Background

Sedentary behaviours (SB) are risk factors for poor cardiovascular health and all-cause mortality. However, their role in cognitive health in older adults is unclear. A few studies have examined associations between sedentary behaviours and cognition, but are limited by heterogeneity and insufficient longitudinal analyses. Therefore more robust studies, which would address identified limitations, are needed to accurately determine associations.

Method

This study analysed data collected from participants aged 50+ years of The Irish Longitudinal Study of Ageing (TILDA). We conducted cross-sectional linear regression with multivariate imputation analyses of baseline data from wave 1 (N = 8163, weekday-sitting time), and wave 3 (N = 6400, weekday-television viewing); longitudinal analyses between waves 1–3 (sitting) and waves 3–4 (television). Sedentary behaviours were analysed as both categorical and continuous variables. Outcome of cross-sectional analyses was standardised regression co-efficient of associations between sedentary exposures and cognitive function in respective waves, while for longitudinal analyses was cognitive change (verbal memory, verbal fluency, and global cognition) between waves based on standardised residuals.

Result

Study found significant but mild cross-sectional associations between 1-h increase in weekday-television viewing and poorer verbal memory (b = −0.02, CI: −0.04, −0.003, P < 0.05) and verbal fluency (b = −0.02, CI: −0.04, −0.002, P < 0.05). Baseline television viewing of 3.5+ h/day had mild but significant association with a decline in verbal fluency 2 years later in participants aged 65+ years, when compared with a reference category of <1.5 h of TV viewing (b = −0.12, CI: −0.23, −0.001, P < 0.05).

Conclusion

Our study findings indicated some association between increased levels of weekday-television viewing time, independent of physical activity, and poor cognition cross-sectionally and longitudinally in middle-aged and older adults. Intervention studies are needed to confirm the effects of SB on cognition in older adults. Public health campaigns should be targeted at displacing high levels of television viewing, in excess of 3.5 h/day among older adults.

中文翻译：

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50岁以上社区居民成年人的久坐行为和认知功能：爱尔兰纵向老龄化研究的结果

背景

久坐的行为（SB）是不良心血管健康和全因死亡率的危险因素。但是，它们在老年人认知健康中的作用尚不清楚。少数研究检查了久坐行为和认知之间的关联，但受到异质性和纵向分析不足的限制。因此，需要更强大的研究来解决已确定的局限性，才能准确地确定关联。

方法

这项研究分析了从爱尔兰纵向老龄化研究（TILDA）50岁以上参与者中收集的数据。我们对第一波（N = 8163，平日坐时间）和第三波（N = 6400，平日看电视）的基线数据进行了多元插补分析，进行了横截面线性回归。在波1-3（坐着）和波3-4（电视）之间进行纵向分析。久坐行为被分析为分类变量和连续变量。横断面分析的结果是久坐暴露与各个波的认知功能之间的关联的标准化回归系数，而纵向分析的结果是基于标准化残差的波之间的认知变化（语言记忆，言语流畅性和整体认知）。

结果

研究发现，平日电视观看时间增加1小时与较差的言语记忆能力（b = -0.02，CI：-0.04，-0.003，P <0.05）和语言流利度（b = -0.02， CI：-0.04，-0.002，P ＜0.05）。与参考类别<1.5 h的电视观看时间相比，每天观看3.5+ h /天的基线电视观看与轻度但显着的关联与2年后65岁以上参与者的口语流利度下降有关（b = −0.12，CI ：-0.23，-0.001，P ＜0.05）。

结论

我们的研究结果表明，中年和老年人的平日电视观看时间增加（独立于体育锻炼）与横断面和纵向认知不良之间存在某种关联。需要进行干预研究以确认SB对老年人认知的影响。公共卫生运动的目标应该是取代高水平的电视观看，老年人中的电视观看每天超过3.5小时。