School of Psychology, University of Birmingham, Birmingham, B15 2TT, UK.
Psychology Department, Clinical Psychology, University of Amsterdam, Amsterdam, 1018 WT, The Netherlands.
Sci Rep. 2019 Oct 31;9(1):15727. doi: 10.1038/s41598-019-52062-3.
Inflammation (immune system activation) affects neuronal function and may have consequences for the efficiency and speed of functional brain processes. Indeed, unusually slow psychomotor speed, a measure predictive of behavioural performance and health outcomes, is found with obesity and ageing, two conditions also associated with chronic inflammation. Yet whether inflammation is the mediating factor remains unclear. Here, we assessed inflammation by indexing interleukin-6 level in blood and measured psychomotor speed as well as indices of selective visual attention in young (mean = 26 years) or old (mean = 71 years) adults (N = 83) who were either lean or currently significantly overweight (mean body mass index = 22.4 and 33.8, respectively). Inflammation was positively and significantly correlated with psychomotor speed, age, and body mass index but not with attention measures. Using mediation analyses we show for the first time that inflammation fully accounts for the significant psychomotor slowing found in those with high BMI. Moreover, we further show that age-related psychomotor slowing is partially mediated by inflammation. These findings support the proposal that reducing inflammation may mitigate weight- and age-related cognitive decline and thereby improve performance on daily tasks and health outcomes more generally.
炎症（免疫系统激活）会影响神经元功能，并可能对大脑功能的效率和速度产生影响。事实上，肥胖和衰老这两种与慢性炎症相关的情况会导致异常缓慢的精神运动速度，这是一种预测行为表现和健康结果的指标。然而，炎症是否是中介因素仍不清楚。在这里，我们通过检测血液中的白细胞介素-6 水平来评估炎症，测量了年轻（平均 26 岁）或年老（平均 71 岁）成年人（N=83）的精神运动速度以及选择性视觉注意力指标，这些成年人要么偏瘦，要么目前明显超重（平均体重指数分别为 22.4 和 33.8）。炎症与精神运动速度、年龄和体重指数呈正相关且具有统计学意义，但与注意力指标无关。通过中介分析，我们首次表明，炎症完全解释了 BMI 较高者精神运动速度明显下降的现象。此外，我们还进一步表明，与年龄相关的精神运动速度下降部分由炎症介导。这些发现支持了这样一种观点，即减轻炎症可能会减轻与体重和年龄相关的认知能力下降，从而提高日常任务的表现和更普遍的健康结果。
