Warning: This is an author submission that is not peer-reviewed or edited. Preprints - unless they show as "accepted" - should not be relied on to guide clinical practice or health-related behavior and should not be reported in news media as established information.
Relations between body mass index trajectories and habitual physical activity measured by smartwatch: Insights from the electronic cohort of the Framingham Heart Study
ABSTRACT
Background:
The prevalence of obesity is rising. Most previous studies that examined the relations between body mass index (BMI) and physical activity (PA) measured BMI at a single time-point. The association between BMI trajectories and habitual PA remains unclear.
Objective:
We assessed the relations between BMI trajectories and habitual PA, among participants enrolled in the electronic Framingham Heart Study (eFHS).
Methods:
We used a semiparametric group-based modelling to identify BMI trajectories from eFHS participants who attended research examinations 1, 2, and 3 over a 14-year period. Daily steps were recorded from the smartwatch provided at examination 3. We excluded participants with <30 days or <5 hours of smartwatch wear data. We used generalized linear models to examine the association between BMI trajectories and daily step counts.
Results:
We identified three trajectory groups for the 837 eFHS participants (mean age: 53 years; 58% Female). Group 1 included 292 participants whose BMI was stable (slope: 0.005, P=.75); Group 2 included 468 participants whose BMI increased slightly (slope: 0.123, P<.001); and Group 3 included 77 participants whose BMI increased greatly (slope: 0.318, P<.001). The median follow-up period for step count was 357 days. Adjusting for age, sex, wear time, and cohort, participants in Group 2 and Group 3 took 422 steps (95% CI: -823, -21) and 1437 (95% CI: -2084, -790) fewer average daily steps, compared to participants in Group 1. After adjusting for metabolic and social risk factors, Group 2 took 382 (95% CI: -773, 10) and Group 3 took 1120 (95% CI: -1766, -475) fewer steps, compared to Group 1.
Conclusions:
In this community-based eFHS, participants whose BMI trajectory increased greatly over time took significantly fewer steps, compared to participants with stable BMI trajectories. Our findings suggest that greater weight gain may correlate with lower levels of physical activity.
Citation
Request queued. Please wait while the file is being generated. It may take some time.
Copyright
© The authors. All rights reserved. This is a privileged document currently under peer-review/community review (or an accepted/rejected manuscript). Authors have provided JMIR Publications with an exclusive license to publish this preprint on it's website for review and ahead-of-print citation purposes only. While the final peer-reviewed paper may be licensed under a cc-by license on publication, at this stage authors and publisher expressively prohibit redistribution of this draft paper other than for review purposes.