Risk Factors for Colorectal Cancer in Thailand.

BACKGROUND

Colorectal cancer (CRC) is one of the most common cancers worldwide. This study aimed to investigate the risk factors for colorectal cancer in the Thai population.

MATERIALS AND

METHODS

A cohort study was carried out in Khon Kaen, Thailand, including 71 cases of histologically confirmed CRC patients among 19,861 participants, aged 30-69 years, who were recruited for a cohort study during the period 1990-2001. Participants were followed-up until 31 December, 2013. To identify factors associated with the incidence of colorectal cancer, hazard ratios were evaluated using Cox proportional hazard regression.

RESULTS

No environmental variables could be shown to be significantly related to the risk of CRC. Although in our sample, CRC was more prevalent among males, ex-smokers, and those who drank alcohol beverages ≥ 50 gram/day, but we could not demonstrate significantly associations (HRmale= 1.67, 95% CI, 0.80-3.49, HR ex-smokers = 1.34, 95% CI, 0.52-3.46, and HRalc≥ 50 = 1.08, 95% CI, 0.43-2.71). Individuals within the sample with a family history of cancer, working hour >8 hours per day, and current-smokers appeared to have decrease risk of CRC, but again these relationship could not be shown to be significantly associated (HRfam cancer= 0.96, 95% CI, 0.85-1.09, HRwork>8= 0.84, 95% CI, 0.36-1.93, and HRcurrent-smoker = 0.51, 95% CI, 0.18-1.38).

CONCLUSIONS

We found no evidence of environmental factors effecting the risk of CRC. There is a need for further research to determine why factors identified risk in other populations appear to not be associated with CRC risk in Thais.