Analysis of the correlation between skin barrier function and age in rosacea patients in Qinghai region

This study aims at investigating the difference in facial skin barrier function between rosacea patients and the healthy population of different ages in the Qinghai region and its correlation with age, providing a basis for clinical nursing and treatment.

endothelial structure, which is reflected on the epidermis and causes rosacea. 2 Studies have shown that the disruption of the skin barrier is one of the reasons for the aggravation of rosacea, and the dysfunction of the stratum corneum barrier allows some irritants to enter the epidermis and dermis, exacerbating vasodilation and inflammation. 3Research has demonstrated prominent permeability barrier alterations in papulopustular rosacea at the molecular level. 4e skin, as the largest organ of the human body, is located on the outermost layer of the body, play an important barrier role, and is more susceptible to exogenous stimuli.Previous studies have shown that the transepidermal water loss rate, water content of the stratum corneum, and pH value of the epidermis all changes with age, manifested as a reduction in the permeability barrier function and pigmentation barrier function of the skin. 5The Xining region of Qinghai is in the transitional zone from the temperate continental climate to the plateau mountain climate.Due to the influence of altitude, it has strong sunlight and dry climate characteristics.Previous research has shown that regardless of whether there is a skin disease, the skin barrier function is relatively poor. 6With the increasing problem of societal aging, research on skin aging has become a hotspot in recent years; age-related alterations of skin lead to age-related skin fragility and diseases. 7There is still a lack of research on the relationship be-

| Source of cases
This study collected patients with rosacea who visited the First

| Instruments
We used the Tewameter 300 from CK Company in Germany to measure the transepidermal water loss (TEWL), the Corneometer 825 to measure epidermal water content, the Sebumeter to measure epidermal oil content, and the Skin-pH-meter 905 pH meter to test the epidermal pH value.

| Statistical methods
Statistical analysis was carried out using SPSS 26.0.Measurements were subjected to a normality test; if they followed a normal distribution, the data were expressed as mean ± standard deviation, and one-way ANOVA was performed.If they did not follow a normal distribution, median (interquartile range) was used, and the Mann-

| General information
This study included 216 patients with rosacea and 211 healthy individuals as a control group.There were 99 males and 117 females in the rosacea group, and 115 males and 96 females in the control group; this difference was not statistically significant (p > 0.05).The ages of both rosacea patients and healthy individuals did not follow a normal distribution; the age of rosacea patients was 39.00 (26.00, 59.75) years, and the age of healthy individuals was 39.00 (25.00, 59.00) years.There was no statistical difference in age between the two groups (p > 0.05), indicating comparability.

| Analysis of skin barrier function results in rosacea and healthy individuals
The TEWL, SCH, SC, and pH values of the rosacea group and the control group did not follow a normal distribution, so the Mann-Whitney U test was performed.In all four age groups, the TEWL of the rosacea group was higher than that of the control group, and the SCH was lower than the control group (p < 0.05); in the two age groups above 40 years, the SC of the rosacea group was lower than that of the control group (p < 0.05); in the 40-59 age group, the pH value of the rosacea group was higher than that of the control group (p < 0.05).Please refer to Table 1 and Figure 1.

| Rosacea and control group age and skin barrier function correlation analysis
In the rosacea group, the TEWL value has a positive correlation with age, with an increase along with age.The rs value is 0.156, and the difference is statistically significant (p < 0.05).The SCH and SC values have a negative correlation with age, both decreasing as age increases, with rs values of −0.268 and −0.249, respectively.The difference is statistically significant (p < 0.05).The pH value has no linear correlation with age.
In the control group, the TEWL value has a positive correlation with age, increasing as age increases, with a rs value of 0.282.The difference is statistically significant (p < 0.05).The SCH value has a negative correlation with age, decreasing as age increases, with a rs value of −0.330.The difference is statistically significant (p < 0.05).
The SC value and pH value have no linear correlation with age.See Table 2. Rosacea is an inflammatory skin syndrome characterized by erythema, papules, and telangiectasia.It is prone to relapse and has a long illness course, often leading to psychological issues such as lack of confidence in appearance and social interaction. 8The stratum corneum water content, epidermal sebum content, and transepidermal water loss rate are the most direct indicators reflecting facial skin function.Previous studies have shown that people with sensitive skin are more likely to experience skin barrier damage due to differences in transepidermal water loss, stratum corneum water content, and epidermal sebum content compared to normal individuals. 9EL and SCH were obviously different from those of healthy people. 10Skin lipids, an important component of the skin, maintain the skin's normal barrier function by preventing skin water loss and invasion by environmental substances.When the epidermal sebum content changes, the skin's barrier function will also be affected. 11e pH value of the skin surface is one of the physiological indicators of the skin.It varies with the growth and development period of the organism and the biological state of the skin.Some skin diseases can cause the pH value of the skin surface to increase, directly or indirectly affecting the metabolism of keratinocytes, thereby causing abnormalities in keratinocyte proliferation, differentiation, changes in skin barrier function, and a decrease in stratum corneum density. 12nghai Province, located deep in the inland, far away from the sea and on the Qinghai-Tibet Plateau, has a plateau continental climate.It is characterized by long daylight hours, strong radiation, scarce precipitation, dry climate, windy weather, oxygen deficiency, and cold temperatures.13 90% of skin aging is caused by photoaging due to ultraviolet radiation.14 One study found that the UV radiation plays a key role in the development of rosacea.UV light is implicated in all significant aspects of rosacea: skin inflammation, neoangiogenesis, telangiectasia, and fibrosis, and may even initiate rosacea.15   This study shows that at different age stages, the transepidermal water loss rate and stratum corneum water content of healthy individuals are better than those of rosacea patients, which is consistent with previous studies.16 In individuals over 40 years old, the epidermal sebum content of rosacea patients is significantly lower than that of healthy individuals, while there is no significant difference in other age groups.This could be due to the skin barrier function As the outermost organ of the body, the skin plays an important barrier role.Evidence shows that senescent cells continue to accumulate in naturally aging and photoaging skin, further leading to age-related skin pathological changes.17 One of the key features of rosacea is a high sensitivity to the environment, 4 which is closely related to skin barrier function.As age increases, skin barrier function continues to decrease.When rosacea is present, it can cause further serious damage to the skin barrier.

