Lead exposure increases cataract risk

Long-term exposure to high levels of lead seems to triple the risk of developing cataract.Previous studies have documented the presence of lead in the lenses of people with cataract, but it was unclear if accumulated lead exposure was a risk factor for the condition. The intrusion of lead into the lens may alter the lens redox status and cause protein conformational changes that decrease lens transparency.Researchers from the Brigham and Women's Hospital in Boston, USA analysed the levels of lead and eye examination data of 642 men who participated in the study. The subjects were at least 60 years old.Cataracts were identified in 122 men. After accounting for cigarette smoking, diabetes, blood lead levels, and vitamin intake, people with the highest levels of lead in their shinbone were 3.2 times more likely to have cataracts than those with the lowest levels.Cataract risk also rose as lead levels in the kneecap climbed, but the association was not as strong as that seen with lead in the shinbone. In contrast, no association was seen with blood lead levels, which only reflect short-term lead exposure.Accumulated lead exposure may be an important risk factor for cataract. This research suggests that reduction of lead exposure could help decrease the global burden of cataract.