Department of Data Science, College of Computing, City University of Hong Kong, Hong Kong SAR, China.
Department of Food Science and Nutrition, Hong Kong Polytechnic University, Hong Kong SAR, China.
BMC Public Health. 2024 Nov 27;24(1):3299. doi: 10.1186/s12889-024-20115-6.
Adequate sleep and physical activity promote longevity among older adults. Caffeine supplementation could be used to increase activity levels, but its effects have not been examined in real-world settings where potential trade-offs regarding sleep quality are also considered. This study sought to examine associations between caffeine intake and accelerometer-derived sleep and activity among older adults under free-living conditions.
Cross-sectional data were gathered from older adults aged 65 + in the 2011-14 National Health and Nutrition Examination Surveys (NHANES). Sleep parameters were derived from accelerometer data using a data-driven machine learning approach. Caffeine consumption was categorized based on weight (in mg/kg: 0, > 0 to 1, > 1 to 2, > 2 to 3, > 3) and absolute consumption (in mg: 0, > 0 to 100, > 100 to 200, > 200 to 300, > 300). Multivariable survey weighted regression models were used to examine associations between caffeine with average total daytime activity, highly active minutes, sleep duration, and sleep efficiency. Covariate adjustments included demographics, body mass index, smoking, alcohol, sleep disorders, sleep parameters (for activity outcomes), and daytime activity (for sleep outcomes).
N = 1,629 NHANES participants were included. Caffeine consumption was highest in the morning. In adjusted models, older adults who consumed > 3 mg/kg were 16.5% more active during the day (95% CI: 9.0, 24.4) and were highly active for 42.8 additional minutes (95% CI: 20.3, 65.4) compared to non-consumers. Similar results were observed for absolute consumption (mg), and significant but lower magnitude effects were observed for lower levels of consumption. Caffeine showed no association with sleep efficiency, while low levels of consumption (≤ 1 mg/kg, ≤ 200 mg) were associated with longer sleep duration.
Under free-living dietary, sleep, and activity patterns, this study found older adults who consumed caffeine were more active than non-consumers. Overall consumption was not associated with sleep efficiency but was associated with longer sleep duration at ≤ 1 mg/kg and ≤ 200 mg. Future causal studies should determine the effectiveness of caffeine for promoting higher activity in older adult populations.
充足的睡眠和身体活动可促进老年人长寿。咖啡因补充剂可用于提高活动水平，但在考虑睡眠质量潜在权衡的现实环境中，其效果尚未得到检验。本研究旨在探讨老年人在自由生活条件下咖啡因摄入与加速度计测量的睡眠和活动之间的关联。
本研究使用数据驱动的机器学习方法从 2011-2014 年国家健康和营养检查调查（NHANES）中年龄在 65 岁及以上的老年人中收集横断面数据。使用加速度计数据推导睡眠参数。根据体重（mg/kg：0、>0 至 1、>1 至 2、>2 至 3、>3）和绝对摄入量（mg：0、>0 至 100、>100 至 200、>200 至 300、>300）对咖啡因摄入量进行分类。使用多变量调查加权回归模型来检验咖啡因与平均白天总活动量、高度活跃分钟数、睡眠时间和睡眠效率之间的关联。协变量调整包括人口统计学、体重指数、吸烟、饮酒、睡眠障碍、睡眠参数（用于活动结果）和白天活动（用于睡眠结果）。
共纳入 1629 名 NHANES 参与者。咖啡因摄入量在早上最高。在调整后的模型中，与不消费咖啡因的老年人相比，消费>3mg/kg 咖啡因的老年人白天活动量增加 16.5%（95%CI：9.0，24.4），高度活跃时间增加 42.8 分钟（95%CI：20.3，65.4）。对于绝对摄入量（mg），也观察到类似的结果，而较低水平的摄入量（≤1mg/kg、≤200mg）与睡眠时间延长相关。咖啡因与睡眠效率无关，而低水平（≤1mg/kg、≤200mg）的咖啡因摄入与睡眠时间延长有关。
在自由生活的饮食、睡眠和活动模式下，本研究发现摄入咖啡因的老年人比不摄入咖啡因的老年人更活跃。总体摄入与睡眠效率无关，但与≤1mg/kg 和≤200mg 的睡眠时间延长有关。未来的因果研究应确定咖啡因对促进老年人群体更高活动水平的有效性。
