This article is more than 5 years old. Information may no longer be current.
Smoking and omega-3 fatty acids shown to affect AMD in twin study
Smokers are twice as likely to develop AMD as nonsmokers. Risk can be reduced by eating fish.
Click Here to Manage Email Alerts
|
|
Smoking and the intake of omega-3 fatty acids had significant impacts on the development of age-related macular degeneration in a recent study in twins.
Johanna M. Seddon, MD, ScM, and colleagues used the World War II Veteran Twin Registry to determine genetic and environmental factors contributing to the development of AMD. The results of their study were published in Archives of Ophthalmology.
“We had shown previously that smoking and fish consumption and omega-3 fatty acid intake are related to macular degeneration in different study designs and different cohorts,” Dr. Seddon explained in an interview with Ocular Surgery News. “This was a unique opportunity to look at the relationship with these modifiable risk factors and macular degeneration in a group of siblings.”
The study
To further investigate the connection between smoking and omega-3 fatty acids with AMD, Dr. Seddon and colleagues evaluated 681 male twins; 222 had intermediate or late-stage AMD.
The subjects completed a food frequency questionnaire and were interviewed via telephone regarding risk factors for AMD. They received complete ophthalmic examinations and fundus photography and had their height, weight and blood pressure measured.
After adjusting for other risk factors, the results showed a 1.9-fold increased risk of developing AMD for current smokers and a 1.7-fold increased risk for past smokers, after adjusting for other factors.
“Even among these siblings who are twins, smoking had an effect, almost a two-fold increased risk in smokers and past smokers,” Dr. Seddon said.
Conversely, increased intake of fish, especially two or more servings per week, significantly reduced the risk of developing AMD. This reduction was seen primarily in subjects with low levels of linoleic acid, which is an omega-6 fatty acid that appears to have a neutralizing effect on omega-3 fatty acids found in fish.
Recommendations
The study concluded that there was enough evidence for ophthalmic practitioners to encourage their patients to quit smoking and improve their diet not only for the sake of their eye health, but also for a host of other health reasons.
In this study, about one-third of the risk of AMD could be attributed to cigarette smoking while about one-fifth could have been prevented with higher fish and omega-3 fatty acid intake.
“These results should emphasize and underscore the message that people with macular degeneration and their relatives should not smoke, and they should not be around people who smoke because passive smoking can also increase risk,” Dr. Seddon said. “They should also eat a good, healthy diet, including at least two servings of fish per week.”
Ophthalmologists should make these recommendations to any patient who shows signs of AMD or who has a family history of AMD, she said.
“These and other modifiable behaviors and preventive measures deserve increased attention and evaluation to reduce the increasing burden of AMD,” the study concluded.
Dr. Seddon said she and her colleagues are also looking at specific genetic factors to better assess the contributions from genetic and environmental factors in the etiology of AMD. AREDS2 will study the effectiveness of fish oil capsules in a randomized trial. Until then, Dr. Seddon said she tells her patients, “Don’t smoke. Don’t be around people who smoke. Eat a good, healthy diet. In addition to eating a lot of fruits and vegetables containing high levels of carotenoids, also consume fish a couple times a week.”
She added that good cardiovascular habits may further protect people from AMD, as the two diseases share many of the same risk factors, including smoking and high body mass index.
For more information:
- Johanna M. Seddon, MD, ScM, can be reached at Massachusetts Eye & Ear Infirmary, 243 Charles St., Boston, MA 02114; 617-573-4010; fax: 617-573-3570; e-mail: johanna_seddon@meei.harvard.edu.
Reference:
- Seddon JM, George S, Rosner B. Cigarette smoking, fish consumption, omega-3 fatty acid intake, and associations with age-related macular degeneration. Arch Ophthalmol. 2006;124:995-1001.
- Katrina Altersitz is an OSN Staff Writer who covers all aspects of ophthalmology.