168,605 items of data are available, covering 152,640 participants.
Defined-instances run from 0 to 3, labelled using Instancing 2
Units of measurement are years.
- Mean = 23.0152
- Std.dev = 18.6059
- 1826 items above graph maximum of 86.7
: Initial assessment visit (2006-2010) at which participants were recruited and consent given
150,945 participants, 150,945 items
- Mean = 23.3819
- Std.dev = 18.8032
- 1612 items above graph maximum of 87.5
Instance 1 : First repeat assessment visit (2012-13)
5,341 participants, 5,341 items
- Mean = 21.0098
- Std.dev = 17.367
- 56 items above graph maximum of 81.65
Instance 2 : Imaging visit (2014+)
11,605 participants, 11,605 items
- Mean = 19.4085
- Std.dev = 16.1287
- 115 items above graph maximum of 76.125
Instance 3 : First repeat imaging visit (2019+)
714 participants, 714 items
- Mean = 19.1129
- Std.dev = 15.2343
- 5 items above graph maximum of 74
Pack years calculated for individuals who have ever smoked according to data field Ever smoking status=1, using appropriate data: Current cigarette (either manufactured or hand rolled) smokers who smoke most days (smoking data fields used: Field 3436
and Field 6183
). Past cigarette (either manufactured or hand rolled) smokers who smoked most days (smoking data fields used: Field 2867
, Field 2897
and Field 2887
). Current cigar/pipe smokers who smoked most days and previously smoked cigarettes (smoking data fields used: Field 3436
, Field 6194
and Field 6183
). The general definition of a pack year is the number of cigarettes smoked per day, divided by twenty, multiplied by the number of years of smoking. The number of years of smoking is calculated by substracting the age of starting smoking from the age smoking was stopped.
Number of cigarettes per day / 20 * (Age stopped smoking - Age start smoking)
The figure is adjusted for individuals who gave up smoking for more than 6 months, according to data fields 2907 or 3486 by subtracting six months from the number of years of smoking.
Number of cigarettes per day / 20 * (Age stopped smoking - Age start smoking - 0.5)
Note: Individuals who started and gave up smoking before 16 years of age were coded as NA. For individuals who started smoking before 16 but gave up after 16, their age start was set as 16. Individuals who reported starting and stopping smoking at the same age and reported giving up smoking for more than 6 months had pack-years set at 0.
This derived data field has come from Professor Martin Tobin at the University of Leicester.
1 Related Data-Fields
|20162||Pack years adult smoking as proporti ...||Field 20162 is derived using Current Field|
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