This chapter summarises the results of the preceding sections, which estimate the
fraction of cancers occurring in the UK in 2010 that can be attributed to
sub-optimal, past exposures of 14 lifestyle and environmental risk factors. For
each of 18 cancer types, we present the percentage of cases attributable to one
or all of the risk factors considered (tobacco, alcohol, four elements of diet
(consumption of meat, fruit and vegetables, fibre, and salt), overweight, lack
of physical exercise, occupation, infections, radiation (ionising and solar),
use of hormones, and reproductive history (breast feeding)).Exposure to less than optimum levels of the 14 factors was responsible for
42.7% of cancers in the UK in 2010 (45.3% in men, 40.1% in
women) – a total of about 134 000 cases.Tobacco smoking is by far the most important risk factor for cancer in the UK,
responsible for 60 000 cases (19.4% of all new cancer cases) in
2010. The relative importance of other exposures differs by sex. In men,
deficient intake of fruits and vegetables (6.1%), occupational exposures
(4.9%) and alcohol consumption (4.6%) are next in importance,
while in women, it is overweight and obesity (because of the effect on breast
cancer) – responsible for 6.9% of cancers, followed by infectious
agents (3.7%).Population-attributable fractions provide a valuable quantitative appraisal of
the impact of different factors in cancer causation, and are thus helpful in
prioritising cancer control strategies. However, quantifying the likely impact
of preventive interventions requires rather complex scenario modelling,
including specification of realistically achievable population distributions of
risk factors, and the timescale of change, as well as the latent periods between
exposure and outcome, and the rate of change following modification in exposure
level.