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Dietary flavonoids and cognitive impairment in Chinese older adults: a cross-sectional study

Introduction:

Cognitive impairment (CI) in older adults refers to impairment in cognition function

beyond normal aging. Previous studies have reported the effect of dietary antioxidants,

especially flavonoids on cognitive function in older adults, suggesting that high

dietary flavonoids intake may reduce the risk of cognitive impairment. However, most

of these studies were reported in Caucasian older populations in Western countries.

Moreover, some studies were positive, which others were negative studies. There was

no previous study regarding dietary flavonoids and cognitive impairment among

Chinese older adults.



Objectives:

The objectives of this study were to explore the association between dietary

intake flavonoids and the risk of cognitive impairment in Chinese older adults, and to

identify the independent factors associated with the risk of cognitive impairment in

Chinese older adults.



Method:

This study was a retrospective cross-sectional study, 200 patients who fulfilled the

inclusion and exclusion criteria and gave written informed consent were recruited

from the Geriatric clinics in Queen Mary Hospital, Hong Kong, from 11th July to 31st

October 2011. All recruited subjects were invited to attend face-to-face interviews.

Brief cognitive assessments by the Mini Mental State Examination (MMSE) and

Montreal Cognitive Assessment (MoCA) were done for all subjects. Every subject

also answered a detailed questionnaire on socio-demographic, type and frequency of

diet items (food frequency questionnaire) and co-morbid diseases.



Main outcome measure:

The primary outcome measure was cognitive function, using an education-adjusted

MMSE cut-off s to categorize the subjects into two groups (i.e. normal cognitive

group and cognitively impaired group).



Results:

200 subjects were recruited, 104 participants (37 males and 67 females) were in the

normal cognitive group and 96 subjects (22 males and 74 females) were in the

cognitively impaired group. The mean amount of dietary flavonoids intake of the

cognitively normal group was higher than that of the cognitively impaired group (i.e.

291.84 grams/day and 240.92 grams/day respectively; p=0.006 Mann-Whitney U test).

Other common dietary nutrients were also compared between the two groups. The

dietary carbohydrate (p<0.001), total sugar (p<0.001), vitamin C (p=0.001) and folic

acid (p<0.001) intakes were significantly related to cognitive impairment (using

chi-square statistics).



After adjustment for age, gender, education, exercise pattern, the dietary flavonoids

intake was not independently associated with cognitive impairment. However, after

adjustment for age, education level, exercise pattern and BMI, the higher to highest

quartile of dietary carbohydrate intake (184.184-1176.703g/d), high total sugar intake

(0.166-35.102g/d), highest quartile of vitamin C intake (139.803-900.952mg/d), the

third and fourth quartiles of folic acid intake (208.899-1544.418mcg/d) were

significantly associated with reduced risks of cognitive impairment. Older adults who

had regular exercise (both less and more than 30 minutes per day) had lower risk of

cognitive impairment than those who never did exercise (OR= 0.361, 95% confidence

interval=0.167-0.784 for less than 30 minutes/d; OR=0.137, 95% confidence

interval=0.048-0.396 for more than 30 minutes/d). We also found high BMI was

associated with a reduced risk of cognitive impairment with an OR of 0.897 (95%

confidence interval=0.816-0.987). Besides, the increasing age was also associated

with cognitive impairment (OR=1.059, 95% confidence interval=1.007-1.115).



Conclusion:

In summary, the present study demonstrated that the dietary flavonoids intake

was not significantly associated with the risk of cognitive impairment in Chinese

older adults in Hong Kong. / published_or_final_version / Medicine / Master / Master of Medical Sciences

  1. 10.5353/th_b4765744
  2. b4765744
Identiferoai:union.ndltd.org:HKU/oai:hub.hku.hk:10722/174446
Date January 2011
CreatorsLi, Wenjia., 李汶嘉.
PublisherThe University of Hong Kong (Pokfulam, Hong Kong)
Source SetsHong Kong University Theses
LanguageEnglish
Detected LanguageEnglish
TypePG_Thesis
Sourcehttp://hub.hku.hk/bib/B47657443
RightsThe author retains all proprietary rights, (such as patent rights) and the right to use in future works., Creative Commons: Attribution 3.0 Hong Kong License
RelationHKU Theses Online (HKUTO)

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