Life-course exposure to green space and its association with physical functioning in older adults

Abstract Background Evidence suggests that green space can contribute to a slower decline in physical functioning at older age. In addition to exposure in later life, green space in early life may have a long-lasting and beneficial effect on physical functioning, although this remained under-explored. This study applies a life-course approach to investigate how green space exposure is associated with physical functioning in older age. Methods Participants (n = 341, 174 males) from the Lothian Birth Cohort, born in 1936, provided lifetime residential history in 2014. Questionnaire based residential history was linked to green spaces during childhood (1940 and 1950), young adulthood (1960 and 1970) and mid-to-late adulthood (1980, 1990, 2000 and 2010). Physical function was assessed by grip strength, 6-m walking time and forced expiratory volume (FEV) in 1 second, measured at five data collection points when the participants were between 70 and 82 years old. We used a structured life-course modelling approach and least angle regression to identify the best fitting life-course models (accumulation, sensitive periods or changes) for green space exposure. All the models were adjusted for relevant covariates. Results Preliminary results showed that for physical function during the first data collection, the best fitting life-course model for grip strength was the sensitive period in mid- to late adulthood (R2=0.004). For FEV and 6-metre walking time, the best fitting life-course model was the childhood sensitive period (R2=0.004 and R2=0.007, respectively). Further analysis will explore the best fitting life-course models for changes in physical function, based on modelling the standardised residuals. Conclusions Amount of green space in residential areas across the life course might play a role in physical function in older age. However, the small magnitude of the observed effects indicates that further analyses are needed to better understand the relationship. Key messages • Exposure to green space over the full life course may be important in understanding physical functioning in older age. • Childhood and mid- to late adulthood appear to be the most important sensitive periods for green space exposure in terms of physical functioning.