Cataracts can occur at any age, but they are most common later in life. More than 20 million Americans over age 40 are estimated to have had one. That number is anticipated to reach about 30 million by 2020. Here are six factors that increase your risk.
Why cigarette smoking raises the risk of developing a cataract is not clear. One possibility is that smoking may reduce blood levels of nutrients required for lens maintenance.
Long-term use of corticosteroids, especially at high doses, is the most common drug-related cause of cataracts. Cataracts can also develop as a result of applying topical corticosteroids to the eyelids or using corticosteroid-containing eyedrops.
Blunt trauma to the eye or damage to the eye from certain chemicals can cause clouding of the lens, either immediately or later on. Rapid formation of cataracts commonly occurs after a penetrating eye injury.
Sunlight and ionizing radiation
Population studies have shown that prolonged exposure to the ultraviolet radiation in sunlight more than doubles the risk of cortical cataracts. In one study the risk of developing cortical cataracts was two times greater in people with the highest levels of sunlight exposure.
People with diabetes are at increased risk for cataracts, particularly the posterior subcapsular type, and they tend to be affected at an earlier age than people who do not have diabetes.
Being overweight also may put you at risk for developing cataracts. Overweight is defined as a body mass index between 25 and 29.9; obesity is a BMI of 30 or greater. A study of men between ages 40 and 84 compared levels of BMI with the risk of developing cataracts. Having a BMI between 22 and 28 increased cataract risk by about 50 percent, and a BMI above 28 more than doubled the risk.