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Macular degeneration is a feared condition, so this study finding a link with calcium supplements and age-related macular degeneration in those 68 and older is a bit alarming. However, it shows association, not causation, because it looked at people only one time. But once again supplements are looking suspect. Another reason to stick with whole foods, especially leafy greens and fish, and don't smoke. From Medscape:

Calcium Supplementation Associated With Macular Degeneration

Individuals who take more than 800 mg of calcium daily are almost twice as likely to be diagnosed with age-related macular degeneration (AMD) as those who did not, according to the results of a new study published online April 9 in JAMA Ophthalmology.

Caitlin L. M. Kakigi, BA, from the Department of Ophthalmology, University of California, San Francisco, and colleagues evaluated 3191 participants in the 2007 to 2008 National Health and Nutrition Examination Survey (NHANES) aged 40 years and older, including 248 patients with AMD diagnosed by fundus photography. Each participant was surveyed about consumption of dietary supplements and antacids during the 30-day period preceding trial enrollment.

The researchers found the odds of an AMD diagnosis were elevated among participants who reported taking 800 mg of calcium or more daily....The association was strongest in older people, with an adjusted OR of 2.63 (95% CI, 1.52 - 4.54) for those aged 68 years and older. In fact, there was no association between AMD diagnosis and calcium intake in participants younger than 68 years. The average age of participants with AMD in this study was 67.2 years compared with 55.8 years for those without an AMD diagnosis.

Rahul Khurana, MD, a clinical spokesperson for the American Academy of Ophthalmology and a partner at Northern California Retina Vitreous Associates in Mountain View, who was not involved in the study, cautioned that it is an exploratory analysis."It shows association but not causation."

Last month (Feb. 12, 2014) I posted two studies that discussed the link between exercise and health, including eye health and macular degeneration. This following article builds on those studies to discuss the link between eye health and exercise, how exercise could protect our eyes from age-related vision loss, and even repair eye damage. From the NY Times:

Exercising for Healthier Eyes

There have been suggestions that exercise might reduce the risk of macular degeneration, which occurs when neurons in the central part of the retina deteriorate. The disease robs millions of older Americans of clear vision. A 2009 study of more than 40,000 middle-aged distance runners, for instance, found that thise covering the most miles had the least likelihood of developing the disease. But the study did not compare runners to non-runners, limiting its usefulness. It also did not try to explain how exercise might affect the incidence of an eye disease. 

So, more recently, researchers at Emory University in Atlanta and the Atlanta Veterans Administration Medical Center in Decatur, Ga., took up that question for a study published last month in the Journal of Neuroscience. Their interest was motivated in part by animal research at the V.A. medical center. That work had determined that exercise increases the levels of substances known as growth factors in the animals’ bloodstream and brains. These growth factors, especially one called brain-derived neurotrophic factor, or B.D.N.F., are known to contribute to the health and well-being of neurons and consequently, it is thought, to improvements in brain health and cognition after regular exercise.

But the brain is not the only body part to contain neurons, as the researchers behind the new study knew. The retina does as well, and the researchers wondered whether exercise might raise levels of B.D.N.F. there, too, potentially affecting retinal health and vision.

To test that possibility, the researchers gathered adult, healthy lab mice. Half of these were allowed to remain sedentary throughout the day, while the other animals began running on little treadmills at a gentle rodent pace for about an hour a day. After two weeks, half of the mice in each group were exposed to a searingly bright light for four hours. The other animals stayed in dimly lit cages. This light exposure is a widely used and accepted means of inducing retinal degeneration in animals. It doesn’t precisely mimic the slowly progressing disease in humans, obviously. But it causes a comparable if time-compressed loss of retinal neurons.

The mice then returned to their former routine — running or not exercising — for another two weeks, after which the scientists measured the number of neurons in each animal’s eyes. The unexercised mice exposed to the bright light were experiencing, by then, severe retinal degeneration. Almost 75 percent of the neurons in their retinas that detect light had died. The animals’ vision was failing.

But the mice that had exercised before being exposed to the light retained about twice as many functioning retinal neurons as the sedentary animals; in addition, those cells were more responsive to normal light than the surviving retinal neurons in the unexercised mice. Exercise, it seems, had armored the runners’ retinas.

Separately, the researchers had other mice run or sit around for two weeks, and then measured levels of B.D.N.F. in their eyes and bloodstreams. The runners had far more. Tellingly, when the scientists injected still other mice with a chemical that blocks the uptake of the growth factor before allowing them to run and exposing them to the bright light, their eyes deteriorated as badly as among sedentary rodents. When the mice could not process B.D.N.F., exercise did not safeguard their eyes.

Taken together, these experiments strongly suggest that “exercise protects vision, at least in mice, by increasing B.D.N.F. in the retina,” said Jeffrey Boatright, an associate professor of ophthalmology at Emory University School of Medicine and a co-author of the study.

She and her colleagues are trying to find ways to determine the impact of exercise on human eyes. But such experiments will take years to return results.

For now, she and Dr. Boatright said, people who are concerned about their vision, and especially those with a family history of retinal degeneration, might want to discuss an exercise program with their doctor. “As potential treatments go,” she said, “it’s cheap, easy and safe.”

