You will be shown an abstract from a biomedical research paper. Given this abstract, your task is to extract all unique entities of the following types: ["Outcome", "Participant", "Intervention"].

Please return the output as a JSON object of the format: {"Participant" : ["patients with COPD", ...], "Intervention" : ["Atenolol", ...], "Outcome" : ["blood pressure", ...]}. The keys should be entity types and values should be lists of extracted entities belonging to the corresponding type. If you cannot find entities belonging to a specific type, the value should be [].

Only output the JSON object and do not include any additional text.

Abstract:

Predictors of local adverse effects caused by topical tretinoin cream 0·1 % in the Veterans Affairs Topical Tretinoin Chemoprevention trial . BACKGROUND Topical tretinoin is commonly prescribed , but its frequent adverse effects are barriers to use . Predictors of resistance or susceptibility to retinoid irritation are not known . OBJECTIVE To identify baseline patient characteristics associated with adverse effects of topical tretinoin . METHODS This cohort study used data collected from 324 participants in the Veterans Affairs Topical Tretinoin Chemoprevention trial who were randomized to apply tretinoin cream on the face and ears . Univariate and multivariate logistic regression models were used to examine the associations between baseline characteristics and local adverse effects . RESULTS One hundred and ninety-seven patients ( 61 % of those randomized to tretinoin ) reported local adverse effects within 6 months . Clinical signs of severe photodamage at baseline [ odds ratio ( OR ) 0·15 , 95 % confidence interval ( CI ) 0·04-0·54 ] and history of acne ( OR 0·46 , 95 % CI 0·27-0·77 ) were associated with a decreased risk of adverse effects to tretinoin . The use of other topical medications at enrolment ( OR 1·88 , 95 % CI 1·15-3·08 ) predicted an increase in adverse effects . CONCLUSIONS In this study population , the common indications of topical tretinoin treatment were associated with lower risks of adverse effects . The concurrent use of other topical medications may worsen irritation caused by tretinoin .
{"Intervention": ["tretinoin"], "Outcome": ["of", "severe photodamage", "reported local adverse effects", "increase in adverse", "lower risks of adverse", "and history of acne", "risk of adverse effects"], "Participant": ["324", "the Veterans Affairs Topical Tretinoin Chemoprevention trial"]}