New research from the University of Alabama at Birmingham has investigated the possible under-reporting of smoking – regarded as a major modifiable risk factor for age-related macular degeneration (AMD) – by persons with the disease. The study concludes that “the rate of possible smoking deception [appears] higher for macular degeneration and those at risk of late-stage AMD than is generally reported in the US population.”
The research, entitled Smoking deception and age-related macular degeneration, was published in the August 2014 Special Issue on AMD of Optometry and Vision Science. The author is Mark W. Swanson, OD, MSPH, FAAO, from the School of Optometry, University of Alabama at Birmingham.
Optometry and Vision Science, the official publication of the American Academy of Optometry, publishes current developments in optometry, optics, and vision science, and promotes interdisciplinary exchange among optometrists and vision scientists worldwide.
About the “Smoking Deception” Research
Excerpted from Study shows patients with AMD deny smoking more often than those without AMD at Healio.com:
“Most, but not all, studies of smoking and macular degeneration have noted an excess risk, with some studies reporting 100% increases among active smokers,” [Doctor Swanson] said.
“Smoking deception, or failing to self-report as a smoker, is a recognized concern in studies involving reports of active smoking status,” he continued. “Studies specifically investigating the underreporting of active smoking have noted rates from a low of 1% to as high as 79%.”
Swanson said he used estimates of smoking deception from the 2005 to 2008 National Health and Nutrition Examination Survey. Patients considered for Swanson’s [study] were at least 40 years old and had cotinine levels performed and gradable fundus photos [i.e., a photograph of the interior surface of the eye, including the retina, optic disc, and macula] for both eyes, for a total of 4,639 subjects.
[Editor’s note: Cotinine is a product formed after the chemical nicotine enters the body. Measuring cotinine in people’s blood is the most reliable way to determine exposure to nicotine both for smokers and for nonsmokers exposed to environmental tobacco smoke. Measuring cotinine is preferred to measuring nicotine because cotinine remains in the body longer.]
Any level of AMD was found in 6.7% of the [study subjects], Swanson reported. He said that self-reporting of cigarette and nicotine usage in those with any level of AMD and those at risk of late-stage AMD was slightly less than that seen in the general U.S. population.
“For both individuals with AMD and at risk for late AMD, about 5% are potential smoking deceivers,” Swanson said. “This is not a large prevalence at the individual level; however, given the approximate 9.5 million people at risk for late-stage AMD, this equates to more than 450,000 persons within the U.S. population who may misidentify themselves as nonsmokers.”
More about Age-Related Macular Degeneration
Age-related macular degeneration (AMD) is gradual, progressive, painless deterioration of the macula, the small sensitive area in the center of the retina that provides clear central vision. Damage to the macula impairs the central (or “detail”) vision that helps with essential everyday activities such as reading, preparing meals, watching television, playing card and board games, and sewing.
AMD is the leading cause of vision loss for people aged 60 and older in the United States. According to the American Academy of Ophthalmology, 10-15 million individuals have AMD and about 10% of people who are affected have the “wet” type of AMD.
Wet Macular Degeneration (AMD)
In wet, or exudative, macular degeneration (AMD), the choroid (a part of the eye containing blood vessels that nourish the retina) begins to sprout abnormal new blood vessels that develop into a cluster under the macula, called choroidal neovascularization (neo = new; vascular = blood vessels).
The macula is the part of the retina that provides the clearest central vision. Because these new blood vessels are abnormal, they tend to break, bleed, and leak fluid under the macula, causing it to lift up and pull away from its base. This damages the fragile photoreceptor cells, which sense and receive light, resulting in a rapid and severe loss of central vision.
Dry Macular Degeneration
The dry (also called “atrophic”) type of AMD affects approximately 80-90% of individuals with AMD. Its cause is unknown, it tends to progress more slowly than the wet type, and there is not – as of yet – an approved treatment or cure. “Atrophy” refers to the degeneration of cells in a portion of the body; in this case, the cell degeneration occurs in the retina.
In dry age-related macular degeneration, small white or yellowish deposits, called drusen, form on the retina, in the macula, causing it to deteriorate or degenerate over time. These small yellow deposits beneath the retina are a buildup of waste materials, composed of cholesterol, protein, and fats. Typically, when drusen first form, they do not cause vision loss. However, they are a risk factor for progressing to vision loss.
Risk Factors for Macular Degeneration
The primary risk factors for AMD include the following:
- Smoking: Current smokers have a 2-3 times higher risk for developing AMD than do people who never smoked. It’s best to avoid second-hand smoke as well.
- Sunlight: Ultraviolet (UV) light is not visible to the human eye, but can damage the lens and retina. Blue light waves that make the sky, or any object, appear blue, are visible to the human eye and can also damage the lens and retina. Living Well with Low Vision reports on these lighting issues in Artificial Lighting and the Blue Light Hazard. Avoid UV light and blue/violet light as much as possible by wearing sunglasses with an amber, brown, or orange tint that blocks both blue and UV light.
- Uncontrolled hypertension: The National Eye Institute (NEI) reports that persons with hypertension were 1.5 times more likely to develop wet macular degeneration than persons without hypertension. It’s important to keep your blood pressure controlled within normal limits.
- A diet high in packaged, processed food and low in fresh vegetables: NEI suggests that eating antioxidant-rich foods, such as fresh fruits and dark green leafy vegetables (kale, collard greens, and spinach) may delay the onset or reduce the severity of AMD. Eating at least one serving of fatty fish (salmon, tuna, or trout) per week may also delay the onset or reduce the severity of AMD.
- Advanced age: The American Academy of Ophthalmology states that AMD is the leading cause of vision loss for people aged 60 and older in the United States.
- Race: According to the NEI, Whites/Caucasians are more likely to have AMD than people of African descent.
- Family history: NEI reports that individuals with a parent or sibling with AMD have a 3-4 times higher risk of developing AMD.
You can read more about the full range of AMD risk factors at Risk Factors for Age-Related Macular Degeneration on the VisionAware website.
More about the Research from Optometry and Vision Science
From the article abstract:
Purpose: Smoking has been identified as a major modifiable risk factor for age-related macular degeneration (AMD). Smoking deception or failing to self-report as a smoker is a recognized concern among studies of smoking-related disease. To date, no studies have evaluated the rates of smoking deception in macular degeneration.
Methods: Data from the 2005 to 2008 National Health and Nutrition Examination Survey were used to produce estimates of smoking deception among three ethnic groups within the US population. Comparisons of self-reported rates of cigarette use, any nicotine product use, and serum cotinine levels were used to produce estimates of potential smoking deception among adults older than 40 years with any-level macular degeneration and those at risk of late-stage disease.
Results: Any-level AMD was found to be present in 6.7% of this cohort. Excluding those with late AMD, 9.7% were at risk of developing late-stage disease. Among individuals with any level of macular degeneration, 5.4% were potential smoking deceivers. A similar rate was seen among those at risk of late-stage disease at 5.0%.
Conclusions: The rate of possible smoking deception seems higher for macular degeneration and those at risk of late-stage AMD than is generally reported in the US population. While the deception rate is low at the individual level, as many as 450,000 adults in the US population at risk of late-stage AMD may misclassify their smoking status.
Additional Research from Optometry and Vision Science
- A New Study Investigates the Abandonment Rate of Low Vision Devices
- A New Method for Measuring Visual Acuity in People with Extremely Low Vision
- What Is Optic Flow? Why Is It Important for People with Low Vision?
Acknowledgment
Cigarette in an ashtray photo is a Wikimedia Commons file, used in accordance with the Creative Commons Attribution-Share Alike 2.0 Generic license.
