Social relationships have a powerful effect on physical activity. However, it is unclear how physical activity patterns are associated with perceived social isolation. A cohort study was performed on 1,162 community-dwelling older adults. In cross-sectional analyses, social isolation was screened using the Lubben Social Network Scale (LSNS-6). Physical activity was measured by an accelerometer (activPAL). Participants kept a contemporary physical activity diary to report outdoor physical activity timeframes. Low levels of physical activity were associated with perceived social isolation. Low indoor physical activity was associated with being socially isolated from family and low outdoor physical activity was associated with being socially isolated from friends and neighbors (−4.5 minutes; p = .012). These findings suggest the need for a more nuanced assessment of nonkin networks and a differentiated analysis of the locations in which physical activity is done in order to understand how social isolation affects everyday physical activity.
Florian Herbolsheimer, Stephanie Mosler, Richard Peter and the ActiFE Ulm Study Group
A. Stefanie Mikolaizak, Jochen Klenk, Dietrich Rothenbacher, Michael D. Denkinger, Kilian Rapp and for the ActiFE Study Group
Time spent out-of-home can increase physical activity (PA) levels. However, the association between the purpose for leaving home and the mode of transport on time out-of-home and PA are not straightforward. In a large sample of community-dwelling older adults (≥65 years), daily walking duration was measured prospectively over 1 week using body-fixed sensors and time-out-of-home questionnaires. Data from 1,277 participants yielded 6,500 full days for analysis. The following statistically significant associations were seen: public transport use increased the time spent out-of-home by 88 min and daily walking duration by 16 min. Social contacts or the use of a car increased the time out-of-home, but decreased PA. Shopping or “going by foot” decreased the time spent out-of-home by 19 and 62 min, respectively, while both increased the daily walking duration by 5 min. The association between time out-of-home and PA (daily walking duration) is strongly dependent on the activity and mode of transport.
Dietrich Rothenbacher, Dhayana Dallmeier, Michael D. Denkinger, Bernhard O. Boehm, Wolfgang Koenig, Jochen Klenk and ActiFE Study Group
Besides its known function as a transport protein for testosterone and other steroid hormones, sex hormone–binding globulin (SHBG) is a biomarker associated with many adverse health effects. The aim of this study was to investigate the association of physical activity with SHBG serum levels in older adults. The physical activity and SHBG values for 1,259 older adults (43.4% female; 56.6% male) with a mean age of 75.6 ± 6.5 years were included in the analysis. The average daily walking duration was 104.2 ± 40.4 (mean ± SD) min. A positive dose–response relationship of daily walking duration with quartiles of SHBG was seen after adjustment for age, sex, history of cardiovascular diseases, diabetes, smoking, γ-glutamyl transferase, and C-reactive protein (p for trend = .010). However, this relationship disappeared after adjustment for body mass index (p for trend = .977). Body mass index seems to be an important determinant of SHBG and a possible confounding factor in the relationship of physical activity and SHBG.