Living long and ageing well: is epigenomics the missing link between nature and nurture?

Human longevity is a complex trait and increasingly we understand that both genes and lifestyle interact in the longevity phenotype. Non-genetic factors, including diet, physical activity, health habits, and psychosocial factors contribute approximately 50 % of the variability in human lifespan with another 25 % explained by genetic differences. Family clusters of nonagenarian and centenarian siblings, who show both exceptional age-span and health-span, are likely to have inherited facilitatory gene groups, but also have nine decades of life experiences and behaviours which have interacted with their genetic profiles. Identification of their shared genes is just one small step in the link from genes to their physical and psychological profiles. Behavioural genomics is beginning to demonstrate links to biological mechanisms through regulation of gene expression, which directs the proteome and influences the personal phenotype. Epigenetics has been considered the missing link between nature and nurture. Although there is much that remains to be discovered, this article will discuss some of genetic and environmental factors which appear important in good quality longevity and link known epigenetic mechanisms to themes identified by nonagenarians themselves related to their longevity. Here we suggest that exceptional 90-year old siblings have adopted a range of behaviours and life-styles which have contributed to their ageing-well-phenotype and which link with important public health messages.

Individual factors and perceived community characteristics in relation to mental health and mental well-being

Background
It has been argued that though correlated with mental health, mental well-being is a distinct entity. Despite the wealth of literature on mental health, less is known about mental well-being. Mental health is something experienced by individuals, whereas mental well-being can be assessed at the population level. Accordingly it is important to differentiate the individual and population level factors (environmental and social) that could be associated with mental health and well-being, and as people living in deprived areas have a higher prevalence of poor mental health, these relationships should be compared across different levels of neighbourhood deprivation.

Methods
A cross-sectional representative random sample of 1,209 adults from 62 Super Output Areas (SOAs) in Belfast, Northern Ireland (Feb 2010 – Jan 2011) were recruited in the PARC Study. Interview-administered questionnaires recorded data on socio-demographic characteristics, health-related behaviours, individual social capital, self-rated health, mental health (SF-8) and mental well-being (WEMWBS). Multi-variable linear regression analyses, with inclusion of clustering by SOAs, were used to explore the associations between individual and perceived community characteristics and mental health and mental well-being, and to investigate how these associations differed by the level of neighbourhood deprivation.

Results
Thirty-eight and 30 % of variability in the measures of mental well-being and mental health, respectively, could be explained by individual factors and the perceived community characteristics. In the total sample and stratified by neighbourhood deprivation, age, marital status and self-rated health were associated with both mental health and well-being, with the ‘social connections’ and local area satisfaction elements of social capital also emerging as explanatory variables. An increase of +1 in EQ-5D-3 L was associated with +1SD of the population mean in both mental health and well-being. Similarly, a change from ‘very dissatisfied’ to ‘very satisfied’ for local area satisfaction would result in +8.75 for mental well-being, but only in the more affluent of areas.

Conclusions
Self-rated health was associated with both mental health and mental well-being. Of the individual social capital explanatory variables, ‘social connections’ was more important for mental well-being. Although similarities in the explanatory variables of mental health and mental well-being exist, socio-ecological interventions designed to improve them may not have equivalent impacts in rich and poor neighbourhoods.

Multiple source quantum well model of porous silicon light emission

Based on photoluminescence, Fourier transform infrared spectroscopy, and atomic force microscopy results, a new light emitting model for porous silicon (multiple source quantum well model) is proposed.

Visual morbidity due to inaccurate spectacles among school children in rural China: the See Well to Learn Well Project, report 1.

PURPOSE: Inadequately corrected refractive error is the leading cause of visual disability among children in China; inaccurate spectacles are a potential cause. The prevalence and visual impact of spectacle inaccuracy were studied among rural, secondary-school children, to determine the optimal timing for updating of refraction. METHODS: A random sample of children from years 1 and 2 in all junior and senior high schools in Fuyang Township, Guangdong Province, underwent ocular examination. All children who reported wearing glasses received cycloplegic refraction, vision assessment, and measurement of current spectacles. RESULTS: Among 3226 examined children, 733 (22.7%) reported owning spectacles. Refractive error and spectacle power were assessed for 588 (80.2%) children. They had a mean age of 15.0 +/- 1.6 years; 70.2% were girls, 83.3% had more than -1.5 D of myopia, and 17.9% had presenting vision < or = 6/12 in the better eye. The glasses of 48.8% of children were inaccurate by > or = 1 D; inaccuracy was > or = 2 D in 17.7%. Children with inaccurate glasses (> or = 1 D) had presenting vision in the better eye significantly (P < 0.001) worse than that of children with accurate glasses, and 30.3% had presenting acuity < or = 6/12. In multivariate models, younger age (P = 0.004), more myopic refractive error (P < 0.001), and having glasses > or = 1 year old (P = 0.04) were associated with inaccurate spectacles. DISCUSSION: Inaccurate spectacles are common and are associated with significant visual impairment among children in rural China. Reducing outdated glasses could lessen the visual burden, although refractive services may have to be offered on an annual basis for optimal benefit.