Rationale
Moderate- to vigorous-intensity physical activity is important for older adults to achieve current physical activity recommendations. Moderate- to vigorous-intensity physical activity is more validly assessed using accelerometers than questionnaires. However, the most commonly-used accelerometer moderate- to vigorous-intensity physical activity cut-point (Freedson et al.’s: ≥1952 counts∙min-1 [2]) is inappropriate for use in Chinese older adults. Additionally, emerging evidence suggests that sedentary behaviour is also a risk factor for health, yet it is unclear whether physical activity and sedentary behaviour are independent behaviours. Thus, identifying correlates of these behaviours is important for public health. Socio-ecological models posit that neighbourhood built environmental attributes may influence these behaviours. Aims
(#1) Develop a moderate- to vigorous-intensity physical activity accelerometer cut-point specific to Chinese older adults;
(#2) Examine associations of neighbourhood attributes with accelerometer-assessed moderate- to vigorous-intensity physical activity (using the new vs. Freedson et al.’s cut-point [2]) and sedentary time and their socio-demographic/health moderators;
(#3) Investigate whether moderate- to vigorous-intensity physical activity mediates associations between sedentary time and neighbourhood attributes. Results
(Aim #1) New moderate- to vigorous-intensity physical activity accelerometer cut-point: ≥1184 counts.min-1.
(Aim #2) Moderate- to vigorous-intensity physical activity was positively associated with land-use mix, bridge/overpass connection access, and social disorder/littering and negatively associated with residential density. Generally, moderate- to vigorous-intensity physical activity defined using our new cut-point had stronger associations with neighbourhood attributes than moderate- to vigorous-intensity physical activity based on Freedson’s cut-point. Age (land-use mix) and the number of diagnosed medical conditions (aesthetics) moderated associations. Sedentary time was negatively associated with street connectivity, bridge/overpass connection access, and social disorder/littering and positively associated with presence of people in the streets. The number of diagnosed medical conditions moderated the effects of crowdedness and fences separating footpaths from traffic.
(Aim #3) Moderate- to vigorous-intensity physical activity fully-mediated associations of sedentary time with bridge/overpass connection access and social disorder/littering. Conclusions
(Aim #1) New ≥1184 counts.min-1 moderate- to vigorous-intensity physical activity accelerometer cut-point was more appropriate than Freedson cut-point.
(Aim #2) Not-overly-dense neighbourhoods with higher land-use mix, bridge/overpass connection access, and social disorder/littering were associated with moderate- to vigorous-intensity physical activity. These latter two neighbourhood attributes were also associated with sedentary time and explained by moderate- to vigorous-intensity physical activity (Aim #3). Finally, some demographic sub-groups have a different relationship between neighbourhood attributes and moderate- to vigorous-intensity physical activity/sedentary time. |