The Moderating Influence of School Achievement on Intelligence: A Cross-National Comparison.

Education-related variables are positively associated with intelligence in both causal directions, but little is known about the associations' underlying genetically and environmentally intertwined processes and many 'third variables' are probably involved too. In this study, we investigated how school achievement, measured by grade point average (GPA), moderated intelligence test score variation in young adulthood in broadly representative samples from the U.S. state of Minnesota, Denmark, and Germany, attempting to improve both understanding of the importance of environmental contexts and the limitations of currently available modelling techniques to help remedy them. School achievement was positively associated with intelligence test scores in all three contexts, but it moderated variances differently, even within the two cohorts comprising the Minnesota sample. One Minnesota cohort and the German sample suggested that shared environmental variance was larger among individuals with extreme GPAs, while the Danish sample suggested that this was only true among individuals with low GPAs. In contrast to these observations, the other Minnesota cohort suggested that genetic and non-shared environmental variances were greater among individuals with high GPAs. These observations indicated that underlying individual developmental processes and population-level impacts differed. However, our statistical models did not capture these differences clearly. The ways in which they failed all suggested the model limitations involve an inability to address degrees to which environmental constraints restrain social movements that are confounded with individual variations in capacities to move within society.

The plasticity of late-onset dementia: A nationwide cohort study in Denmark.

INTRODUCTION: The determinants of the secular decline in the incidence of dementia are not clear. The aim of this study was to investigate the influences of four factors-education, wealth, cerebrovascular health, and general health-on the secular decline. METHODS: A cohort study was conducted of all individuals aged ≥65 years in Denmark from 2005 through 2018 (N = 1,757,168). Annual incidence rates of dementia and population attributable risks of the four factors were calculated and birth cohort trends were examined. RESULTS: The incidence of dementia declined by 22.5% in men and 34.2% in women from 2005 through 2018. Population attributable risks of lower education, lower wealth, and stroke likewise declined. Independent of these improvements, the incidence of dementia fell across successive birth cohorts. DISCUSSION: Most of the observed plasticity in late-onset dementia is associated with a risk decline across successive birth cohorts that is independent of improvements in traditional risk factors.

Association of Tumor Necrosis Factor-α Inhibitors with Incident Dementia: Analysis Based on Population-Based Cohort Studies.

BACKGROUND AND OBJECTIVE: Preliminary evidence suggests a possible preventive effect of tumor necrosis factor-α inhibitors (TNFi) on incident dementia. The objective of the analysis was to investigate the association between TNFi and the risk of incident dementia in a population undergoing treatment for rheumatological disorders. METHODS: We followed patients aged ≥ 65 years with dementia and rheumatological conditions in two cohort studies, DANBIO (N = 21,538), a Danish clinical database, and AOK PLUS (N = 7112), a German health insurance database. We defined incident dementia using diagnostic codes and/or medication use and used Cox regression to compare the associations of TNFi with other rheumatological therapies on the risk of dementia. To ensure that the patients were receiving long-term medication, we included patients with rheumatic diseases and systemic therapies. RESULTS: We observed similar trends towards a lower risk of dementia associated with TNFi versus other anti-inflammatory agents in both cohorts (hazard ratios were 0.92 [95% confidence interval 0.76, 1.10] in DANBIO and 0.89 [95% confidence interval 0.63, 1.24] in AOK PLUS, respectively). CONCLUSIONS: Tumor necrosis factor-α inhibitors may decrease the risk of incident dementia although the association did not reach statistical significance in this analysis. Further research, ideally with randomization, is needed to gauge the potential of repurposing TNFi for dementia prevention and/or treatment.

Effect of maternal fish oil supplementation during lactation on socioemotional wellbeing and physical activity in 13-year-old children: A randomized clinical trial.

Early dietary long-chain n-3PUFA (n-3LCPUFA) may affect brain development. We investigated if fish oil supplementation of lactating mothers affected socioemotional wellbeing in adolescents in a potentially gender-specific manner. At age 13, we invited 92 children of mothers who completed a randomized trial with 1.5 g/d n-3 LCPUFA or olive oil during the first 4 months of lactation and 48 children of mothers with a high habitual fish intake. Children and parents answered validated questionnaires regarding socioemotional wellbeing and physical activity was monitored by ActiGraph for 7 days. Participation rate was 71%. Univariate correlations between children's and parents' ratings on the individual scales were moderate-strong, but correlations across questionnaires indicated that parents might base their ratings on proxy markers. We found no group differences in self-rated socioemotional outcomes or physical activity. Although the study was small, it was the first follow-up on effects of perinatal n-3LCPUFA supply on socioemotional wellbeing in adolescence.

Prevalence and Incidence Rates of Atrial Fibrillation in Denmark 2004-2018.

Purpose: To estimate the prevalence and incidence of atrial fibrillation (AF) in Denmark during 2004-2018 and to investigate whether methodological choices influence these estimates. Patients and Methods: A register-based cohort study was conducted of all individuals aged ≥18 years in Denmark 2004-2018. The cumulative prevalence of AF at the end of the study period was calculated as the number of AF cases alive with at least one inpatient or two outpatient diagnoses during 1994-2018 divided by the number of Danish residents in 2018. Incidence rates were calculated as the number of annual AF cases with no previous diagnosis in the past 10 years (ie, a 10-year washout period) divided by the person-time contributed by the population free of AF on 1 January in the same calendar year. Furthermore, the influence of varying case definitions was investigated. Results: The cumulative prevalence of AF was 3.0% in 2018. The incidence rate increased from 391 to 481 per 100,000 person-years (PYs) from 2004 to 2015 (1.7% average annual increase) after which it declined to 367 per 100,000 PYs in 2018 (8.5% average annual decrease). This pattern was observed in both sexes irrespective of age. Methodological choices, particularly the case definition's strictness and the length of the washout period, had a substantial influence on the reported estimates. Conclusion: The cumulative prevalence of AF is currently around 3.0% in the Danish population, but the incidence has declined since 2015. As these estimates are influenced by methodological choices, future studies should strive for precise reporting of study methodology.

The secular trend of intelligence test scores: The Danish experience for young men born between 1940 and 2000.

The present study investigated the Danish secular trend of intelligence test scores among young men born between 1940 and 2000, as well as the possible associations of birth cohort changes in family size, nutrition, education, and intelligence test score variability with the increasing secular trend. The study population included all men born from 1940 to 2000 who appeared before a draft board before 2020 (N = 1,556,770). At the mandatory draft board examination, the approximately 19-year-old men underwent a medical examination and an intelligence test. In the statistical analyses, the IQ mean and standard deviation (SD) were estimated separately for each of the included annual birth cohorts based on information from birth cohorts with available total intelligence test scores for all tested individuals (i.e. 1940-1958 and 1987-2000; the mean and SD were interpolated for the intermediate birth cohorts). Moreover, the possible associations with birth cohort changes in family size, height as a proxy for nutritional status, education, and IQ variability were investigated among those birth cohorts for whom a secular increase in intelligence test scores was found. The results showed that the estimated mean IQ score increased from a baseline set to 100 (SD: 15) among individuals born in 1940 to 108.9 (SD: 12.2) among individuals born in 1980, since when it has decreased. Focusing on the birth cohorts of 1940-1980, for whom a secular increase in intelligence test scores was found, birth cohort changes in family size, height, and education explained large proportions of the birth cohort variance in mean intelligence test scores, suggesting that these factors may be important contributors to the observed Flynn effect in Denmark.