, new research suggests.
In an analysis of more than 900 study participants, women in their 70s with more advanced abdominal aortic calcification (AAC) seen on lateral spine images during dual-energy x-ray absorptiometry (DXA) had a two- to fourfold higher risk for late-life dementia than those with low AAC.
This finding was independent of cardiovascular risk factors and apolipoprotein E (APOE ) genotype.
“While these results are exciting, we now need to undertake further large screening studies in older men and women using this approach to show that the findings are generalizable to older men and can identify people with greater cognitive decline,” coinvestigator Marc Sim, PhD, Edith Cowan University, Joondalup, Australia, said in an interview.
“This will hopefully open the door to studies of early disease-modifying interventions,” Sim said.
The findings were published online in The Lancet Regional Health – Western Pacific.
AAC and cognition
Late-life dementia occurring after age 80 is increasingly common because of both vascular and nonvascular risk factors.
Two recent studies in middle-aged and older men and women showed that AAC identified on bone densitometry was associated with poorer cognition, suggesting it may be related to cognitive decline and increased dementia risk.
This provided the rationale for the current study, Dr. Sim noted.
The researchers assessed AAC using DXA lateral spine images captured in the late 1990s in a prospective cohort of 958 older women who were participating in an osteoporosis study.
AAC was classified into established low, moderate, and extensive categories. At baseline, all women were aged 70 and older, and 45% had low AAC, 36% had moderate AAC, and 19% had extensive AAC.
Over 14.5 years, 150 women (15.7%) had a late-life hospitalization and/or died.
Improved risk prediction
Results showed that, compared with women who had low AAC, women with moderate and extensive AAC were more likely to experience late-life dementia hospitalization (9.3% low, 15.5% moderate, and 18.3% extensive) and death (2.8%, 8.3%, and 9.4%, respectively).
After multivariable adjustment, women with moderate AAC had a two- and threefold increased relative risk for late-life dementia hospitalization or death, compared with their peers who had low AAC.
Women with extensive AAC had a two- and fourfold increase in the adjusted relative risk for late-life dementia hospitalization or death.
“To our knowledge this is the first time it has been shown that AAC from these scans is related to late-life dementia,” Dr. Sim said.
“We demonstrated that AAC improved risk prediction in addition to cardiovascular risk factors and APOE genotype, a genetic risk factor for Alzheimer’s disease, the major form of dementia,” he added.
Dr. Sim noted “these additional lateral spine images” can be taken at the same time that hip and spine bone density tests are done.
“This provides an opportunity to identify AAC in large numbers of people,” he said.
He cautioned, however, that further studies with detailed dementia-related phenotypes, brain imaging, and measures of cognition are needed to confirm whether AAC will add value to dementia risk prediction.