BackgroundRandomized controlled trials have reported no effect of moderate‐to‐vigorous physical activity (MVPA) on reducing blood pressure (BP) in youth, probably due to short trial durations. This study examined the longitudinal effect of sedentary time (ST), light PA (LPA) and MVPA on BP in 11‐year‐old children followed up for 13 years to determine the confounding and mediating role of body composition.MethodsData included 2513 children from the Avon Longitudinal Study of Parents and Children (ALSPAC), UK birth cohort who had data on at least one time‐point measure of accelerometer‐based movement behaviour across the follow‐up and complete BP measures at ages 11, 15 and 24 years. Body composition was assessed with dual‐energy x‐ray absorptiometry at all time points. Multivariate adjusted generalized linear mixed‐effect model and structural equation causal mediation model analyses were conducted.ResultsAmong 2513 participants (61% female, mean [SD] age 11.72 [0.21] years), ST steadily increased from ~6 h/day in childhood (age 11 years) to ~9 h/day in young adulthood (age 24 years), whereas LPA and MVPA decreased, but BP had an inverted U‐shaped increase. In the longitudinal analysis, after full adjustment, a 1‐min cumulative ST from ages 11 to 24 years was positively associated with increased systolic BP (0.009 mmHg [95% CI 0.007–0.011]; p < 0.001) and diastolic BP. A 1‐min cumulative LPA was inversely associated with systolic BP (−0.007 mmHg [−0.009 to −0.004]; p < 0.001), but not diastolic BP. In isotemporal substitution analyses, longitudinal replacement of 10 min of ST with equal time in LPA during childhood, adolescence and young adulthood cumulatively decreased systolic BP by −2.63 mmHg [95% CI −3.17 to −2.08] (p < 0.0001) and diastolic BP by −1.93 mmHg [95% CI −2.36 to −1.50] (p < 0.0001). Replacing 10 min of ST with 10 min of MVPA had no statistically significant effect due to an absolute confounding effect of lean mass. The association of ST with systolic BP was fully mediated by increased lean mass (93% mediation). Increased total fat mass partially mediated (19%–27%) the inverse associations of cumulative MVPA with cumulative systolic and diastolic BP.ConclusionsTheoretically replacing 10 min/day spent sedentary with 10 min/day of LPA during growth from childhood through young adulthood may lower systolic BP by −3 mmHg and diastolic BP by −2 mmHg. Lean mass seems more significant than fat mass in the relations of ST and PA with BP and should be accounted for in future intervention studies in the paediatric and young adult population.

中文翻译：

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瘦体重纵向混淆了 2513 名儿童的久坐时间和身体活动与血压进展


背景随机对照试验报告称，中度至剧烈体力活动 （MVPA） 对降低青少年血压 （BP） 没有影响，可能是由于试验持续时间短。本研究检查了久坐时间 （ST） 、轻 PA （LPA） 和 MVPA 对 11 岁儿童血压的纵向影响，随访 13 年，以确定身体成分的混杂和中介作用。方法数据包括来自英国出生队列 Avon Enditudinal Study of Parents and Children （ALSPAC） 的 2513 名儿童，他们在 11 、 15 岁和 24 岁的随访和完整血压测量中至少有一项基于加速度计的运动行为的时间点测量数据。在所有时间点使用双能 X 射线吸收测定法评估体成分。进行了多变量调整的广义线性混合效应模型和结构方程因果中介模型分析。结果在 2513 名参与者 （61% 为女性，平均 [SD] 年龄 11.72 [0.21] 岁） 中，ST 从儿童期 （11 岁） 的 ~6 小时/天稳步增加到成年早期 （24 岁） 的 ~9 小时/天，而 LPA 和 MVPA 降低，但血压呈倒 U 形升高。在纵向分析中，完全调整后，11 至 24 岁 1 分钟累积 ST 与收缩压升高 （0.009 mmHg [95% CI 0.007–0.011];p < 0.001） 和舒张压呈正相关。1 min 累积 LPA 与收缩压 （-0.007 mmHg [-0.009 至 -0.004];p < 0.001） 呈负相关，但与舒张压无关。在等时间替代分析中，在儿童期、青春期和青年期以相同的时间纵向替代 10 分钟的 ST 和 LPA 使收缩压累计降低 -2.63 mmHg [95% CI -3.17 至 -2.08] （p < 0.0001） 和舒张压降低 -1。93 mmHg [95% CI -2.36 至 -1.50] （p < 0.0001）。由于 Lean Mass 的绝对混杂效应，用 10 min 的 MVPA 代替 10 min 的 ST 没有统计学意义的影响。ST 与收缩压的关联完全由瘦体重增加 （93% 介导） 介导。总脂肪量增加部分介导 （19%-27%） 累积 MVPA 与累积收缩压和舒张压的负相关。结论从理论上讲，从儿童期到成年早期的生长过程中，用 10 分钟/天的 LPA 代替久坐 10 分钟/天可能会使收缩压降低 -3 mmHg，舒张压降低 -2 mmHg。在 ST 和 PA 与 BP 的关系中，瘦体重似乎比脂肪量更重要，应在未来对儿科和年轻人群的干预研究中加以考虑。