Risk Factors for AMD
Thanks to ongoing research, we now understand that a number of factors increase a person’s risk of developing AMD. Some of these risk factors are unavoidable. If you have several unavoidable risk factors for AMD, it is more important than ever to consider changes in the modifiable risk factors that we know (or suspect) lead to AMD.
The unavoidable risk factors that increase the risk of developing AMD are:
Age – As a person ages, their risk of developing AMD increases. For example, in a person under age sixty with a normal retina, the risk of developing AMD in the next five years is less than 1%; for a person over age 80, the risk rises to 22%. [1]
Family History (Genetics) - Fifteen to twenty percent of people living with AMD also have at least one close relative with the disease. Over the past 10 years, scientists have identified a number of specific genetic changes that are associated with AMD. [2] Many of these genes also control aspects of our immune system. This genetic research is helping us understand the underlying causes of AMD, and has led to some of the new treatments now in clinical trials.
Other unavoidable risk factors for AMD include:
Family History (Genetics) - Fifteen to twenty percent of people living with AMD also have at least one close relative with the disease. Over the past 10 years, scientists have identified a number of specific genetic changes that are associated with AMD. [2] Many of these genes also control aspects of our immune system. This genetic research is helping us understand the underlying causes of AMD, and has led to some of the new treatments now in clinical trials.
Other unavoidable risk factors for AMD include:
- Being Female
- Being Farsighted (hyperopic)
- Having light coloured skin and eye colour
There is also evidence for several modifiable risk factors for AMD:
Smoking – More than a dozen studies have now found conclusive evidence of a link between AMD and smoking [3]. Large-scale studies of both men [4] and women [5] in the United States have shown that smokers are more than twice as likely to get AMD than non-smokers, and that the risk increases with the number of cigarettes smoked each day. A study of more than 2300 people in the Blue Mountain area of Australia has shown that smokers (on average) develop AMD about 10 years earlier than non-smokers (average age 67 compared to an average age of 77 for non-smokers) [6]. This study and others have also shown that quitting works – ex-smokers have a lower rate of AMD then current smokers.
Alcohol Consumption - Scientists have been able to pool together information from five different studies of AMD, to look at the influence of alcohol use on the risk of developing AMD [7]. Together these studies include more than 135,000 people. They show that drinking more than 3 alcoholic drinks each day increases the risk of developing AMD by 47%. Some studies suggest that moderate levels of alcohol consumption (a single drink each day) may actually help protect against AMD, but this has not yet been proven.
Diet – It is difficult to get solid evidence about how people’s eating habits affect their risk of disease, because the information is based on people’s memories and reports of their own eating habits. However, a growing amount of evidence is suggesting that the risk factors for AMD may be similar to those associated with heart attack and stroke. A recent study from Australia, which looked specifically at the correlation between fat intake and AMD risk, showed that people who ate the most trans-saturated fatty acids had twice the risk of developing AMD as those who ate the least [8]. These fats are found in processed foods and are listed on nutritional labels in Canada. This same study also found that people with the highest consumption of healthy fats, like olive oil or fish oils, had the lowest risk for AMD. Other studies have also found that people who consume fish more than once a week are less likely to develop AMD. [9]
A combination of vitamins and minerals has been shown to be a useful treatment for dry AMD, helping to slow vision loss and the development of wet AMD in people who already have high-risk AMD. These nutrients are found naturally in green leafy vegetables and in colourful vegetables such as peppers and carrots. While there is no evidence that supplements help people who do not have signs of AMD, eating a diet high in these vegetables may help protect you from AMD. [9]
Other Risk Factors – Studies are continuing of other risk factors for AMD, including body weight, cholesterol levels, physical activity levels and the regular consumption of nuts. Some studies have also looked at the influence of light exposure (being in bright sun for long periods of time). However, the influence of all of these factors continues to be debated in the medical literature.
Learn more about some of the research on AMD currently being supported by your donations to the Foundation Fighting Blindness. Use this link to donate online.
Updated: Sept 15, 2010. This section has been reviewed by Dr. Peter Kertes, Associate Professor of Ophthalmology and Vision Sciences at the University of Toronto and Dr. William Stell, FFB Director of Research Programs and Professor of Ophthalmology at the University of Calgary.
Updated: Sept 15, 2010. This section has been reviewed by Dr. Peter Kertes, Associate Professor of Ophthalmology and Vision Sciences at the University of Toronto and Dr. William Stell, FFB Director of Research Programs and Professor of Ophthalmology at the University of Calgary.
Learn more about AMD: |
|
| What is AMD? | AMD Prevention |
| Early Detection | AMD Treatment |
| AMD Research | Frequently Asked Questions |
1. Macular Degeneration Info in The Eye Digest, University of Illinois Eye & Ear Infirmary, Chicago, IL, Updated May 19, 2009.
2. Gehrs K, Jackson J et al. Complement, Age-Related Macular Degeneration and a Vision of the Future. Arch Ophthalmol. 2010;128(3):349-358.
3. Thornton J, Edwards, R, Mitchell P et al. Smoking and Age-related macular degeneration: a review of association. Eye 2005:19; 935–944.
4. Christen WG et al. A Prospective Study of Cigarette Smoking and Risk of Age-Related Macular Degeneration in Men. JAMA, 1996 Oct; 276: 1147 - 1151.
5. Seddon JM et al. A prospective study of cigarette smoking and age-related macular degeneration in women. JAMA 1996 Oct:276;1141-6.
6. Mitchell P, Wang JJ, Smith W, Leeder SR. Smoking and the 5-year incidence of age-related maculopathy: the Blue Mountains Eye Study. Arch Ophthalmol 2002; 120: 1357–1363.
7. Chong EW, Kreis AJ, et al. Alcohol consumption and the risk of age-related macular degeneration: a systematic review and meta-analysis. Am J Ophthalmol. 2008 Apr;145(4):707-715.
8. Chong EWT et al. Fat Consumption and Its Association With Age-Related Macular Degeneration. Arch Ophthalmol. 2009;127(5):674-680.
9. Tam JT, et al. Dietary Fatty Acids and the 10-Year Incidence of Age-Related Macular Degeneration. Arch Ophthalmol. 2009;127(5):656-665.
4. Christen WG et al. A Prospective Study of Cigarette Smoking and Risk of Age-Related Macular Degeneration in Men. JAMA, 1996 Oct; 276: 1147 - 1151.
5. Seddon JM et al. A prospective study of cigarette smoking and age-related macular degeneration in women. JAMA 1996 Oct:276;1141-6.
6. Mitchell P, Wang JJ, Smith W, Leeder SR. Smoking and the 5-year incidence of age-related maculopathy: the Blue Mountains Eye Study. Arch Ophthalmol 2002; 120: 1357–1363.
7. Chong EW, Kreis AJ, et al. Alcohol consumption and the risk of age-related macular degeneration: a systematic review and meta-analysis. Am J Ophthalmol. 2008 Apr;145(4):707-715.
8. Chong EWT et al. Fat Consumption and Its Association With Age-Related Macular Degeneration. Arch Ophthalmol. 2009;127(5):674-680.
9. Tam JT, et al. Dietary Fatty Acids and the 10-Year Incidence of Age-Related Macular Degeneration. Arch Ophthalmol. 2009;127(5):656-665.