Carvalho, Diego de

Abstract Introduction Observational studies have reported associations between hypnotic use and increased risk of cognitive decline. These findings may reflect confounding from insomnia severity, healthcare utilization, and comorbidity burden. We evaluated whether hypnotic exposure is independently associated with incident mild cognitive impairment (MCI) or dementia after rigorous adjustment, including a comprehensive propensity score (PS) and Apolipoprotein E (APOE) ε4 status. Methods We conducted a retrospective cohort study using a biobank sample with linked electronic health records and genetic data. Hypnotic exposure was derived from orders data and categorized as unexposed (n=27,055), single prescription (n=4243), shorter-term use (n=3999), long-term use (≥6 orders for ≥1 year; n=3214), and by drug class: benzodiazepines (n=376), Z-drugs (n=6222), trazodone (n=2395), and mixed exposure (≥2 classes; n=2435). Incident MCI/dementia diagnoses (ICD-9/10) occurring ≥12 months after initial prescription constituted outcomes. The PS modeled likelihood of receiving hypnotics based on demographics; sleep-related conditions; healthcare utilization (record length, visit frequency, diagnostic burden); psychiatric comorbidities; alcohol use and chronic pain. Hypnotic users were 1:2 matched to unexposed individuals on age, sex, healthcare utilization, and PS. Cox proportional hazards models with a 60-month lag tested associations of exposure category, duration, and class with outcomes. Models adjusted for all PS covariates, cardiovascular risk score, and APOE ε4 status. Results Matched but unadjusted analyses suggested slightly higher hazards of MCI/dementia among hypnotic users versus unexposed (HR=1.08; CI=0.99–1.18). However, after PS adjustment and APOE ε4 inclusion, hypnotic users showed significantly lower hazards (HR=0.81; CI=0.74–0.89). Class-specific analyses indicated reduced hazards for Z-drugs (HR=0.83; CI=0.74–0.93), trazodone (HR=0.71; CI=0.60–0.86), and mixed users (HR=0.79; CI=0.68–0.91), with all classes showing lower hazards than benzodiazepine-only users. Long-term hypnotic use was associated with lower hazards than no prescription (HR=0.69; CI=0.61–0.80), single prescription (HR=0.81; CI=0.68–0.97), or short-term use (HR=0.76; CI=0.65–0.90). Conclusion The elevated cognitive risk among hypnotic users appears largely attributable to underlying clinical/utilization factors rather than hypnotic exposure itself. After comprehensive confounding control, all hypnotic classes except benzodiazepines demonstrated lower risk of MCI/dementia. These findings underscore the need for rigorous adjustment in studies of insomnia pharmacotherapy and suggest potential protective effects of certain hypnotics that warrant further investigation. Support (if any) None

Abstract Introduction The relationship between sleep and brain metabolism remains unclear. This study aimed to examine whether overnight sleep features, using a home sleep apnea system based on peripheral arterial tonometry, are associated with regional FDG-PET changes in older adults. Methods We analyzed cognitively unimpaired adults (≥60 years) from the Mayo Clinic Study of Aging (MCSA) cohort who were not receiving sleep apnea treatment. Participants underwent overnight sleep assessment with the WatchPAT system, followed by FDG-PET imaging the next morning. FDG-PET data were co-registered to 3T MRI and automatically segmented into 122 anatomical regions. PET signal was referenced to the pons (SUVR). We computed voxel-weighted median FDG signal across 47 bilateral cortical and subcortical regions of interest (ROIs), excluding brainstem and cerebellum. Associations between sleep architecture and sleep apnea/hypoxemia burden and regional metabolism were assessed using partial Spearman’s rank correlation, adjusting for age. Results Thirty-seven participants were included (70.3% female; median [IQR] age: 72.0 [68.0–78.0] years). Wake after sleep onset (WASO) showed widespread negative associations with FDG uptake in cortical regions (p< 0.05), particularly the ventromedial/ventrolateral (rs=–0.47 to –0.33) prefrontal cortex, lateral temporal (rs=–0.38 to –0.33), and occipital (rs=–0.47 to –0.37) cortices. Total sleep time (TST) was positively associated with medial structures (p< 0.05), including the posterior cingulate (rs=0.39), retrosplenial cortex (rs=0.48), hippocampus/parahippocampal (rs=0.34 to 0.36), calcarine cortex (ρ=0.38), thalamus (rs=0.37), and caudate (rs=0.43). Hypoxic burden was positively associated with medial occipital regions (rs=0.35 to 0.39) and AHI-4% with cuneus (rs=0.33). Regional gray matter volume did not mediate these associations. WASO correlated with Insomnia Severity Index (rs=0.43, p=0.008) and self-reported refreshing sleep (rs=0.046). Conclusion Overnight sleep macrostructure features (WASO and TST) and hypoxic burden are significantly associated with brain metabolism, potentially underlying symptoms of sleep disturbance and cognitive aging. Support (if any) Mayo Clinic Alzheimer’s Disease Research Center Development Award (P30 AG062677), R01 AG056366, U01 AG006786, R01 AG056366, R01 AG034676, R37 AG011378, R01 AG041851, R01 NS097495, R01 AG068206, P30 AG062677, R01 HL065176. CLARA project work with funding from the European Union’s HORIZON EUROPE research and innovation programme (No 101136607).