Cancers attributable to dietary factors in the UK in 2010

The relative risk (RR) of stomach cancer in relation to salt intake has been taken from the meta-analysis of cohort studies ( WCRF, 2007 ), suggesting a RR of 1.08 per g per day, an excess RR of 0.08 per g. The durations of follow-up in the two studies contributing to this pooled value ( van den Brandt et al, 2003 ; Tsugane et al, 2004 ) were 6.3 and 11 years, respectively. The latent period, or interval between ‘exposure’ to salt and the appropriate increase in risk of cancers of the stomach, is therefore taken to be 10 years, and the 2010 fraction of avoidable cancers is based on an estimate of salt intake in 2000–2001. Table 1 shows the results from the 2000–2001 National Diet and Nutrition Survey in which average daily urinary excretion of salt was 11 g per day in men and 8.1 g per day in women ( Food Standards Agency, 2003 ). On the basis of an excess risk of 0.08 per gram of salt per day, the risk of stomach cancer associated with an intake of x g salt per day in excess of the recommended 6 g per day is as follows: so that, in the lowest consumption category (women in the age group of 50–64 years), where average salt intake ( x ) is 7.5 g per day, the RR is as follows: Table 2 shows the estimated intake of salt in 2000–2001 ( Food Standards Agency, 2003 ), and the RRs of stomach cancer (by sex and age group) associated with the excess intake, compared with the recommended level of 6 g per day. Table 3 shows the estimated number of cases of stomach cancer ‘caused’ in 2010 by the excessive consumption of salt in 2000–2001. These excess cases are calculated as (observed–expected), where the number expected=(observed/RR). Approximately 24% of stomach cancer cases can be attributed to this cause. The excess number of cases is also expressed in terms of cancer as a whole. About 0.5% of cancers in 2010 are due to salt consumption in excess of the recommended daily maximum of an average of 6 g.