Scientists have linked a disease known to cause blindness to obesity.

Researchers from the University of Montreal published research linking obesity to macular degeneration on January 10 in Science.

Age-related macular degeneration (AMD) is the world’s leading cause of blindness and vision loss in Americans ages 65 and up, according to the CDC. The organization estimates that 1.8 million Americans 40 years old and older are affected by the disease, and 7.3 million more are at risk of developing it.

The CDC has already linked risk factors such as smoking, high cholesterol, and high blood pressure to AMD. These risk factors are also commonly associated with obesity and being overweight.

Przemyslaw Sapieha, an ophthalmology professor at the University of Montreal, led the new study alongside then postdoctoral fellow Dr. Masayuki Hata, now an ophthalmology professor at Kyoto University in Japan, to find out why some with a genetic disposition to AMD develop the disease, whereas others do not.

Scientists used obesity as a model in this new study to hasten and exacerbate “stressors” experienced by a human body in a given life span. Researchers observed that those with a history of obesity were more susceptible to the production of “inflammatory molecules” due to changes in the genetic structure of immune cells.

“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,” said Sapieha in the study, according to SciTechDaily.

“This observation suggests that we must gain a better understanding of how other factors such as environment and lifestyle contribute to disease development.”

The National Library of Medicine produced a similar study in 2016 that also sought to explore the relationship between AMD and obesity. However, unlike the 2023 study, this one found that “excess body weight was weakly associated with an increase in the risk of AMD.”

“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,” said Hata about the new study, per SciTechDaily.

Obesity continues to be one of the most prolific epidemics in the United States, with rates across the state and nation continuing to rise.