Associations between tri-axial accelerometer-determined physical activity and self-reported health-related quality of Life of older Malay adults using cut-points for vector magnitude

Abstract

There are few data on the association between health-related quality of life (HRQoL) and objectively-measured physical activity (PA) in non-Westernised populations, especially the older population. Furthermore, in light of recent accelerometer models introduced in the market which assess acceleration along three axes, we theorised that a population study using cut-points based on composite vector magnitude (VM) is needed. Therefore, the aim of this study was to determine the associations between tri-axial accelerometer-determined PA and HRQoL in community-dwelling older Malay adults, using cut-points for VM. Method: The study design was cross-sectional, involving 146 community-dwelling older Malay adults aged 60 to 85 years old (59 men, 87 women) living in Seberang Perai Utara, Penang, Malaysia. PA data was collected using tri-axial accelerometers (Actigraph GT3X or GT3X+) worn around the hip during waking hours for 7 days. Intensities were categorised using cut-points for VM. HRQoL was measured using the Short Form 36-item Health Survey (SF-36®) and scored using the norm-based scoring system. Analyses included sex differences in PA variables and HRQoL and correlation (Spearman’s rho) between PA and HRQoL. Results: Significant positive association was found between moderate PA and bodily pain, but only for men (rho=0.263, p<0.05). Men scored higher in all eight domains of SF-36®, but significantly higher in norm-based physical functioning (p<0.05) and vitality (p<0.05), compared to women. When scored using 0-100 scales, it was found that men scored significantly higher on four domains of SF-36® compared to women: PF (p<0.05), BP (p<0.001), VIT (p<0.05), and MH (p<0.05). There were no sex differences found in overall activity counts. Conclusion: In this sample population, tri-axial accelerometer-determined PA has minimal association to the domains of health, and men are likely to have better self-perceived health compared to women.