RT Journal
A1 Buchman AS, Boyle PA, Wilson RS, Fleischman DA, Leurgans SE, Bennett DA
T1 LAte-life social activity—reply
JF Archives of Internal Medicine
JO Archives of Internal Medicine
YR 2009
FD November 9
VO 169
IS 20
SP 1932
OP 1932
DO 10.1001/archinternmed.2009.409
UL http://dx.doi.org/10.1001/archinternmed.2009.409
AB 
We thank Verkleij et al for their comments regarding our recent article.1 We agree that the social activity measure used in our study includes components of physical and cognitive activities. It is for this reason that in our analyses we carefully controlled for physical and cognitive activities, in addition to many other potential confounding variables such as disability, cognitive function, depressive symptoms, body mass index, and chronic medical conditions.1 The association of social activity with motor decline remained robust even after controlling for these covariates, supporting the hypothesis that social engagement may make a unique and independent contribution to the maintenance of motor abilities above and beyond physical and cognitive activities. Notably, however, causal inferences must be drawn with caution in all observational cohort studies. Moreover, we agree that the ongoing trial of the Experience Corps will not settle this issue because the volunteer program is heterogeneous and includes factors that extend beyond social engagement. However, early results suggest that the program may benefit motor abilities, and we are unaware of any other ongoing intervention trials that include social engagement with motor function as an outcome.2