Knowledge of general risk factors could help primary care physicians anticipate AMD

HONG KONG — Knowledge of easily discernable risk factors for age-related macular degeneration, such as age, family history and smoking status, could help primary care physicians anticipate the disease in their patients, a presenter said here.

Paul Mitchell

"We aimed to identify the major risk factors for late AMD that could be evaluated by non-specialists like family doctors," Paul Mitchell, MD, PhD, FRANZCO, said at the World Ophthalmology Congress, where he presented his meta-analysis study of past research.

"I think the knowledge of these risk factors could assist physicians providing primary health care to identify people at the greatest risk of progression to late AMD," he said.

The meta-analysis considered major risk factors identified in late AMD cases examined through many previous population-based studies, but excluded genetic and dietary factors as those could not be easily identified by a non-specialist, Dr. Mitchell said. Of the 16 risk factors analyzed, the meta-analysis identified very strong, moderate but consistent, and borderline associations with late AMD.

Very strong correlations were seen with increasing age, family history of AMD, which showed an overall odds ratio of 3.7, current smoking status, which had a combined odds ratio of 2.0, and previous cataract surgery, with an odds ratio of 1.8.

Moderate but consistent associations were identified with high body mass index, an odds ratio of 1.3 for a relatively modest effect; history of cardiovascular disease, which showed an odds ratio of 1.4; history of presence of hypertension, at an odds ratio of 1.3; and elevated plasma fibrinogen.

Borderline associations were seen with diabetes and dark iris color.

"I think this meta-analysis confirms family history and smoking as key risk factors for AMD in addition to the known risk associated with increasing age and diet and genetic factors," Dr. Mitchell said. "I think it also highlights the significant risk of progression to late AMD after cataract surgery. ... And even though we need further long-term data, I think these are reasonably strong data already."