Associations of sweet potato consumption and other influencing factors with high and low mortality of colorectal cancer in Fujian province

Objective To investigate sweet potato intake and other influence factors in relation to the mortality of colorectal cancer in areas with high and low prevalence of the cancer in Fujian province.Methods Totally 60 urban communities and rural villages in Meilie,Yongding,Jianou,Jiaocheng,and Hui'an county or municipality with different incidence rate of colorectal cancer (from 6.24/100 000 to 16.394/100 000) were selected as study sites with multi-stage stratified random sampling; then 50 households in each of the study sites were randomly selected and one resident aged>18 years and living in the local areas at least 5 years in each of the 50 households were surveyed with self-designed questionnaires,including a Semi-Quantitative Food Frequency Questionnaire (SQFFQ),face-to-face during September to December 2014.Univariate and multivariate conditional logistic regression were adopted in data analyses.Results Altogether 2 853 participants (1 118 and 1 735 from the sites with high and low colorectal cancer mortality) were surveyed and the average age of the participants was 51.8±13.7 years.The results of univariate analyses showed that there were statistically significant differences in colorectal high-risk areas and low-risk areas in age (t=-6.053),gender (χ²=16.708),educational level (u=-12.908),marital status (χ²=19.606),and occupation (χ²=19.606) between the participants from the sites with high and low colorectal cancer mortality (P<0.001 for all).The multivariate analyses revealed that increased risk of colorectal cancer death was associated with age (odds ratioOR=4.642),educational level (OR=6.550),excessive consumption of cereal (OR=1.855),and excessive consumption of aquatic products (OR=1.965); while the decreased risk of colorectal cancer death was associated with frequent consumption of sweet potato (OR=0.439),higher ratio of sweet potato as staple food 10 years ago (OR=0.244),higher consumption of sweet potato 10 years ago (OR=0.258),higher consumption of sweet potato during previous one year (OR=0.624),preparing food with steaming or stewing method (OR=0.591),drinking black tea or oolong tea (OR=0.186),with a clean drinking water source (OR=0.694),being a slow coach (OR=0.599),and married (OR=0.523).Conclusion The study results suggest that high intake of sweet potato could decrease the risk of colorectal cancer death and there is a reverse correlation between colorectal cancer death and the amount of sweet potato intake 10 years ago.Therefore,increasing dietary sweet potato intake may be one of measures for the prevention of colorectal cancer among residents in Fujian province.