Risk Factors for Macular Degeneration
When we talk about risk factors for a disease, it means any characteristic or exposure that might increase the chances of an individual developing the disease. Having one or more risk factors doesn’t necessarily mean you will develop the disease, and having no risk factors doesn’t mean you won’t get the disease. They are things to keep in mind when going to the doctor and can provide guidance to help you make healthy choices to minimize the risk of developing certain kinds of disease and maintain overall health.
AMD risk factors
According to the American Academy of Ophthalmology (AAO), the main risk factors for age-related macular degeneration (AMD) include:1
- Older age (over 55- 60)
- Family history of AMD
- Smoking cigarettes
- High blood pressure (hypertension)
Other risk factors can include gender, race, and iris color. There are genetic mutations and biomarkers that might also be factors.
Of all the risk factors for AMD, age is the strongest.2 The prevalence of AMD continues to increase as one gets older, which is why it’s so important to get regular eye exams, especially as you age.
Family history, genetics, and biomarkers
Studies have shown that both early and late AMD are correlated with a family history of the disease, especially immediate family members, most notably a parent. The risk for developing late AMD is increased by almost 4 times for those with a family history of AMD. Right now, there are approximately 40 genes that have been identified as being associated with AMD development. While this does not necessarily mean these genes cause AMD, there are associations, and more research needs to be done.2
There are conflicting studies on gender, with some finding no increased risk factor, and others finding some associations, regardless of race or age.2 Women might have an increased risk of developing AMD, but this might also be because their life expectancy is longer than that of men, and thus, the rate of diagnosis is increased the older they get. More research is needed before a definitive conclusion can be drawn.
White people are significantly more likely to develop AMD than African-Americans or Latinos/as. The Baltimore Eye Study found almost a 4-fold risk of developing any kind of AMD for white patients, but especially late AMD and wet AMD.2,3
Smoking doubles the risk of developing AMD and is the most impactful modifiable risk factor.4 Smoking cessation can reduce your risk of developing AMD, and if you have AMD, quitting smoking can help slow down the progression of AMD. Smokers receiving injections of medication into the eyes for AMD may also have a poor response to the therapy when compared to nonsmokers.
The iris of the eye is what defines your eye color. Studies have shown that those with lighter irises have a two-fold higher incidence of developing AMD than those with darker irises.2 Another study found that individuals with brown eyes were more likely than those with blue eyes to develop early AMD, but less likely to show features of late AMD.2 There may be a protective factor associated with darker irises, but more research needs to be done to make any definitive statements.
Obesity has been associated with AMD, although more research needs to be done to find a causal link.2 The association seems to be more pronounced for men than for women, but further exploration is necessary. This may also be linked with the risk factor of hypertension, and other lifestyle factors.
The studies are conflicted on hypertension (high blood pressure) as being a risk factor, as well. Several studies have found that even if high blood pressure is controlled, hypertension is still a risk factor in developing AMD.2 Drusen size has been correlated with hypertension, which is important to note.2 As with obesity and AMD, there might be other lifestyle risk factors present that link it to AMD, so more research needs to be done.
Risk factors for Stargardt disease
Stargardt disease is an inherited retinal disorder that causes symptoms similar to AMD, but at a much younger age; often childhood or early adolescence.5 Because Stargardt is an inherited condition, the biggest risk factor for the disease is either having an affected parent, or having two parents who carry the most common Stargardt mutation, which is a mutation of the ABCA4 gene.5
Risk factors for MMD
If you are nearsighted, which means you can see objects near you clearly, you have myopia. When an eye doctor measures your myopia, she will measure it in something called diopters. The more diopters, the more nearsighted you are. If you have high myopia, usually classified as –6 diopters or more, you are at greater risk for myopic macular degeneration.6 The risk increases as myopia increases, especially at –10 diopters or more.6
What can you do?
While there are some risk factors that are out of your control, like age, race, or gender, there are some risk factors that can be modified include smoking cigarettes, hypertension, and obesity. These issues are also risk factors for a wide variety of diseases, and modifying your behaviors to minimize these risk factors is beneficial for your overall health, if not specifically for your eye health.
Find out your risk factors
Talk with your eye doctor about your general risk factors for macular degeneration, as well as any personal risk factors you might have. They can tell you about the newest research and what to look out for, as well as suggest any steps you might be able to take to minimize your risk of developing the condition.