Genome-wide DNA methylation analysis of body composition in Chinese monozygotic twins.

BACKGROUND: Little is currently known about epigenetic alterations associated with body composition in obesity. Thus, we aimed to explore epigenetic relationships between genome-wide DNA methylation levels and three common traits of body composition as measured by body fat percentage (BF%), fat mass (FM) and lean body mass (LBM) among Chinese monozygotic twins. METHODS: Generalized estimated equation model was used to regress the methylation level of CpG sites on body composition. Inference about Causation Through Examination Of Familial Confounding was used to explore the evidence of a causal relationship. Gene expression analysis was further performed to validate the results of differentially methylated genes. RESULTS: We identified 32, 22 and 28 differentially methylated CpG sites (p < 10-5 ) as well as 20, 17 and eight differentially methylated regions (slk-corrected p < 0.05) significantly associated with BF%, FM and LBM which were annotated to 65 genes, showing partially overlapping. Causal inference demonstrated bidirectional causality between DNA methylation and body composition (p < 0.05). Gene expression analysis revealed significant correlations between expression levels of five differentially methylated genes and body composition (p < 0.05). CONCLUSIONS: These DNA methylation signatures will contribute to increased knowledge about the epigenetic basis of body composition and provide new strategies for early prevention and treatment of obesity and its related diseases.

Does older subjective age predict poorer cognitive function and higher risk of dementia in middle-aged and older adults?

As a biopsychosocial marker of aging, subjective age (i.e., the age individuals feel regardless of their actual age) was related to many health issues in the elderly. The purpose of this study is to investigate whether subjective age is associated with subsequent cognition and dementia risk in middle-aged and older adults. Samples were drawn from the English Longitudinal Study of Ageing (ELSA). Participants reported their subjective ages at the baseline (2004/2005), and their cognitive functions were measured after 10 years (2014/2015). Newly diagnosed dementias were recorded between 2006/2007 to 2014/2015. Overall, 6,475 adults aged 50 years or older were included in the current analyses. The relationship between subjective age reported at baseline and cognition assessed ten years later was modeled using multiple linear regression models. Compared to participants who reported a younger subjective age, those who reported an older subjective age were more likely to have poorer cognition after ten years (ß = -0.705, P = .002 for memory, ß = -1.567, P = .001 for executive function). A Cox proportional hazard regression model suggested that older subjective age was an independent risk factor for incident dementia (HR = 1.737, 95% CI =1.060-2.848). Other than chronological age, subjective age could also be considered as an important predictor for the development of cognitive dysfunction.

Poor lung function accelerates cognitive decline in middle-aged and older adults: Evidence from the English Longitudinal Study of Ageing.

BACKGROUND/OBJECTIVE: Previous studies have linked lung function to cognitive performance. However, it is not clear whether baseline lung function has an effect on the trajectory of cognitive decline during normal aging. This study aimed to examine the association of baseline lung function with long-term changes in cognition among the middle-aged and older adults. METHODS: Lung function as indicated by forced expiratory volume 1 s (FEV1) and forced vital capacity (FVC), was measured at the baseline examination. Cognition, including memory, time orientation, executive function and processing speed, were tested four times over six years. Generalized estimating equation (GEE) models were used to test the associations between baseline lung function and four visits of cognition in 6080 participants aged 50 years or over from the English Longitudinal Study of Ageing (ELSA). RESULTS: Compared to participants with higher lung function, those who had lower lung function at baseline experienced a faster rate of decline in memory (joint test: χ2interaction = 12.07, df = 3, P = 0.007 for FVC), time orientation (joint test: χ2interaction = 9.49, df = 3, P = 0.023 for FVC) and executive function (joint test: χ2interaction = 9.13, df = 3, P = 0.028 for FEV1 and joint test: χ2interaction = 12.76, df = 3, P = 0.005 for FVC). No association was found between baseline lung function and the rate of decline in processing speed (joint test: χ2interaction = 1.29, df = 3, P=0.733 for FEV1 and joint test: χ2interaction = 2.35, df = 3, P = 0.503 for FVC). CONCLUSIONS: Poor lung function at baseline predicted a faster rate of cognitive decline in memory, time orientation and executive function. The mechanism for this association deserves further investigation.