A1 Journal article (refereed)
Associations of physical activity intensities, impact intensities and osteogenic index with proximal femur bone traits among sedentary older adults (2021)

Savikangas, Tiina; Sipilä, Sarianna; Rantalainen, Timo (2021). Associations of physical activity intensities, impact intensities and osteogenic index with proximal femur bone traits among sedentary older adults. Bone, 143, 115704. DOI: 10.1016/j.bone.2020.115704

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Publication details

All authors or editors: Savikangas, Tiina; Sipilä, Sarianna; Rantalainen, Timo

Journal or series: Bone

ISSN: 8756-3282

eISSN: 1873-2763

Publication year: 2021

Volume: 143

Article number: 115704

Publisher: Elsevier

Publication country: United States

Publication language: English

DOI: https://doi.org/10.1016/j.bone.2020.115704

Open Access: Publication channel is not openly available

Publication is parallel published (JYX): https://jyx.jyu.fi/handle/123456789/72478


Dynamic high-intensity physical activity is thought to be beneficial for older adults’ bone health. Traditional volume-based processing of accelerometer-measured physical activity data, quantified on a minute-per-minute basis, may average out sporadic high impact activity, whereas accelerometer data processing approaches based on identifying impacts can capture also these potentially beneficial short activity bursts. We investigated the associations between habitual physical activity and proximal femur bone traits among sedentary older adults utilizing three different numerical treatments of accelerometer-data to examine, if impact-based processing approaches are more suitable to assess bone loading than volume-based processing of physical activity data among older adults.

This cross-sectional study utilized the baseline data from the PASSWORD-study (n=284, mean ± SD age 74 ± 4 years, 57 % women). Total femur bone mineral content (BMC) and bone mineral density (BMD), femoral neck BMC, BMD, section modulus and minimal width (MNW) were measured with dual energy x-ray absorptiometry. Physical activity was measured for seven consecutive days with a tri-axial accelerometer. Raw acceleration data was processed in three different ways and quantified as i) mean daily minutes in sedentary, light and moderate-to-vigorous-intensity activity, ii) mean daily number of acceleration peaks divided into low (1.5 g to 2.0 g), medium (2.0 g to 2.5 g) and high (> 2.5 g) impacts, and iii) mean daily osteogenic index, which is a summary score calculated from log-transformed number of impact peaks in 32 intensity bands (≥ 1.3 g). Associations between physical activity measures and each bone trait were estimated with multiple linear regression adjusted with covariates (age, sex, weight, height, smoking, physical function, medication).
Participants recorded on average 10 h sedentary, 2.5 hrs light and 32 min moderate-to-vigorous activity, and 3937 low, 494 medium and 157 high impacts per day. Mean osteogenic index score was 173. Light physical activity was positively associated with all bone traits (beta = 0.147 to 0.182, p<0.001 to p=0.005) except MNW. Sedentary or moderate-to-vigorous activity, low, medium or high impacts or osteogenic index were not associated with any bone parameter.
Light physical activity may decelerate the age-related bone loss in older adults who do not meet the physical activity recommendations. In this population, the amount of high impact activity may be insufficient to stimulate bone remodelling.

Keywords: physical activeness; sitting; senior citizens; minerals; skeletal system; bone density; acceleration

Free keywords: accelerometer; physical activity; sedentary; older adults; bone mineral content; bone mineral density

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Last updated on 2020-04-11 at 11:07