In a recent study published in Alzheimer's and Dementia, a group of researchers investigated the effect of vigorous physical activity (VPA) on the risk of incident mild cognitive impairment (MCI) and probable dementia among individuals with high-risk hypertension.
Study: Effect of vigorous-intensity physical activity on incident cognitive impairment in high-risk hypertension. Image Credit: Evgeny Atamanenko/Shutterstock.com
Background
Hypertension, affecting one-third of adults worldwide, significantly increases the risk of cardiovascular diseases (CVDs) and dementia, projected to impact over 175 million people by 2050. As a key modifiable risk factor for cognitive impairments, including MCI, Alzheimer's, and vascular dementia, hypertension's impact on cognitive health is profound.
The Systolic Blood Pressure Intervention Trial Memory and Cognition in Decreased Hypertension (SPRINT MIND) study highlighted that intensive blood pressure control can prevent cognitive impairment.
While physical activity (PA) also slows cognitive decline, the optimal volume and intensity for maximum benefit are unclear, necessitating further research to determine the most effective PA regimen for reducing cognitive impairment risk in high-risk hypertensive individuals.
About the study
The present post hoc analysis used data from the SPRINT MIND study, part of the SPRINT trial (NCT01206062), which included 9361 nondiabetic United States (U.S.) adults aged 50 and older with hypertension and high CVD risk.
The trial compared the effects of intensive (target systolic blood pressure (SBP) <120 mm Hg) versus standard (target SBP <140 mm Hg) blood pressure treatment on various health outcomes, including myocardial infarction, stroke, heart failure, and cognitive function. The trial was halted early due to significant benefits in the intensive treatment group.
The study focused on the impact of intensive blood pressure treatment on rates of MCI and probable dementia. Data was sourced from the National Heart, Lung, and Blood Institute, with all participants providing informed consent. Cognitive assessments were conducted at baseline, at 2 and 4 years, and at study closeout.
Participants were divided into low (<1 session/week) and high (≥1 session/week) VPA groups. Exclusions included significant physical limitations or missing data, resulting in 7670 participants.
Statistical analysis used Cox proportional hazards models to examine the association between VPA and cognitive outcomes, with sensitivity analyses accounting for competing risks and additional comorbidities. Analyses were conducted using SAS and R software.
Study results
Overall, the participants had an average age of 70.0 years (Standard deviation (SD) 9.2), with 34.5% being women and 59.4% identified as White. Notably, 59.3% of participants reported engaging in VPA at least once weekly, placing them in the high VPA category.
Compared to their high VPA counterparts, participants in the low VPA group were more likely to be female, current smokers, less educated, have higher body mass index (BMI), higher prevalence of chronic kidney disease (CKD), and require more antihypertensive medications.
Over a maximum follow-up of 7.4 years (median [25%, 75%] = 4.5 [3.6, 5.9] years), there were 570 adjudicated events of MCI, 273 events of probable dementia, and 759 events of the combined MCI/probable dementia outcome.
The incidence of MCI, probable dementia, and the combined MCI/probable dementia outcome were lower in the high VPA group compared to the low VPA group, with rates of 6.5% versus 8.8%, 3.1% versus 4.3%, and 8.7% versus 11.7%, respectively.
Similarly, event rates per 1,000 person-years were lower for the high VPA group: 13.9 versus 19.7 for MCI, 6.3 versus 9.0 for probable dementia, and 18.5 versus 25.8 for the combined outcome.
Cumulative incidence (CI) rates of cognitive impairment were significantly higher in the low VPA group. After adjusting for sociodemographic factors, the high VPA group had a substantially lower risk of MCI (Hazard ratio (HR) = 0.80, 95% CI: 0.67–0.95) and combined MCI/probable dementia (HR = 0.82, 95% CI: 0.70–0.94) compared to the low VPA group.
The association between higher VPA and lower risk of probable dementia approached significance (HR = 0.80, 95% CI: 0.63–1.02). Further adjustments for other factors did not alter these associations. There was significant heterogeneity by age and race, with stronger associations for those under 75 and Black participants.
Participants included in the analysis were similar in age, blood pressure, and randomization to the intensive SBP lowering trial arm compared to those excluded. Excluded participants were more likely to be female, less educated, current smokers, and had a higher prevalence of depression, CKD, and CVD.
Considering the competing risk of death, HR remained consistent with the main analysis. Adjustments for additional comorbidities and the exclusion of early MCI cases did not significantly change the results, indicating that different self-reported frequencies of VPA were consistently associated with a lower risk of cognitive impairment outcomes.
Conclusions
To summarize, participants who engaged in VPA had a lower risk of MCI and probable dementia compared to those with less frequent VPA, regardless of SBP treatment intensity.
The results were consistent across various subgroups, with some variations by age and race. The study highlights VPA as a potential low-risk intervention to preserve cognitive function in hypertensive patients.
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