| BackgroundThe prevalence of cognitive impairment and dementia is increasing in the past decades in China,and dietary pattern may play an important role in prevention of cognitive impairment.Some studies focusing on association of dietary pattern and cognitive function were conducted,while little was known about the certain dietary patterns,besides,whether and how dietary patterns change in the long term and associations of change in scores with cognitive function was scarcely investigated.Studies in this field were very limited in Chinese elderly.ObjectiveTo investigate associations of dietary patterns,using the dietary diversity index,exploratory factor analysis and reduced rank regression,with cognitive function,and investigate the long-term changes of dietary patterns and the effect of these changes on the risk of cognitive impairment.MethodsUsing the Chinese Longitudinal Healthy Longevity Survey(CLHLS)and the Nutrition and Chronic Disease Family Cohort(NCDFaC),four aspects of studies were conducted:First,using CLHLS cross-sectional dataset,dietary diversity index was constructed and associations of this index with cognitive function were investigated.Second,using NCDFaC study,we extracted dietary patterns using exploratory factor analysis,and investigated associations of dietary patterns with cognitive function and cognitive decline 2 years follow up later.Third,we further extracted two specific dietary patterns,cardiovascular factors related dietary pattern and kidney function-related dietary pattern,using reduced rank regression,and investigated associations of the two dietary patterns with cognitive impairment and cognitive decline 2 years later.Finally,we analyzed the long-term(13years)changes of dietary pattern,using food group consumption analysis,exploratory and confirmatory factor analysis.After extracting cardiovascular factors related dietary pattern and kidney function-related dietary pattern using reduced rank regressions,we further explored associations of scores change of the two dietary patterns during the past 13 years with the risk of cognitive impairment.Results1.Comparing with the subjects with good dietary diversity,those with poor dietary diversity have poor cognitive function scores,and the risk of cognitive impairment was significantly increased,with OR(95%Cl)of 1.29(1.14,1.47),and these associations were more significant in the oldest old.2.Two dietary patterns,"cereal vegetables and fruits" and "meat and soybean",were extracted.The former one was characterized by high intake of vegetables,fruits,legumes and cereals,and less intake of meat and soybean products.The latter one was characterized by appropriate consumption(but still in the recommended intake range by Chinese Guideline of dietary)of red meat,poultry meat,organ meat and aquatic products and soybean products,and less consumption of vegetable,fruits,legumes and mushrooms.3.Both cross-sectional and cohort studies showed significant negative association of "cereal,vegetables and fruits" dietary pattern with cognitive impairment.Results of cohort analysis showed,comparing with those who had not good adherence to the pattern "cereal,vegetables and fruits",those subjects who had a good adherence to it had a decreased risk of cognitive impairment two years later,with OR(95%CI)was 0.38(0.24,0.62);and this value was 0.32(0.12,0.62)among the participants with normal cognition at baseline in 2015.4.Cross-sectional studies rather than the cohort studies showed significant negative association of adherence to the "meat and soybean" dietary pattern with cognitive impairment(p<0.05).As the cohort studies showed,comparing with those who did not adhere well to the "meat and soybean" dietary pattern,the risk of cognitive impairment 2 years later among those participants who have a good adherence to this pattern was not different significantly(p>0.05),with OR of 1.24(0.79,1.97);and it was the same case among the participants with normal cognition at baseline in2015(p>0.05),with OR of 1.40(0.78,2.51).5.Two dietary patterns,cardiovascular risk(high SBP,GLU and low HDL)dietary pattern and kidney healthy(high estimated glomerular filtration rate,eGFR)dietary pattern,were extracted using reduced rank regression.The former was characterized by high consumption of tea,soybean milk,mushroom,less intake of nut,and very low intake of meat,egg(much less than the intake recommended by Chinese dietary guideline).The latter was characterized by high consumption of cereal,vegetables,legume and fruits,and less intake of soybean products and dessert.6.Cross-sectional analysis showed cardiovascular risk dietary pattern was positively with cognitive impairment(p<0.05),comparing with the lowest tertile,the risk of cognitive impairment in the highest tertile was significantly high,with OR of 2.12(1.02,4.39);while cohort studies showed no association of this dietary pattern with cognitive decline 2 years later(p>0.05);and it was the same case among those have normal cognition at baseline,no association of this pattern with the risk of cognitive impairment 2 years later.7.Contrary to the cardiovascular risk dietary pattern,cross-sectional analysis showed no association of kidney healthy dietary pattern with cognitive impairment(p>0.05).However,cohort analysis showed,comparing with those did not have a good adherence to the kidney healthy dietary pattern,those had a good adherence to kidney healthy pattern was found to have decreased risk of cognitive decline 2 years later,with OR of 0.57(0.37,0.85).It was the same case among the participants with normal cognition at baseline,the risk of cognitive impairment 2 years later among those who had a good adherence to kidney healthy dietary pattern decreased significantly,with OR of 0.52(0.29,0.93).8.The consumptions of food groups and the dietary patterns changed dramatically from the year 2002 to the year 2015.Two dietary patterns,cardiovascular risk("high SBP and GLU,low HDL")dietary pattern and kidney healthy("high eGFR")dietary pattern,were extracted using reduced rank regression.Great increase of score of the cardiovascular risk dietary pattern in the past 13 years was associated with increased risk of cognitive impairment;interaction effect of change in the score of this pattern and age group at baseline was observed(p=0.02).Stratified analysis showed,this association was significant in the younger(<52.89 years)middle-aged adults,with OR of 4.81(1.80,17.80),while not in those much older ones.No significant associations of score change in the kidney healthy dietary pattern in the past 13 years with the risk of cognitive impairment were observed(p>0.05).Conclusion1.Dietary diversity was inversely associated with the risk of cognitive impairment,especially among the oldest old.2.Two extracted dietary patterns,including "cereal vegetables and fruits" and"meat and soybean" dietary pattern,were significantly associated with cognitive performance in the cross-sectional analysis;the former was significantly associated with cognitive decline and cognitive impairment 2 years later,while not for the latter one.3.Cardiovascular risk dietary pattern score was significantly associated with increased risk of cognitive impairment in the cross-sectional analysis,while no association of this pattern with cognitive decline 2 years later was observed.However,a good adherence the kidney healthy dietary pattern was associated with decreased risk of cognitive decline and cognitive impairment 2 year later,although no association was observed in the cross-sectional analysis.4.The dietary patterns of the subjects changed dramatically from the year 2002 to the year 2015.Increase in score of cardiovascular healthy dietary pattern in the past 13 years was associated with the lower risk of cognitive impairment,especially among those adults who were younger in their early middle life;while change in score of kidney health dietary pattern was not significantly associated with cognitive impairment. |
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