***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: OBJECTIVES We sought to investigate the effects of  sleep loss  on high-sensitivity C-reactive protein ( CRP ) levels . BACKGROUND Concentrations of high-sensitivity CRP are predictive of future cardiovascular morbidity . In epidemiologic studies , short sleep duration and sleep complaints have also been associated with increased cardiovascular morbidity . Two studies were undertaken to examine the effect of acute total and short-term partial sleep deprivation on concentrations of high-sensitivity CRP in healthy human subjects . METHODS In Experiment 1 , 10 healthy adult subjects stayed awake for 88 continuous hours . Sample s of high-sensitivity CRP were collected every 90 min for 5 consecutive days , encompassing the vigil . In Experiment 2 , 10 subjects were r and omly assigned to either 8.2 h ( control ) or 4.2 h ( partial sleep deprivation ) of nighttime sleep for 10 consecutive days . Hourly sample s of high-sensitivity CRP were taken during a baseline night and on day 10 of the study protocol . RESULTS The CRP concentrations increased during both total and partial sleep deprivation conditions , but remained stable in the control condition . Systolic blood pressure increased across deprivation in Experiment 1 , and heart rate increased in Experiment 2 . CONCLUSIONS Both acute total and short-term partial sleep deprivation result ed in elevated high-sensitivity CRP concentrations , a stable marker of inflammation that has been shown to be predictive of cardiovascular morbidity . We propose that sleep loss may be one of the ways that inflammatory processes are activated and contribute to the association of sleep complaints , short sleep duration , and cardiovascular morbidity observed in epidemiologic surveys Although sleep quality and duration have been related to cardiovascular end points , little is known about the association between sleep duration and incident atrial fibrillation ( AF ) . Hence , we prospect ively examined the association between  sleep duration and incident AF in a cohort of 18,755 United States male physicians .  Self-reported sleep duration was ascertained during a 2002 annual follow-up question naire . Incident AF was ascertained through annual follow-up question naires . Cox regression analysis was used to estimate the relative risks of AF . The average age at baseline was 67.7 ± 8.6 years . During a mean follow-up of 6.9 ± 2.1 years , 1,468 cases of AF occurred . Using 7 hours of sleep as the reference group , the multivariate adjusted hazard ratio for AF was 1.06 ( 95 % confidence interval 0.92 to 1.22 ) , 1.0 ( reference ) , and 1.13 ( 95 % confidence interval 1.00 to 1.27 ) from the lowest to greatest category of sleep duration ( p for trend = 0.26 ) , respectively . In a secondary analysis , no evidence was seen of effect modification by adiposity ( p for interaction = 0.69 ) ; however , prevalent sleep apnea modified the relation of sleep duration with AF ( p for interaction = 0.01 ) . From the greatest to the lowest category of sleep duration , the multivariate-adjusted hazard ratio for AF was 2.26 ( 95 % confidence interval 1.26 to 4.05 ) , 1.0 ( reference ) , and 1.34 ( 95 % confidence interval 0.73 to 2.46 ) for those with prevalent sleep apnea and 1.01 ( 95 % confidence interval 0.87 to 1.16 ) , 1.0 ( reference ) , and 1.12 ( 95 % confidence interval 0.99 to 1.27 ) for those without sleep apnea , respectively . Our data showed a modestly elevated risk of AF with long sleep duration among United States male physicians . Furthermore , a shorter sleep duration was associated with a greater risk of AF in those with prevalent sleep apnea BACKGROUND Positive pressure therapy ( CPAP ) in patients with cardiac arrhythmias and obstructive sleep apnea ( OSAS ) may have favorable effects by correcting intermittent hypoxemia and sympathetic activation . OBJECTIVE To assess the effect of CPAP added to pharmacological treatment in the rate control and prevention of arrhythmias recurrence in