277
The first follow - up was at a nearly constant interval of 5 . 1 years in Caerphilly and 3 . 2 years in Speedwell ; 251 major IHD events had occurred .
 None
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: GENE 
Text: {0} 
Answer:
 None