Cognitive health among older adults in the United States and in England

<p>Abstract</p> <p>Background</p> <p>Cognitive function is a key determinant of independence and quality of life among older adults. Compared to adults in England, US adults have a greater prevalence of cardiovascular risk factors and disease that may lead to poorer cognitive function. We compared cognitive performance of older adults in the US and England, and sought to identify sociodemographic and medical factors associated with differences in cognitive function between the two countries.</p> <p>Methods</p> <p>Data were from the 2002 waves of the US Health and Retirement Study (HRS) (n = 8,299) and the English Longitudinal Study of Ageing (ELSA) (n = 5,276), nationally representative population-based studies designed to facilitate direct comparisons of health, wealth, and well-being. There were differences in the administration of the HRS and ELSA surveys, including use of both telephone and in-person administration of the HRS compared to only in-person administration of the ELSA, and a significantly higher response rate for the HRS (87% for the HRS vs. 67% for the ELSA). In each country, we assessed cognitive performance in non-hispanic whites aged 65 and over using the same tests of memory and orientation (0 to 24 point scale).</p> <p>Results</p> <p>US adults scored significantly better than English adults on the 24-point cognitive scale (unadjusted mean: 12.8 vs. 11.4, P < .001; age- and sex-adjusted: 13.2 vs. 11.7, P < .001). The US cognitive advantage was apparent even though US adults had a significantly higher prevalence of cardiovascular risk factors and disease. In a series of OLS regression analyses that controlled for a range of sociodemographic and medical factors, higher levels of education and wealth, and lower levels of depressive symptoms, accounted for some of the US cognitive advantage. US adults were also more likely to be taking medications for hypertension, and hypertension treatment was associated with significantly better cognitive function in the US, but not in England (P = .014 for treatment × country interaction).</p> <p>Conclusion</p> <p>Despite methodological differences in the administration of the surveys in the two countries, US adults aged ≥ 65 appeared to be cognitively healthier than English adults, even though they had a higher burden of cardiovascular risk factors and disease. Given the growing number of older adults worldwide, future cross-national studies aimed at identifying the medical and social factors that might prevent or delay cognitive decline in older adults would make important and valuable contributions to public health.</p

Variações ecomorfológicas e de uso de habitat em Piabina argentea (Characiformes, Characidae) da bacia do Rio das Velhas, Minas Gerais, Brasil

O presente estudo teve como objetivo investigar os padrões local e regional de uso de habitat de Piabina argentea Reinhardt, 1867 em quatro diferentes rios da bacia do rio das Velhas. Os habitat amostrados foram caracterizados quanto à velocidade da água, profundidade e tipo de substrato. Para a análise ecomorfológica, foram calculados 17 atributos ecomorfológicos de 40 exemplares de cada rio. Embora estas populações tenham se sobreposto no espaço ecomorfológico, a Análise Discriminante Canônica mostrou haver diferença significativa entre elas, principalmente da população do rio das Velhas em relação às demais. A separação se deu em termos do índice de compressão, altura relativa do corpo e índice de achatamento ventral. Os padrões locais de seleção de habitat não foram congruentes em todos os rios, mas em geral, houve predomínio do padrão regional: habitat lênticos, profundidade entre 20 e 40 cm e 60 e 80 cm e substrato areia, silte+argila e banco de folhas. Considerando as características físicas de cada rio e o padrão regional da espécie, a maior parte dos seus requerimentos de habitat é contemplada nos quatro rios. Entretanto, um corpo d'água assoreado como o trecho do rio das Velhas, tende a ter maiores velocidades da água, menores profundidades e substrato finos, o que atende em parte à seleção de habitat da espécie estudada

Person-Specific Non-shared Environmental Influences in Intra-individual Variability : A Preliminary Case of Daily School Feelings in Monozygotic Twins

Most behavioural genetic studies focus on genetic and environmental influences on inter-individual phenotypic differences at the population level. The growing collection of intensive longitudinal data in social and behavioural science offers a unique opportunity to examine genetic and environmental influences on intra-individual phenotypic variability at the individual level. The current study introduces a novel idiographic approach and one novel method to investigate genetic and environmental influences on intra-individual variability by a simple empirical demonstration. Person-specific non-shared environmental influences on intra-individual variability of daily school feelings were estimated using time series data from twenty-one pairs of monozygotic twins (age = 10 years, 16 female pairs) over two consecutive weeks. Results showed substantial inter-individual heterogeneity in person-specific non-shared environmental influences. The current study represents a first step in investigating environmental influences on intra-individual variability with an idiographic approach, and provides implications for future behavioural genetic studies to examine developmental processes from a microscopic angle

Genetic and environmental variation in educational attainment: an individual-based analysis of 28 twin cohorts

We investigated the heritability of educational attainment and how it differed between birth cohorts and cultural-geographic regions. A classical twin design was applied to pooled data from 28 cohorts representing 16 countries and including 193,518 twins with information on educational attainment at 25 years of age or older. Genetic factors explained the major part of individual differences in educational attainment (heritability: a2 = 0.43; 0.41-0.44), but also environmental variation shared by co-twins was substantial (c2 = 0.31; 0.30-0.33). The proportions of educational variation explained by genetic and shared environmental factors did not differ between Europe, North America and Australia, and East Asia. When restricted to twins 30 years or older to confirm finalized education, the heritability was higher in the older cohorts born in 1900-1949 (a2 = 0.44; 0.41-0.46) than in the later cohorts born in 1950-1989 (a2 = 0.38; 0.36-0.40), with a corresponding lower influence of common environmental factors (c2 = 0.31; 0.29-0.33 and c2 = 0.34; 0.32-0.36, respectively). In conclusion, both genetic and environmental factors shared by co-twins have an important influence on individual differences in educational attainment. The effect of genetic factors on educational attainment has decreased from the cohorts born before to those born after the 1950s