All cause mortality and the case for age specific alcohol consumption guidelines: pooled analyses of up to 10 population based cohortsBMJ 2015; 350 doi: https://doi.org/10.1136/bmj.h384 (Published 10 February 2015) Cite this as: BMJ 2015;350:h384
- Craig S Knott, research associate1,
- Ngaire Coombs, research associate23,
- Emmanuel Stamatakis, associate professor245,
- Jane P Biddulph, lecturer1
- 1Department of Epidemiology and Public Health, University College London, London, UK
- 2Physical Activity Research Group, Department of Epidemiology and Public Health, University College London, London, UK
- 3Department of Social Statistics and Demography, University of Southampton, Southampton, UK
- 4Charles Perkins Centre, University of Sydney, Sydney, Australia
- 5Exercise Health and Performance Faculty Research Group, Faculty of Health Sciences, University of Sydney, Sydney, Australia
- Correspondence to: C S Knott
- Accepted 2 December 2014
Objectives To examine the suitability of age specific limits for alcohol consumption and to explore the association between alcohol consumption and mortality in different age groups.
Design Population based data from Health Survey for England 1998-2008, linked to national mortality registration data and pooled for analysis using proportional hazards regression. Analyses were stratified by sex and age group (50-64 and ≥65 years).
Setting Up to 10 waves of the Health Survey for England, which samples the non-institutionalised general population resident in England.
Participants The derivation of two analytical samples was based on the availability of comparable alcohol consumption data, covariate data, and linked mortality data among adults aged 50 years or more. Two samples were used, each utilising a different variable for alcohol usage: self reported average weekly consumption over the past year and self reported consumption on the heaviest day in the past week. In fully adjusted analyses, the former sample comprised Health Survey for England years 1998-2002, 18 368 participants, and 4102 deaths over a median follow-up of 9.7 years, whereas the latter comprised Health Survey for England years 1999-2008, 34 523 participants, and 4220 deaths over a median follow-up of 6.5 years.
Main outcome measure All cause mortality, defined as any death recorded between the date of interview and the end of data linkage on 31 March 2011.
Results In unadjusted models, protective effects were identified across a broad range of alcohol usage in all age-sex groups. These effects were attenuated across most use categories on adjustment for a range of personal, socioeconomic, and lifestyle factors. After the exclusion of former drinkers, these effects were further attenuated. Compared with self reported never drinkers, significant protective associations were limited to younger men (50-64 years) and older women (≥65 years). Among younger men, the range of protective effects was minimal, with a significant reduction in hazards present only among those who reported consuming 15.1-20.0 units/average week (hazard ratio 0.49, 95% confidence interval 0.26 to 0.91) or 0.1-1.5 units on the heaviest day (0.43, 0.21 to 0.87). The range of protective effects was broader but lower among older women, with significant reductions in hazards present ≤10.0 units/average week and across all levels of heaviest day use. Supplementary analyses found that most protective effects disappeared where calculated in comparison with various definitions of occasional drinkers.
Conclusions Beneficial associations between low intensity alcohol consumption and all cause mortality may in part be attributable to inappropriate selection of a referent group and weak adjustment for confounders. Compared with never drinkers, age stratified analyses suggest that beneficial dose-response relations between alcohol consumption and all cause mortality may be largely specific to women drinkers aged 65 years or more, with little to no protection present in other age-sex groups. These protective associations may, however, be explained by the effect of selection biases across age-sex strata.
Contributors: CSK conceived the study and completed analyses with advice from JPB. CSK and JPB interpreted these data and drafted the paper. ES acquired the data. NC and ES created the custom dataset comprising pooled data from multiple Health Surveys for England and follow-up through linkage to national mortality registration data. NC and ES both contributed to revisions of the paper. CSK and JPB are the guarantors.
Funding: The Health Survey for England was initially funded by the Department of Health. Since April 2005, the Health Survey for England has been funded by the NHS Information Centre for Health and Social Care. The developers and funders of the Health Survey for England do not bear any responsibility for the analyses or interpretations presented here. The views expressed in this article are those of the authors and do not necessarily reflect those of the funders. CSK is supported by a three year PhD studentship from the European Research Council.
Competing interests: All authors have completed the ICMJE uniform disclosure form at www.icmje.org/coi_disclosure.pdf and declare: no support from any organisation for the submitted work; no financial relationships with any organisation that might have an interest in the submitted work in the previous three years; no other relationships or activities that could appear to have influenced the submitted work.
Ethical approval: The Health Survey for England 1998-99 was approved by London North Thames multicentre research ethics committee (MREC/97/2/9, MREC/98/2/89), the Health Survey for England 2000-07 by the London multicentre research ethics committee (MREC/99/2/91; MREC/00/2/81, MREC/01/2/82, MREC/02/2/72, MREC/03/2/97, 04/MRE02/50, 05/MREC02/47, 06/MRE02/62), and the Health Survey for England 2008 by Oxford A (07/H0604/102). Each participant gave verbal consent to be interviewed for the survey.
Transparency: The lead authors (CSK and JPB) affirm that this manuscript is an honest, accurate, and transparent account of the study being reported; that no important aspects of the study have been omitted; and that any discrepancies from the study as planned have been explained.
This is an Open Access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/.