Abstract：
BACKGROUND: Exercise reduces adiposity, but its influence on bone marrow fat fraction (BMFF) is unknown; nor is it known whether a reduction in liver fat content mediates this reduction.
OBJECTIVE: (i) To determine whether incorporating exercise into a lifestyle program reduces the lumbar spine (LS)-BMFF, and (ii), to investigate whether changes in liver fat mediate any such effect.
METHODS: Ancillary analysis of a two-arm, parallel, non-randomized clinical trial.
METHODS: Primary care centres in Vitoria-Gasteiz (Spain).
METHODS: A total of 116 children with overweight/obesity were assigned to a 22-week family-based lifestyle program (control group [n=57]) or the same program plus an exercise intervention (exercise group [n=59].
METHODS: The compared interventions consisted of a family-based lifestyle program (two 90-minute sessions/month) and the same program plus supervised exercise (three 90-minute sessions/week).
METHODS: The primary outcome examined was the change in LS-BMFF between baseline and 22 weeks, as estimated by MRI. The effect of changes in hepatic fat on LS-BMFF were also recorded.
RESULTS: Mean weight loss difference between groups was 1.4±0.5 kg favour of the exercise group. Only the children in the exercise group experienced a reduction in LS-BMFF (effect size [Cohen d] -0.42, CI: -0.86, -0.01). Importantly, 40.9% of the reductions in LS-BMFF were mediated by changes in percentage hepatic fat (indirect effect: β=-0.104, 95%CI=-0.213, -0.019). The impact of changes in hepatic fat on LS-BMFF was independent of weight loss.
CONCLUSIONS: The addition of exercise to a family-based lifestyle program designed to reduce cardiometabolic risk improves bone health by reducing LS-BMFF in children with overweight or obesity. This beneficial effect on bone marrow appears to be mediated by reductions in liver fat.
OBJECTIVE: (i) To determine whether incorporating exercise into a lifestyle program reduces the lumbar spine (LS)-BMFF, and (ii), to investigate whether changes in liver fat mediate any such effect.
METHODS: Ancillary analysis of a two-arm, parallel, non-randomized clinical trial.
METHODS: Primary care centres in Vitoria-Gasteiz (Spain).
METHODS: A total of 116 children with overweight/obesity were assigned to a 22-week family-based lifestyle program (control group [n=57]) or the same program plus an exercise intervention (exercise group [n=59].
METHODS: The compared interventions consisted of a family-based lifestyle program (two 90-minute sessions/month) and the same program plus supervised exercise (three 90-minute sessions/week).
METHODS: The primary outcome examined was the change in LS-BMFF between baseline and 22 weeks, as estimated by MRI. The effect of changes in hepatic fat on LS-BMFF were also recorded.
RESULTS: Mean weight loss difference between groups was 1.4±0.5 kg favour of the exercise group. Only the children in the exercise group experienced a reduction in LS-BMFF (effect size [Cohen d] -0.42, CI: -0.86, -0.01). Importantly, 40.9% of the reductions in LS-BMFF were mediated by changes in percentage hepatic fat (indirect effect: β=-0.104, 95%CI=-0.213, -0.019). The impact of changes in hepatic fat on LS-BMFF was independent of weight loss.
CONCLUSIONS: The addition of exercise to a family-based lifestyle program designed to reduce cardiometabolic risk improves bone health by reducing LS-BMFF in children with overweight or obesity. This beneficial effect on bone marrow appears to be mediated by reductions in liver fat.
摘要：
背景：运动可以减少肥胖，但其对骨髓脂肪含量（BMFF）的影响尚不清楚；也不知道肝脏脂肪含量的减少是否介导了这种减少。
目的：（i）确定将运动纳入生活方式计划是否会降低腰椎（LS）-BMFF，and(ii),调查肝脏脂肪的变化是否介导了任何这样的影响。
方法：双臂辅助分析，平行,非随机临床试验。
方法：位于Vitoria-Gasteiz（西班牙）的初级保健中心。
方法：共有116名超重/肥胖儿童被分配到22周的以家庭为基础的生活方式计划（对照组[n=57]）或相同的计划加运动干预（运动组[n=59]。
方法：比较的干预措施包括基于家庭的生活方式计划（两次90分钟的课程/月）和相同的计划加上监督锻炼（三次90分钟的课程/周）。
方法：检查的主要结果是基线和22周之间LS-BMFF的变化，MRI估计。还记录了肝脂肪变化对LS-BMFF的影响。
结果：两组之间的平均体重减轻差异为1.4±0.5kg，有利于运动组。只有运动组的儿童经历了LS-BMFF的减少（效应大小[Cohend]-0.42，CI：-0.86，-0.01）。重要的是,LS-BMFF减少的40.9％是由肝脂肪百分比的变化介导的（间接作用：β=-0.104，95CI=-0.213，-0.019）。肝脏脂肪变化对LS-BMFF的影响与体重减轻无关。
结论：在基于家庭的生活方式计划中增加运动，旨在降低心脏代谢风险，通过降低超重或肥胖儿童的LS-BMFF来改善骨骼健康。这种对骨髓的有益作用似乎是由肝脏脂肪减少介导的。
目的：（i）确定将运动纳入生活方式计划是否会降低腰椎（LS）-BMFF，and(ii),调查肝脏脂肪的变化是否介导了任何这样的影响。
方法：双臂辅助分析，平行,非随机临床试验。
方法：位于Vitoria-Gasteiz（西班牙）的初级保健中心。
方法：共有116名超重/肥胖儿童被分配到22周的以家庭为基础的生活方式计划（对照组[n=57]）或相同的计划加运动干预（运动组[n=59]。
方法：比较的干预措施包括基于家庭的生活方式计划（两次90分钟的课程/月）和相同的计划加上监督锻炼（三次90分钟的课程/周）。
方法：检查的主要结果是基线和22周之间LS-BMFF的变化，MRI估计。还记录了肝脂肪变化对LS-BMFF的影响。
结果：两组之间的平均体重减轻差异为1.4±0.5kg，有利于运动组。只有运动组的儿童经历了LS-BMFF的减少（效应大小[Cohend]-0.42，CI：-0.86，-0.01）。重要的是,LS-BMFF减少的40.9％是由肝脂肪百分比的变化介导的（间接作用：β=-0.104，95CI=-0.213，-0.019）。肝脏脂肪变化对LS-BMFF的影响与体重减轻无关。
结论：在基于家庭的生活方式计划中增加运动，旨在降低心脏代谢风险，通过降低超重或肥胖儿童的LS-BMFF来改善骨骼健康。这种对骨髓的有益作用似乎是由肝脏脂肪减少介导的。
