Rising rates of colorectal cancer among younger Iranians: is diet to blame?

Abstract

Background: Colorectal cancer (crc) is one of the most prevalent cancers in the world. Although the incidence of crc is currently very low in the older Iranian population compared with Western populations, young Iranians show a rising trend of crc-that is, the age-adjusted rate is close in the young Iranian population compared with the U.S. population, and the rate in older Iranians is much lower.

Methods: To assess a putative relationship between diet and a rising rate of crc in younger Iranians, a combined text word and mesh heading search strategy identified relevant studies through Google Scholar and medline.

Results: A critical look at diet among Iranians shows major issues that might be raising the risk for crc. There are also scenarios other than diet for the rise, such as the young age structure of the country. However, the actual scenario is more complex.

Conclusions: In Iran, crc is one of the most common incident cancers and a common cause of cancer death. Primary and secondary prevention-with attention to a healthy lifestyle, physical activity, and screening-should be enhanced in the general population.

Keywords: Colorectal cancer; Iran; diet; epidemiology; lifestyle factors; obesity; physical activity.

FIGURE 1

Age-adjusted rates of colorectal cancer per 100,000 population, Iran and the United States. The U.S. rates were calculated using 5-year age-specific Surveillance, Epidemiology, and End Results data for 1995–1999 and the age structure of the U.S. population during the same years (used with permission from the Archives of Iranian Medicine).