J Phys Act Health. 2018 Aug 1;15(8):620-625. doi: 10.1123/jpah.2017-0483. Epub 2018 Mar 28.
Nerve growth factor (NGF) and brain-derived neural factor (BDNF) are important for brain function and detectable in the blood. This study explored the longitudinal associations of physical activity and body fat with serum NGF and BDNF in children.
Two waves of measurements were performed 2 years apart in 8- to 11-year-old children, including physical activity using the ActiGraph model 7164, body composition by dual-energy X-ray absorptiometry, and serum NGF and BDNF determined by multiplex immunoassay. The first wave included 248 children. Full information maximum likelihood estimation with robust standard errors was applied in structural equation modeling.
Vigorous physical activity showed a direct positive longitudinal relationship with NGF (standardized coefficient β = 0.30, P = .01) but not with BDNF (β = 0.04, P = .84). At the same time, body fat percentage was positively related to both NGF (β = 0.59, P < .001) and BDNF (β = 0.17, P = .04). There was an indication of an indirect relationship of vigorous physical activity with NGF (product of unstandardized coefficient β = -0.18, P = .02) and BDNF (β = -0.07, P = .05) through the negative relationship with body fat percentage (β = -0.36, P < .001).
Vigorous physical activity is directly related to serum NGF and indirectly through the level of body fat. The relationships with serum BDNF are more complex.
神经生长因子（NGF）和脑源性神经营养因子（BDNF）对大脑功能很重要，并且可以在血液中检测到。本研究探讨了儿童身体活动和体脂与血清 NGF 和 BDNF 的纵向关联。
在 8 至 11 岁儿童中，每两年进行两次测量，包括使用 ActiGraph 模型 7164 进行身体活动、双能 X 射线吸收法进行身体成分以及通过多重免疫测定法测定血清 NGF 和 BDNF。第一波测量包括 248 名儿童。在结构方程模型中应用了具有稳健标准误差的全信息极大似然估计。
剧烈身体活动与 NGF 呈直接正纵向关系（标准化系数 β=0.30，P=0.01），但与 BDNF 无关系（β=0.04，P=0.84）。与此同时，体脂百分比与 NGF（β=0.59，P<0.001）和 BDNF（β=0.17，P=0.04）均呈正相关。剧烈身体活动与 NGF（未标准化系数乘积β=-0.18，P=0.02）和 BDNF（β=-0.07，P=0.05）之间存在间接关系，通过与体脂百分比的负相关（β=-0.36，P<0.001）。
剧烈身体活动与血清 NGF 直接相关，通过体脂水平间接相关。与血清 BDNF 的关系更为复杂。
