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document
Ambient temperature and biomarkers of heart failure : a repeated measures analysis . BACKGROUND Extreme temperatures have been associated with hospitalization and death among individuals with heart failure , but few studies have explored the underlying mechanisms . OBJECTIVES We hypothesized that outdoor temperature in the Boston , Massachusetts , area ( 1- to 4-day moving averages ) would be associated with higher levels of biomarkers of inflammation and myocyte injury in a repeated-measures study of individuals with stable heart failure . METHODS We analyzed data from a completed clinical trial that randomized 100 patients to 12 weeks of tai chi classes or to time-matched education control . B-type natriuretic peptide ( BNP ) , C-reactive protein ( CRP ) , and tumor necrosis factor ( TNF ) were measured at baseline , 6 weeks , and 12 weeks . Endothelin-1 was measured at baseline and 12 weeks . We used fixed effects models to evaluate associations with measures of temperature that were adjusted for time-varying covariates . RESULTS Higher apparent temperature was associated with higher levels of BNP beginning with 2-day moving averages and reached statistical significance for 3- and 4-day moving averages . CRP results followed a similar pattern but were delayed by 1 day . A 5°C change in 3- and 4-day moving averages of apparent temperature was associated with 11.3 % [ 95 % confidence interval ( CI ) : 1.1 , 22.5 ; p = 0.03 ) and 11.4 % ( 95 % CI : 1.2 , 22.5 ; p = 0.03 ) higher BNP . A 5°C change in the 4-day moving average of apparent temperature was associated with 21.6 % ( 95 % CI : 2.5 , 44.2 ; p = 0.03 ) higher CRP . No clear associations with TNF or endothelin-1 were observed . CONCLUSIONS Among patients undergoing treatment for heart failure , we observed positive associations between temperature and both BNP and CRP-predictors of heart failure prognosis and severity .
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Intervention_Educational
12 weeks of tai chi classes or to
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Intervention_Control
time-matched education control
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Intervention_Educational
.
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Outcome_Physical
higher levels of biomarkers of inflammation
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Outcome_Physical
myocyte injury
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Outcome_Physical
B-type natriuretic peptide ( BNP )
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Outcome_Physical
C-reactive protein ( CRP )
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Outcome_Physical
tumor necrosis factor ( TNF )
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Outcome_Physical
Endothelin-1
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Outcome_Physical
BNP
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Outcome_Physical
CRP
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Outcome_Physical
CRP
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Outcome_Physical
TNF
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Outcome_Physical
endothelin-1
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Participant_Condition
heart failure
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Participant_Condition
stable heart failure
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Participant_Sample-size
100