A Swedish study showed that the risk of developing a cataract is reduced after ceasing smoking, but remains higher than the risk in people who have never smoked.
The study included 44,371 men aged 45 to 79, among whom 25% were active smokers and 39% were former smokers. The findings show that smoking more than 15 cigarettes per day was associated with 42% higher likelihood of a cataract surgery during 12 years of follow-up. In patients who had quit smoking for 20 years, that risk had declined to a relative 21% above that of never-smokers.
Smoking increases the oxidative stress in the lens by generating free radicals and reduces the plasma concentration of several antioxidants, such as ascorbic acid, the researchers said. Cigarette smoke also contains toxic metal ions, and cadmium can accumulate in cataractous lenses of smokers. Cadmium affects anti-oxidative lens enzymes, which weakens the defense against oxidative damage and hastens cataract development.
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