A new study suggests that maintaining high levels of serum vitamin D may help protect against Parkinson disease.

The study led by Paul Knekt and colleagues from National Institute for Health and Welfare in Helsinki, Finland shows men and women with high levels of serum vitamin D were less likely to develop Parkinson disease.

The association was derived after adjustment for sex, age, marital status, education, alcohol consumption, leisure-time physical activity, smoking, body mass index, and a month of blood draw.

For the study, a total 3173 men and women ages 50 to 79 who were free of Parkinson disease at baseline were enrolled in the Mini-Finland Health Survey conducted between 1978 and 1980 with Parkinson disease occurrence monitored through the end of 2007. 

During the 29-year follow-up, 50 incident cases of Parkinson disease were identified and frozen blood samples stored at baseline were then analysed for the level of vitamin D.

The researchers found individuals with their levels of serum vitamin D in the highest quartile were 67 percent less likely to be diagnosed with Parkinson disease.

The study is observational, meaning that no causal relationship between vitamin D and Parkinson disease has been established. Further studies are needed to confirm taking vitamin D protects against Parkinson disease.

Parkinson disease is a brain disorder that affects neurons in part of the brain that controls muscle movement. 

Symptoms of Parkinson disease include trembling of hands, arms, legs, jaw and face, stiffness of the arms, legs and trunk, slowness of movement, poor balance and coordination.

The onset of the disease is about 60 years of age. The disease, for which there is no cure, is estimated to affect half a million men and women in the United States.

David Liu and editing by Rachel Stockton