Impact of lifestyle in middle-aged women on mortality: evidence from the Royal College of General Practitioners' Oral Contraception Study.
BACKGROUND
Although many individuals have multiple lifestyle risk factors, few studies have investigated the impact of lifestyle risk factor combinations among women.


OBJECTIVE
To investigate the relationship between individual and combinations of lifestyle risk factors in middle-aged women with subsequent mortality, and to estimate the associated population attributable risks.


METHODS
Prospective cohort study.


METHODS
Royal College of General Practitioners' (RCGP) Oral Contraception Study, UK.


METHODS
In 1994-1995, women remaining under follow-up in the RCGP Oral Contraception Study were sent a lifestyle survey, from which modifiable risk factors were identified: pack-years smoked, physical inactivity, never drinking versus consuming at least 7 units of alcohol weekly, and being underweight, overweight, or obese. The cohort was followed to December 2006 or death. Population attributable risks were calculated.


RESULTS
Of 10 059 women studied, 896 died. Pack-years smoked (11-20 years: adjusted hazard ratio [HR] = 1.82, 95% confidence interval [CI] = 1.46 to 2.27; >20 years: adjusted HR = 2.34, 95% CI = 2.00 to 2.74); never drinking alcohol (adjusted HR = 1.66, 95% CI = 1.34 to 2.05); being underweight (adjusted = HR 1.66, 95% CI = 1.03 to 2.68); and physical inactivity (<15 hours/week: adjusted HR = 1.73, 95% CI = 1.46 to 2.04) were significantly associated with mortality compared with their respective reference group. Women with multiple lifestyle risk factors had higher mortality risks than those reporting one factor. The population attributable risk of the combination of smoking, physical inactivity, body mass index outside normal range, and alcohol (never drinking or excess intake) was 59% (95% CI = 31% to 78%).


CONCLUSIONS
Assuming a causal relationship between lifestyle and mortality, avoidance of four lifestyle risk factors would have prevented 60% of the deaths. The importance of avoiding smoking and undertaking physical inactivity during midlife should continue to be emphasised.
Iversen
Lisa
L
Section of Primary Care, Centre of Academic Primary Care, College of Life Sciences & Medicine, University of Aberdeen, Aberdeen. l.iversen@abdn.ac.uk
Hannaford
Philip C
PC
Lee
Amanda J
AJ
Elliott
Alison M
AM
Fielding
Shona
S
D000328:Adult; D000368:Aged; D015992:Body Mass Index; D003276:Contraceptives, Oral; D015444:Exercise / Q000502:physiology; D005260:Female; D006306:Health Surveys; D006801:Humans; D008019:Life Style; D008875:Middle Aged; D009026:Mortality; D011446:Prospective Studies; D012907:Smoking; D016387:Women's Health
D003276:Contraceptives, Oral
J Epidemiol Community Health. 1998 Jul;52(7):420-4
9799875
PLoS Med. 2008 Jan 8;5(1):e12
18184033
Heart. 2009 Aug;95(15):1250-7
19389720
Cancer Causes Control. 2007 Jun;18(5):571-9
17387622
Br J Cancer. 2004 Jan 26;90(2):299-303
14735167
Am J Prev Med. 2007 Apr;32(4):320-327
17383563
J Clin Epidemiol. 1995 Apr;48(4):455-65
7722599
BMJ. 1996 Sep 21;313(7059):711-5; discussion 715-6
8819439
Am J Epidemiol. 1997 Aug 15;146(4):322-8
9270411
Int J Epidemiol. 1997;26 Suppl 1:S181-9
9126546
Gend Med. 2009;6 Suppl 1:17-36
19318217
BMJ. 2008 Sep 16;337:a1440
18796495
N Engl J Med. 1995 May 11;332(19):1245-50
7708067