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BP fluctuations may raise dementia risk
Patients with increased day-to-day variations in BP had an elevated risk for all-cause dementia, vascular dementia and Alzheimer’s disease, according to a study published in Circulation.
“Home monitoring of [BP] may be useful to assess the future risk of dementia,” Tomoyuki Ohara, MD, PhD, assistant professor of neuropsychiatry at the Graduate School of Medical Sciences at Kyushu University in Fukuoka City, Japan, said in a press release.
Home BP measurement
The researchers reviewed data from 1,674 participants (mean age, 71 years; 56% women) in Japan who were free from dementia at the start of the study. Participants measured their BP at home three times in the morning for a median of 28 days. Periodic follow-up included a survey on dementia, regular health examinations and a comprehensive assessment of cognitive function. Follow-up was conducted for up to 5 years.
Participants were categorized into four quartiles based on the calculated coefficient of variation for systolic and diastolic BP: 4.83%, 5.08% to 6.21%, 6.22% to 7.59% or 7.61%.
During follow-up, 194 participants (72 men, 122 women) were diagnosed with all-cause dementia. Of those, 134 participants had Alzheimer’s disease and 47 had vascular dementia. Seven participants had a combination of vascular dementia and Alzheimer’s disease.
Increased risk for dementia
As coefficient of variant levels increased, so did age- and sex-adjusted risk for all-cause dementia (P for trend < .001), vascular dementia (P = .01) and Alzheimer’s disease (P < .001). Results were unchanged after adjustment for potential confounders.
Participants with the highest levels of systolic BP variation ( 7.61%) had a higher risk for all-cause dementia (HR = 2.27; 95% CI, 1.45-3.55), vascular dementia (HR = 2.79; 95% CI, 1.04-7.51) and Alzheimer’s disease (HR = 2.22; 95% CI, 1.31-3.75) compared with participants with the least variability. The researchers observed a similar trend with the highest vs. lowest levels of variation of diastolic BP.
In other findings, the researchers reported a significant association between home systolic BP levels and risk for vascular dementia (P for trend = .03), but not risk for all-cause dementia or Alzheimer’s disease.
Implications, greater awareness
“These findings raise the possibility that the measurement of day-to-day BP variability on a home BP basis would be useful for assessing future risk of dementia and elucidating BP-related pathological processes in each dementia subtype,” Emi Oishi, MD, from the department of epidemiology and public health and department of medicine and clinical science at the Graduate School of Medical Sciences at Kyushu University, and colleagues wrote in Circulation.
Alexander E. Merkler, MD, assistant professor of neurology at Weill Cornel Medical College in New York, and Costantino Iadecola, MD, Anne Parrish Titzell Professor of Neurology, director of the Feil Family Brain and Mind Research Institute and professor of neuroscience at Weill Cornell Medical College, discussed the findings in a related editorial in light of previous research.
“Given the limitations of long-term BP monitoring, the results of Oishi et al, based on day-to-day monitoring of BP at home, add considerable strength to the association between higher BP variability and dementia,” Merkler and Iadecola wrote.
“The novel findings of Oishi et al, in concert with prior work, suggest that BP variability, independent of the average systolic BP or diastolic BP value, may be associated with the development of dementia. If confirmed in a larger cohort, these findings may guide future prospective studies aimed at curtailing the risk of dementia by reducing BP variability,” they wrote.
Participants in this study were part of the large, ongoing Hisayama Study, which has tracked for decades the health and cognitive performance in adult residents of a suburb of Fukuoka City, Japan. Because the study population was Japanese, the findings may not apply to other populations or racial/ethnic groups, according to a press release. – by Darlene Dobkowski
Disclosures: The authors, Iadecola and Merkler report no relevant financial disclosures.