INTRODUCTION:

Research indicate that cognitive impairment might be related to hospitalization, but little is known about these effects over time.

OBJECTIVE:

To assess cognitive change before and after hospitalization among older adults in a population-based longitudinal study with up to 25 years of follow-up.

METHOD:

A longitudinal study on 828 community living men and women aged 50-86 from the Swedish Adoption/Twin Study of Ageing (SATSA) were linked to The Swedish National Inpatient Register. Up to 8 assessments of cognitive performance (general cognitive ability, verbal, spatial/fluid, memory, and processing speed) from 1986 to 2010 were available. Latent growth curve modelling was used to assess the association between cognitive performance and hospitalization including spline models to analyse cognitive trajectories pre- and post-hospitalization.

RESULTS:

A total of 735 persons (89%) had at least one hospital admission during the follow-up. Mean age at first hospitalization was 70.2 (±9.3)years. Persons who were hospitalized exhibited a lower mean level of cognitive performance in general ability, processing speed and spatial/fluid ability compared with those who were not hospitalized. The two-slope models revealed steeper cognitive decline before hospitalization than after among those with at least one hospitalization event, as compared to non-hospitalized persons who showed steeper cognitive decline after the centering age of 70 years.

CONCLUSIONS:

Persons being hospitalized in late life have lower cognitive performance across all assessed domains. The results indicate that the main decline occurs before the hospitalization, and not after. This might indicate that when you get treatment you also benefit cognitively.

BACKGROUND: Population-based health registers are potential assets in epidemiological research; however, the quality of case ascertainment is crucial.

OBJECTIVE: To compare the case ascertainment of dementia, from the National Patient Register (NPR) and the Cause of Death Register (CDR) with dementia diagnoses from six Swedish population based studies.

METHODS: Sensitivity, specificity, and positive predictive value (PPV) of dementia identification in NPR and CDR were estimated by individual record linkage with six Swedish population based studies (n = 19,035). Time to detection in NPR was estimated using data on dementia incidence from longitudinal studies with more than two decades of follow-up.

RESULTS: Barely half of the dementia cases were ever detected by NPR or CDR. Using data from longitudinal studies we estimated that a record with a dementia diagnosis appears in the NPR on average 5.5 years after first diagnosis. Although the ability of the registers to detect dementia cases was moderate, the ability to detect non-dementia cases was almost perfect (99%). When registers indicate that there is a dementia diagnosis, there are very few instances in which the clinicians determined the person was not demented. Indeed, PPVs were close to 90%. However, misclassification between dementia subtype diagnoses is quite common, especially in NPR.

CONCLUSIONS: Although the overall sensitivity is low, the specificity and the positive predictive value are very high. This suggests that hospital and death registers can be used to identify dementia cases in the community, but at the cost of missing a large proportion of the cases.

Background: While research has shown that sleep disorders are prevalent among people with dementia, the temporal relationship is unclear. We investigated whether atypical sleep characteristics were associated with incident dementia while accounting for baseline cognitive functioning.

Methods: Screening Across the Lifespan Twin Study (SALT) participants were 11,247 individuals from the Swedish Twin Registry who were at least 65 years at baseline (1998-2002). Sleep and baseline cognitive functioning were assessed via the SALT telephone screening interview. Data on dementia diagnoses came from national health registers. Cox regression was performed to estimate hazard ratios (HR) for dementia.

Results: After 17 years of follow-up, 1,850 dementia cases were identified. Short (≤ 6 hours) and extended (> 9 hours) time-in-bed (TIB) compared to the middle reference group (HR=1.40, 95% CI=1.06-1.85, HR=1.11, 95% CI=1.00-1.24, respectively) and rising at 8:00AM or later compared to earlier rising (HR=1.12, 95% CI=1.01-1.24) were associated with higher dementia incidence. Bedtime, sleep quality, restorative sleep, and heavy snoring were not significant predictors. Findings stratified by baseline cognitive status indicated that the association between short TIB and dementia remained in those cognitively intact at the start.

Conclusions: Short and extended TIB as well as delayed rising among older adults predicted increased dementia incidence in the following 17 years. The pattern of findings suggests that extended TIB and late rising represent prodromal features whereas short TIB appeared to be a risk factor for dementia.

