Impact of smoking on cataract formation difficult to gauge

Issue: October 2008

Physicians in India have known for years that smoking has become an epidemic in their country, but it is only recently that studies have been conducted to determine whether there is a specific correlation between smoking and ocular complications.

According to Praveen K. Nirmalan, MD, MPH, 57% of men aged 15 to 49 years and 10.9% of women aged 15 to 49 years use some form of tobacco.

“The National Family Health Survey-III from India reports … oral use of smokeless tobacco and smoking of ‘bidis’ (tobacco wrapped in dry leaves) is the dominant form of smoking in India,” Dr. Nirmalan told Ocular Surgery News in an e-mail interview. “Tobacco use is more prevalent in rural areas than in urban areas among both men and women.”

A study published in the New England Journal of Medicine estimated that there are about 120 million smokers in India and that, among men, 61% of those who smoke can expect to die between the ages of 30 to 69 years, compared with 41% of those men who do not smoke. For women, the study found that 62% of smokers can expect to die between the ages of 30 and 69 years, compared with 38% of nonsmokers.

Smoking and cataracts

Dr. Nirmalan and other researchers in India are currently trying to evaluate the relationship between this smoking epidemic and its widespread effect on ocular issues. However, because cataract formation is multifactorial, it is difficult to conclude that smoking increases the risk of cataracts.

“Large epidemiological studies from India (Aravind Comprehensive Eye Study, Andhra Pradesh Eye Disease Study) have suggested a correlation between smoking and cataracts and even among subgroups of cataracts. Age-related cataracts are a major issue in India, with a high prevalence of lens opacities even at younger ages,” Dr. Nirmalan said. “At this point, although logical to assume that the growing epidemic of smoking will have an effect on cataracts, we do not have enough evidence to suggest how much of an impact can be attributed to smoking.”

Abhay R. Vasavada, MD, FRCS, agrees with Dr. Nirmalan.

Abhay R. Vasavada

“We did a small study on 200 patients undergoing cataract surgery to find out how many are actually heavy smokers,” Dr. Vasavada said. “And there were only 10 heavy smokers. There were plenty [of patients] only smoking a few a day, but 10 were almost two packs a day. We were expecting more [heavy smokers], but we didn’t find much.”

Dr. Vasavada said the use of tobacco, in any form, including chewing tobacco, is harmful to the eyes. Tobacco use can also increase the risk of developing advanced macular degeneration, as well as retinal problems.

“To me, the cataract, I’m not sure how exactly it’s related, but I see many patients [who smoke], where I check the vision, and the vision is not good. When I look at the macula, some of them have some mild maculopathy. And I attribute many of them to smoking or chewing tobacco,” he said. “The onset of these retinal changes and macular changes are [occurring] at an earlier age. Sometimes they are nonspecific changes, but they do affect the retina and the vision.”

Dr. Vasavada said he tries to explain to his patients the dangers of smoking in association with their surgeries.

“We need to ask [patients] to reduce the smoking 2 to 3 weeks prior to surgery and also for a month or so after surgery because the patients can cough and they can have irritation in the eye, infection and so on. From a cataract surgery point of view, we counsel them on how important it is for the visual function and recovery from the surgery and so on,” he said. “We make a point to educate them, but you know it’s only for a short time, and then they go back to their old habits.”

Public education, government involvement

Dr. Vasavada said chewing tobacco causes damage, not only to the eyes but also when used in combination with smoking, which can greatly increase mortality rates.

“The real menace, more than smoking, is the tobacco chewing. … [It] manages to keep some form of tobacco in the mouth, so oral cancers and oral hygiene and all that stuff is really bad, and I see some effects in the eye also,” Dr. Vasavada said.

Dr. Nirmalan said there are some problems with the government’s approach to limiting smoking and educating the population. The bidi industry tends to be a rural livelihood issue, and the government is still finding ways to educate rural citizens on the dangers of smoking.

“Drying of the leaves and rolling of the bidis was (to a large extent, still remains) a major source of livelihood for rural women in many pockets of India, with women getting paid based on the number of bidis they roll. As an activity, this found favor in many rural settings since this was a household activity that brought in additional revenue to the family,” Dr. Nirmalan said.

“The government has been moving strongly, especially in recent times, against smoking and tobacco in any form. One constraint to change behavior, however, is the need to identify alternate employment and revenue generation, and this has slowed down the process,” he said.

The bidi industry was well-entrenched in politics as well, Dr. Nirmalan said, and had grown into a mobilizing power, especially when cooperating with political parties. This cooperation also slows the desire to find alternate employment.

“Some of the large bidi cooperatives in Kerala have closed down and are now engaged in alternate business. However, it does not mean that a large number of people who were engaged in the bidi business have found alternate employment,” he said.

Dr. Vasavada said the government tends to focus mainly on tobacco’s effect on causing cancer in smokers and will gloss over other complications that could also arise, namely blindness.

“The smoking and its association with cancer is so much that the other issues, like eye issues, are neglected … by the teachers and by the government and by everybody. They don’t pay enough attention to education,” he said. “It’s not good. I talked to the health commissioner a few months ago, and they said the priority of the resources we have are such that we give priority to other diseases and other strategies, so I don’t see that [the Indian] government is likely to take up this issue.”

For more information:

Praveen K. Nirmalan, MD, MPH, can be reached at Prashasa Health Consultants Pvt. Ltd., A4/1st Floor, Siddartha Enclave, Sreeramanagar, Off Road 12, Banjara Hills, Hyderabad, Andhra Pradesh - 500 034; 40-40218474; e-mail: echasapt@gmail.com. Abhay R. Vasavada, MD, FRCS, can be reached at Iladevi Cataract & IOL Research Center, Raghudeep Eye Clinic, Gurukul Road, Memnagar, Ahmedabad – 380 052; 79-27492303; fax: 79-27411200; e-mail: icirc@abhayvasavada.com.

References:

Jha P, Jacob B, et al, and the RGI-CGHR Investigators. A nationally representative case-control study of smoking and death in India. N Engl J Med. 2008; 358:1137-1147. Epub 2008 Feb 13.

Krishnaiah S, Vilas K, et al. Smoking and its association with cataract: results of the Andhra Pradesh eye disease study from India. Invest Ophthalmol Vis Sci. 2005; 46:58-65.