• subjective memory impairment;
  • cognitive impairment;
  • social activity

OBJECTIVES: To investigate the association between subjective memory deficit (SMD) and cognitive impairment in a community population and modification of this association by level of social activity.

DESIGN: Cross-sectional survey.

SETTING: A defined geographic catchment area in north London, England.

PARTICIPANTS: Six hundred fifty-four residents aged 65 and older.

MEASURMENTS: SMD and cognitive impairment were derived from the relevant sections of the short Comprehensive Assessment and Referral Evaluation instrument, and social activity was derived from the Social Support Deficit Scale. Potential confounding factors taken into account included depression and level of functioning.

RESULTS: Twenty-nine percent of the sample reported SMD, which was associated with objective impairment (odds ratio (OR)=3.4, 95% confidence interval (CI)=2.1–5.8). This association was stronger in participants with higher social activity (OR=6.1, 95% CI=2.9–13.0) than in those who were more isolated (OR=1.8, 95% CI=0.8–3.8). The interaction with social activity remained significant after adjustment for potential confounding factors (P=.03).

CONCLUSION: A person's social environment influences the accuracy of SMD. This may reflect the level of cognitive demands encountered in daily life or the extent to which others notice cognitive impairment.