19587
Our study population consisted of 223 Caucasian and 35 African American women ( mean age 87 ) from the Study of Osteoporotic Fractures ( SOF ) cohort , who had usable pQCT scans of the tibia at sites 4 % ( T4 % ) , 33 % ( T33 % ) , and 66 % ( T66 % ) from the ankle .
 None
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 None