Department of Epidemiology, School of Public Health (Guangdong Provincial Key Laboratory of Tropical Disease Research), Southern Medical University, Guangzhou, Guangdong, China.
Department of Regional Research, School of Social Sciences, Waseda University, Tokyo, Japan.
Clin Nutr. 2021 Apr;40(4):1452-1462. doi: 10.1016/j.clnu.2021.02.041. Epub 2021 Mar 2.
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.
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).
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).
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.
饮食多样性在国内外指南中被广泛推荐；然而，其对认知功能的有益影响是否在最年长的老年人（80 岁以上）中仍然适用，这一点很少被研究。本研究旨在评估饮食多样性与中国一个大型前瞻性队列中最年长老年人认知功能之间的关联。
我们对 11970 名 80 岁以上（6581 名 80 岁老人，3730 名 90 岁老人，1659 名 100 岁老人）参与者进行了长期前瞻性分析。我们根据食物频率问卷中的 8 种食物构建了基线饮食多样性评分（DDS）。采用简易精神状态检查（MMSE）将参与者分为认知障碍组和非认知障碍组，并将其作为连续指标。采用带惩罚样条的 Cox 模型评估 DDS 与认知障碍的非线性关联。对于 1998 年至 2014 年期间随访期间最多 7 次的 MMSE 重复测量的纵向数据，我们使用混合效应模型。
在 46738 人年的随访期间，我们记录了 4778 例认知障碍。DDS 每增加 1 个单位，认知障碍的风险就降低 4%（调整后的危险比（HR）：0.96；95%置信区间（CI）：0.94-0.98）。与 DDS 得分为 0 分的参与者相比，DDS 得分为 1-2、3-4 和大于 5 分的参与者认知障碍风险较低，HR 分别为 0.86（0.79-0.95）、0.82（0.74-0.91）和 0.72（0.64-0.82），且呈显著趋势（p<0.001）。与 DDS 得分为 0 分相比，DDS 得分为 1-2、3-4 和≥5 分与 MMSE 下降速度较慢有关（β=0.128、0.162、0.301，p<0.01）。
即使在 80 岁以上的年龄，饮食多样性也可能是一种简单直接的方法，可以识别和筛选认知障碍风险高的个体。在最年长的老年人中，建议饮食多样性可以减缓认知衰退并降低认知障碍的风险，特别是在低收入或中等收入国家。
