BackgroundSleep apnea (SA) has been associated with cognitive impairment. However, no data regarding the risk of dementia in patients with SA has been reported in the general population. This retrospective matched-control cohort study was designed to estimate and compare the risk of dementia in SA and non-SA patients among persons aged 40 and above over a 5-year period follow-up.MethodsWe conducted a nationwide 5-year population-based study using data retrieved from the Longitudinal Health Insurance Database 2005 (LHID2005) in Taiwan. The study cohort comprised 1414 patients with SA aged 40 years who had at least 1 inpatient service claim or 1 ambulatory care claim. The comparison cohort comprised 7070 randomly selected patients who were matched with the study group according to sex, age, and index year. We performed Cox proportional-hazards regressions to compute the 5-year dementia-free survival rates after adjusting for potentially confounding factors.ResultsThe SA patients in this study had a 1.70-times greater risk of developing dementia within 5 years of diagnosis compared to non-SA age- and sex-matched patients, after adjusting for other risk factors (95% confidence interval (CI) = 1.26-2.31; P < .01). For the gender-dependent effect, only females with SA were more likely to develop dementia (adjust HR: 2.38, 95% CI =1.51–3.74; P < .001). For the age-dependent effect of different genders, males with SA aged 50-59 years had a 6.08 times greater risk for developing dementia (95% CI = 1.96-18.90), and females with SA aged ≥ 70 years had a 3.20 times greater risk of developing dementia (95% CI =1.71–6.00). For the time-dependent effect, dementia may be most likely to occur in the first 2.5 years of follow-up (adjusted HR:2.04, 95% CI =1.35-3.07).ConclusionsSA may be a gender-dependent, age-dependent, and time-dependent risk factor for dementia.
Schizophrenia is characterized by heterogeneous pathophysiology. Using multiscale entropy (MSE) analysis, which enables capturing complex dynamics of time series, we characterized MSE patterns of blood-oxygen-level-dependent (BOLD) signals across different time scales and determined whether BOLD activity in patients with schizophrenia exhibits increased complexity (increased entropy in all time scales), decreased complexity toward regularity (decreased entropy in all time scales), or decreased complexity toward uncorrelated randomness (high entropy in short time scales followed by decayed entropy as the time scale increases). We recruited 105 patients with schizophrenia with an age of onset between 18 and 35 years and 210 age- and sex-matched healthy volunteers. Results showed that MSE of BOLD signals in patients with schizophrenia exhibited two routes of decreased BOLD complexity toward either regular or random patterns. Reduced BOLD complexity toward regular patterns was observed in the cerebellum and temporal, middle, and superior frontal regions, and reduced BOLD complexity toward randomness was observed extensively in the inferior frontal, occipital, and postcentral cortices as well as in the insula and middle cingulum. Furthermore, we determined that the two types of complexity change were associated differently with psychopathology; specifically, the regular type of BOLD complexity change was associated with positive symptoms of schizophrenia, whereas the randomness type of BOLD complexity was associated with negative symptoms of the illness. These results collectively suggested that resting-state dynamics in schizophrenia exhibit two routes of pathologic change toward regular or random patterns, which contribute to the differences in syndrome domains of psychosis in patients with schizophrenia.
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