1992
INTERPRETATION : Smoking of crack cocaine was found to be an independent risk factor for HIV seroconversion among people who were injection drug users .
 Chemical: crack cocaine; Disease: HIV seroconversion
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Disease, Chemical 
Text: {0} 
Answer:
 Chemical: crack cocaine; Disease: HIV seroconversion