Nelson A M, Casperson S L, Jahns L, Palmer D G, Roemmich J N
USDA, Agriculture Research Service, Grand Forks Human Nutrition Research Center.
USDA, National Institute of Food and Agriculture.
JAR Life. 2022 Jul 1;11:20-25. doi: 10.14283/jarlife.2022.4. eCollection 2022.
The purpose of this longitudinal, observational study was to examine whether age and seasonal changes in sedentary activity (sedAct), moderate-to-vigorous physical activity (MVPA), and energy intake (EI) predict changes in body composition among midlife women. We hypothesized that reductions in MVPA and increases in sedAct and EI in winter, along with greater baseline age would predict increases in percentage body fat (%BF) across seasons.
This study used a longitudinal, within-subjects design. This study took place in Grand Forks, North Dakota.
Participants included 52 midlife women (aged 40-60 years) who were observed over the course of one year.
Percentage body fat measures were obtained via whole body Dual Energy X-ray absorptiometry. Participants were scanned once per season. We measured EI using the ASA24®. We used a GTX3 accelerometer to measure physical activity. Each season, participants wore the monitors for 7 days, 12 hours per day. All measures began in summer.
Results of hierarchical multiple regression (MR) analyses showed that age increases (β = 0.310, = 0.021) and summer-to-fall increases in EI (β = 0.427, = 0.002) predicted seasonal increases in %BF ( = .36, (5, 42)= 4.66, = 0.02). Changes in MVPA and sedAct were not significant predictors. Repeated measures ANCOVA revealed that summer ( = 37.7263, 95% CI [35.8377, 39.6149]) to winter ( = 38.1463, 95% CI [36.1983, 40.0942]) increases in %BF are not reversed by spring ( = 37.8761, 95% CI [35.9365, 39.8157]).
To minimize increases in %BF and maintain health, midlife women, particularly older women, should be encouraged to pay extra attention to their diet in the fall months.
这项纵向观察性研究的目的是检验久坐活动（sedAct）、中度至剧烈身体活动（MVPA）和能量摄入（EI）的年龄及季节性变化是否能预测中年女性身体成分的变化。我们假设，冬季MVPA的减少、sedAct和EI的增加，以及更高的基线年龄，将预测各季节身体脂肪百分比（%BF）的增加。
本研究采用纵向、受试者内设计。本研究在北达科他州的大福克斯进行。
参与者包括52名年龄在40至60岁之间的中年女性，她们在一年的时间里接受观察。
通过全身双能X射线吸收法获得身体脂肪百分比测量值。每个季节对参与者进行一次扫描。我们使用ASA24®测量EI。我们使用GTX3加速度计测量身体活动。每个季节，参与者佩戴监测器7天，每天12小时。所有测量均从夏季开始。
分层多元回归（MR）分析结果显示，年龄增加（β = 0.310， = 0.021）和夏季到秋季EI的增加（β = 0.427， = 0.002）预测了%BF的季节性增加（ = .36，(5, 42)= 4.66， = 0.02）。MVPA和sedAct的变化不是显著的预测因素。重复测量协方差分析显示，夏季（ = 37.7263，95%可信区间[35.8377, 39.6149]）到冬季（ = 38.1463，95%可信区间[36.1983, 40.0942]）%BF的增加在春季（ = 37.8761，95%可信区间[35.9365, 39.8157]）并未逆转。
为尽量减少%BF的增加并保持健康，应鼓励中年女性，尤其是老年女性，在秋季格外关注自己的饮食。
