Combined effect of health behaviours and risk of first ever stroke in 20 040 men and women over 11 years’ follow-up in Norfolk cohort of European Prospective Investigation of Cancer (EPIC Norfolk): prospective population studyBMJ 2009; 338 doi: http://dx.doi.org/10.1136/bmj.b349 (Published 20 February 2009) Cite this as: BMJ 2009;338:b349
- Phyo K Myint, clinical senior lecturer12,
- Robert N Luben, senior research associate2,
- Nicholas J Wareham, director3,
- Sheila A Bingham, director4,
- Kay-Tee Khaw, professor of clinical gerontology2
- 1School of Medicine, Health Policy and Practice, University of East Anglia, Norwich NR4 7TJ
- 2Department of Public Health and Primary Care, University of Cambridge, Cambridge
- 3MRC Epidemiology Unit, Cambridge
- 4MRC Centre for Nutritional Epidemiology in Cancer Prevention and Survival, Cambridge
- Correspondence to: P K Myint
- Accepted 3 November 2008
Objective To quantify the potential combined impact of four health behaviours on incidence of stroke in men and women living in the general community.
Design Population based prospective study (EPIC-Norfolk).
Setting Norfolk, United Kingdom.
Participants 20 040 men and women aged 40-79 with no known stroke or myocardial infarction at baseline survey in 1993-7, living in the general community, and followed up to 2007.
Main outcome measure Participants scored one point for each health behaviour: current non-smoking, physically not inactive, moderate alcohol intake (1-14 units a week), and plasma concentration of vitamin C ≥50 µmol/l, indicating fruit and vegetable intake of at least five servings a day, for a total score ranging from 0 to 4.
Results There were 599 incident strokes over 229 993 person years of follow-up; the average follow-up was 11.5 years. After adjustment for age, sex, body mass index (BMI), systolic blood pressure, cholesterol concentration, history of diabetes and aspirin use, and social class, compared with people with the four health behaviours the relative risks for stroke for men and women were 1.15 (95% confidence interval 0.89 to 1.49) for three health behaviours, 1.58 (1.22 to 2.05) for two, 2.18 (1.63 to 2.92) for one, and 2.31 (1.33 to 4.02) for none (P<0.001 for trend). The relations were consistent in subgroups stratified by sex, age, body mass index, and social class, and after exclusion of deaths within two years.
Conclusion Four health behaviours combined predict more than a twofold difference in incidence of stroke in men and women.
We thank the participants and general practitioners who took part in the study and the staff of EPIC-Norfolk and our funders.
Contributors: K-TK, SAB, and NJW are principal investigators in EPIC-Norfolk population study. RNL was responsible for data management, computing and data linkages. PKM conducted the analysis. All authors contributed in writing of this paper. K-TK is the guarantor.
Funding: EPIC-Norfolk is supported by research programme grant funding from Cancer Research UK and the Medical Research Council with additional support from the Stroke Association, British Heart Foundation, Research Into Ageing, Academy of Medical Sciences, and Wellcome Trust.
Competing interests: None declared.
Ethical approval: The study was approved by the Norwich local research ethics committee and informed consent was given by all participants.
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