The main objective of this study was to investigate reading habits in older adults in relation to level and 15-year changes in verbal fluency and episodic recall. We examined a sample of 1157 participants (55 years at baseline) up to 15 years after the baseline assessment using latent growth curve modeling of cognitive measures with baseline reading frequency (books, weekly magazines) as a predictor of cognitive level (intercept) and rate of change (slope). Subgroup analyses were performed to investigate the role of an early adult g factor in the association between reading habits and cognitive ability in midlife. Frequent reading of books, but not of magazines, was associated with higher levels of verbal fluency and recall but unrelated to rate of longitudinal decline. Subgroup analyses indicated that the g factor in early adulthood predicted reading and cognitive level in midlife and this factor removed the current association between reading habits and level of cognitive ability (both cognitive factors). The results indicate an enduring relationship between book reading and level of cognitive ability across the adult life span and provide little support of the hypothesis that frequent reading protects against latelife cognitive decline. The extent to which book reading promotes cognitive functioning in childhood/youth remains to be demonstrated. Intervention studies may be useful in this regard.

The objective of the present study was to examine relations between social network size and three cognitive abilities (episodic memory, semantic memory, visuospatial ability) in middle-aged adults. We analyzed cross-sectional data on social network size and cognitive functioning that were available for 804 participants aged 40–60 years. In addition, we examined 5- and 10-year follow-up measurements of cognitive functioning that were available for 604 and 255 participants, respectively. Cross-sectional analyses revealed a positive association between social network size and each of the three cognitive abilities. Baseline network size was positively related to 5-year changes in semantic memory, and to 10-year changes in semantic as well as episodic memory, but was unrelated to changes in visuospatial performance. A minor portion of the sample (n = 131) had 10-year follow-up data on network size. Cross-lagged panel correlations revealed that baseline network size was associated with follow-up measurement in cognitive functioning (episodic memory, semantic memory), whereas baseline cognitive performance was unrelated to future network size. Together, the results demonstrate a small but positive relation between network size and declarative memory abilities, in line with models proposing a cognitive reserve built up by factors such as the increased cognitive stimulation associated with a more extensive social network.

The aim of this study was to examine the relationship between social network variables and levels of and longitudinal changes in blood pressure in a middle-aged/older sample. The participants (50-75 years at baseline; n=1097) responded to questions concerning social relationships at baseline and their blood pressure (diastolic, systolic) was measured. Blood pressure levels were reassessed 5, 10, and 15 years later. Latent growth models with responses to questions concerning social relationships as predictors and basic demographic factors (age, sex) as covariates, unexpectedly indicated that a more limited social network (no close friend, few visits, little contact with friends in other ways, not living with someone, and a composite index based on all questions) was associated with significantly lower diastolic blood pressure levels. For systolic blood pressure a similar result was observed for one of the variables (lack of a close friend). In general, these effects diminished over time, as indexed by the positive relationship between several of the social variables and slope. The results were little affected by inclusion of additional covariates (e.g. measures of psychological distress, smoking/alcohol habits, and BMI) suggesting that the origins of this unexpected pattern of findings must probably be sought for in other subjectrelated factors, such as, for example, increased help seeking. Future studies should consider qualitative aspects (e.g. feelings of loneliness, quality of social relationships) in addition to structural aspects to provide a better understanding of these associations.

Background: The objective was to examine whether aspects of social relationships in old age are associated with all-cause dementia and Alzheimer's disease (AD).

Methods: We studied 1,715 older adults (≥ 65 years) who were dementia-free at baseline over a period of up to 16 years. Data on living status, contact/visit frequency, satisfaction with contact frequency, and having/not having a close friend were analyzed using Cox proportional hazards regressions with all-cause dementia or AD as the dependent variable. To control for reverse causality and to identify potential long-term effects, we additionally performed analyses with delayed entry.

Results: We identified 373 incident cases of dementia (207 with AD) during follow-up. The variable visiting/visits from friends was associated with reduced risk of all-cause dementia. Further, a higher value on the relationships index (sum of all variables) was associated with reduced risk of all-cause dementia and AD. However, in analyses with delayed entry, restricted to participants with a survival time of three years or more, none of the social relationship variables was associated with all-cause dementia or AD.

Conclusions: The results indicate that certain aspects of social relationships are associated with incident dementia or AD, but also that these associations may reflect reverse causality. Future studies aimed at identifying other factors of a person's social life that may have the potential to postpone dementia should consider the effects of reverse causality.

Det sägs ibland att aktivteter som stimulerar hjärnan förbättrar minnet. En rad studier indikerar också att olika typer av livsstilsfaktorer hänger samman med prestation i kognitiva test. De visar att dålig minnesförmåga är överrepresenterad hos dem som inte ägnar sig åt fritidsaktiviteter såsom att läsa, idrotta och lägga pussel.