From the Department of Epidemiology (T.X., S.G., S.S.M., K.T., M.K.I., M.A.I.), Department of Internal Medicine (S.G., K.T., L.O., M.M.G., F.R.), and Department of Neurology (M.K.I.), Erasmus MC University Medical Center Rotterdam, the Netherlands.
Neurology. 2023 May 16;100(20):e2125-e2133. doi: 10.1212/WNL.0000000000207220. Epub 2023 Mar 22.
Low bone mineral density (BMD) and dementia commonly co-occur in older individuals, with bone loss accelerating in patients with dementia due to physical inactivity and poor nutrition. However, uncertainty persists over the extent to which bone loss already exists before onset of dementia. Therefore, we investigated how dementia risk was affected by BMD at various skeletal regions in community-dwelling older adults.
In a prospective population-based cohort study, BMD at the femoral neck, lumbar spine, and total body and the trabecular bone score (TBS) were obtained using dual-energy X-ray absorptiometry in 3,651 participants free from dementia between 2002 and 2005. Persons at risk of dementia were followed up until January 1, 2020. For analyses of the association between BMD at baseline and the risk of incident dementia, we used Cox proportional hazards regression analyses, adjusting for age, sex, educational attainment, physical activity, smoking status, body mass index, systolic and diastolic blood pressure, cholesterol level, high-density lipoprotein cholesterol, history of comorbidities (stroke and diabetes mellitus), and genotype.
Among the 3,651 participants (median age 72.3 ± 10.0 years, 57.9% women), 688 (18.8%) developed incident dementia during a median of 11.1 years, of whom 528 (76.7%) developed Alzheimer disease (AD). During the whole follow-up period, participants with lower BMD at the femoral neck (per SD decrease) were more likely to develop all-cause dementia (hazard ratio [HR] 1.12, 95% CI 1.02-1.23) and AD (HR 1.14, 95% CI 1.02-1.28). Within the first 10 years after baseline, the risk of dementia was greatest for groups with the lowest tertile of BMD (femoral neck BMD, HR 2.03; 95% CI 1.39-2.96; total body BMD, HR 1.42; 95% CI 1.01-2.02; and TBS, HR 1.59; 95% CI 1.11-2.28).
In conclusion, participants with low femoral neck and total body BMD and low TBS were more likely to develop dementia. Further studies should focus on the predictive ability of BMD for dementia.
低骨密度（BMD）和痴呆症在老年人中常同时发生，由于身体活动减少和营养不良，痴呆症患者的骨丢失会加速。然而，在痴呆症发病前骨丢失已经存在到何种程度仍存在不确定性。因此，我们研究了社区居住的老年人在不同骨骼区域的 BMD 对痴呆症风险的影响。
在一项前瞻性基于人群的队列研究中，2002 年至 2005 年间，3651 名无痴呆症的参与者使用双能 X 射线吸收法（DXA）测量了股骨颈、腰椎和全身的 BMD 以及小梁骨评分（TBS）。在 2020 年 1 月 1 日之前对痴呆症风险人群进行随访。为了分析基线 BMD 与新发痴呆症风险之间的关系，我们使用 Cox 比例风险回归分析进行调整，包括年龄、性别、教育程度、身体活动、吸烟状况、体重指数、收缩压和舒张压、胆固醇水平、高密度脂蛋白胆固醇、合并症（中风和糖尿病）史和基因分型。
在 3651 名参与者（中位年龄 72.3±10.0 岁，57.9%为女性）中，688 名（18.8%）在中位时间 11.1 年内发生了新发痴呆症，其中 528 名（76.7%）发生了阿尔茨海默病（AD）。在整个随访期间，股骨颈 BMD 较低的参与者发生全因痴呆症（危险比[HR]1.12，95%置信区间[CI]1.02-1.23）和 AD（HR 1.14，95% CI 1.02-1.28）的风险更高。在基线后的头 10 年内，BMD 最低三分位组的痴呆症风险最高（股骨颈 BMD，HR 2.03；95%CI 1.39-2.96；全身 BMD，HR 1.42；95%CI 1.01-2.02；和 TBS，HR 1.59；95%CI 1.11-2.28）。
总之，股骨颈和全身 BMD 较低以及 TBS 较低的参与者发生痴呆症的风险更高。进一步的研究应侧重于 BMD 对痴呆症的预测能力。
