Introduction

Active travel (walking and cycling) is increasingly being recognised as a potentially effective means of increasing physical activity levels and thereby contribute to physical and mental health. To date, however, much of the empirical evidence related to the health benefits of active travel is based on cross-sectional data. As such, the direction of causation remains uncertain, i.e. does active travel lead to improved health or vice-versa, are healthier individuals more inclined to participate in active travel? This study aims to systematically assess the bidirectional relationships between active travel, on the one hand, and two relevant health outcomes on the other, namely body-mass index (BMI) and mental health.

Method

To this end, random-intercept cross-lagged panel models are estimated using data from 10 waves (years) of the Longitudinal Internet Studies for the Social sciences panel, a panel that is representative for the Dutch population. Active travel was assessed using a measure of walking frequency and mental health was measured using the 5-item mental health inventory (MHI-5).

Results

The results indicate that active travel does not affect later BMI levels, but, vice versa, BMI does negatively influence later levels of active travel, a pattern that is in line with earlier research related to general physical activity and BMI. Regarding mental health, the pattern is exactly opposite. In this case, the effect of active travel on mental health is significant, while the reverse effect is not (at the 5% level of statistical significance).

Conclusion

Overall, the results underline the notion that cross-sectional estimates of the effects between active travel and health outcomes should be interpreted with care, as they can be the result of effects in either direction. In addition, the results suggest that the uptake of active travel may be increased by decreasing BMI levels in the population, e.g. via dietary programs.

中文翻译：

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积极的旅行会使人们更健康，还是健康的人们更倾向于主动旅行？

介绍

越来越多的人认为主动旅行（散步和骑自行车）是增加身体活动水平的潜在有效手段，因此有助于身心健康。然而，迄今为止，与主动旅行对健康的益处有关的许多经验证据均基于横截面数据。这样，因果关系的方向仍然不确定，即，积极旅行是否会改善健康状况，反之亦然，更健康的个人是否更愿意参加积极旅行？这项研究旨在一方面系统地评估主动出行与另一方面与两个相关健康结局之间的双向关系，即身体质量指数（BMI）和心理健康。

方法

为此，使用来自社会科学纵向互联网研究小组（代表荷兰人口的小组）的10个波（年）的数据来估计随机拦截的交叉滞后面板模型。使用步行频率来评估主动出行，并使用5个项目的心理健康清单（MHI-5）来衡量心理健康。

结果

结果表明，主动出行不会影响以后的BMI水平，反之亦然，BMI会对以后的主动出行水平产生负面影响，这一模式与早期有关一般身体活动和BMI的研究相一致。关于心理健康，情况恰恰相反。在这种情况下，积极旅行对心理健康的影响是显着的，而相反的影响却不明显（统计显着性水平为5％）。

结论

总的来说，这些结果强调了这样一种观念，即应该谨慎地解释主动旅行和健康结果之间影响的横截面估计，因为它们可能是任一方向的影响的结果。另外，结果表明，通过降低人群中的BMI水平，例如通过饮食计划，可以增加主动旅行的摄取。