Evaluation Of Sunlight UV Exposure Based On Skin Aging And Its Relationship With Cognitive Function

Object: By investigating the cognitive level of the elderly in rural areas of Shenyang,the skin aging index is used to represent the degree of solar exposure,and the long-term vitamin D level of the body is measured to further explore its relationship with cognitive function.Methods: In this study,a cluster random sampling method was used to select 600 elderly people over 60 years old from 14 villages in Shenyang City,Liaoning Province.Collect the general situation of the subjects,rich in vitamin D food consumption,daily activity ability and cognitive function,and obtain the images of skin from UV-exposed(dorsal hand)and UV-protected(inner forearm)sites from each individual by the Beagley-Gibson system.Daily activity ability was evaluated using the Activity of Daily Living Scale(ADL),cognitive function was evaluated using the Montreal cognitive assessment(MoCA).The cutoff value of Mild cognitive impairment(MCI)is illiterate ≤ 13 points,primary school ≤ 19 points,middle school and above ≤ 24 points.Skin aging indicators were evaluated using the Beagley-Gibson hand aging grading method and MATLAB software to extract image eigenvalues.Differences in skin grade between the 2 sites were used to indicate cumulative UV exposure level.Principal component analysis was used to extract comprehensive indicators of solar exposure.Associations between cognitive function and UV exposure were analyzed using logistic regression.Results: The average age of the surveyed population was 70.84±5.14 years old,including 335 males and 265 females.The average years of schooling are 6.36 ± 2.93 years.The average MoCA score was 20.33 ± 4.08.The cognitive level of those who were less than or equal to 70 years old in the survey population was higher than those older than 70 years old,and the difference was statistically significant(P<0.001).There is no gender difference in the cognitive level of the respondents,but there are significant differences between different years of education and marital status(P<0.001).Married peoples cognitive level is greater than divorce and widowed(P<0.001).After adjustment for age,gender,education,marital status,ADL,hypertension,and diabetes,a high UV exposure level was associated with better cognitive function.Conclusions: Greater cumulative UV exposure appears to be associated with better cognitive function in rural elderly of northern China.The reason for this result may be that the cumulative long-term vitamin D level is maintained at a high level due to cumulative sun exposure,thus protecting cognitive function.