What are your odds of surviving into your hundreds?
A genetic factor that protects you against heart disease during middle age could reduce the odds that you'll celebrate your hundredth birthday. Research published in BMC Medical Genetics shows that a genetic trait, which is rarely found in centenarians, is associated with lower cholesterol levels.
The risk of suffering from heart disease is increased by a number of factors, including having high levels of low-density lipoprotein cholesterol in your blood. The main component of low-density lipoprotein is apoliprotein (b) whose quality and quantity are related to the quality and expression of the APOB genes you have.
In a previous study, Professor Giovanna De Benedictis found that older, healthy people were most unlikely to carry short versions of a DNA region that neighbours the APOB gene. "This indicates that the short alleles are unfavourable to longevity," she says. In contrast, these short versions are over-represented in healthy, middle-aged adults, indicating that these variants of the APOB gene region play a protective role at this point in your life.
Her group have now analysed both the variability in the DNA surrounding the APOB gene and the low-density lipoprotein cholesterol levels in over 400 healthy volunteers, between the ages of 20 and 102. The aim was to see if there was any link between the two factors.
Their results show that people with short variants of the APOB gene region have significantly lower levels of total cholesterol and low-density lipoprotein cholesterol in their blood.
The authors of the study write: "On the whole, the short alleles would be advantageous in adults, by protecting them from high levels of LDL-Cholesterol, while dangerous in the elderly, probably by lowering serum cholesterol below a critical threshold."
In line with these findings, the researchers showed that patients suffering from heart disease as a consequence of having high low-density lipoprotein cholesterol levels were less likely to have one or more short variants of the APOB gene region, compared to healthy volunteers.
"On the whole, the study confirms that genetic risk factors are age-specific and gives possible insights into another 'paradox of centenarians'," write the authors.
Source: Eurekalert & othersLast reviewed: By John M. Grohol, Psy.D. on 21 Feb 2009
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