***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: Six studies were selected for inclusion (106 participants). No results were combined as the studies were all of a crossover design. EFFECTS OF NEGATIVE ION GENERATORS (five studies) No study reported a significant difference in lung function between ionised and control air (morning Peak expiratory flow (PEF) - three studies; forced expiratory flow in one second (FEV1) - one study). There were no significant differences in symptoms or beta-2 agonist usage between ionised and control air in three studies. EFFECTS OF POSITIVE ION GENERATORS (one study) This study demonstrated that although positively ionised air was associated with a larger fall in FEV1 with exercise, this did not reach statistical significance. Baseline FEV1 was not demonstrated to be significantly different between treatment groups. Based on the evidence currently available from randomised controlled trials, a recommendation cannot be given for the use of room air ionisers to reduce symptoms in patients with chronic asthma.
Output:

Although complex laboratory studies show that ion generators alter airways function, the few studies which have been conducted in the homes of people with asthma, demonstrate no significant benefit in improving lung function or symptoms.