Association Of Dietary Diversity With Cognitive Impairment And Activities Of Daily Living Disability Among The Chinese Oldest-old:a Cohort Study

ObjectiveThe purpose of this study was to explore the relationship between dietary diversity and cognitive impairment and disability of activities of daily living(ADL)in the oldest-old(aged 80 and over).MethodsThis study is based on the seven survey data of Chinese Longitudinal Healthy Longevity Survey(CLHLS).I participated in the eighth round of CLHLS project in Guangdong.According to the mode of field investigation,the dietary status of the respondents was collected;The baseline assessment of dietary diversity scores was conducted through direct interviews based on the food frequency questionnaire.The questionnaire covered eight main food groups:meat,fish,eggs,beans,fruits,tea,garlic and fresh vegetables,and was recorded as "often or almost every day","occasionally" or "rarely or never".The "often or almost every day" option(regardless of the minimum intake)is classified as a dietary diversity scoring unit,with a full score of 8 points Cognitive function and ADL were measured by simple mental state examination scale and Katz daily living function index scale,respectively.Cox proportional hazards regression model was used to estimate the association between dietary diversity and the risk of cognitive impairment and ADL disability.Results(1)Dietary diversity and cognitive impairment:11970 elderly people were included,with a total follow-up of 46738 person years.A total of 4876 people had cognitive impairment during the follow-up period.Each unit increase in the dietary diversity score reduced the risk of cognitive impairment by 4%(HR:0.96;95%CI:0.94-0.98).Compared with the subjects with dietary diversity of 0,dietary diversity of 1-2 points(HR=0.86,95%CI:0.79-0.95),3-4 points(HR=0.82,95%CI:0.740.91)and≥ 5 points(HR=0.72,95%CI:0.64-0.82)were associated with a lower risk of cognitive impairment,and trend test p<0.05.A protective effect on cognitive function was observed in the following foods:meat(HR=0.90,95%CI:0.85-0.96),fish(HR=0.85,95%CI:0.78-0.92),beans(HR=0.91,95%CI:0.85-0.97)and garlic(HR=0.91,95%CI:0.84-0.98).Smoking and ADL disability interact with eating beans(P<0.05).Beans have a stronger protective effect on current or former smokers and ADL disabled people.(2)Dietary diversity and ADL disability:11675 elderly people were included,with a total follow-up of 46679 person years.A total of 4895 cognitive impairment occurred during the follow-up period.For each unit increase in dietary diversity score,the risk of ADL disability decreased by 4%(HR:0.96;95%CI:0.94-0.98).Compared with the respondents with dietary diversity of 0,dietary diversity of 1-2 points(HR=0.87,95%CI:0.80-0.96),3-4 points(HR=0.82,95%CI:0.74-0.91)and≥ 5 points(HR=0.73,95%CI:0.65-0.83)were associated with the reduced risk of ADL disability,and trend test p<0.05.There was an interaction between smoking and eating beans(P<0.05),and beans had a stronger protective effect on current or former smokers.ConclusionThis study is the first to find in the elderly with Eastern dietary patterns:(1)Higher dietary diversity scores are associated with lower risk of cognitive impairment in the elderly;(2)Higher dietary diversity scores are associated with lower risk of ADL disability in the elderly;(3)Consumption of meat,beans,fish and garlic is associated with lower risk of cognitive impairment and ADL disability;(4)Soy is associated with lower risk of cognitive impairment and ADL disability in smokers The protective effect of beans on the cognitive function of smokers was stronger;the protective effect of beans on the ADL function of smokers was stronger.