Incidence and mortality by colorectal cancer in Spain during 1951-2006 and its relationship with behavioural factors.

Incidence of colorectal cancer has steadily increased in both the sexes and across all age groups during the last decades in Spain, in contrast with other countries where incidence decreased during this period. This increase is more marked among men, probably due to a high exposure to risk factors such as smoking, heavy drinking, overweight and diabetes. Annual age-adjusted mortality rates have increased in Spain during the period 1951-2000, but from that time until 2006 these rates have kept steady in males and fallen in females. When analyzing the evolution of exposure to behavioural factors during this period, known as risk or protective factors for colorectal cancer in Spain, notorious increases in tobacco and alcohol consumption, red and processed meats intake and a decreased ingestion of vegetables, cereals and beans were observed. Cigarette smoking, alcohol consumption, red meats, poultry, fish, vegetables and fruit were highly, positively correlated with colorectal cancer incidence and mortality, and cereals and beans consumption showed strong, negative correlations. At the same time and during this period, physical exercise decreased and overweight, obesity and diabetes mellitus notably increased. Certain changes in diet and lifestyle can be attributed to the growth in income during the last decades, but the lack and delay in implementing legislative and educational measures by the State and Regional Governments during decades cannot be ignored. In colorectal cancer, a minimal time span of 10-15 years is necessary for changes in exposure to risk factors to be able to modify the incidence of the tumour. Therefore, the implementation of more vigorous legislative and educational measures in Spain against smoking, heavy drinking, red meat intake, sedentary lifestyle, overweight and others reviewed in this study, is urgent.