patients with OSA . MATERIAL S AND METHODS Prospect i ve , interventional study study which included patients diagnosed with OSAS ( cardiorespiratorypolygraphy , AHI>5/hour ) , and arrhythmias ( ECG , Holter ECG ) , divided in two groups : group A ( pharmacological therapy only ) and group B ( pharmacological therapy and CPAP ) . The patients were evaluated at enrollment ( T0 ) , at 3 and 6 months ( T3 and T6 ) regarding the type , severity and recurrence of cardiac arrhythmias . RESULTS 36 patients ( 31 men ) , mean age : 63.2 ± 12 years were enroled . In group A : 7 patients with ventricular extrasystoles , 8 with permanent atrial fibrillation , 1 patient with atrial flutter and 2 patients with paroxystic supraventricular tachycardia . In group B : 8 patients with ventricular extrasystoles , 5 with permanent atrial fibrillation , 2 patients with recurrent episodes of atrial fibrillation and 3 with paroxystic supraventricular tachycardia . A positive correlation ( r : 0.74 , p < 0.001 ) between Oxygen Desaturation Index and AHI was found . At T6 , 12 patients from group B , and 18 from group A were evaluated . In group B , the mean heart rate in patients with atrial fibrillation was 69/min . , lower than in group A ( 82/min . ) , no cases with recurrent atrial fibrillation were found , and more patients with class II Lown ventricular extrasystoles passed in class I Lown , compared to group A. In group B , heart rate statistically correlated with AHI ( r : 0.53 , p < 0.005 ) . CONCLUSION In patients with OSAS , adding CPAP to pharmacological therapy has favorable effects on preventing recurrences , heart rate control in patients with atrial fibrillation and in reducing frequency and /or severity of ventricular extrasystoles AIMS Recent studies have suggested an emerging link between sleep apnoea and atrial fibrillation ( AF ) . These studies included patients with reduced left ventricular ( LV ) function which may cause both AF and sleep disordered breathing ( SDB ) . We examined the prevalence of SDB in a population of patients with AF and normal LV function . METHODS AND RESULTS Ninety patients with paroxysmal or persistent AF and 45 controls were prospect ively enrolled and matched 2:1 for age ( AF 56 + /- 12 years ; controls 54 + /- 11years ) and sex . All patients had normal LV function .  SDB was diagnosed using all-night  portable polysomnography . Apnoea-hypopnoea index ( AHI ) in AF patients was higher than in controls ( 23.19 + /- 19.26 vs. 14.66 + /- 12.43 , P = 0.01 ) . The proportion with significant SDB ( AHI > 15 ) was also greater in AF patients ( 62 vs. 38 % , P = 0.01 ) . After adjustment for relevant covariates , the odds ratio for the association between AF and SDB ( AHI > 15 ) was 3.04 ( 95 % CI 1.24 - 7.46 , P = 0.02 ) . The paroxysmal AF group was classified as either ' low-frequency AF ' ( < or = 6 ) or ' high-frequency AF ' ( > 6 ) episodes in the past year . High-frequency AF was associated with a higher prevalence ( 75 vs. 43 % , P = 0.012 ) and severity ( mean AHI 28.08 + /- 22.94 vs. 16.69 + /- 15.06 , P = 0.028 ) of SDB when compared with those with low-frequency AF . CONCLUSION A high prevalence of SDB is found in relatively young patients with both paroxysmal and persistent AF with normal LV function . This AF population warrants careful consideration for the presence of SDB PURPOSE We examined the association between the body mass index analyzed as a continuous variable and by categorization according to World Health Organization criteria ( normal weight , overweight and obesity ) and the risk of a hospital ( inpatient as well as outpatient ) diagnosis of atrial fibrillation or flutter . METHODS Population -based prospect i ve cohort study conducted from December 1993 to December 2001 among 47589 participants ( 22482 men and 25107 women ) without preexisting cardiovascular or endocrine disease and with a mean age at baseline of 56 years ( range 50 - 64 years ) in the Danish Diet , Cancer , and Health Study . Subjects were followed up in the Danish