Batty G David, Galobardes Bruna, Starr John M, Jeffreys Mona, Davey Smith George, Russ Tom C
Department of Epidemiology and Public Health, University College, London, UK.
Centre for Cognitive Ageing & Cognitive Epidemiology, University of Edinburgh, Edinburgh, UK.
J Negat Results Biomed. 2016 Nov 2;15(1):19. doi: 10.1186/s12952-016-0062-z.
Recent large-scale studies suggest that obesity and overweight may confer protection against future dementia. This observation could, however, be generated by reverse causality. That is, weight loss in the incipient phase of dementia ascribed to diminished self-care, including sub-optimal nutrition, would have the effect of generating such an inverse association. One approach to circumventing this problem would be to measure weight in a population which is young enough to be free of the symptoms of dementia which is then followed up for dementia occurrence over many decades.
In a prospective cohort study, body mass index, and other potential risk factors, were measured in 9547 male university undergraduates (mean age 20.5 years) in 1948-68 who were then linked to national mortality registers.
Of 2537 deaths over a mean of 50.6 years follow up, 140 were ascribed to dementia. There was no association between overweight and future dementia deaths (age-adjusted hazard ratio; 95 % confidence interval: 0.93; 0.49, 1.79).
In this cohort study of former university students, being overweight in youth did not confer protection against later dementia death.
近期大规模研究表明，肥胖和超重可能对未来患痴呆症具有保护作用。然而，这一观察结果可能是由反向因果关系导致的。也就是说，痴呆症初期阶段因自我护理能力下降（包括营养摄入不足）导致的体重减轻，会产生这种负相关关系。规避此问题的一种方法是在足够年轻、尚无痴呆症状的人群中测量体重，然后对其进行数十年的随访以观察痴呆症的发生情况。
在一项前瞻性队列研究中，于1948年至1968年对9547名男性大学本科生（平均年龄20.5岁）测量了体重指数及其他潜在风险因素，随后将他们与国家死亡登记册进行关联。
在平均50.6年的随访期内发生的2537例死亡中，有140例归因于痴呆症。超重与未来痴呆症死亡之间无关联（年龄调整风险比；95%置信区间：0.93；0.49，1.79）。
在这项对 former university students的队列研究中，年轻时超重并不能预防后期痴呆症死亡。 （注：原文中“former university students”直译为“以前的大学生”，结合语境这里应该是指“曾经的大学生”，译文做了相应调整）
