A study published in the journal Opthalmology and funded by the National Eye Institute found that a variety of factors, from genes to lifestyle habits, play into a person's chances of getting age-related macular degeneration (AMD).
AMD is the deterioration of the eye's macula, the part of the retina that is responsible for central vision. Most patients remain unaware that they have AMD until the symptoms such as blurring and dark spots at the center of the vision worsen. Though AMD alone usually don't cause complete blindness, it is still the leading cause of vision loss for people 50 years old and above.
To find possible contributing factors that increase risk for AMD, the researchers studied 1,663 women from ages 50 to 70, gathering data on modifiable risk factors such as their diet, physical activity, smoking habits and non-modifiable ones like their genetic data. Among the study group, 337 women developed AMD, with 91 percent of them at the early stage of the disease.
The participants' modifiable factors were given corresponding healthy life score points based on their answers and were assessed alongside their genetic risk factor.
The results showed that the chance of having AMD was 3.3 times higher in women who had poor healthy lifestyle scores and were genetically predisposed to having AMD compared to those who had lower genetic risk and led healthier lifestyles. Researchers also found that vitamin D deficiency was associated with increased chances of having AMD, as high as 6.7 times more among women who are genetically predisposed to the condition.
Research findings clearly showed that unhealthy lifestyle practices are associated with the eventual degeneration, which are then compounded by genetic factors and vitamin D deficiency.
"The findings of both studies support the notion of biologic synergy. That is, that one's genes, lifestyle factors and nutrition all come together in a synergistic way to mediate inflammation, which is a key mechanism involved in AMD," said Dr. Julia Mares of the University of Wisconsin-Madison and research team leader.
However, according to Mares, these findings also bring hope that even those who are at high genetic risk can prevent developing AMD by adopting healthier eating habits, regular exercise and quitting smoking.
"If you have a family history of AMD, the good news is that the study findings suggest that there are things you can do to potentially lower your risk of developing AMD yourself," Mares adds.