The benefits of antioxidants or DHA/EPA supplementation for CF , although observed in some studies , are not consistent enough to recommend routine use of these supplements .
Antioxidant micronutrients and essential fatty acids supplementation intake appears to have a protective effect in some diseases such as cardiovascular disease , cancer , and asthma .
The aim of this study was to perform a systematic review to evaluate the effects of these nutrients on nutritional and clinical outcomes of patients with cystic fibrosis ( CF ) .
This is a systematic review of r and omized clinical trials ( RCTs ) in CF .
The Method Quality of Cross-Over Studies Involved in Cochrane Systematic Reviews
Background It is possible that cross-over studies included in current systematic review s are being inadequately assessed , because the current risk of bias tools do not consider possible biases specific to cross-over design . We performed this study to evaluate whether this was being done in  cross-over studies included in Cochrane  Systematic Review s ( CSRs ) . Methods We search ed the Cochrane Library ( up to 2013 issue 5 ) for CSRs that included at least one cross-over trial . Two authors independently undertook the study selection and data extraction . A r and om sample of the CSRs was selected and we evaluated whether the cross-over trials in these CSRs were assessed according to criteria suggested by the Cochrane h and book . In addition we reassessed the risk of bias of these cross-over trials by a checklist developed form the Cochrane h and book . Results We identified 688 CSRs that included one or more cross-over studies . We chose a r and om sample of 60 CSRs and these included 139 cross-over studies . None of these CSRs undertook a risk of bias assessment specific for cross-over studies . In fact items specific for cross-over studies were seldom considered anywhere in quality assessment of these CSRs . When we reassessed the risk of bias , including the 3 items specific to cross-over trials , of these 139 studies , a low risk of bias was judged for appropriate cross-over design in 110(79 % ) , carry-over effects in 48(34 % ) and for reporting data in all stages of the trial in 114(82 % ) . Assessment of biases in cross-over trials could affect the GRADE assessment of a review ’s findings . Conclusion The current Cochrane risk of bias tool is not adequate to assess cross-over studies . Items specific to cross-over trials leading to potential risk of bias are generally neglected in CSRs . A proposed check list for the evaluation of cross-over trials is provided
The benefits of antioxidants or DHA/EPA supplementation for CF , although observed in some studies , are not consistent enough to recommend routine use of these supplements .
Antioxidant micronutrients and essential fatty acids supplementation intake appears to have a protective effect in some diseases such as cardiovascular disease , cancer , and asthma .
The aim of this study was to perform a systematic review to evaluate the effects of these nutrients on nutritional and clinical outcomes of patients with cystic fibrosis ( CF ) .
This is a systematic review of r and omized clinical trials ( RCTs ) in CF .