Association of Cardiovascular Risk Factors With MRI Indices of Cerebrovascular Structure and Function and White Matter Hyperintensities in Young Adults

Abstract

<div class="section"> <a class="named-anchor" id="ab-jpc180006-1"> <!-- named anchor --> </a> <h5 class="section-title" id="d2064132e548">Question</h5> <p id="d2064132e550">Are modifiable cardiovascular risk factors in young adults associated with cerebral blood vessel structure and function and neuroimaging white matter hyperintensities? </p> </div><div class="section"> <a class="named-anchor" id="ab-jpc180006-2"> <!-- named anchor --> </a> <h5 class="section-title" id="d2064132e553">Results</h5> <p id="d2064132e555">In this cross-sectional study of 125 young adults without clinical evidence of cerebrovascular disease, a higher number of optimal cardiovascular health metrics was correlated with higher cerebral vessel density, higher cerebral blood flow, and lower number of white matter hyperintensity lesions. </p> </div><div class="section"> <a class="named-anchor" id="ab-jpc180006-3"> <!-- named anchor --> </a> <h5 class="section-title" id="d2064132e558">Meaning</h5> <p id="d2064132e560">These preliminary findings suggest a relationship between modifiable cardiovascular risk factors and biomarkers of cerebrovascular structure and function and white matter hyperintensities in young adults. Further research is needed to verify these findings and determine clinical importance. </p> </div><div class="section"> <a class="named-anchor" id="ab-jpc180006-4"> <!-- named anchor --> </a> <h5 class="section-title" id="d2064132e564">Importance</h5> <p id="d2064132e566">Risk of stroke and brain atrophy in later life relate to levels of cardiovascular risk in early adulthood. However, it is unknown whether cerebrovascular changes are present in young adults. </p> </div><div class="section"> <a class="named-anchor" id="ab-jpc180006-5"> <!-- named anchor --> </a> <h5 class="section-title" id="d2064132e569">Objective</h5> <p id="d2064132e571">To examine relationships between modifiable cardiovascular risk factors and cerebrovascular structure, function, and white matter integrity in young adults. </p> </div><div class="section"> <a class="named-anchor" id="ab-jpc180006-6"> <!-- named anchor --> </a> <h5 class="section-title" id="d2064132e574">Design, Setting, and Participants</h5> <p id="d2064132e576">A cross-sectional observational study of 125 young adults (aged 18-40 years) without clinical evidence of cerebrovascular disease. Data collection was completed between August 2014 and May 2016 at the University of Oxford, United Kingdom. Final data collection was completed on May 31, 2016. </p> </div><div class="section"> <a class="named-anchor" id="ab-jpc180006-7"> <!-- named anchor --> </a> <h5 class="section-title" id="d2064132e579">Exposures</h5> <p id="d2064132e581">The number of modifiable cardiovascular risk factors at recommended levels, based on the following criteria: body mass index (BMI) &lt;25; highest tertile of cardiovascular fitness and/or physical activity; alcohol consumption &lt;8 drinks/week; nonsmoker for &gt;6 months; blood pressure on awake ambulatory monitoring &lt;130/80 mm Hg; a nonhypertensive diastolic response to exercise (peak diastolic blood pressure &lt;90 mm Hg); total cholesterol &lt;200 mg/dL; and fasting glucose &lt;100mg/dL. Each risk factor at the recommended level was assigned a value of 1, and participants were categorized from 0-8, according to the number of risk factors at recommended levels, with higher numbers indicating healthier risk categories. </p> </div><div class="section"> <a class="named-anchor" id="ab-jpc180006-8"> <!-- named anchor --> </a> <h5 class="section-title" id="d2064132e584">Main Outcomes and Measures</h5> <p id="d2064132e586">Cerebral vessel density, caliber and tortuosity, brain white matter hyperintensity lesion count. In a subgroup (n = 52), brain blood arrival time and cerebral blood flow assessed by brain magnetic resonance imaging (MRI). </p> </div><div class="section"> <a class="named-anchor" id="ab-jpc180006-9"> <!-- named anchor --> </a> <h5 class="section-title" id="d2064132e589">Results</h5> <p id="d2064132e591">A total of 125 participants, mean (SD) age 25 (5) years, 49% women, with a mean (SD) score of 6.0 (1.4) modifiable cardiovascular risk factors at recommended levels, completed the cardiovascular risk assessment and brain MRI protocol. Cardiovascular risk factors were correlated with cerebrovascular morphology and white matter hyperintensity count in multivariable models. For each additional modifiable risk factor categorized as healthy, vessel density was greater by 0.3 vessels/cm ³ (95% CI, 0.1-0.5; <i>P</i> = .003), vessel caliber was greater by 8 μm (95% CI, 3-13; <i>P</i> = .01), and white matter hyperintensity lesions were fewer by 1.6 lesions (95% CI, −3.0 to −0.5; <i>P</i> = .006). Among the 52 participants with available data, cerebral blood flow varied with vessel density and was 2.5 mL/100 g/min higher for each healthier category of a modifiable risk factor (95% CI, 0.16-4.89; <i>P</i> = .03). </p> </div><div class="section"> <a class="named-anchor" id="ab-jpc180006-10"> <!-- named anchor --> </a> <h5 class="section-title" id="d2064132e609">Conclusions and Relevance</h5> <p id="d2064132e611">In this preliminary study involving young adults without clinical evidence of cerebrovascular disease, a greater number of modifiable cardiovascular risk factors at recommended levels was associated with higher cerebral vessel density and caliber, higher cerebral blood flow, and fewer white matter hyperintensities. Further research is needed to verify these findings and determine their clinical importance. </p> </div><p class="first" id="d2064132e614">This cross-sectional study examines associations between modifiable cardiovascular risk factors—such as BMI, cholesterol and glucose levels, smoking, and alcohol use—and MRI measures of cerebrovascular structure, function, and white matter integrity in adults aged 18 to 40. </p>