More studies showing health benefits of moving and exercise. From Science Daily:

Dangers of ... sitting? Regardless of exercise, too much sedentary time is linked to major disability after 60

If you're 60 and older, every additional hour a day you spend sitting is linked to doubling the risk of being disabled -- regardless of how much moderate exercise you get, reports a new Northwestern Medicine study.

The study is the first to show sedentary behavior is its own risk factor for disability, separate from lack of moderate vigorous physical activity. In fact, sedentary behavior is almost as strong a risk factor for disability as lack of moderate exercise.

If there are two 65-year-old women, one sedentary for 12 hours a day and another sedentary for 13 hours a day, the second one is 50 percent more likely to be disabled, the study found.

"This is the first time we've shown sedentary behavior was related to increased disability regardless of the amount of moderate exercise," said Dorothy Dunlop, professor of medicine at Northwestern University Feinberg School of Medicine and lead author of the study. "Being sedentary is not just a synonym for inadequate physical activity."

Disability affects more than 56 million Americans. It's defined by limitations in being able to do basic activities such as eating, dressing or bathing oneself, getting in and out of bed and walking across a room. Disability increases the risk of hospitalization and institutionalization and is a leading source of health care costs, accounting for $1 in $4 spent.

The study focused on a sample of 2,286 adults aged 60 and older from the National Health and Nutrition Examination Survey. It compared people in similar health with the same amount of moderate vigorous activity. Moderate activity is walking briskly, as if you are late to an appointment.

The participants wore accelerometers from 2002 to 2005 to measure their sedentary time and moderate vigorous physical activity. The accelerometer monitoring is significant because it is objective.

From Science Daily:

Exercise may slow progression of retinal degeneration

Moderate aerobic exercise helps to preserve the structure and function of nerve cells in the retina after damage, according to an animal study appearing February 12 in The Journal of Neuroscience. The findings suggest exercise may be able to slow the progression of retinal degenerative diseases.

Age-related macular degeneration, one of the leading causes of blindness in the elderly, is caused by the death of light-sensing nerve cells in the retina called photoreceptors. Although several studies in animals and humans point to the protective effects of exercise in neurodegenerative diseases or injury, less is known about how exercise affects vision.

This is the first report of simple exercise having a direct effect on retinal health and vision," Pardue said. "This research may one day lead to tailored exercise regimens or combination therapies in treatments of blinding diseases."

The following two articles discuss exercise and healthy aging. The first discusses Olga Kotelko and Bruce Grierson (author of the book "What Makes Olga Run").  From the Feb. 10, 2014 New York Times:

Seeking the Keys to Longevity in ‘What Makes Olga Run?’

No one would mistake Olga Kotelko for one of the Olympians competing in Sochi, Russia, but at age 94, she holds more world records than most: 26, to be exact, including age-group bests in the high jump, the hammer throw and the 200-meter run. Not bad for someone who took up track and field at age 77.

The result is this jolly book, which follows the pair as they consult researchers in fields like gerontology, exercise physiology and genetics for insights into Ms. Kotelko’s remarkable youthfulness.

What they find are countless opinions, but little definitive proof. Genes, diet, temperament, the theories abound. (Mr. Grierson rules out performance-enhancing drugs.) Or maybe it’s the exercise itself.

Research on twins suggests that heredity accounts for only about 25 percent to 30 percent of longevity, so it is not enough simply to label Ms. Kotelko a “genetic freak.” Besides, tests show she lacks at least one gene associated with longevity, and it turns out that her telomeres, chromosome caps that shorten with age, are merely average in length.

As for her diet, it is abundant and promiscuous. Her staples include red meat, sauerkraut, cottage cheese and sour milk, and she eats “immoderate amounts” of tapioca pudding. A centenarian friend of hers, the Australian shot-putter Ruth Frith, eschews vegetables altogether.

Among the potential anti-aging elixirs Mr. Grierson explores, exercise appears most potent. This old standby doesn’t just keep hearts pumping and muscles strong; studies suggest it may protect the mind too, by promoting the formation of neurons in the hippocampus — a part of the brain associated with memory.

Since she began her track and field career, Ms. Kotelko has rarely remained still, and that active lifestyle may be more important than her workouts at the track.

From the Feb. 7, 2014 Science Daily:

Exercise may slow progression of retinal degeneration

Moderate aerobic exercise helps to preserve the structure and function of nerve cells in the retina after damage, according to an animal study appearing February 12 in The Journal of Neuroscience. The findings suggest exercise may be able to slow the progression of retinal degenerative diseases.

Age-related macular degeneration, one of the leading causes of blindness in the elderly, is caused by the death of light-sensing nerve cells in the retina called photoreceptors. Although several studies in animals and humans point to the protective effects of exercise in neurodegenerative diseases or injury, less is known about how exercise affects vision.

Machelle Pardue, PhD, together with her colleagues Eric Lawson and Jeffrey H. Boatright, PhD, at the Atlanta VA Center for Visual and Neurocognitive Rehabilitation and Emory University, ran mice on a treadmill for two weeks before and after exposing the animals to bright light that causes retinal degeneration. The researchers found that treadmill training preserved photoreceptors and retinal cell function in the mice.