Associations Between Sleep‐Disordered Breathing, Nocturnal Hypoxemia, and Subsequent Cognitive Decline in Older Community‐Dwelling Men: The Osteoporotic Fractures in Men Sleep Study

Abstract

OBJECTIVES Sleep-disordered breathing (SDB) is a group of disorders common among older adults, characterized by breathing pauses during sleep often accompanied by hypoxemia. Few studies have examined if SDB is associated with cognitive decline. DESIGN A population-based longitudinal study. SETTING 6 centers in the United States. PARTICIPANTS 2,636 community-dwelling older men (age 76.0 ± 5.3 years) without mild cognitive impairment, followed 3.4 ± 0.5 years. MEASUREMENTS SDB, measured by in-home polysomnography: nocturnal hypoxemia [≥1% of sleep time with oxygen saturation (SaO2) <90% vs. <1%; oxygen desaturation index (ODI: number of oxygen desaturations ≥3% per hour sleep)]; apnea-hypopnea index (AHI, number of apneas and hypopneas at ≥3% desaturation per hour sleep). Cognitive decline, measured by the Modified Mini-Mental State examination (3MS) and Trails B test at baseline and 2 follow-up timepoints. Associations of predictors and cognitive decline were examined with linear mixed models adjusted for multiple confounders. Models were further adjusted by potential mediators (sleep duration, sleep fragmentation, resting SaO2). RESULTS Nocturnal hypoxemia was related to greater decline on the 3MS. Men with ≥1% of sleep time with SaO2<90% had an adjusted annualized decline of 0.43 points compared to 0.25 for men in the referent group (P = .003). For each 5-point increase in ODI there was an average annualized decline of 0.36 points (P = .01). Results were robust to further adjustment for potential mediators. The association between AHI and cognitive decline did not reach significance. No associations were seen with SDB and decline on the Trails B test. CONCLUSION Among older community-dwelling men, there was a modest association of nocturnal hypoxemia with global cognitive decline, suggesting the importance of overnight oxygenation to cognitive function.

Amyloid Burden in Obstructive Sleep Apnea

“…Our interpretation of these results is that OSA may account for these findings. Further, OSA may play an important role in amyloid deposition, significantly increasing risk for the development of dementia as well as acceleration of cognitive decline, as has been previously demonstrated by prospective observational studies [3][4][5][6]. However, our results need to be supported by additional basic, translational, and observational studies.…”

“…Observational studies demonstrated that OSA is associated with slower cognitive processing speed [2], increased risk of incident dementia in older women [3], and accelerated cognitive decline in the elderly [4][5][6]. Cerebral white matter change, a risk factor for dementia, is more frequently observed in OSA [7].…”

Periodic Limb Movements in Sleep are Associated with Greater Cognitive Decline in Older Men without Dementia

“…Detailed descriptive statistics are not presented in this short note, but characteristics of similar study samples can be found in previous publications. 2,3,11 After multivariable adjustment, the rate of increase in Trails B test time (decline in function) was significantly greater for those with a PLMI ≥ 30, whereas the rate of decrease in 3MS scores was smaller, but not significant, for those with a PLMI ≥ 30. The adjusted increase in Trails B test completion time over 3.4 y were 3.5, 6.3, and 8.1 sec for PLMI category of < 5, 5 to 30, and ≥ 30, respectively (P for trend = 0.02); adjusted decline in 3MS score for PLMI categories were 1.3, 0.9, and 1.0 points over 3 y, respectively (P for trend = 0.23).…”

“…11 After excluding men with significant cognitive impairment at the sleep visit (Modified Mini-Mental State examination (3MS) score < 80 or taking a medication for dementia), the current analysis In-home sleep studies were completed using unattended polysomography (Safiro, Compumedics, Inc., Melbourne, Australia), following a standardized protocol as described previously. 2 Bilateral tibialis leg movements were measured with piezoelectric sensors.…”

“…Characteristics of participants were compared by categories of PLMS. Randomeffects models, as used in similar analysis, 11 were utilized to study the association between PLMS and changes in cognition from the baseline to the follow-up visits. Covariates (fixed effects) were selected for inclusion in a multivariable model by examining both the univariate association of the covariate and the PLMS parameters and the association to the changes in 3MS and Trails B in random-effects models.…”