Age-related Eye Disease Heightens Parkinson’s Risk, Study Suggests

Patricia Inácio, PhD avatar

by Patricia Inácio, PhD |

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People with age-related macular degeneration, an eye disease that blurs central vision, may have a higher risk of developing Parkinson’s disease, a Taiwanese population‐based retrospective study suggests.

The study, ‘Increased risk of Parkinson’s disease among patients with age-related macular degeneration,” was published in the journal BMC Ophthalmology.

Age-related macular degeneration (AMD) causes blindness among the elderly and usually affects people older than 55. Parkinson’s is also an aging-related disease, and some researchers classify both diseases as neurodegenerative disorders.

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A person with several eyeglasses near his hand, holds the other hand over one eye while a vision chart is seen in the background.

Eyes’ Pupils May Be Window Into Assessing Disease Stage

Prior studies have suggested that Parkinson’s patients have a higher tendency for AMD. However, these failed to account for potential additional diseases, or comorbidities.

Now, researchers at the China Medical University Hospital conducted a population‐based retrospective cohort study to assess whether the risk of AMD is elevated in those with Parkinson’s, taking into account comorbidities.

They reviewed data from Taiwan’s National Health Insurance Research Database (NHIRD), specifically the Longitudinal Health Insurance Database 2000 (LHID2000).

In total, they analyzed data from 20,848 individuals, of which 10,424 had AMD (mean age 70.4; 49.2% women) and 10,424 did not have AMD (mean age 70.3 years; 49.2% women). Patients in each group were followed for a mean of 5.66 and 5.48 years, respectively. AMD and non-AMD groups were established from January 1, 2000, to December 31, 2012, to determine the diagnosis of Parkinson’s.

The prevalence of comorbidities (more than one) was significantly higher in the AMD group (91.33%) than in the non-AMD (82.13%). Medication use, including statins (cholesterol-lowering agents) and calcium channel blockers (medications used to lower blood pressure) differed slightly between groups.

After adjusting for potential confounders, the data revealed there was a higher risk of developing Parkinson’s, both for men and women, in the AMD group than in the non-AMD group.

Specifically, this risk was significantly higher in patients older than 60 and with more than one comorbidity.

A significant association between increased risk of Parkinson’s and AMD was found among those with osteoporosis, diabetes, and hypertension. Use of statin and calcium channel blockers were also associated with significantly increased risk of Parkinson’s and AMD.

During the 12-year follow up period, the cumulative incidence of PD — a measure of the risk of a disease for long periods of time — was significantly higher in the AMD group.

“AMD is associated with a higher risk of PD [Parkinson’s disease] with adjustment for sufficient clinical comorbidities and long follow-up time,” the researchers concluded.