***TASK***
the task is to simplify the input abstract of a biomedical literature

***INPUT***
the input is the abstract of a biomedical literature

***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature

***DOCUMENTATION***

***EXAMPLES***

Input: We included seven trials involving a total of 75 people with mild to moderate asthma. The studies were all of cross-over design. Six trials involving 55 people showed that in comparison with placebo, caffeine, even at a 'low dose' (less than 5 mg/kg body weight), appears to improve lung function for up to two hours after consumption. Forced expiratory volume in one second (FEV1) showed a small improvement up to two hours after caffeine ingestion (standardised mean difference 0.72; 95% confidence interval 0.25 to 1.20), which translates into a 5% mean difference in FEV1. However in two studies the mean differences in FEV1 were 12% and 18% after caffeine. Mid-expiratory flow rates also showed a small improvement with caffeine and this was sustained up to four hours. One trial involving 20 people examined the effect of drinking coffee versus a decaffeinated variety on the exhaled nitric oxide levels in patients with asthma and concluded that there was no significant effect on this outcome. Caffeine appears to improve airways function modestly, for up to four hours, in people with asthma. People may need to avoid caffeine for at least four hours prior to lung function testing, as caffeine ingestion could cause misinterpretation of the results. Drinking caffeinated coffee before taking exhaled nitric oxide measurements does not appear to affect the results of the test, but more studies are needed to confirm this.
Output:

This review carefully examines all the available high-quality clinical trials on caffeine in asthma. This review was conducted to discover if people should avoid consuming caffeine before taking lung function tests. This review found that even small amounts of caffeine can improve lung function for up to four hours. Therefore caffeine can affect the result of a lung function test (e.g. spirometry) and so caffeine should be avoided before taking a lung function test if possible, and previous caffeine consumption should be recorded. It is not known if taking caffeine leads to improvements in symptoms. It may be that in order to improve the symptoms of asthma, caffeine is needed in such large amounts that the drug's adverse effects would become a problem, so more research is needed. Another clinical trial looked at the effect of caffeine on exhaled nitric oxide levels and found that there is no significant effect, so it appears unlikely that patients would need to avoid caffeine before taking this type of test. However, this is the result of just a single study so more research is needed to clarify this.