You will be presented with a collection of medical randomized controlled trial (RCT) reports addressing a shared clinical question -- for instance, the efficacy of a medical intervention on a disease or condition. Given the titles and abstracts of these reports, your task is to generate the conclusion of the systematic review article synthesizing the key findings. Your conclusion should be a few sentences long. In your response, include only the conclusion and no other text. The RCT reports are below.



Title 1:
Fasting serum glucose level and cancer risk in Korean men and women.
Abstract 1:
CONTEXT Diabetes is a serious and costly disease that is becoming increasingly common in many countries . The role of diabetes as a cancer risk factor remains unclear . OBJECTIVE To examine the relationship between fasting serum glucose and diabetes and risk of all cancers and specific cancers in men and women in Korea . DESIGN , SETTING , AND PARTICIPANTS Ten-year prospect i ve cohort study of 1,298,385 Koreans ( 829,770 men and 468,615 women ) aged 30 to 95 years who received health insurance from the National Health Insurance Corp and had a biennial medical evaluation in 1992 - 1995 ( with follow-up for up to 10 years ) . MAIN OUTCOME MEASURES Death from cancer and registry-documented incident cancer or hospital admission for cancer . RESULTS During the 10 years of follow-up , there were 20,566 cancer deaths in men and 5907 cancer deaths in women . Using Cox proportional hazards models and controlling for smoking and alcohol use , the stratum with the highest fasting serum glucose ( > or = 140 mg/dL [ > or = 7.8 mmol/L ] ) had higher death rates from all cancers combined ( hazard ratio [ HR ] , 1.29 ; 95 % confidence interval [ CI ] , 1.22 - 1.37 in men and HR , 1.23 ; 95 % CI , 1.09 - 1.39 in women ) compared with the stratum with the lowest level ( < 90 mg/dL [ < 5.0 mmol/L ] ) . By cancer site , the association was strongest for pancreatic cancer , comparing the highest and lowest strata in men ( HR , 1.91 ; 95 % CI , 1.52 - 2.41 ) and in women ( HR , 2.05 ; 95 % CI , 1.43 - 2.93 ) . Significant associations were also found for cancers of the esophagus , liver , and colon/rectum in men and of the liver and cervix in women , and there were significant trends with glucose level for cancers of the esophagus , colon/rectum , liver , pancreas , and bile duct in men and of the liver and pancreas in women . Of the 26,473 total cancer deaths in men and women , 848 were estimated as attributable to having a fasting serum glucose level of less than 90 mg/dL. For cancer incidence , the general patterns reflected those found for mortality . For persons with a diagnosis of diabetes or a fasting serum glucose level greater than 125 mg/dL ( 6.9 mmol/L ) , risks for cancer incidence and mortality were generally elevated compared with those without diabetes . CONCLUSION In Korea , elevated fasting serum glucose levels and a diagnosis of diabetes are independent risk factors for several major cancers , and the risk tends to increase with an increased level of fasting serum glucose


Title 2:
Higher Glucose and Insulin Levels Are Associated with Risk of Liver Cancer and Chronic Liver Disease Mortality among Men without a History of Diabetes
Abstract 2:
Insulin resistance likely increases the risk of chronic liver disease ( CLD ) and liver cancer , but long-term prospect i ve studies with measured fasting glucose and insulin are lacking . We evaluated the associations of prediagnostic fasting glucose , insulin , and the homeostasis model assessment of insulin resistance ( HOMA-IR ) with liver cancer and CLD mortality in a prospect i ve study of Finnish male smokers with extended follow-up time ( ≤22 years ) and information on known risk factors using data from 138 incident primary liver cancer cases , 216 CLD deaths , and 681 matched controls .  Fasting glucose and insulin  were measured in baseline serum . We used unconditional logistic regression to estimate ORs and 95 % confidence intervals adjusted for age , alcohol , education , smoking , body mass index , and hepatitis B and C viral status . Among those without self-reported diabetes , glucose was positively associated with liver cancer [ quartile 3 vs. quartile 1 ( Q3/Q1 ) : OR = 1.88 ; 1.03–3.49 ; Q4/Q1 : OR = 2.40 ; 1.33–4.35 ; Ptrend = 0.002 ] , and undiagnosed , biochemically defined , diabetes was associated with higher risk of liver cancer ( OR = 2.95 ; 1.46–5.96 ) and CLD mortality ( OR = 1.88 ; 1.00–3.56 ) . Serum insulin and HOMA-IR were also positively associated with liver cancer ( Q4/Q1 : OR = 3.41 ; 1.74–6.66 ; Ptrend < 0.0001 ; OR = 3.72 ; 1.89–7.32 , Ptrend < 0.0001 , respectively ) and CLD ( OR = 2.51 ; 1.44–4.37 ; Ptrend = 0.0002 ; OR = 2.31 ; 1.34–3.97 ; Ptrend = 0.001 , respectively ) , with stronger associations observed for liver cancer diagnosed > 10 years after baseline . In conclusion , elevated fasting glucose and insulin and insulin resistance were independently associated with risk of liver cancer and CLD mortality , suggesting a potentially important etiologic role for insulin and glucose dysregulation even in the absence of diagnosed diabetes . Cancer Prev Res ; 9(11 ) ; 866–74 . © 2016 AACR


