/ 25 July 2006

Smokeless tobacco use increases cataract risk

Using snuff or chewing tobacco is associated with an increased likelihood of developing cataracts, Indian researchers report.

Dr Prema Raju of the Vision Research Foundation, Sankar Netralaya, Chennai and colleagues evaluated tobacco use among 3 924 adults from rural areas. In all, 1 705 used tobacco in various forms.

Nine hundred subjects, mainly women, used smokeless tobacco — either as snuff or for chewing — while 731 smoked tobacco predominantly in rolled cigarette-style bidis. The remainder used both forms.

Overall, tobacco users had 72% higher prevalence of cataracts, the team reports in the British Journal of Ophthalmology. However, the prevalence of cataracts was more than twice as great among those using the smokeless forms as compared to smokers.

Also, cataracts affected nine times more heavy users of smokeless tobacco as compared to heavy smokers, the researchers report.

Raju said that smokeless tobacco users have three-times higher levels of cadmium in their blood than non-users. Cadmium present in tobacco inactivates superoxide dismutase, an antioxidant, resulting in oxidant damage to the lens of the eye. – Reuters