Dear Dr. Gott: I injured my back in a fall on ice six years ago. I had surgery on my back in 2007, with three spacers inserted. I still have one disc that burst and bulged. Could this all cause Parkinson's disease? I ask because my walking is very unstable.

Dear reader: Your back injury and subsequent surgery are completely unrelated to Parkinson's disease.

The back is a complex structure. Pain often occurs from strained muscles and ligaments following heavy lifting or twisting the wrong way. Other common causes include arthritis, osteoporosis or sciatica. Unfortunately, as you have indicated, it can also arise from a bulging, ruptured or compressed disc, a condition that could definitely present as an instability when walking.

It is important that people lead a healthful lifestyle, as obesity, anxiety, depression and remaining sedentary increase the risk of developing lower-back pain. Exercise such as walking, yoga, mild aerobics and physical or hydrotherapy has been found helpful in strengthening the back.

Over-the-counter pain relievers provide temporary relief for the average person confronting back pain. If there's no noticeable improvement, a physician might prescribe muscle relaxants or pain relievers, depending on the circumstances. Short periods of bed rest may be recommended; however, longer episodes have been found to cause more harm than good. It appears the body prefers to be upright and in motion.

In your case, I would follow the recommendations of your orthopedic surgeon. Be sure to ask whether a few sessions at your local hospital's physical-therapy department would improve your condition.

Parkinson's disease is a progressive neurological disorder that occurs when nerve cells in a portion of the brain die or become impaired. The cells normally produce a chemical called dopamine that allows a coordinated function of the body's muscles and their movement. When 80 percent of the cells that produce dopamine are damaged, symptoms of Parkinson's appear.

Symptoms vary and can occur slowly but include tremor, rigidity, gait and postural abnormalities, lack of facial expression, memory loss, sleep disorders, depression, irritability and others.

There are no X-rays or blood tests for confirmation. People with the condition should be under the care of a neurologist. Medication is available for this complex disorder.

To provide related information, I am sending you a copy of my Health Report "Parkinson's Disease." Other readers who would like a copy should send a self-addressed stamped No. 10 envelope and a check or money order for $2 to Newsletter, P.O. Box 167, Wickliffe, OH 44092. Be sure to mention the title.

Dear Dr. Gott: Quite a while ago, you answered a complaint about soft, splitting, ridged fingernails. You advised the reader to use white iodine every day for one week and then apply it once a week. I have done this for about six months now, and my nails have remarkably improved. It may not work for everyone, but it surely has worked for me.

Dear reader: I have received many letters that claim positive results from using white/colourless iodine to improve nail quality. To the best of my knowledge, there is no limit to the length of time that it can be applied. It is also unclear why or how it works, but like most of my home remedies, I don't question success. If it works for you, then keep it up.

To provide related information, I am sending you copies of my Health Reports "Dr. Gott's Compelling Home Remedies" and "More Compelling Home Remedies." Other readers who would like copies should send a self-addressed stamped No. 10 envelope and a check or money order for $2 per report to Newsletter, P.O. Box 167, Wickliffe, OH 44092. Be sure to mention the title(s).

Dr. Peter Gott is a retired physician and the author of the book "Dr. Gott's No Flour, No Sugar Diet," available at most chain and independent bookstores, and the recently published "Dr. Gott's No Flour, No Sugar Cookbook."