A new study identifies several new risk factors for age-related macular degeneration, a sight-robbing disease mainly seen in older people.
As the population ages, more and more people worldwide are showing signs of age-related macular degeneration, or AMD. About 30 percent of people over 70 are diagnosed with the condition. While most have mild or moderate forms of the disease, 6 percent to 8 percent have an advanced form, which can lead to blindness. Doctors know smoking can increase the risk of AMD, but few other risk factors have come to light.
This study examined the role of body weight and body type on AMD risk. Participants were 261 individuals age 60 or older who showed early signs of the disease but who still had visual acuity of at least 20/200 in at least one eye. Patients were followed for about four and a half years to see what role body mass index, waist circumference, waist-to-hip ratio, and physical activity would have on the progression of the disease.
About 100 patients progressed to more advanced disease during the study. Results showed those with a higher body mass index, higher waist circumference, and higher waist-to-hip ratio were all around two-times more likely to develop the worsening condition. However, regular exercise -- defined as three times a week -- protected against progression. Compared to those who did no exercise, patients in this group had about 25-percent less chance of having their AMD progress.