Given the rising awareness of health-related lifestyle modifications, the impact of changes in body weight (BW) on cognitive function and dementia generates significant concern. This study aimed to investigate the association between BW changes and dementia in a middle-aged Korean population. A retrospective, population-based longitudinal study was conducted utilizing data from the National Health Insurance Service (NHIS) database. Participants aged 40 years or older in 2011 who underwent at least five health checkups between 2002 and 2011 were followed-up for dementia until 2020. A total of 3,635,988 dementia-free Korean aged < 65 at baseline were examined. We analyzed the association between BW variability independent of the mean (VIM) with BW cycle, defined as either an upward or a downward direction of BW, and the risk of incident dementia. The results showed an increased risk of dementia in the highest quartile of VIM quartile (hazard ratio [HR] 1.52, 95% confidence interval [CI] 1.47–1.58) compared to the lowest quartile of VIM. Additionally, the results showed an even higher increased risk of dementia in the highest BW cycle (≥ 2 cycles of 10% BW = HR 2.00, 95% CI 1.74–1.29). Notably, the combined concept of VIM with BW cycle showed an even higher dementia risk (highest quartile of VIM with ≥ 2 cycles of 10% BW = HR 2.37, 95% CI 2.05–2.74) compared to the baseline group (lowest quartile of VIM with < 3% BW cycle). The present study highlights the importance of considering BW changes with BW variability along with the BW cycle to assess dementia risk in detail, providing valuable insights for preventive strategies.

中文翻译：

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中年体重变异性和周期与早期痴呆症发病的关联：一项全国队列研究

鉴于人们对与健康相关的生活方式改变的认识不断提高，体重 (BW) 变化对认知功能和痴呆症的影响引起了人们的极大关注。本研究旨在调查韩国中年人群的体重变化与痴呆症之间的关联。利用国民健康保险服务 (NHIS) 数据库的数据进行了一项基于人群的回顾性纵向研究。 2011 年年龄在 40 岁以上且在 2002 年至 2011 年间至少接受过 5 次健康检查的参与者接受了痴呆症随访直至 2020 年。总共对 3,635,988 名基线年龄 < 65 岁的无痴呆韩国人进行了检查。我们分析了独立于平均值 (VIM) 的体重变异性与体重周期（定义为体重的向上或向下方向）与痴呆风险之间的关联。结果显示，与 VIM 最低四分位数相比，VIM 四分位数最高四分位数（风险比 [HR] 1.52，95% 置信区间 [CI] 1.47–1.58）患痴呆症的风险增加。此外，结果显示，在最高 BW 周期（≥ 2 个 10% BW 周期 = HR 2.00，95% CI 1.74–1.29）中，痴呆风险甚至更高。值得注意的是，与基线组（VIM 最低四分位数）相比，VIM 与 BW 周期的组合概念显示出更高的痴呆风险（≥ 2 个 10% BW 周期的 VIM 最高四分位数 = HR 2.37，95% CI 2.05–2.74） < 3% BW 周期）。本研究强调了考虑体重变化、体重变异性以及体重周期来详细评估痴呆风险的重要性，为预防策略提供了宝贵的见解。