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Poor sleep quality linked to cognitive decline

Researchers have found link for poor sleep quality with the development of cognitive decline over three to four years.

Results show that higher levels of fragmented sleep and lower sleep efficiency were associated with a 40 to 50 per cent increase in the odds of clinically significant decline in executive function, which was similar in magnitude to the effect of a five-year increase in age. In contrast, sleep duration was not related to subsequent cognitive decline.

Lead author Terri Blackwell, MA, senior statistician at the California Pacific Medical Centre Research Institute (CPMCRI) in San Francisco, California, said that it was the quality of sleep that predicted future cognitive decline in this study, not the quantity.
Blackwell said with the rate of cognitive impairment increasing and the high prevalence of sleep problems in the elderly, it is important to determine prospective associations with sleep and cognitive decline.

The study involved 2,822 community-dwelling older men at six clinical centres in the US. Participants had a mean age of 76 years.

An average of five nights of objective sleep data were collected from each participant using a wrist actigraph. Cognitive function assessment included evaluation of attention and executive function using the Trails B test.

Two new genes linked to intellectual disability found

Researchers have found two new genes linked to intellectual disability.

In the first study, CAMH Senior Scientist Dr John Vincent, who heads the MiND (Molecular Neuropsychiatry and Development) Laboratory in the Campbell Family Mental Health Research Institute at CAMH, and his team used microarray genotyping to map the genes of a large Pakistani family which had intermarriage. Five members of the youngest generation were affected with mild to moderate intellectual disability.
Dr Vincent identified a truncation in the FBXO31 gene, which plays a role in the way that proteins are processed during development of neurons, particularly in the cerebellar cortex.

In the second study, using the same techniques, Dr Vincent and his team analysed the genes of two families with intermarriage, one Austrian and one Pakistani, and identified a disruption in the METTL23 gene linked to mild recessive intellectual disability. The METTL23 gene is involved in methylation—a process important to brain development and function.

About one per cent of children worldwide are affected by non-syndromic (i.e., the absence of any other clinical features) intellectual disability, a condition characterised by an impaired capacity to learn and process new or complex information, leading to decreased cognitive functioning and social adjustment.

Although trauma, infection and external damage to the unborn fetus can lead to an intellectual disability, genetic defects are a principal cause.

This type of autosomal recessive gene mutation has traditionally been more difficult to trace, resulting in a paucity of research in this area. Parents of affected children show no symptoms, and the child must inherit one defective copy of the gene from each parent, so that only one in four offspring are likely to be affected.

Seven daily portions of fruit and veg to stave off death

Researchers have suggested that eating at least seven daily portions of fruit and vegetables could be the best chance to stave off death from any cause.

According to the data, vegetables may pack more of a protective punch than fruit. The authors analysed lifestyle data of more than 65,000 randomly selected adults aged at least 35, derived from annual national health surveys for England between 2001 and 2008. And they tracked recorded deaths from among the sample for an average of 7.5 years. The analysis revealed that eating fruit and vegetables was associated with a lower risk of death, overall, and deaths from heart disease/stroke and cancer. The higher the intake of fruit and vegetables, the greater the protective effects seemed to be.

Eating at least seven daily portions was linked to a 42 per cent lower risk of death from all causes and from cancer and heart disease/stroke of 25 per cent and 31 per cent, respectively, after excluding deaths within the first year of the monitoring period. Vegetables may be more protective, the figures suggest: 2-3 daily portions were linked to a 19 per cent lower risk of death, compared with a 10 per cent lower risk for the equivalent amount of fruit. And each portion of salad or vegetables seemed to confer a 12-15 per cent lower risk of death.

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