]. This means that when a person is in the sunlight for a long time, water evaporation on the skin is severe and sunburns and photoaging are caused [36]. The results of this study show that moisture is higher in the hands and feet than in other areas, so the differences between each body part are considered to be differences in the distribution of the eccrine glands. Some studies have reported that pigmented skin and melanin damage are caused by ultraviolet radiation, which causes photochemical reactions. This affects the keratogenesis in the basal layer cell activity, making UVA active [37] [38]. The most important physiological function of all from the outside of the epidermal surface serves as a backstop of stimulus, or of the stratum corneum to build up the skin, of which exposure to sunlight’s ultraviolet radiation creates a thick layer of stratum corneum to make the role of external stimulation [39]. Thus, the thicker the stratum corneum, sebaceous gland and irritation may occur as in, this part occurs that is released in acne and can be formed easily [40]. Enjoying outdoor activities outside of elite sports includes exposure of 10 to 20 units of UVB. Therefore, as the face is highly exposed to sunlight, the pigmentation rate is higher than in other areas. On the other hand, the pigmentation rate of the upper limb area is not high. In view of the use of sunscreen by Koreans, many of them use it on the face, neck, and upper limbs. Our results show a high pigment rate on the face, neck, thigh, and shin, which are frequently exposed to sunlight. However, the face and upper limbs are often protected by sunscreen usage, because many people use sunscreen in those areas. Sunscreen is used less on the thighs and shins, so in Korea, men in their 20s express a high pigmentation rate in these areas. Due to wearing long sleeves and using a sunscreen blocker on upper limbs, this skin has a low pigmentation rate [13] [41]. The distribution of sebaceous glands is high on the face and scalp. A study reported that the distribution of sebum among men and women is likely quite different because it is affected by hormones and hormone levels due to activity and nature [42]. Men in their 20 s have the most abundant amount of sebum, so they will be susceptible to skin diseases [10]. Studies have shown that hormonal effects are a big part of the consequences that a big factor. There is considered to be a correlation between sebum and pores. As sebum increases, research has shown that the pores increase in size [9] [11]. Our results show that face sebum and pores are higher than in other areas and that there is a correlation between sebum and pores. Our results and pilot studies get to know that it is no difference. The UV radiation consists of UVA (320 - 400 nm), UVB (280 - 320 nm), and UVC (200 - 280 nm) [15]. Of these three types of UV radiation, UVA and UVB include the highest amount of energy, resulting mainly in photoaging [43]. The characteristics of UVB primarily affect the epidermal layer, where a large proportion of UVB is absorbed [44]. This causes side effects in the DNA of keratinocytes and melanocytes, and induces the production of inflammatory cytokines and proteolytic enzymes, leading to the destruction of collagen and elastin [37]. The characteristics of UVA penetrate more deeply into the dermis and damage the epidermis and dermis more than UVB. Another side effect of UV radiation at the cellular level is the accumulation of reactive oxygen species (ROS) through a complex cascade of biochemical reactions in the human skin [38]. UV-induced pro-inflammatory cytokines, oxidative stress, and loss of antioxidant enzymes cause the destruction of collagen in skin tissue, leading to wrinkle formation. The results of this study showed that face, neck, and lower limb values were higher than in other sites. However, the face and neck are almost constantly exposed to the sun’s rays in comparison with the lower limbs. Some studies have reported that elastic fiber density is in accordance with the electrical stimulus period expires, tend to grow. And increasing elastic fiber density by electrical impulses results from fibroblast activation by electrical impulses, as well as collagen type I [45]. The previous results by Guler reported that electric stimulation increased connective tissue [46]. Another study reported that UV irradiation impairs TGF-beta 1, reduces type I procollagen production by fibroblasts in human skin [47]. Our study found that elasticity in the hands and feet is higher than in other areas. In the above study comparison, electrical impulses increased collagen and skin elasticity. We do a lot of work using our hands, and always walk on our feet. So, to increase the density of many parts of the stimulus, skin elasticity will increase the elasticity, as well as collagen. According to the correlation analysis, the sebum and pore were positively correlated. In a previous study, similar correlations were found among the variables. For example, Roh et al. performed a correlation analysis, the sebum and pore, the results were that the sebum output level correlated most significantly with the pore size [11]. A study showed a positive relationship between sebum and pore. Our study showed that sebum and pore positively relates in Korean’s male. A study by Khan showed that cream containing Ficus carica increased the skin hydration, and sebum was decreased [48]. Other study of facial photoaing skin in patients showed that the sebum was increased, and hydration was decreased in patients affected by photoaing. In this study, its data showed that a difference values between sebum and hydration [49]. According to the correlation analysis, in our data, the sebum and moisture were negatively correlated. Although this study is concentrated on the patient, our data could be a big indicator for general adult. According to the correlation analysis, the wrinkle and elasticity were negatively correlated. In previous study, As a result, aloe decreased wrinkles and it increased elasticity in patients with an increase of the net procollagen [19]. Although our data focuses on normal skin conditions, this data could be a barometer of other studies. The data in this study provides index for a whole body skin condition in terms of the health male.

For nearly the first time, this study resulted in systematic reference values for standardized biophysical measuring methods and body parts reflecting the skin physiology of men. The results show that skin’s surface sebum, moisture, pores, wrinkles, pigmentation, and elasticity vary with the part of the body.

