Epidemiology and Public Health, Institute of Biomedical and Clinical Science, University of Exeter Medical School, Barrack Road, Exeter, UK.
Unit of Clinical and Translational Neuroscience, Laboratory of Behavioral Neuroscience, National Institute on Aging, National Institutes of Health, USA.
Age Ageing. 2019 May 1;48(3):367-373. doi: 10.1093/ageing/afz002.
overweight or obesity at ages <65 years associates with increased dementia incidence, but at ≥65 years estimates are paradoxical. Weight loss before dementia diagnosis, plus smoking and diseases causing weight loss may confound associations.
to estimate weight loss before dementia diagnosis, plus short and longer-term body mass index associations with incident dementia in 65-74 year olds within primary care populations in England.
we studied dementia diagnosis free subjects: 257,523 non-smokers without baseline cancer, heart failure or multi-morbidity (group A) plus 161,927 with these confounders (group B), followed ≤14.9 years. Competing hazard models accounted for mortality.
in group A, 9,774 were diagnosed with dementia and in those with repeat weight measures, 54% lost ≥2.5 kg during 10 years pre-diagnosis. During <10 years obesity (≥30.0 kg/m2) or overweight (25.0 to <30.0) were inversely associated with incident dementia (versus 22.5 to <25.0). However, from 10 to 14.9 years, obesity was associated with increased dementia incidence (hazard ratio [HR] 1.17; 95% CI: 1.03-1.32). Overweight protective associations disappeared in longer-term analyses (HR, 1.01; 95% CI: 0.90-1.13). In group B, (n = 6,070 with incident dementia), obesity was associated with lower dementia risks in the short and longer-term.
in 65-74 year olds (free of smoking, cancer, heart failure or multi-morbidity at baseline) obesity associates with higher longer-term incidence of dementia. Paradoxical associations were present short-term and in those with likely confounders. Reports of protective effects of obesity or overweight on dementia risk in older groups may reflect biases, especially weight loss before dementia diagnosis.
65 岁以下超重或肥胖与痴呆发病率增加相关，但 65 岁及以上的估计结果则相反。痴呆症诊断前的体重减轻、加上吸烟和导致体重减轻的疾病可能会混淆这些关联。
评估在英国初级保健人群中，65-74 岁人群中痴呆症诊断前的体重减轻，以及短期和长期 BMI 与痴呆症发病的相关性。
我们研究了无痴呆症诊断的受试者：257523 名不吸烟者，无基线癌症、心力衰竭或多种疾病（A 组），以及 161927 名有这些混杂因素的受试者（B 组），随访时间≤14.9 年。竞争风险模型考虑了死亡率。
在 A 组中，9774 人被诊断为痴呆症，在那些有重复体重测量的人中，54%的人在诊断前 10 年内体重减轻了≥2.5 公斤。在<10 年内，肥胖（≥30.0kg/m2）或超重（25.0 至<30.0）与痴呆症发病呈负相关（与 22.5 至<25.0 相比）。然而，从 10 年到 14.9 年，肥胖与痴呆症发病率增加相关（危险比 [HR] 1.17；95%置信区间：1.03-1.32）。超重的保护作用在长期分析中消失（HR 1.01；95%置信区间：0.90-1.13）。在 B 组中（n=6070 例有痴呆症的患者），肥胖与短期和长期痴呆症风险较低相关。
在 65-74 岁（基线时无吸烟、癌症、心力衰竭或多种疾病）人群中，肥胖与痴呆症的长期发病率增加相关。在短期和有潜在混杂因素的人群中，也存在矛盾的关联。关于肥胖或超重对老年人群痴呆风险的保护作用的报告可能反映了偏见，尤其是痴呆症诊断前的体重减轻。
