Risk Factors
Aging is the primary risk factor for cataracts, but other factors are also involved.
Age
Nearly everyone who lives long enough will develop cataracts to some extent. A major study reported that:
- About 40% of people between 55 and 64 years old had some opaque areas in their lenses, and 5% had fully-developed cataracts
- About 70% of people between 65 and 74 years old had opaque areas, and 18% had cataracts
- More than 90% of people between 75 and 84 years old had opaque areas, and almost half had cataracts
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One study indicated that posterior subcapsular cataracts are the most common type in people under 70 years old, while nuclear and mixed cataracts are most common in people over 80. The risk for nuclear cataracts also increases with age.
Gender
Women face a higher risk than men. Women who started menstruating late are at an even higher risk.
Physical Features
Eye Features. People who are nearsighted and those with brown eyes may be at higher than average risk. (Not all studies, however, report a higher risk in people with darker eyes.)
Obesity and Height. Studies are now reporting obesity as a risk factor for cataracts, notably posterior subcapsular cataracts, which form toward the back of the lens. A study of 17,150 people found a specifically higher rate of cataracts in overweight people who are tall and whose fat distribution is primarily in the abdomen.
Ethnicity
A 9-year population study, published in 2004, revealed that African Americans have nearly twice the risk of developing cataracts then whites. Analysis of the 3,000 participants also demonstrated for the first time that the risk of cortical cataracts is 3 times higher in African Americans than Caucasians. Earlier studies also identified a higher cataract risk in the black population, suggesting that it may be due to other medical illnesses, particularly diabetes. It has long been known that African Americans are much more likely to become blind from cataracts and glaucoma than white Americans, mostly due to lack of treatment.
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