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Dementia risk no higher in people with AMD

But people with dementia less likely to have AMD treatment

Louise Prime

Friday, 15 November 2013

People with age-related macular degeneration (AMD) are no more likely than those without the eye condition to later develop dementia or Alzheimer’s disease (AD), shows research from Manchester. Authors of the study, published this morning in JAMA Ophthalmology, say that although the diseases share environmental risk factors – such as smoking, hypertension, high blood cholesterol and deposition of plaques in the brain – AMD and AD appear to have different genetic risk factors.

Researchers from the Universities of Manchester and Oxford used hospital admissions data for NHS England to construct a cohort of 65,894 people who had been admitted or had day-case treatment in for AMD over a 12-year period. They also constructed, by similar means, a cohort of 168,092 people with dementia and a reference cohort of more than 7.7m people. They then analysed the data to calculate the risk of AD or dementia following AMD; and the risk of AMD following AD or dementia.

They found that having AMD was not associated with an increased risk of subsequently developing dementia or AD: compared with people without AMD, the rate ratio was 0.86 for AD and 0.91 for dementia. They said: “These neurodegenerative conditions may share environmental risk factors and histopathologic features. However, considering AD and other dementia after AMD, their coexistence at the individual level is no different from that expected by chance.”

In addition, the researchers calculated that the likelihood of being admitted for AMD was very low for people with AD (rate ratio 0.04) or dementia (0.07), which they said indicated that, in England, people with dementia might be less likely than others to receive treatment for AMD. They suggested several factors that might contribute to this – including that people with dementia might be less likely to get their eyes examined.

They concluded: “People with dementia in England are substantially less likely to undergo treatment for AMD than those without dementia. Potential barriers to care for these vulnerable individuals need to be examined and addressed in the near future.”

DOI:10.1001/.jamaopthalmol.2013.5696

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