Objective: To evaluate the effect of nutrition combined physical exercise interventions on age-related cognitive decline by a systematic review and meta-analysis.
Methods: We searched 9 databases, including PubMed, EMbase, The Cochrane Library, Web of Science, Science Direct, China National Knowledge Infrastructure (CNKI), VIP Information, China Biological Medical Database (CBM) and Wanfang for studies published until the end of December 2019. The selected trials should meet the following criteria, study objects: healthy adults aged 65 and over with cognitive dysfunction or diagnosed as MCI, but not meet the diagnostic criteria for dementia as well as no restriction on follow-up time, race or gender. Study interventions: multiple interventions including nutrition and exercise.
Exclusion criteria: (1) studies included elderly people with any type of dementia or patients with cognitive impairment induced by secondary causes, including drug, alcohol, severe organic brain diseases, mental disorders. (2) Republished literature. (3) Studies with significant differences in baseline data between groups. (4) The data in the study cannot be converted into the required data format. We reviewed and extracted information and assessed the risk of bias of recruited studies independently. Meta-analysis was performed using STATA v.15.1 software. The bias of publication was estimated by Egger test.
Results: A total of six RCTs representing 1039 participates were included in our meta-analysis. In terms of global cognitive function that has been assessed by neuropsychological test in different combinations, the result showed that the beneficial effect of nutrition combined exercise interventions was statistically significant [SMD = 0.23, 95% CI (0.1, 0.36), P = 0.0004]. There were no statistical differences from assays on MMSE scores, Memory, Executive Function, Attention, and Information Processing Speed across groups.
Conclusions: The current study shows that nutrition combined exercise interventions can improve global cognitive function in the aged with cognitive decline. Further researches emphasizing on longer follow-up time, experimental randomness, credibility and scale would better elucidate the effect of nutrition combined exercise interventions on cognitive function, particularly in older adults. (registration number: CRD42020159291, date of registration: 28/04/2020).
Keywords: Aging; Cognitive impairment; Exercise; Meta-analysis; Nutrition.