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Assessment of selection bias due to dropouts in the follow-up of the Scania Public Health Cohort

Canivet, Catarina LU ; Nilsson, Anton LU ; Björk, Jonas LU ; Moghaddassi, Mahnaz LU and Östergren, Per Olof LU (2020) In Scandinavian Journal of Public Health
Abstract

Aims: To investigate potential differences between participants and dropouts in the 2005 follow-up of the Scania Public Health Cohort Study regarding the prevalence of commonly studied health determinants and whether these factors had differential associations with three health outcomes: all-cause mortality and purchase of prescribed cardiovascular or psychotropic drugs during a 10-year follow-up period. Methods: The Scania Public Health Cohort was initiated in 1999/2000, with randomly invited participants aged 18–80 years from the general population (58% participation). Questionnaire data from 10,462 participants and 2576 dropouts in the 2005 follow-up (80% participation) were linked to public registers on mortality and purchase of... (More)

Aims: To investigate potential differences between participants and dropouts in the 2005 follow-up of the Scania Public Health Cohort Study regarding the prevalence of commonly studied health determinants and whether these factors had differential associations with three health outcomes: all-cause mortality and purchase of prescribed cardiovascular or psychotropic drugs during a 10-year follow-up period. Methods: The Scania Public Health Cohort was initiated in 1999/2000, with randomly invited participants aged 18–80 years from the general population (58% participation). Questionnaire data from 10,462 participants and 2576 dropouts in the 2005 follow-up (80% participation) were linked to public registers on mortality and purchase of prescribed drugs. Results: Age, male gender, being born abroad, low educational level, low self-rated mental and general health and daily smoking were all related to dropping out. The 10-year mortality was higher among dropouts (13.4% versus 11.9%; age-adjusted hazard ratio 1.6, 95% confidence interval: 1.4–1.8). In 13 out of 18 analyses, similar associations between health determinants and outcomes were found across participants and dropouts. However, being born outside of Sweden was associated with higher risks for all three poor health outcomes among participants, but not so among dropouts. Conclusions: Despite selective participation at follow-up, there was little evidence of selection bias, insofar as estimated associations were generally similar across participants, dropouts and the whole cohort. This finding is important for the assessment of the validity of prospective findings from this cohort and similar ones, where the loss of individuals at consecutive follow-ups of exposure is non-negligible.

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author
; ; ; and
organization
publishing date
type
Contribution to journal
publication status
epub
subject
keywords
bias, cohort studies, epidemiology, follow-up studies, Population-based study, public health, register data, selection
in
Scandinavian Journal of Public Health
publisher
SAGE Publications
external identifiers
  • scopus:85085601682
  • pmid:32466718
ISSN
1403-4948
DOI
10.1177/1403494820919544
project
Nya statistiska ansatser för att bedöma betydelsen av selektion och variation i befolkningsbaserade kohort- och screeningundersökningar
language
English
LU publication?
yes
id
b4d9fd16-ba25-4c91-8262-d1495fd82462
date added to LUP
2020-06-25 11:18:02
date last changed
2020-07-14 11:00:52
@article{b4d9fd16-ba25-4c91-8262-d1495fd82462,
  abstract     = {<p>Aims: To investigate potential differences between participants and dropouts in the 2005 follow-up of the Scania Public Health Cohort Study regarding the prevalence of commonly studied health determinants and whether these factors had differential associations with three health outcomes: all-cause mortality and purchase of prescribed cardiovascular or psychotropic drugs during a 10-year follow-up period. Methods: The Scania Public Health Cohort was initiated in 1999/2000, with randomly invited participants aged 18–80 years from the general population (58% participation). Questionnaire data from 10,462 participants and 2576 dropouts in the 2005 follow-up (80% participation) were linked to public registers on mortality and purchase of prescribed drugs. Results: Age, male gender, being born abroad, low educational level, low self-rated mental and general health and daily smoking were all related to dropping out. The 10-year mortality was higher among dropouts (13.4% versus 11.9%; age-adjusted hazard ratio 1.6, 95% confidence interval: 1.4–1.8). In 13 out of 18 analyses, similar associations between health determinants and outcomes were found across participants and dropouts. However, being born outside of Sweden was associated with higher risks for all three poor health outcomes among participants, but not so among dropouts. Conclusions: Despite selective participation at follow-up, there was little evidence of selection bias, insofar as estimated associations were generally similar across participants, dropouts and the whole cohort. This finding is important for the assessment of the validity of prospective findings from this cohort and similar ones, where the loss of individuals at consecutive follow-ups of exposure is non-negligible.</p>},
  author       = {Canivet, Catarina and Nilsson, Anton and Björk, Jonas and Moghaddassi, Mahnaz and Östergren, Per Olof},
  issn         = {1403-4948},
  language     = {eng},
  month        = {05},
  publisher    = {SAGE Publications},
  series       = {Scandinavian Journal of Public Health},
  title        = {Assessment of selection bias due to dropouts in the follow-up of the Scania Public Health Cohort},
  url          = {http://dx.doi.org/10.1177/1403494820919544},
  doi          = {10.1177/1403494820919544},
  year         = {2020},
}