Differential effects of enriched environment at work on cognitive decline in old age.

Obesity or excess bodyweight results from an imbalance in energy expenditure and food intake which is controlled by different neural circuits such as the hypothalamus and the reward network1. Central structures of the dopamine-dependent reward network are the nucleus accumbens, the orbitofrontal cortex (OFC), the putamen and the caudate nucleus2. Recently, it has been shown that obesity is associated with reduced structural connectivity of this network3 but it remains unclear whether reduced structural connectivity relates to differences in eating behavior. Goals: In this study, we aim to replicate and extend previous results on structural connectivity differences in obesity and investigate potential associations with eating behavior. Research questions: Is obesity (defined as body mass index (BMI) > 30 kg/m2) associated with white matter structural connectivity of the reward network in healthy adults and are obesity-related structural differences linked to self-reported eating behavior?

OBJECTIVES: The aim of the present study was to investigate how different mentally demanding work conditions during the professional life-i.e., enriched environments at work-might influence the rate of cognitive decline in old age. METHODS: Individuals (n = 1,054) of the Leipzig Longitudinal Study of the Aged, a representative population-based cohort study of individuals aged 75 years and older, underwent cognitive testing via the Mini-Mental State Examination (MMSE) in up to 6 measurement waves. Type and level of mentally demanding work conditions in the participants' former professional life were classified based on the O*NET job descriptor database. RESULTS: In multivariate mixed-model analyses (controlling for sociodemographic and health-related factors), a high level of mentally demanding work tasks stimulating verbal intelligence was significantly associated with a better cognitive functioning at baseline (on average 5 MMSE points higher) as well as a lower rate of cognitive decline (on average 2 MMSE points less) over the 8-year follow-up period compared with a low level. The rate of cognitive decline in old age was also significantly lower (on average 3 MMSE points less) in individuals who had a high level of mentally demanding work tasks stimulating executive functions than those who had a low level. CONCLUSIONS: The results suggest that a professional life enriched with work tasks stimulating verbal intelligence and executive functions may help to sustain a good cognitive functioning in old age (75+ years). The findings thus emphasize that today's challenging work conditions may also promote positive health effects.