Skip navigation

Lifestyle factors and risk

Clinical bottom line

It is possible to take good epidemiological research and express the results as risk - odds of dying, for instance - as well as more statistical ways like relative risk. Lifestyle has a huge impact on our likelihood of living and dying, many many times greater than risks from other behaviours - even riding motorcycles.


Data sources

References to data sources are in the Table. Those chosen are seminal studies concerning the relationship between lifestyle factors - smoking, eating, exercise - and mortality.

What the sources tell us

The studies have different starting populations and look at different behaviours for varying follow up periods. It is not possible to standardise the risks, so the risks given are for the study population and the follow up period.

What they show is to some extent what we already know. Lifestyle choices have a huge effect on length of life - and for that matter quality as well. Behaviours that help hearts generally help prevent cancers, and osteoarthritis, and macular degeneration, and a host of other conditions no sensible person wants. Most of the studies have already appeared in bandolier's pages over the years, but this is a different way of looking at the results.

The first three studies emphasise the effect of lifestyle on risk in the middle aged westerner.

Studies of individual factors tend to be less spectacular, but walking has big effects on cancer and heart disease. Showing any effect of a single intervention on death in older people followed up for a longer period is harder, because people eventually die of something, but even overall mortality can be shown to be lower in people who walk.

The big effect is smoking - both on overall mortality, and especially on lung cancer.

Give us the odds

Table 1: Effect of behaviours on risk of dying. The odds quoted are for the population studies and the duration of follow up

Study
Risk group
Baseline population
Deaths

Odds of dying over period studied and for cause

(1 in )

Stampfer et al. N Engl J Med 2000;343:16-22. Primary Prevention of Coronary Heart Disease in Women Through Diet and Lifestyle

 

Data from US Nurses' Health Study; population aged 30-55 at start of study; mortality from coronary heart disease only; 14 yrs follow up

Overall
84,129
296
284
2 or fewer low-risk factors
64,779
272
238
3 low-risk factors
10,684
16
657
4 low-risk factors
6,057
6
962
5 low-risk factors
2,608
1
1,988

Khaw et al. PLoS Medicine 2008;5(1): e12. Combined Impact of Health Behaviours and Mortality in Men and Women: The EPIC-Norfolk Prospective Population Study

 

Population aged 45-79 (mean age 58.2) at start of study; mortality from all causes; 14 yrs of follow up

Overall
20,244
1,977
10
0 low-risk factors
196
49
4
1 low-risk factors
1,407
277
5
2 low-risk factors
4,568
651
7
3 low-risk factors
7,788
682
11
4 low-risk factors
6,285
318
20

Akesson et al. Arch Intern Med. 2007;167(19):2122-2127. Combined Effect of Low-Risk Dietary and Lifestyle Behaviors in Primary Prevention of Myocardial Infarction in Women

 

Study population of women aged 48-83 yrs at baseline; mean follow up duration 6.2 yrs

Overall
24,444
51
479
1 or fewer low risk factors
9,289
38
245
2 low risk factors
7,089
7
1,019
3 low risk factors
5,133
4
1,148
4 low risk factors
1,711
1
1,476
5 low risk factors
1,222
0
2,460

Hakim et al. N Engl J Med 1998;338:94-9. Effects of Walking on Mortality Among Nonsmoking Retired Men

 

Population aged 61 - 81 (mean age 68.9) at start of study; 12 yrs of follow up; all causes of mortality

Overall
707
208
3
Walking < 1 mile/day
151
65
2
Walking > 1 mile/day
556
143
4
Walking 1-2 miles/day
379
105
4
Walking > 2 miles/day
177
38
5

Hakim et al. N Engl J Med 1998;338:94-9. Effects of Walking on Mortality Among Nonsmoking Retired Men

 

Population aged 61 - 81 (mean age 68.9) at start of study; 12 yrs of follow up; coronary heart disease as mortality outcome

Overall
588
29
20
Walking < 1 mile/day
122
8
15
Walking > 1 mile/day
466
21
22
Walking 1-2 miles/day
321
18
18
Walking > 2 miles/day
145
3
48

Hakim et al. N Engl J Med 1998;338:94-9. Effects of Walking on Mortality Among Nonsmoking Retired Men

 

Population aged 61 - 81 (mean age 68.9) at start of study; 12 yrs of follow up; cancer as mortality outcome

Overall
672
62
11
Walking < 1 mile/day
142
19
7
Walking > 1 mile/day
530
43
12
Walking 1-2 miles/day
361
34
11
Walking > 2 miles/day
169
9
19

Knoops et al. JAMA. 2004;292(12):1433-1439. Mediterranean Diet, Lifestyle Factors, and 10-Year Mortality in Elderly European Men and Women: The HALE Project

 

10 yrs of follow up, data from graph, mean age of population at start of study was 74 yrs

Healthful lifestyle factor score 0-1
246
145
2
Healthful lifestyle factor score 2
702
309
2
Healthful lifestyle factor score 3
954
334
3
Healthful lifestyle factor score 4
437
131
3

Doll et al. BMJ 2004;328(7455):1519. Mortality in relation to smoking: 50 years’ observations on male British doctors

 

50 yrs follow up, population aged from 21-51+ at baseline; all causes of mortality

Lifelong non-smoker
52
Former smoker
41
Current smoker
28
Current smoker (>25 per day)
22
50 yrs follow up, population aged from 21-51+ at baseline; lung cancer as only mortality indicator Lifelong non-smoker
5,882
Former smoker
1,471
Current smoker
402
Current smoker (>25 per day)
240