Title 3:
Smoking as an independent risk factor for hepatocellular carcinoma: the Singapore Chinese Health Study
Abstract 3:
Background : Given the close correlation between smoking and alcohol intake in most epidemiologic studies , it is difficult to exclude the residual confounding effect of alcohol in the association between smoking and hepatocellular carcinoma ( HCC ) . Method : We evaluated the association between smoking and risk of HCC  in the Singapore Chinese Health Study , a prospect i ve cohort with a low prevalence of alcohol intake . Information on cigarette smoking and  alcohol consumption was obtained through in-person interviews conducted at enrolment . Results : After a mean of 11.5 years of follow-up , there were 394 incident cases of HCC . Participants who consumed more than two alcoholic drinks per day showed an increased risk for HCC ( hazard ratio (HR)=2.24 ; 95 % confidence interval (CI)=1.46–3.41 ) . After adjusting for alcohol consumption and other potential confounders , current vs never smokers had a statistically significant , increased risk of HCC ( HR=1.63 ; 95 % CI=1.27–2.10 ) that was dose-dependent ( number of cigarettes per day , P for trend<0.001 ) . The observed tobacco – HCC association also was duration -dependent ( years of smoking in ever smokers , P for trend=0.002 ) . When we excluded daily drinkers from the analysis , all risk estimates remained essentially the same and statistically significant . Conclusion : Our findings strongly implicate tobacco smoke as a causal factor of HCC development


Title 4:
Insulin-like growth factor-related components and the risk of liver cancer in a nested case-control study
Abstract 4:
Insulin-like growth factor-1 ( IGF1 ) is a potent mitogen . IGF-binding protein-3 ( IGFBP3 ) binds and inhibits IGF1 . High circulating IGF1 levels and low IGFBP3 levels are associated with increased risk of several cancers . We examined relationships between serum levels of these factors and hepatoma risk in a case-control study nested in a prospect i ve cohort study ( the Japan Collaborative Cohort Study ( JACC Study ) ) . A baseline survey was conducted from 1988 to 1990 , and 39,242 subjects donated blood sample s. Participants diagnosed with hepatoma by 1997 were considered cases for nested case-control studies . Ninety-one cases and 263 sex- and age-matched controls were analyzed . A conditional logistic model was used to estimate odds ratios ( ORs ) for the incidence of hepatoma associated with serum IGF1 and IGFBP3 levels . Neither IGF1 nor the molar ratio of IGF1/IGFBP3 was correlated with hepatoma risk . After adjustment for hepatitis viral infection , body mass index , smoking , and alcohol intake , a higher molar difference of ( IGFBP3 − IGF1 ) was associated with a decreased hepatoma risk more than IGFBP3 alone ( p for trend < 0.001 and = 0.003 , respectively ) . People in the highest quartile had a lower risk ( OR = 0.098 ; 95 % confidence interval = 0.026–0.368 ) . In subgroup analyses of males and females , the molar difference was associated with a decreased hepatoma risk ( p for trend < 0.05 ) . In non-elderly individuals , the difference was inversely correlated with the incidence of hepatoma ( p for trend < 0.01 ) . The molar difference of ( IGFBP3 − IGF1 ) may be inversely associated with the incidence of hepatoma


Title 5:
Insulin, glucose and hepatocellular carcinoma risk in male hepatitis B carriers: results from 17-year follow-up of a population-based cohort.
Abstract 5:
This study aim ed to investigate the association of fasting insulin and glucose levels with  hepatocellular carcinoma ( HCC ) risk in a case-cohort study within a cohort ( 1989 - 2006 ) of 2903 male government employees chronically infected with hepatitis B virus ( HBV ) in Taiwan .  Insulin , glucose and HBV-related factors  were assayed in baseline plasma among 124 HCC cases and a r and om subcohort of 1084 of the total cohort . After adjustment for demographics and HBV-related factors , including viral load and genotype , the HCC risk was higher for the highest [ > 6.10 μU/ml , hazard ratio ( HR ) = 2.36 , 95 % confidence interval ( CI ) : 1.43 - 3.90 ] and lowest ( < 2.75 μU/ml , HR = 1.57 , 95 % CI : 0.96 - 2.58 ) categories of insulin , compared with insulin of 2.75 - 4.10 μU/ml . The dose-response relationship between insulin and HCC varied by follow-up time , with stronger association for the HCC cases that occurred ≥8 years after baseline ( P for trend < 0.0001 ) . The effect of higher insulin on HCC risk remained after adjustment for other metabolic factors , and was fairly consistent across strata of age , body mass index , and HBV genotypic variants . However , it was more profound among those with viral load < 4.39 log(10 ) copies/ml at recruitment ( > 6.10 μU/ml , HR = 6.15 , 95 % CI : 2.48 - 15.22 ) . Higher insulin  was also associated with an increased risk for cirrhosis diagnosed by ultrasonography and elevated alanine aminotransferase . No association with either cirrhosis or HCC was noted for glucose or diabetes after adjusting for insulin . In conclusion , elevated insulin levels  are an independent risk factor for HCC among HBV carriers , especially for those with lower viral load
There is evidence that elevated blood glucose increases risk of liver cancer across the range of prediabetes and diabetes .
Considering the rapidly increasing prevalence of prediabetes and diabetes , controlling blood glucose may lower the risk of liver cancer