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Unhealthy behaviours and disability in older adults: Three-City Dijon cohort study

BMJ 2013; 347 doi: https://doi.org/10.1136/bmj.f4240 (Published 23 July 2013) Cite this as: BMJ 2013;347:f4240
  1. Fanny Artaud, PhD candidate12,
  2. Aline Dugravot, statistician12,
  3. Séverine Sabia, research associate3,
  4. Archana Singh-Manoux, research director1234,
  5. Christophe Tzourio, professor of epidemiology56,
  6. Alexis Elbaz, research director123
  1. 1INSERM, Centre for research in Epidemiology and Population Health (CESP), U1018, Social and occupational determinants of health, F-94807, Villejuif, France
  2. 2Université de Versailles St-Quentin, UMRS 1018, F-78035, Versailles, France
  3. 3Department of Epidemiology and Public Health, University College London, London, UK
  4. 4Centre de Gérontologie, Hôpital Ste Périne, AP-HP, France
  5. 5INSERM U708, Neuroepidemiology, Bordeaux, France
  6. 6Université de Victor Segalen Bordeaux 2, Bordeaux, France
  1. Correspondence to: A Elbaz alexis.elbaz{at}inserm.fr
  • Accepted 25 June 2013

Abstract

Objectives To examine the individual and combined associations of unhealthy behaviours (low/intermediate physical activity, consuming fruit and vegetables less than once a day, current smoking/short term ex-smoking, never/former/heavy alcohol drinking), assessed at start of follow-up, with hazard of disability among older French adults and to assess the role of potential mediators, assessed repeatedly, of these associations.

Design Population based cohort study.

Setting Dijon centre of Three-City study.

Participants 3982 (2410 (60.5%) women) French community dwellers aged 65 or over included during 1999-2001; participants were disability-free at baseline when health behaviours were assessed.

Main outcome measure Hierarchical indicator of disability (no, light, moderate, severe) combining data from three disability scales (mobility, instrumental activities of daily living, basic activities of daily living) assessed five times between 2001 and 2012.

Results During the 12 year follow-up, 1236 participants (861 (69.7%) women) developed moderate or severe disability. Interval censored survival analyses (adjusted for age, sex, marital status, and education) showed low/intermediate physical activity (hazard ratio 1.72, 95% confidence interval 1.48 to 2.00), consuming fruit and vegetables less than once a day (1.24, 1.10 to 1.41), and current smoking/short term ex-smoking (1.26, 1.05 to 1.50) to be independently associated with an increased hazard of disability, whereas no robust association with alcohol consumption was found. The hazard of disability increased progressively with the number of unhealthy behaviours independently associated with disability (P<0.001); participants with three unhealthy behaviours had a 2.53 (1.86 to 3.43)-fold increased hazard of disability compared with those with none. Reverse causation bias was verified by excluding participants who developed disability in the first four years of follow-up; these analyses on 890 disability events yielded results similar to those in the main analysis. 30.5% of the association between the unhealthy behaviours score and disability was explained by body mass index, cognitive function, depressive symptoms, trauma, chronic conditions, and cardiovascular disease and its risk factors; the main contributors were chronic conditions and, to a lesser extent, depressive symptoms, trauma, and body mass index.

Conclusions An unhealthy lifestyle is associated with greater hazard of incident disability, and the hazard increases progressively with the number of unhealthy behaviours. Chronic conditions, depressive symptoms, trauma, and body mass index partially explained this association.

Footnotes

  • We thank Célia Touraine for her help in implementing interval censored analyses.

  • Contributors: FA, SS, AS-M, and AE designed the study. FA did the statistical analyses. AD provided assistance with the statistical analyses. FA and AE drafted the manuscript. All authors critically revised the manuscript for important intellectual content. CT obtained funding and supervised the study. FA and AE are the guarantors.

  • Funding: The 3C study is conducted under a partnership agreement between the Institut National de la Santé et de la Recherche Médicale (INSERM), the Victor Segalen-Bordeaux II University, and the Sanofi-Synthélabo Company. The Fondation pour la Recherche Médicale funded the preparation and initiation of the study. The 3C study is also supported by the Caisse Nationale Maladie des Travailleurs Salariés, Direction Générale de la Santé, Conseils Régionaux of Bourgogne, Fondation de France, Ministry of Research-INSERM Program, “Cohortes et collections de données biologiques,” Mutuelle Générale de l’Education Nationale, Institut de la Longévité, Conseil Général de la Côte d’or, and Fondation Plan Alzheimer. This research was also funded by Institut national de prévention et d’éducation pour la santé (INPES, N°063/11-DAS). FA is the recipient of a doctoral grant from the Ministère de l’Enseignement Supérieur et de la Recherche, Paris, France, and the EHESP (Ecole des Hautes Etudes en Santé Publique), Rennes, France. The sponsors had no role in study design, data collection, data analysis, data interpretation, the writing of the report, or the decision to submit the paper for publication.

  • Competing interests: All authors have completed the ICMJE uniform disclosure form at www.icmje.org/coi_disclosure.pdf (available on request from the corresponding author) and declare: CT has received research support from Agence Nationale de la Recherche (ANR) and Fondation Plan Alzheimer for the Three-City Study; CT has served on scientific advisory boards for Merck Sharp and Dohme and Fondation Plan Alzheimer and has received speaker honorariums from Abbott and Fondation Recherche HTA; no relationships with other companies that might have an interest in the submitted work in the previous three years; no other non-financial interests that may be relevant to the submitted work.

  • Ethical approval: The study protocol was approved by the ethical committee of the Kremlin-Bicêtre University-Hospital (France), and all participants gave written informed consent.

  • Data sharing: No additional data available.

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