In contrast to the SMC, earlier large HRT and cataract risk studies in the United States, Australia and Europe reported mixed results; importantly, some of these studies included women who were premenopausal and so possibly protected by endogenous estrogen. Results of the Swedish study may have been impacted by factors unique to this population: for example, nearly all participating women shared the same ethnicity, and all had equal access to care. The study did not identify type of HRT, type of cataract, or measure exposure to excess sunlight (a risk factor for cataract, although unlikely to impact residents of northern Europe).
Another Serious Eye Disease Linked to Smoking
Smoking is already a known risk factor for age-related macular degeneration, cataract and thyroid eye disease. Now, the first study to specifically examine the impact of smoking on uveitis-inflammation of the eye’s middle layer of tissue-indicates that tobacco smoke likely plays a role in this serious eye disease, as well. In the United States about 10 percent of blindness is caused by uveitis.
Researchers led by Nisha Acharya, MD, analyzed medical records for smoking status and the type and cause of inflammation for all uveitis clinic patients seen at the University of California, San Francisco’s F.I. Proctor Foundation between 2002 and 2009. Results for this patient group were compared with a matched control group and the data were adjusted for differences in age, race, gender, and median income. Smokers were 2.2 times more likely to have uveitis than those who had never smoked. Smoking correlated with higher risk of uveitis for all anatomical locations within the eye and for both infectious and non-infectious disease types. A particularly strong relationship was found between smoking and inflammatory central macular edema (swelling of the central area of the retina) in patients with certain types of uveitis.
“Cigarette smoke includes compounds that stimulate inflammation within the blood vessels, and this may contribute to immune system disruption and uveitis,” Dr. Acharya said. If other research replicates the UCSF findings, uveitis risk would be another reason for healthcare providers to advise people to stop smoking.
If uveitis symptoms such as eye redness, blurred vision, pain and sensitivity to light occur, people should seek medical care right away. Uveitis can harm important structures like the iris in the front of the eye, and the retina, the light-sensitive tissue at the back of the eye where images are focused and relayed to the optic nerve. The condition can develop in people with systemic diseases such as multiple sclerosis or juvenile arthritis or be part of the body’s response to an infection like herpes simplex or tuberculosis. Often, though, uveitis has no apparent cause.
Provided by American Academy of Ophthalmology