In this report we analyzed genetically informative data to investigate within-person change and between-person differences in late-life cognitive abilities as a function of childhood social class. We used data from nine testing occasions spanning 28 y in the Swedish Adoption/Twin Study of Aging and parental social class based on the Swedish socioeconomic index. Cognitive ability included a general factor and the four domains of verbal, fluid, memory, and perceptual speed. Latent growth curve models of the longitudinal data tested whether level and change in cognitive performance differed as a function of childhood social class. Between-within twin-pair analyses were performed on twins reared apart to assess familial confounding. Childhood social class was significantly associated with mean-level cognitive performance at age 65 y, but not with rate of cognitive change. The association decreased in magnitude but remained significant after adjustments for level of education and the degree to which the rearing family was supportive toward education. A between-pair effect of childhood social class was significant in all cognitive domains, whereas within-pair estimates were attenuated, indicating genetic confounding. Thus, childhood social class is important for cognitive performance in adulthood on a population level, but the association is largely attributable to genetic influences.

Background: The comparison of traits in twins from opposite-sex (OS) and same-sex (SS) dizygotic twin pairs is considered a proxy measure of prenatal hormone exposure. To examine possible prenatal hormonal influences on anthropometric traits, we compared mean height, body mass index (BMI) and the prevalence of being overweight or obese between men and women from OS and SS dizygotic twin pairs.

Methods: The data were derived from COllaborative project of Development of Anthropometrical measures in Twins (CODATwins) database, and included 68,494 SS and 53,808 OS dizygotic twin individuals above the age of 20 years from 31 twin cohorts representing 19 countries. Zygosity was determined by questionnaires or DNA genotyping depending on the study. Multiple regression and logistic regression models adjusted for cohort, age and birth year with the twin type as a predictor were carried out to compare height and BMI in twins from OS pairs with those from SS pairs and to calculate the adjusted odds ratios and 95% confidence intervals for being overweight or obese.

Results: OS females were, on average, 0.31 cm (95% confidence interval (CI): 0.20, 0.41) taller than SS females. OS males were also, on average, taller than SS males, but this difference was only 0.14 cm (95% CI: 0.02, 0.27). Mean BMI and the prevalence of overweight or obesity did not differ between males and females from SS and OS twin pairs. The statistically significant differences between OS and SS twins for height were small and appeared to reflect our large sample size rather than meaningful differences of public health relevance.

Conclusions: We found no evidence to support the hypothesis that prenatal hormonal exposure or postnatal socialization (i.e., having grown up with a twin of the opposite sex) has a major impact on height and BMI in adulthood.

Whether monozygotic (MZ) and dizygotic (DZ) twins differ from each other in a variety of phenotypes is important for genetic twin modeling and for inferences made from twin studies in general. We analyzed whether there were differences in individual, maternal and paternal education between MZ and DZ twins in a large pooled dataset. Information was gathered on individual education for 218,362 adult twins from 27 twin cohorts (53% females; 39% MZ twins), and on maternal and paternal education for 147,315 and 143,056 twins respectively, from 28 twin cohorts (52% females; 38% MZ twins). Together, we had information on individual or parental education from 42 twin cohorts representing 19 countries. The original education classifications were transformed to education years and analyzed using linear regression models. Overall, MZ males had 0.26 (95% CI [0.21, 0.31]) years and MZ females 0.17 (95% CI [0.12, 0.21]) years longer education than DZ twins. The zygosity difference became smaller in more recent birth cohorts for both males and females. Parental education was somewhat longer for fathers of DZ twins in cohorts born in 1990-1999 (0.16 years, 95% CI [0.08, 0.25]) and 2000 or later (0.11 years, 95% CI [0.00, 0.22]), compared with fathers of MZ twins. The results show that the years of both individual and parental education are largely similar in MZ and DZ twins. We suggest that the socio-economic differences between MZ and DZ twins are so small that inferences based upon genetic modeling of twin data are not affected.

Introduction

Research indicates gender differences in functional performance at advanced ages, but little is known about their impact on longevity for men and women.

Objective

To derive a set of motor function factors from a battery of functional performance measures and examine their associations with mortality, incorporating possible gender interactions.

Method

Analyses were performed on the longitudinal Swedish Adoption/Twin Study of Aging (SATSA) including twenty-four assessments of motor function up to six times over a 19-year period. Three motor factors were derived from several factor analyses; fine motor, balance/upper strength, and flexibility. A latent growth curve model was used to capture longitudinal age changes in the motor factors and generated estimates of intercept at age 70 (I), rates of change before (S1) and after age 70 (S2) for each factor. Cox regression models were used to determine how gender in interaction with the motor factors was related to mortality.

