Objective  To explore the relationship between vitamin D and cognitive function under Chinese dietary patterns and outdoor activities among elderly residents.

  Methods  We recruited 1 200 community residents aged 60 years and above in 4 cities of Liaoning province conducted a face-to-face survey among the residents from June to September 2017. Mini-Mental State Examination (MMSE) was used to assess cognitive function in the residents and information on demographics, previous intake of food rich in vitamin D and outdoor activities were collected using a self-designed questionnaire. Partitioning cluster analysis was adopted to divide the residents into groups with high, moderate, and low intake of food rich in vitamin D and groups having high, moderate, and low outdoor activity, respectively, for analyses on the relationship between vitamin D intake, outdoor activity and cognitive function among the residents.

  Results  Valid information were collected from 1 115 residents. The residents with low intake of food rich in vitamin D had significantly lower MMSE score compared to the residents with moderate and high intake (25.7 ± 3.3 vs. 26.1 ± 3.3 and 26.4 ± 2.9, F = 4.42; P < 0.05); the residents with low outdoor activity had significantly lower MMSE score compared to the residents with moderate and high outdoor activity (25.4 ± 3.2 vs. 26.5 ± 3.2 and 26.4 ± 3.0, F = 17.08; P < 0.01). After adjusting other influencing factors such as age and education, significant effects of intake of food rich in vitamin D and outdoor activity on cognitive function still remained. Eating more food rich in vitamin D and having more outdoor activities are protective factors for cognitive function with the odds ratio of 0.62 (95% confidence interval: 0.46 – 0.83) and 0.69 (0.49 – 0.98).

  Conclusion  Increasing intake of food rich in vitamin D and having more outdoor activities with effective sunshine exposure may help prevent cognitive impairment in Chinese elder people.