Sleep-Related Breathing Issues Tied to Brain Changes in Hispanic, Latino Adults

Sleep disordered breathing (SDB) and poor oxygenation during sleep are linked to brain changes, such as increased hippocampal and white matter hyperintensity (WMH) volumes in Hispanic and Latino adults, according to study results published in Neurology journal.

Research has shown mixed results in the association between SDB and brain volumes. In addition, limited data are available on the association between SDB and brain magnetic resonance imaging (MRI) measures in ethnic minority groups, such as Hispanic and Latino adults who have a greater risk for Alzheimer disease and related dementia and cognitive decline.

Researchers aimed to assess the effect of SDB on brain volumes in Hispanic and Latino populations.  

Study participants were enrolled in the Hispanic Community Health Study/Study of Latinos (HCHS/SOL) and had available neuroimaging and MRI data. All participants underwent MRI, following which WMH and hippocampal volume were assessed. Cognitive testing was also conducted.

Main exposure was respiratory event index (REI), defined as 3% oxygen desaturation. Study outcomes included brain volume, cortical gray matter, hippocampus, and WMH.

A total of 2150 individuals (mean age, 67.7 years; women, 58.4%) were identified for the study. Of these, 1324 (55.7%) had an REI score of less than 5; 538 (27.7%) had an REI score of between 5 and 15; and 288 (16.6%) had an REI score of 15 or greater, indicating moderate to severe SDB. Overall, those with higher vs lower REI scores had a higher body mass index (BMI) and rates of hypertension, as well as were more likely to be men.

Based on data from regression models, the researchers noted that a 1-point increase in REI resulted in increased hippocampal volumes (b_hippocampus=0.006; 0.001-0.012; P <.05).

Compared with participants with REI scores less than 5, those with scores of 15 or greater had larger hippocampal volumes (b_hippocampus=0.243; 0.066-0.419; P <.01).

Measures of poor oxygenation during sleep, such as mean SpO₂, were associated with increased hippocampal and WMH volumes (b_WMH=-0.095; -0.164 to -0.025; P <.01) and minimum SpO₂ was associated with increased hippocampal volume (b_hippocampus=-0.013; -0.021 to -0.004; P <.01).

Study limitations included the lack of obtaining a polysomnography, the gold standard measure of SDB, which would have provided details about sleep architecture and limb movements; the majority of participants did not have medical insurance; and dementia was not accounted for at the time of MRI.

“A comprehensive understanding of the mechanisms underlying brain volumes in SDB is needed for informing effective management strategies, advocating for early intervention, more so in at-risk populations such as Hispanic/Latino adults,” the researchers concluded.