National Registry of Patients and in the Danish Civil Registration System . RESULTS During follow-up ( mean , 5.7 years ) atrial fibrillation or flutter developed in 553 subjects ( 372 men and 181 women ) . The adjusted hazard ratio for atrial fibrillation or flutter per unit of increase in the body mass index was 1.08 ( 95 % confidence interval [ CI ] : 1.05 to 1.11 ) in men and 1.06 ( 95 % CI : 1.03 to 1.09 ) in women . When using normal weight as a reference , the adjusted hazard ratio for atrial fibrillation or flutter by overweight was 1.75 ( 95 % CI : 1.35 to 2.27 ) in men and 1.39 ( 95 % CI : 0.99 to 1.94 ) in women . The adjusted hazard ratio by obesity was 2.35 ( 95 % CI : 1.70 to 3.25 ) in men and 1.99 ( 95 % CI : 1.31 to 3.02 ) in women . CONCLUSION Overweight and obesity are associated with an increased risk of a diagnosis of atrial fibrillation or flutter In a retrospective survey , 487 research projects approved by the Central Oxford Research Ethics Committee between 1984 and 1987 , were studied for evidence of publication bias . As of May , 1990 , 285 of the studies had been analysed by the investigators , and 52 % of these had been published . Studies with statistically significant results were more likely to be published than those finding no difference between the study groups ( adjusted odds ratio [ OR ] 2.32 ; 95 % confidence interval [ Cl ] 1.25 - 4.28 ) . Studies with significant results were also more likely to lead to a greater number of publications and presentations and to be published in journals with a high citation impact factor . An increased likelihood of publication was also associated with a high rating by the investigator of the importance of the study results , and with increasing sample size . The tendency towards publication bias was greater with observational and laboratory-based experimental studies ( OR = 3.79 ; 95 % Cl = 1.47 - 9.76 ) than with r and omised clinical trials ( OR = 0.84 ; 95 % Cl = 0.34 - 2.09 ) . We have confirmed the presence of publication bias in a cohort of clinical research studies . These findings suggest that conclusions based only on a review of published data should be interpreted cautiously , especially for observational studies . Improved strategies are needed to identify the results of unpublished as well as published studies The association between sleep apnea and atrial fibrillation ( AF ) has not been examined in a multiethnic adult population in prospect i ve community-based studies . We prospect ively ( 2000 - 2011 ) investigated the associations of physician-diagnosed sleep apnea ( PDSA ) , which is considered more severe sleep apnea , and self-reported habitual snoring without PDSA ( HS ) , a surrogate for mild sleep apnea , with incident AF in white , black , and Hispanic participants in the Multi-Ethnic Study of Atherosclerosis ( MESA ) who were free of clinical cardiovascular disease at baseline ( 2000 - 2002 ) . Cox proportional hazards models were used to assess the associations , with adjustment for socioeconomic status , traditional vascular disease risk factors , race/ethnicity , body mass index , diabetes , chronic kidney disease , alcohol intake , and lipid-lowering therapy . Out of 4,395 respondents to a sleep question naire administered in MESA , 181 reported PDSA , 1,086 reported HS , and 3,128 reported neither HS nor PDSA ( unaffected ) . Over an average 8.5-year follow-up period , 212 AF events were identified . As compared with unaffected participants , PDSA was associated with incident AF in the multivariable analysis , but HS was not ( PDSA : hazard ratio = 1.76 , 95 % confidence interval : 1.03 , 3.02 ; HS : hazard ratio = 1.02 , 95 % confidence interval : 0.72 , 1.44 ) . PDSA , a marker of more severe sleep apnea , was associated with higher risk of incident AF in this analysis of MESA data 
    Output:
    
Our findings suggest an absence in association between AF and sleep duration but reveal the potential association between AF and both insomnia and frequent nocturnal awakening .