Age-Related Macular Degeneration Risk Factors
It is important to know whether you are at a high risk of developing AMD. If you know you are at higher risk, it’s important to focus on early detection to reduce severe vision loss, and modify the risk factors that you do have control over.The unavoidable risk factors that increase the risk of developing AMD are:
- Age
- Family history of AMD/genetics
- Gender (being female)
- Being farsighted (hyperopia)
- Being of light skin and eye colour
The modifiable risk factors are:
- Smoking
- Lack of nutrients and antioxidants
- Obesity, high blood pressure, fat intake and cholesterol levels
- Light exposure
The only avoidable risk factor that can be regarded as proven is the link between AMD and smoking. The most recent study on smoking and AMD was published in the British Journal of Ophthalmology on April 14, 2005. A study of more than 4,000 Britons aged 75 and older showed that those who smoke were twice as likely to have age-related macular degeneration as those who did not. Other studies have come to the conclusion that the risk may be as high as three to four times that of a non-smoker18]. In addition, a review of the association between smoking and age-related macular degeneration that examined the results of 17 studies into the link has found that scientific evidence is sufficiently strong to prove that smoking causes visual impairment. The causality criteria used were the same as those applied to proving the link between smoking and lung cancer.
Studies in a number of countries confirm that people who stopped smoking 20 years ago have a similar risk of developing AMD as non-smokers and the risk starts to decrease after 10 years of not smoking. Some studies also suggest that there is a link between the number of packs smoked and the likelihood of developing AMD.
Relatively low levels of micronutrients and antioxidants
The main supplements discussed in the context of prevention are lutein and zeaxanthin. Lutein and zeaxanthin are two antioxidants that are concentrated in the macula and constitute the macular pigment. It has been suggested that they may play a significant role in preventing oxidative damage to the macula thereby preventing the development of AMD. What is particularly significant is the fact that some studies have shown lutein to improve some measures of visual function. However, samples studied were small and further studies are required to come to a firm conclusion on the benefits of both antioxidants and decide whether food supplementation is to be generally recommended as a preventative measure.
Obesity, high blood pressure, fat intake and cholesterol levels
Age-related macular degeneration has also been linked with obesity and high blood pressure (hypertension) particularly in people taking antihypertensive drugs. In addition, a high intake of dietary fats (especially saturated and mono-unsaturated) was linked to a higher risk of developing AMD and of progressing from the early and intermediate stages to the late stages of the condition. In addition, AMD has been linked with high cholesterol levels but again the evidence is not conclusive.
Light exposure
Ultraviolet light does not harm the macula. However, there is some evidence that blue or visible light (400-700nm wavelength) may be associated with a higher risk of developing AMD. The Beaver Dam Eye study showed an increased incidence of AMD in people who spent long periods in the summer sun but no significant link with exposure to environmental light in general. On the other hand McCarty et al did not find any link between light exposure and AMD.
For more information about AMD or to make a donation to vision research, contact:
The Foundation Fighting Blindness
Tel: 1-800-461-3331 or 416-360-0060
Or donate online
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