Vitamin d & parkinson's disease finnish cohort
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Transcript of Vitamin d & parkinson's disease finnish cohort
www.pronutritionist.net
Serum Vitamin D and the Risk of Parkinson Disease
Knekt P et al.
Arch Neurol 2010; 67: 808-811.
Page 1 Knekt P. et al. Arch Neurol 2010; 67: 808-811.
Page 2
Background (1/2)
• Parkinson disease is a major cause of disability in elderly individuals
• Its risk factors are relatively unknown • Vitamin D plays an important role in the pathogenesis of skeletal
disorders and calcium homeostasis• Vitamin D inadequacy also predicts increased risk of other
chronic conditions as– cancer– cardiovascular diseases– type 2 diabetes
• Higher 25-hydroxyvitamin D level is also associated with lower relapse risk in multiple sclerosis
• Vitamin D deficiency might be also associated with neurodevelopmental disorders as autism and schizophrenia
Knekt P. et al. Arch Neurol 2010; 67: 808-811. www.pronutritionist.net
Background (2/2)
• Recently chronically inadequate vitamin D intake was proposed to play a significant role in the pathogenesis of Parkinson disease
– Possible mechanism might be a continuously inadequate vitamin D status leading to a chronic loss of dopaminergic neurons in the brain
• The exact mechanisms by which vitamin D may protect against Parkinson disease are not fully understood
• The epidemiological evidence of an association between vitamin D and Parkinson disease is limited to cross-sectional studies
– showing lower vitamin D status in patients with Parkinson disease compared with healthy controls
www.pronutritionist.netKnekt P. et al. Arch Neurol 2010; 67: 808-811.3
Methods
• Prospective follow-up study (The Mini-Finland Health Survey)
• Follow-up 29 years• n = 3173, aged 50 to 79 years• Serum 25-hydroxyvitamin D level was
determined from frozen samples stored at baseline
• Estimates of the relationship between serum vitamin D concentration and Parkinson disease incidence were calculated using the Cox model
Page 4 Knekt P. et al. Arch Neurol 2010; 67: 808-811. www.pronutritionist.net
Results (1/2)
• At baseline, Parkinson disease cases more often were– nonsmokers
– did not have hypertension or diabetes
than subjects who were free of the disease
• Serum vitamin D concentration was lower among Parkinson disease cases
• A significant inverse association between sex- and ageadjusted serum vitamin D level and Parkinson disease incidence was found
Page 5 Knekt P. et al. Arch Neurol 2010; 67: 808-811. www.pronutritionist.net
Results (2/2)
• Individuals with a serum vitamin D concentration
of at least 50 nmol/L had a 65% lower risk than those with values less than 25 nmol/L
• Mean serum vitamin D level in the present population was about 50% of the suggested optimal level (75-80 nmol/L)
• Despite the overall low vitamin D levels in the study population, a dose-response relationship was also found.
www.pronutritionist.netKnekt P. et al. Arch Neurol 2010; 67: 808-811.6
Discussion
• This cohort study shows that low serum vitamin D level predicts an elevated risk of Parkinson disease incidence
• Only a single measurement of serum 25 hydroxyvitamin D was available, which fails to take into account the intraindividual seasonal variation– However no interaction between serum vitamin D
concentration and season was observed
• Because of the small number of cases and the possibility of residual confounding, large cohort studies are needed
• In addition, more studies from association of vitamin D and neurological disorders is needed
Page 7 Knekt P. et al. Arch Neurol 2010; 67: 808-811. www.pronutritionist.net