Analysis Of Population Screening Results For Colorectal Cancer And The Risk Factors Of Colorectal Polyps In Prediabetes Subjects In Hefei Communities As Well The Effect Of Metformin On Rectal Aberrant Crypt Foci In Patients With Impaired Glucose Tolerance

Part 1 Analysis of population screening results for colorectal cancer and the risk factors of colorectal polyps in prediabetes in Hefei communitiesObjective To explore the prevalence of colorectal cancer and the risk factors associated with colorectal polyps in prediabetes in community population in Hefei City.Methods Analysis of physical examination data from 9 986 community residents and preliminary screening was carried out to prediabetes,which are diagnosed according to 75-gram oral glucose tolerance test(OGTT)aged over 40 years in four communities in Hefei City,by combining questionnaire and fecal occult blood test.Colonscopy were performed among high risk people,and the clinical characteristics of colorectal polyps and related risk factors were also analyzed.Results(1)A total of 1 912 people were investigated,and 547 cases of them were referred to high-risk group.Colonscopy were performed to 501 cases,and colorectal mucosa lesions were found in 281 cases,the detection rate was 56.1%(281/501).Of which colorectal cancer were found in 21 cases,the detection rate was 4.19%(21/501),nearly two-thirds belong to middle-late stage.In addition,colorectal polyps were found in 248 cases,the detection rate was 49.5%(248/501),including high-risk polyps account for 63.7%,multiple polyps account for 43.1%,adenomatous polyps account for 58.1% and the size of polyp account for 57.3% was more than 1cm.(2)Compared with the control group,the proportion of male,average age,the values of body mass index(BMI),waist hip ratio(WHR),fasting plasma insulin(FINS),2h plasma glucose(2h PG),triglyceride(TG),low density lipoprotein cholesterol(LDL-c)and homeostasis model assessment insulin resistance index(HOMA-IR),as well the detection rate of smoking,alcohol drinking,metabolic syndrome(MS),diabetes family history,colorectal family history and impaired glucose tolerance(IGT)were all significantly higher in the polyp group(all P<0.05).In addition,the detection rate of habitual exercise and the levels of plasma adiponectin in the polyp group were significantly lower than those in the control group(all P<0.05).However,no significant differences were observed between the two group in the values of systolic blood pressure(SBP),diastolic blood pressure(DBP),high density lipoprotein cholesterol(HDL-c),total cholesterol(TCH),fasting plasma glucose(FPG),carcinoembryonic antigen(CEA),Hb A1 c,and plasma visfatin(P>0.05).(3)Compared with the low-risk colorectal polyp group,the proportion of male,average age,and the values of BMI,WHR,FINS,2h PG as well the detection rate of smoking,MS,colorectal family history and IGT were significantly higher in the high-risk colorectalpolyp group(all P<0.05).In addition,the levels of plasma adiponectin in the high-risk polyp group was significantly lower than those in the low-risk polyp group(P<0.05).However,there were no significant difference between the two group in the values of SBP,DBP,HDL-c,TCH,FPG,CEA,Hb A1 c,plasma visfatin and the detection rate of alcohol as well exercise(P>0.05).(4)The results of analysis of risk factors of colorectal polyps by uninominal unconditional logistic regression showed that the variables including sex(male),age,BMI,WHR,FINS,2h PG,LDL-c,HOMA-IR,smoking,colorectal family history,diabetes family history,MS,IGT were associated with a statistically significant increase in the risk of colorectal polyps(OR=4.25,1.92,2.48,3.71,2.23,4.03,2.02,1.41,2.07,2.98,3.22,2.05,2.64,respectively,all P <0.05~0.01).Whereas,the higher levels of plasma adiponectin and habitual exercise were associated with a statistically significant decrease in the risk of colorectal polyps(OR=0.54,0.76,respectively,all P<0.05~0.01).(5)The multiple logistic regression analyses showed that sex(male),WHR,2h PG levels,and diabetes family history were independently associated with a statistically significant increase in the risk of colorectal polyps(OR=1.98,3.03,2.18,1.35,respectively,all P <0.05~0.01).By contrast,the higher levels of plasma adiponectin were independently associated with a statistically significant decrease in the risk of colorectal polyps(P<0.05).Conclusion Prediabetes should be considered as the high-risk groups of colorectal neoplasia.It is essential to carry out early colorectal cancer screening in prediabetes subjects,in particular,towards the male subjects with visceral obesity and diabetes family history.Thus,appropriate intervention measures including reducing weight and blood glucose and upregulating the levels of plasma adiponectin should be taken in prediabetes.Part 2 Effects of different dose metformin treatment for3-month on rectal aberrant crypt foci in patients with impaired glucose toleranceObjective To evaluate the chemopreventive effects of different dose metformin treatment for 3-month on rectal aberrant crypt foci(ACF)in subjects with impaired glucose tolerance(IGT).Methods A total of 90 patients with IGT were enrolled and randomly assigned to low-dose metformin group(LDG,n=30,metformin at 250mg/day),middle-dose metformin group(MDG,n=30,metformin at 500mg/day),and control(untreated with metformin)group(UTG,n=30),respectively,at a 1:1:1ratio.Each participant was followed for 3 months by protocol,and the number of ACF per patient in the above three groups was examined by magnifying colonoscopy before,and 3 months after the beginning of treatment.Anthropometric and metabolic parameters were determined in each participant.Spearman correlation and multivariate linear regression analysis were carried out to evalue the correlations between the changes from baseline in the mean number of ACF and selected anthrometric and metabolic parameters in LDG,MDG,UTG.Results(1)The proportion of male,body mass index(BMI),waist circumference(WC),hip circumference,waist to hip ratio(WHR),systolic blood pressure(SBP),diastolic blood pressure(DBP),fasting plasma glucose(FPG),fasting insulin(FINS),homeostatic model insulin resistance index(HOMA-IR),2-h plasma glucose(2h PG),serum triglyceride(TG)and total cholesterol(TCH)as well the number of ACF were not significantly different in LDG,MDG and UTG in the baseline(P>0.05).(2)The mean ACF number in MDG were decreased significantly(5.6±4.7 vs 7.9±6.3,P=0.012)in the time period from baseline to 3 months of treatment,while it did not change in LDG and UTG.(3)The values of FPG,2h PG,BMI,WC,WHR,FINS,HOMA-IR,SBP,DBP,TG and TCH did not significantly change in the time of 3 months compard with the baseline value in LDG,MDG and UTG(P>0.05).(4)The results of correlation analysis showed that changes in ACF number were not correlated with changes in the values of BMI,WC,WHR,FPG,FINS,HOMA-IR,2h PG,TG,and TCH(P>0.05).Conclusion Metformin suppressed ACF formation in IGT subjects in a dose-dependent manner.The anti-ACF of metformin at the dose of 500 mg/day may be possibly through direct mechanisms,rarher than through indirect mechansms such as attenuating insulin resistance,reducing blood glucose and weight.