Jiazhen Zheng1, Rui Zhou1, Furong Li1, Liren Chen2, Keyi Wu1, Jinghan Huang3, Huamin Liu1, Zhiwei Huang1, Lin Xu4, Zelin Yuan1, Chen Mao5, Xianbo Wu6. 1. Department of Epidemiology, School of Public Health (Guangdong Provincial Key Laboratory of Tropical Disease Research), Southern Medical University, Guangzhou, Guangdong, China. 2. Department of Regional Research, School of Social Sciences, Waseda University, Tokyo, Japan. 3. Department of Biostatistics, School of Public Health, Boston University, Boston, USA. 4. Department of Nutrition and Food Hygiene, School of Public Health (Guangdong Provincial Key Laboratory for Food, Nutrition and Health), Sun Yat-sen University, Guangzhou, Guangdong, China. 5. Department of Epidemiology, School of Public Health (Guangdong Provincial Key Laboratory of Tropical Disease Research), Southern Medical University, Guangzhou, Guangdong, China. Electronic address: maochen9@smu.edu.cn. 6. Department of Epidemiology, School of Public Health (Guangdong Provincial Key Laboratory of Tropical Disease Research), Southern Medical University, Guangzhou, Guangdong, China. Electronic address: wuxb1010@smu.edu.cn.
Abstract
BACKGROUND & AIMS: Dietary diversity is widely recommended in national and international guidelines; however, whether the beneficial effects on cognitive function still apply in the oldest-old (80+) has rarely been studied. This study aimed to evaluate the associations of dietary diversity with cognitive function among the oldest-old in a large prospective cohort in China. METHODS: We conducted a long-term prospective analysis on 11,970 participants aged 80+ (6581 octogenarians, 3730 nonagenarians, and 1659 centenarians). We constructed the baseline dietary diversity score (DDS) based on eight food items of a food frequency questionnaire. Mini-mental state examination (MMSE) was used to classify the participants as having cognitive impairment or not and was also used as a continuous metric. Non-linear associations of DDS with cognitive impairment was evaluated by cox models with penalized splines. We used mixed-effect models for longitudinal data with repeated measurements of MMSE (for up to seven time during the follow-up between 1998 and 2014). RESULTS: We documented 4778 cognitive impairment during 46,738 person-years of follow-up. Each one unit increase in DDS was associated with a 4% lower risk of cognitive impairment (adjusted hazard ratio (HR): 0.96; 95% confidential interval (CI): 0.94-0.98). Compared to participants with DDS of 0 score, those with a DDS of 1-2, 3-4, and higher than 5 scores had a lower cognitive impairment risk, the HRs were 0.86 (0.79-0.95), 0.82 (0.74-0.91), and 0.72 (0.64-0.82) respectively, and a significant trend emerged (p < 0.001). Compared with DDS of zero score, a DDS of 1-2,3-4, ≥5 was related to slower MMSE decline (β = 0.128, 0.162, 0.301, respectively, p < 0.01). CONCLUSIONS: Even after the age of 80, dietary diversity may offer a simple and straightforward mean of identifying and screening individuals at high risk for cognitive impairment. Recommendation of dietary diversity may be advocated to attenuate cognitive decline and decrease the risk of cognitive impairment in the oldest-old, especially in a low income or middle-income countries.
BACKGROUND & AIMS: Dietary diversity is widely recommended in national and international guidelines; however, whether the beneficial effects on cognitive function still apply in the oldest-old (80+) has rarely been studied. This study aimed to evaluate the associations of dietary diversity with cognitive function among the oldest-old in a large prospective cohort in China. METHODS: We conducted a long-term prospective analysis on 11,970 participants aged 80+ (6581 octogenarians, 3730 nonagenarians, and 1659 centenarians). We constructed the baseline dietary diversity score (DDS) based on eight food items of a food frequency questionnaire. Mini-mental state examination (MMSE) was used to classify the participants as having cognitive impairment or not and was also used as a continuous metric. Non-linear associations of DDS with cognitive impairment was evaluated by cox models with penalized splines. We used mixed-effect models for longitudinal data with repeated measurements of MMSE (for up to seven time during the follow-up between 1998 and 2014). RESULTS: We documented 4778 cognitive impairment during 46,738 person-years of follow-up. Each one unit increase in DDS was associated with a 4% lower risk of cognitive impairment (adjusted hazard ratio (HR): 0.96; 95% confidential interval (CI): 0.94-0.98). Compared to participants with DDS of 0 score, those with a DDS of 1-2, 3-4, and higher than 5 scores had a lower cognitive impairment risk, the HRs were 0.86 (0.79-0.95), 0.82 (0.74-0.91), and 0.72 (0.64-0.82) respectively, and a significant trend emerged (p < 0.001). Compared with DDS of zero score, a DDS of 1-2,3-4, ≥5 was related to slower MMSE decline (β = 0.128, 0.162, 0.301, respectively, p < 0.01). CONCLUSIONS: Even after the age of 80, dietary diversity may offer a simple and straightforward mean of identifying and screening individuals at high risk for cognitive impairment. Recommendation of dietary diversity may be advocated to attenuate cognitive decline and decrease the risk of cognitive impairment in the oldest-old, especially in a low income or middle-income countries.