TA B L E 1 Comparison of skin barrier function between rose acne and controls at different ages [M (P25, P75)].
In conclusion, due to the strong ultraviolet radiation and cold climate in Qinghai, the skin barrier is more easily damaged compared to other regions in China, and skin aging progresses faster.Therefore, both rosacea patients and healthy individuals in this area should strengthen skin hydration, moisturization, and sun protection to protect the skin barrier and delay the aging process.

2 |
tween skin barriers and age in patients with rosacea in the Qinghai region.This study conducted a large-scale epidemiological survey to analyze the skin barrier function characteristics of healthy people and patients with rosacea at different ages, explore the correlation between skin barriers and aging, and provide new ideas for the diagnosis and treatment of rosacea in the Qinghai region.MATERIAL S AND ME THODS 2.1 | Inclusion criteria ① Living in the Qinghai area for more than 3 years; ② diagnosed by the same physician according to the "Chinese Rosacea Diagnosis and Treatment Guidelines (2021 Edition)" 1 ; ③ complete case data; ④ healthy test participants have no skin diseases or other systemic diseases that may affect the skin at the measurement site; ⑤ the individual agrees to provide personal-related information; ⑥ age 18 years and above, regardless of gender.Diagnosis criteria: necessary performance: ① Cheeks: Persistent erythema accompanied by transient flushing, which may periodically worsen; ② perioral/nose: Persistent erythema which may periodically worsen.Selective performance: ① Transient flushing; ② capillary dilation; ③ papules and pustules; ④ hypertrophic changes; ⑤ eye symptoms (lid margin telangiectasia, blepharitis, keratitis, conjunctivitis, and keratoconjunctivitis).If the cheeks meet the necessary diagnosis, rosacea can be diagnosed regardless of whether there is selective performance; the perioral/nose part should meet at least one selective performance based on the necessary conditions.If either of the two parts meets the diagnostic criteria, rosacea can be diagnosed.At the same time, it is necessary to exclude other causes of transient flushing or persistent erythema, including external medication, systemic medication, local chemical treatment or phototherapy, menstrual or perimenopausal symptoms, and systemic diseases.

2. 2 |
Exclusion criteria ① Does not meet the diagnosis of rosacea; ② incomplete data; ③ disagreement to participate in this study or refusal to provide personal information; ④ healthy test participants have local acne, eczema, chloasma, psoriasis, scars, and other skin lesions or suffer from other systemic diseases that may affect the skin; ⑤ residents in the Qinghai area for less than 3 years.
People's Hospital of Xining City from January to June 2023.All patients were diagnosed by the same doctor, met the diagnosis criteria for rosacea, and did not use any local external drugs, phototherapy, or oral medication in the past 3 months.They were compared with the control group.All subjects have lived in the Qinghai area for more than 3 years.They are divided into 4 groups according to age: 18-24 years old, 25-39 years old, 40-59 years old, and ≥60 years old.
Both healthy individuals and patients with rosacea were selected for examination.The left cheek and center forehead were chosen for noninvasive skin physiological function testing, including transepidermal water loss (TEWL), stratum corneum hydration (SCH), skin sebum (SC), and pH value measurement.All tests were conducted in the dermatology department of the First People's Hospital of Xining City, with average humidity of 20% and average temperature of 26°C.Before measurement, faces were washed with warm water without any cosmetics applied, and the skin was left to rest for 20 min.TEWL, SCH, SC, and pH value were measured three times each, and the average values were recorded.
Whitney U test was performed.The correlation between age and each indicator was analyzed using the Spearman correlation coefficient, with rs value representing the correlation coefficient.An rs value of 0.8-1.0indicates a very strong correlation, 0.6-0.8indicates a strong correlation, 0.4-0.6 indicates a moderate correlation, 0.2-0.4indicates a weak correlation, and 0.0-0.2indicates a very weak or no correlation.A p value of less than 0.05 was considered statistically significant.

F I G U R E 1
Therefore, due to the strong ultraviolet radiation and cold climate in Qinghai, facial aging and skin barrier damage are more likely to occur.This study aims at providing evidence for skin care and disease treatment in Qinghai by comparing the skin barrier function indicators at different age stages of rosacea patients and healthy individuals in the area.Comparison of skin barrier function between rose acne and controls at different ages.
being damaged and sebaceous gland function decreasing as a result of rosacea at this age stage, reducing sebum secretion and further leading to changes in the epidermal pH value.Both rosacea patients and healthy individuals have an increase in the transepidermal water loss rate and a decrease in stratum corneum water content as they age, and the correlation is weak.The epidermal sebum content of rosacea patients decreases with age, showing a weak correlation.