Study Results Link Obesity to Macular Degeneration

Life stressors, such as obesity reprogram immune system cells, could cause age-related macular degeneration (AMD), according to the results of a study published in Science.¹

“We wanted to know why some [individuals] with a genetic predisposition develop AMD, while others are spared,” Przemyslaw (Mike) Sapieha, PhD, an ophthalmology professor at the Université de Montréal, said in a statement. “Although considerable effort has been invested in understanding the genes responsible for AMD, variations and mutations in susceptibility genes only increase the risk of developing the disease but do not cause it.”¹

In the study, investigators used obesity as a model to accelerate and exaggerate the stressor experienced in the body throughout life. They found that a history of obesity or transient obesity leads to changes in the DNA structure within immune cells, which causes them to produce more inflammatory molecules.¹

Previous research results have shown that the immune system in the eye of someone with AMD can become aggressive and dysregulated. The immune cells protect the eye from bacteria and viruses but can also be activated when the body is exposed to stressors, including excess fat in obesity.¹

Being overweight is 1 of the biggest non-genetic risk factors for developing AMD, after smoking.¹

“Our findings provide important information about the biology of the immune cells that cause AMD and will allow for the development of more tailored treatments in the future,” Masayuki Hata, PhD, MD, an ophthalmology professor at Kyoto University, in Japan, said in the statement.¹

Investigators hope that the results will lead to more research beyond obesity-related diseases and focus on other diseases characterized by increased neuroinflammation, including Alzheimer disease and multiple sclerosis.¹

The leading causes of blindness and low vision in the United States are age-related eye diseases, such as AMD, cataract, diabetic retinopathy, and glaucoma, according to the CDC.²

AMD is an eye disorder that is related to aging and can damage sharp and central vision, which helps individuals see objects clearly. There are 2 forms: dry and wet.

Wet AMD occurs when abnormal blood vessels behind the retina start to grow under the macula, which leads to blood and fluid leakage. The bleeding, leaking, and scarring can cause damage and lead to central vision loss. One symptom is that straight lines can appear wavy.²

Dry AMD occurs when the macula thins as part of the aging process and gradually blurs central vision. Dry AMD accounts for approximately 70% to 90% of all AMD cases. It affects both eyes and occurs more slowly than wet AMD. One symptom is drusen, which are tiny white or yellow deposits under the retina.²

Approximately 1.8 million Americans aged 40 years and older are affected by AMD, according to the CDC.

There were an estimated at 2.95 million individuals with AMD in 2020.²

References

1. Obesity linked to macular degeneration. EurekAlert. News release. January 10, 2023. Accessed January 11, 2023. https://www.eurekalert.org/news-releases/976228

2. Common eye disorders and disease. CDC. Updated December 19, 2022. Accessed January 11, 2023. https://www.cdc.gov/visionhealth/basics/ced/index.html#:~:text=Dry%20AMD%20is%20when%20the,lost%20in%20the%20affected%20eye