Objectives: Previous studies have shown that individuals with poor social relationships have an increased risk for dementia. Dementia risk, however, can also be positively influenced by lifestyle factors. One such very important factor is high mental demands at work, in particular as the work environment affects a very long lifetime period. Thus, our objective was to investigate whether the cognitive functioning of socially isolated individuals may profit from high mental work demands.
Methods: Analyses were based on n = 10,000 participants (aged 40 – 80 years) of the population-based German LIFE-Adult-Study. All participants underwent medical examinations and filled out standardized questionnaires. Cognitive functioning was assessed via the Verbal Fluency Test (VFT) and the Trail-Making Test (TMT). Social relationships were assessed via the Lubben Social Network Scale (LSNS-6). The interaction between social isolation and mental demands on cognitive functioning was analyzed via multivariate regression analyses.
Results: The difference in cognitive functioning between high and low mental work demand conditions was larger in socially isolated individuals (VFT: 2.7 words, TMT-B: 26 seconds) compared to socially well integrated individuals (VFT: 2.1 words, TMT-B: 9 seconds). Multivariate regression analyses – adjusted for age, gender, and education – indicated that both mental work demands as well as social relationships are significantly associated with the level of cognitive functioning (p < 0.001). Results also suggest interaction effects indicating a stronger impact of mental work demands on cognitive functioning in socially isolated individuals than in well integrated individuals.
Conclusion: The findings imply that individuals with poor social relationships may particularly benefit from high mental work demands regarding their risk for dementia. The level of mental demands at work could therefore be an important target for tailored preventative approaches.
