Actor Michael J. Fox, who has been the most famous promoter of Parkinson's disease research since his diagnosis 12 years ago, recently published an autobiography that makes jokes of the past and has a hopeful look at the future.

In a recent interview on Good Morning America, Fox discussed the book, which is what he says is a letter to those graduating from high school from a high school drop out.

You can read an excerpt from the book, 'A Funny Thing Happened on the Way to the Future,' and watch his interview with George Stephanopolous on ABC.com.

A recent study published in the Neurology Journal found longtime smoking reduces the risk of developing Parkinson's disease.

The study looked at the lifetime smoking history of more than 300,000 people, and confirmed the inverse relationship between smoking and Parkinson's disease, established in earlier scientific studies.

But don't be so quick to light up those cig's.

Researchers say they've found a critical new piece to the puzzle: It appears to be the length of time one has been a smoker - not the number of cigarettes smoked - that has the most effect on disease risk reduction.

"Nobody should advocate smoking to prevent Parkinson's disease," Dr. Honglei Chen, the lead study author and a tenure-track investigator at the National Institute of Environmental Health Science, told CNN. "It's important to make that very, very clear."

Smoking continues to be the leading cause of preventable death in the United States and has been linked to an increase in heart-disease risk, stroke risk, and several types of cancers.

There's a new treatment option available for patients with early Parkinson's disease. Mirapex ER is the "extended release" version of Mirapex, a drug that's already on the market. The difference between the two is that Mirapex ER only needs to be taken once a day, while Mirapez has to be taken three times daily.

Studies comparing the two drugs found that one daily dose of Mirapex ER improved Parkinson's symptoms to about the same degree as the three-times-daily Mirapex. The potential side effects of both drugs are similar: nausea, sweating, sleepiness, hallucination, dizziness, constipation, vomiting, fatigue, muscle spasms, and dry mouth.

Talk to your doctor about whether Mirapex ER may be an option for you.

A study by the Parkinson's Institute found that the risk of developing Parkinson's disease was nearly six times greater in people exposed to the common industrial solvent trichloroethylene (TCE).

Trichloroethylene, or TCE, is a solvent that was once widely used in dry cleaning and to clean grease off metal parts, and it was once used as an anesthetic, especially during childbirth. But concerns about its toxicity led to it being mostly abandoned and replaced by other anesthetics and solvents.

For the study researchers took job histories of 99 pairs of twins in which only one twin had Parkinson's Disease. Scientists used twins in the study because they are genetically identical or very similar and provide an ideal population for evaluating environmental risk factors.

"This is the first time a population-based study has confirmed case reports that exposure to TCE may increase a person's risk of developing Parkinson's disease," said Samuel Goldman, MD, MPH of the Parkinson's Institute. "TCE has been widely used for more than 50 years in a range of industrial settings and products.  It is now primarily used to clean grease off metal parts, and as a component in glues, paints, lubricants and stain removers.  PERC is the predominant solvent used in dry-cleaning."

Parkinson's disease, caused by the death of cells in the brain that secrete the neurotransmitter dopamine, is characterized by severe tremors, rigidity in the limbs and other symptoms.  It strikes an estimated 100,000 Americans each year and is ultimately fatal.  Genetics may play a role in susceptibility to Parkinson's, but the disease has also been linked to environmental factors such as pesticides and head trauma.