Cited by 71Advanced Statistical Methods and ModelsPhysical Activity and HealthStatistical Methods and Applications

Quantifying the lifetime circadian rhythm of physical activity: a covariate-dependent functional approach

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Xiao, L., Huang, L., Schrack, J. A., Ferrucci, L., Zipunnikov, V., Crainiceanu, C. M.·2015·Biostatistics

Abstract

Objective measurement of physical activity using wearable devices such as accelerometers may provide tantalizing new insights into the association between activity and health outcomes. Accelerometers can record quasi-continuous activity information for many days and for hundreds of individuals. For example, in the Baltimore Longitudinal Study on Aging physical activity was recorded every minute for [Formula: see text] adults for an average of [Formula: see text] days per adult. An important scientific problem is to separate and quantify the systematic and random circadian patterns of physical activity as functions of time of day, age, and gender. To capture the systematic circadian pattern, we introduce a practical bivariate smoother and two crucial innovations: (i) estimating the smoothing parameter using leave-one-subject-out cross validation to account for within-subject correlation and (ii) introducing fast computational techniques that overcome problems both with the size of the data and with the cross-validation approach to smoothing. The age-dependent random patterns are analyzed by a new functional principal component analysis that incorporates both covariate dependence and multilevel structure. For the analysis, we propose a practical and very fast trivariate spline smoother to estimate covariate-dependent covariances and their spectra. Results reveal several interesting, previously unknown, circadian patterns associated with human aging and gender.

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Authors
Xiao, L., Huang, L., Schrack, J. A., Ferrucci, L., Zipunnikov, V., & Crainiceanu, C. M.
Affiliations
  • Johns Hopkins University (US)
  • National Institutes of Health (US)
Corresponding author
Xiao, L.
Venue
Biostatistics
Published
2014-10-30
Volume
16
Issue
2
Pages
352-367
ISSN
  • 1465-4644 (ISSN-L)
  • 1468-4357
OpenAlex
W2171991316
Cited by
71
References
39
Citations by year
2026: 3 · 2025: 6 · 2024: 3 · 2023: 7 · 2022: 6 · 2021: 8 · 2020: 8 · 2019: 6 · 2018: 3 · 2017: 12 · 2016: 7 · 2015: 2
FWCI
7.40
Type
journal article
Language
en
Open access
Locations
  • Biostatistics (publishedVersion)
  • Europe PMC (PubMed Central) (publishedVersion)
  • PubMed Central (publishedVersion)
  • PubMed (publishedVersion)
Funders
National Institute of Neurological Disorders and Stroke (R01NS060910)
Topics
  • Physical Sciences › Mathematics › Statistics and Probability › Advanced Statistical Methods and Models
  • Health Sciences › Medicine › Physiology › Physical Activity and Health
  • Physical Sciences › Mathematics › Statistics and Probability › Statistical Methods and Applications
Keywords
circadian rhythm, physical activity, accelerometry, wearable devices, functional principal component analysis, leave-one-subject-out cross-validation, smoothing parameter estimation, within-subject correlation, multilevel structure, aging, gender differences, time-of-day patterns
MeSH terms
Adult, Aged, Aged, 80 and over, Aging, Circadian Rhythm, Female, Humans, Male, Middle Aged, Motor Activity, Sex Factors, Principal Component Analysis, Accelerometry

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