Results

Females demonstrated lower functional performance in all motor functions relative to men. Cox regression survival analyses demonstrated that both balance/upper strength, and fine motor function were significantly related to mortality. Gender specific analyses revealed that this was true for women only. For men, none of the motor factors were related to mortality.

Conclusion

Women demonstrated more difficulties in all functioning facets, and only among women were motor functioning (balance/upper strength and fine motor function) associated with mortality. These results provide evidence for the importance of considering motor functioning, and foremost observed gender differences when planning for individualized treatment and rehabilitation.

Objectives The few studies of shift work and late life cognitive functioning have yielded mixed findings. The aim of the present study is to estimate the association between shift-work experience and change in cognitive performance before and after retirement age among older adults who were gainfully employed.

Methods Five hundred and ninety five participants with no dementia were followed up for a mean of 17.6 standard deviation (SD) 8.8 years from a Swedish population-based sample. Participants had self-reported information on any type of shift-work experience (ever/never) in 1984 and measures of cognitive performance (verbal, spatial, memory, processing speed, and general cognitive ability) from up to 9 waves of cognitive assessments during 1986–2012. Night work history (ever/never) from 1998–2002 was available from a subsample (N=320). Early adult cognitive test scores were available for 77 men.

Results In latent growth curve modeling, there were no main effects of "any-type" or night shift work on the mean scores or rate of change in any of the cognitive domains. An interaction effect between any-type shift work and education on cognitive performance at retirement was noted. Lower-educated shift workers performed better on cognitive tests than lower-educated day workers at retirement. Sensitivity analyses, however, indicated that the interactions appeared to be driven by selection effects. Lower-educated day workers demonstrated poorer cognitive ability in early adulthood than lower-educated shift workers, who may have selected jobs entailing higher cognitive demand.

Conclusion There was no difference in late-life cognitive aging between individuals with a history of working shifts compared to those who had typical day work schedules during midlife.

Background: Hospitalization among older people is common and associated with adverse outcomes. However, knowledge about long-term effects on motor functions and cognitive abilities in relation to hospitalization is scarce. In order to explore development of motor functions and cognition after hospitalization, a longitudinal study among middle-aged and older adults with up to 25 years of follow-up was conducted.

Methods: Overall, 828 participants from the Swedish Adoption/Twin Study of Ageing (SATSA) were linked to the Swedish National Inpatient Register, which contains information on participants’ hospital admissions. Up to 8 assessments of cognitive performance and 7 assessments of motor functions i.e. fine motor, balance/upper strength, and flexibility, from 1986 to 2010 were available. Latent growth curve modelling was used to assess the association between hospitalization and subsequent motor function and cognitive performance.

Results: A total of 735 (89 %) persons had at least one hospital admission during the follow-up. The mean age at first hospitalization was 70.2 (± 9.3) years. Persons who were hospitalized exhibited a lower mean level of cognitive performance in all domains and in motor functions compared with those who were not hospitalized. A significantly steeper decline was observed in motor function abilities as well as in processing speed, spatial/fluid, and general cognitive ability performance of hospitalized participants. These patterns remained even after comorbidities and dementia prevalence were controlled for.

Discussion: We are the first to show that hospitalization is associated with steeper decline in both motor function and cognitive abilities across more than two decades of post-hospitalization follow-up.

It is well known that malnutrition is common among older persons and has a negative impact on health. Even though there is a growing literature on nutrition and aging, few studies focus on longitudinal changes in later life. The aims of this study are to characterize general nutritional status development over time, to identify clusters of nutritional status trajectories, as well as to study the association between the nutritional status trajectories and death. The baseline sample is drawn from the Screening Across the Lifespan Twins (SALT) study. All participants of SALT that had at least 3 assessments according to Mini Nutritional Status Shortform (MNA-SF) documented in the Senior Alert quality register between 2008 and 2015 were included for analyses (N=1509). At the first registration, mean age was 82.4 ± 7.5. According to MNA-SF, 13.3% persons were malnourished, 44.9% were at risk of malnutrition, and 41.8 % were well nourished. Preliminary analysis indicate that despite a general decline in nutritional status in old age, there is a large variability in the sample, making the data suitable for latent class trajectory analyses. Initial analyses also indicate that decrease in nutritional status is associated with decreased survival. Consequently, deterioration in nutritional status seems to be associated with mortality. Detecting malnutrition in older age is important in order to avoid premature death.