ArticleBMJ open2023
Loss to 5-year follow-up in the population-based Telemark Study: risk factors and potential for bias.
Article in BMJ open, 2023. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 5 papers.
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Who cites it
5 citing papers in PubMed, 11 citations in OpenAlex.
- Impact of the intensified follow-up procedure of patients lost to 6-month follow-up after an intensive smoking and nicotine cessation intervention in practice: a cohort study.Tobacco control · 2026Article
- Incidence, Mechanisms, and Clinical Characteristics of Traumatic Iritis: A Population-Based Analysis.Ocular immunology and inflammation · 2025Article
- Occupational exposure and new-onset asthma in the population-based Telemark study: a 5-year follow-up.BMJ open · 2024Article
- Public attitudes towards personal health data sharing in long-term epidemiological research: a Citizen Science approach in the KORA study.BMC public health · 2024Article
- Risk factors for SARS-CoV-2 infection: a test-negative case-control study with additional population controls in Norway.BMJ open · 2024Article
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Authors and funding
8 authors at 4 institutions in 5 countries.
Funding
No grant is acknowledged in the PubMed record.
Abstract
objectivesThis study aimed to characterise participants lost to follow-up and identify possible factors associated with non-participation in a prospective population-based study of respiratory health in Norway. We also aimed to analyse the impact of potentially biased risk estimates associated with a high proportion of non-responders.
designProspective 5-year follow-up study.
settingRandomly selected inhabitants from the general population of Telemark County in south-eastern Norway were invited to fill in a postal questionnaire in 2013. Responders in 2013 were followed-up in 2018.
participants16 099 participants aged 16-50 years completed the baseline study. 7958 responded at the 5-year follow-up, while 7723 did not.
main outcome measuresχ
results7723 (49%) participants were lost to follow-up. Loss to follow-up was significantly higher for male participants, those in the youngest age group (16-30 years), those in lowest education level category and among current smokers (all p<0.001). In multivariable logistic regression analysis, loss to follow-up was significantly associated with unemployment (OR 1.34, 95% CI 1.22 to 1.46), reduced work ability (1.48, 1.35 to 1.60), asthma (1.22, 1.10 to 1.35), being woken by chest tightness (1.22, 1.11 to 1.34) and chronic obstructive pulmonary disease (1.81, 1.30 to 2.52). Participants with more respiratory symptoms and exposure to vapour, gas, dust and fumes (VGDF) (1.07 to 1.00-1.15), low-molecular weight (LMW) agents (1.19, 1.00 to 1.41) and irritating agents (1.15, 1.05 to 1.26) were more likely to be lost to follow-up. We found no statistically significant association of wheezing and exposure to LMW agents for all participants at baseline (1.11, 0.90 to 1.36), responders in 2018 (1.12, 0.83 to 1.53) and those lost to follow-up (1.07, 0.81 to 1.42).
conclusionThe risk factors for loss to 5-year follow-up were comparable to those reported in other population-based studies and included younger age, male gender, current smoking, lower educational level and higher symptom prevalence and morbidity. We found that exposure to VGDF, irritating and LMW agents can be risk factors associated with loss to follow-up. Results suggest that loss to follow-up did not affect estimates of occupational exposure as a risk factor for respiratory symptoms.
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