[Blindtlk] Fwd: Genes, lifestyle raise macular degeneration risk

[David Andrews]

>
>  Monday, January 8, 2007
>
>
>By Megan RauscherNEW YORK (Reuters Health) - New 
>research suggests that one's genetic make-up 
>interacts with two modifiable risk factors -- 
>obesity and smoking -- to multiply the risk of 
>developing age-related macular degeneration 
>(AMD), a potentially blinding degenerative eye disorder.
>"These new data suggest that the level of risk 
>conferred by these factors (obesity and smoking) 
>depends pretty strongly on a person's underlying 
>genetic predisposition," said Dr. Debra A. 
>Schaumberg from Brigham and Women's Hospital in Boston.
>In addition to obesity and smoking, a variation 
>in a gene called complement factor H (CFH) is 
>also known to increase the risk that a person 
>will develop AMD. A mutation in another gene -- 
>known as LOC387715 -- also raises the risk of AMD.
>Schaumberg's team studied how genes and 
>lifestyle interact to increase the risk of AMD 
>in 457 men and women with AMD and 1,071 
>"controls," subjects of the same age without 
>AMD. All of these individuals have been followed 
>regularly since the late 1970s or 1980s as part 
>of either the Nurses' Health Study or the Health Professionals Follow-Up Study.
>According to the report, published in the 
>Archives of Ophthalmology, individuals with one 
>or two copies of the CFH mutation were nearly 
>two-fold and four-fold, respectively, more likely to develop AMD.
>Those with one or two copies of the LOC387715 
>mutation raised the odds of AMD more than 
>two-fold and more than five-fold, respectively.
>The proportion of AMD cases attributable to 
>these two gene mutations was 63 percent.
>Compared with individuals with two normal copies 
>of each gene, individuals with two copies of the 
>risk mutation in both gene types were 50 times more likely to develop AMD.
>This work, Schaumberg said, provides 
>"confirmation...of the importance of these two 
>very common genetic (mutations) in determining a 
>person's risk of macular degeneration."
>"But these genes alone do not tell the whole 
>story," she said, noting that cigarette smoking 
>and obesity multiplied the risks associated with these mutations.
>For example, obese individuals who carried two 
>copies of the CFH gene mutation were 12-times as 
>likely as non-obese non-carriers to develop AMD. 
>For LOC387715, risk increased more than 6-fold 
>for those with two copies of the gene mutation 
>who did not smoke and more than 22-fold for 
>those with two copies of the mutant gene who did smoke.
>"Although the identification of the genetic risk 
>factors is a milestone in our understanding of 
>macular degeneration, we should not forget the 
>importance of the 'traditional' risk factors 
>such as smoking and obesity," Schaumberg said.
>"These are the factors that a person can do 
>something about now. Never start smoking, or 
>stop if you already have; eat well to prevent 
>obesity, or lose weight if already obese," she 
>advised.SOURCE: Archives of Ophthalmology, January 2007.
>
>
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>
>Related MedlinePlus Pages:Genes and Gene Therapy 
>- 
>http://www.nlm.nih.gov/medlineplus//genesandgenetherapy.html 
>Macular Degeneration - 
>http://www.nlm.nih.gov/medlineplus//maculardegeneration.html 
>Obesity - 
>http://www.nlm.nih.gov/medlineplus//obesity.html 
>Date last updated: 09 January 2007

David Andrews and white cane Harry.