Effects Of Sun Exposure And Consumption Of Foods Rich In Vitamin D On Cognitive Function In The Elderly

Object: We investigated sun exposure and dietary intake of vitamin D food among over 60 years old to explored the long-term relationship between vitamin D and cognitive function,in the rural area,Shenyang.Methods: This study is a cross-sectional survey.We randomly selected participants aged over 60 years old from the rural area in Sujiatun district,Shenyang.Participants should live in rural for over 5 years,without suffering from acute diseases,depression,traumatic brain injury,cerebral hemorrhage,blindness,deafness,dumbness and be willing to cooperate with this survey composed our study population.Finally we received 1165 effective questionnaires and the effective response rate was 83.8%.The survey tools include: basic information questionnaire,sun exposure questionnaire,dietary intake of vitamin D food questionnaire,cognitive function evaluation questionnaire,daily living activity evaluation questionnaire.MMSE scale was used to evaluate cognitive function.ADL scale was applied to evaluate the ability on daily living.The data analysis was performed by SPSS 22.0.Measurement data were compared between two groups using independent samples T test,multiple groups were compared using single-factor analysis of variance and LSD test;count data used chi-square test.Multivariate linear regression was used to analyze the possible influencing factors of cognitive function.Binary logistic regression analysis was conducted to study the effects of general demographic characteristics,sun exposure and dietary intakes of vitamin D on cognitive function.Result: Participants with wearing long-sleeved shirt and trousers have inverse association with cognitive function(?=-0.865,P<0.05).However,Eating mushrooms and vitamin D-containing nutritional supplements have a positive effect on cognitive function(?=0.704,P<0.05;?=0.774,P<0.05).Participants with wearing long-sleeved shirt and trousers have negative relationship with orientation(OR=1.795,95 % CI: 1.261,2.555).Those eat mushrooms and fatty fishes have positive association with orientation(OR=0.607,95 % CI: 0.434,0.850;OR=0.648,95 % CI: 0.446,0.940).Participants with longer outdoor time before 60 years old have a lower risk of word registration impairment(OR=0.650,95% CI: 0.489,0.864).Participants who eat mushrooms have a lower risk of being impaired in word registration(OR=0.729,95% CI: 0.539,0.986).Participants with the habit of outdoor activities at noon have a lower risk of recall impairment(OR=0.679,95% CI: 0.500,0.922).Participants who eat fatty fishes have a lower risk of attention and computation impairment(OR=0.628,95% CI: 0.412,0.958).While those who eat liver have a higher risk of language impairment(OR=1.469,95% CI: 1.062,2.032).Smoking is the risks of recall and attention and computation(OR=1.451,95% CI: 1.015,2.076;OR=1.675,95% CI: 1.134,2.473).Age,ADL are risk factors of cognitive function,the year of education is protective factor for cognitive function.Conclusion: Participants with the lower frequency of wearing long-sleeved shirt and trousers,having habit of outdoor activities at noon and having longer outdoor time have relationship with the better cognitive function.Participants with eating fatty fishes,mushrooms,which are mainly vitamin D foods also have association with better cognitive function.The year of education is positive factor for cognitive function.However,age and ADL are risks for cognitive function.