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Is calculating pack-years retrospectively a valid method to estimate life-time tobacco smoking? A comparison between prospectively calculated pack-years and retrospectively calculated pack-years.
- Source :
-
Addiction . Nov2001, Vol. 96 Issue 11, p1653-1661. 9p. 1 Diagram, 2 Charts, 1 Graph. - Publication Year :
- 2001
-
Abstract
- Aims. To investigate the relative validity of retrospectively calculated pack-years (py-retro) by comparing py-retro with prospectively calculated pack-years (py-pro). Design. A 23-year ongoing cohort study (1977-2000). Participants. One hundred and fifty-four males and females, 13 years old in 1977 and 36 years old in 2000. Setting. Amsterdam, the Netherlands. Measurements. To calculate py-pro, current smoking and quitting efforts were investigated nine times in a period of 23 years with the help of an interview or a questionnaire. At the age of 36, subjects filled out a comprehensive questionnaire about their smoking history, to calculate py-retro. Individual differences between py-pro and py-retro were calculated. In addition, Cohen's kappa was calculated after categorising py-pro and py-retro into three groups. Findings. (1) Py-retro does not under- or overestimate life-time tobacco smoking. (2) The relative validity of py-retro was moderate due to large individual differences between py-pro and py-retro. (3) The individual differences between py-pro and py-retro became larger, the higher the number of pack-years. (4) Mean difference (and 95% limits of agreement) between py-pro and py-retro was -0.039 (-5.23, 5.32) when average pack-years was <5.2 and -1.17 (-10.00, 14.65) when pack-years ≥5.2. 5. Cohen's kappa between categorized py-pro and py-retro was 0.79. Conclusions. Future researchers in the field of smoking should be aware of the moderate relative validity of py-retro. Categorizing py-retro into smoking groups results in a misclassification error that is smaller than the quantitative error in continuous py-retro, but goes together with a loss of information. [ABSTRACT FROM AUTHOR]
- Subjects :
- *SMOKING
*HUMAN sexuality
Subjects
Details
- Language :
- English
- ISSN :
- 09652140
- Volume :
- 96
- Issue :
- 11
- Database :
- Academic Search Index
- Journal :
- Addiction
- Publication Type :
- Academic Journal
- Accession number :
- 5402337
- Full Text :
- https://doi.org/10.1046/j.1360-0443.2001.9611165311.x