We thank to the Yongin University students for supporting this work. There are actively supported by Dan-Ho academy.

Kim, S.-J., Kim, J.-H., Lee, J.-U., Kim, M.-Y., Lee, L.-K., Park, B.-S., Yang, S.-M., Lee, W.-D., Noh, J.-W., Shin, Y.-S., Kim, D.-H., Kim, I.-H. and Kim, J. (2018) Analysis of Skin Parameters of Korean Men According to the Parts of the Body for Integumentary Physiotherapy Research. Health, 10, 467-486. https://doi.org/10.4236/health.2018.104038

All data were presented as the mean ± SE. P1-P5, point of face; A, anterior; P, posterior; Rt and Lt, right and left side; UL, upper limb; Pa, palm; D, dorsal part; So, sole; LL, lower limb. Statistically significant differences exist in face P1 vs. P2, P3, P4, and P5 (*p < 0.05), in P2 vs. P3, P4, and P5 (^†p < 0.05), in P3 vs. P4 and P5 (^‡p < 0.05), in P4 vs. P5 (^#p < 0.05), respectively. Statistically significant differences exist in ear ARtP1 vs. ALtP1 (*p < 0.05), PRtP1 vs. PRtP2, PLtP1, and PLtP2 (*p < 0.05), PRtP2 vs. PLtP1, and PLtP2 (^†p < 0.05), in PLtP1 vs. PLtP2 (^‡p < 0.05), respectively. Statistically significant differences exist in neck AP1 vs. PP1 (*p < 0.05). Statistically significant differences exist in upper limb ARtP1 vs. ARtP2, ALtP1, and ALtP2 (*p < 0.05), in ARtP2 vs. ALtP1, and ALtP2 (^†p < 0.05), in ALtP1 vs. ALtP2 (^‡p < 0.05), in PRtP1 vs. PRtP2, PLtP1, and PLtP2 (*p < 0.05), in PRtP2 vs. PLtP1, and PLtP2 (^†p < 0.05), in PLtP1 vs. PLtP2 (^‡p < 0.05), respectively. Furthermore, statistically significant differences exist in hand PaRtP1 vs. PaRtP2, PaRtP3, PaRt4, PaLtP1, PaLtP2, PaLtP3, and PaLtP4 (*p < 0.05), in PaRtP2 vs. PaRtP3, PaRtP4, PaLtP1, PaLtP2, PaLtP3, and PaLtP4 (^†p < 0.05), in PaRtP3 vs. PaRtP4, PaLtP1, PaLtP2, PaLtP3, and PaLtP4 (^‡p < 0.05), in PaRtP4 vs. PaLtP1, PaLtP2, PaLtP3, and PaLtP4 (^#p < 0.05), in PaLtP1 vs. PaLtP2, PaLtP3, and PaLtP4 (^§p < 0.05), in PaLtP2 vs. PaLtP3, and PaLtP4 (^$p < 0.05), in PaLtP3 and PaLtP4 (^&p < 0.05), in DRtP1 vs. DRtP2, DRtP3, DLtP1, DLtP2, and DLtP3 (*p < 0.05), in DRtP2 vs. DRtP3, DLtP1, DLtP2, and DLtP3 (^†p < 0.05), in DRtP3 vs. DLtP1, DLtP2, and DLtP3 (^‡p < 0.05) in DLtP1 vs. DLtP2, and DLtP3 (^#p < 0.05), in DLtP2 vs. DLtP3(^§p < 0.05). Statistically significant differences exist in lower limb ARtP1 vs. ARtP2, ALtP1, and ALtP2 (*p < 0.05), in ARtP2 vs. ALtP1, and ALtP2 (^†p < 0.05), in ALtP1 vs. ALtP2 (^‡p < 0.05), in PRtP1 vs. PRtP2, PLtP1, and PLtP2 (*p < 0.05), in PRtP2 vs. PLtP1, and PLtP2 (^†p < 0.05), in PLtP1 vs. PLtP2 (^‡p < 0.05). Statistically significant differences exist in foot SoRtP1 vs. SoRtP2, SoRtP3, SoRt4, SoLtP1, SoLtP2, SoLtP3, and SoLtP4 (*p < 0.05), in SoRtP2 vs. SoRtP3, SoRtP4, SoLtP1, SoLtP2, SoLtP3, and SoLtP4 (^†p < 0.05), in SoRtP3 vs. SoRtP4, SoLtP1, SoLtP2, SoLtP3, and SoLtP4 (^‡p < 0.05), in SoRtP4 vs. SoLtP1, SoLtP2, SoLtP3, and SoLtP4 (^#p < 0.05), in SoLtP1 vs. SoLtP2, SoLtP3, and SoLtP4 (^§p < 0.05), in SoLtP2 vs. SoLtP3, and SoLtP4 (^$p < 0.05), in SoLtP3 and SoLtP4 (^&p < 0.05), in DRtP1 vs. DRtP2, DRtP3, DLtP1, DLtP2, and DLtP3 (*p < 0.05), in DRtP2 vs. DRtP3, DLtP1, DLtP2, and DLtP3 (^†p < 0.05), in DRtP3 vs. DLtP1, DLtP2, and DLtP3 (^‡p < 0.05) in DLtP1 vs. DLtP2, and DLtP3 (^#p < 0.05), in DLtP2 vs. DLtP3 (^§p < 0.05), respectively.