Where used:
| Attribute | NUMBER OF YEARS SMOKED | references in description CIGARETTES PER DAY |
| Class | TOBACCO USAGE | has attribute CIGARETTES PER DAY |
| Data Element | ESTIMATED PACK YEARS | references in description CIGARETTES PER DAY |
| Attribute | NUMBER OF YEARS SMOKED | references in description CIGARETTES PER DAY |
| Class | TOBACCO USAGE | has attribute CIGARETTES PER DAY |
| Data Element | ESTIMATED PACK YEARS | references in description CIGARETTES PER DAY |