Min Kyung Lim

Impact of Prediagnosis Smoking, Alcohol, Obesity, and Insulin Resistance on Survival in Male Cancer Patients: National Health Insurance Corporation Study

PURPOSE Although many studies have demonstrated that smoking, alcohol, obesity, and insulin resistance are risk factors for cancer, the role of those factors on cancer survival has been less studied. PATIENTS AND METHODS The study participants were 14,578 men with a first cancer derived from a cohort of 901,979 male government employees and teachers who participated in a national health examination program in 1996. We obtained mortality data for those years from the Korean Statistical Office. We used a standard Poisson regression model to estimate the hazard ratio (HR) for survival in relation to smoking, alcohol, obesity, and insulin resistance before diagnosis. RESULTS Poor survival of all cancer combined (HR, 1.24; 95% CI, 1.16 to 1.33), cancer of the lung (HR, 1.45; 95% CI, 1.15 to 1.82), and cancer of the liver (HR, 1.36; 95% CI, 1.21 to 1.53) were significantly associated with smoking. Compared with the nondrinker, heavy drinkers had worse outcomes for head and neck (HR, 1.85; 95% CI, 1.23 to 2.79) and liver (HR, 1.25; 95% CI, 1.11 to 1.41) cancer, with dose-dependent relationships. Patients with a fasting serum glucose level above 126 mg/dL had a higher mortality rate for stomach (HR, 1.52; 95% CI, 1.25 to 1.84) and lung (HR, 1.48; 95% CI, 1.18 to 1.87) cancer. Higher body mass index was significantly associated with longer survival in head and neck (HR, 0.54; 95% CI, 0.39 to 0.74) and esophagus (HR, 0.44; 95% CI, 0.28 to 0.68) cancer. CONCLUSION Prediagnosis risk factors for cancer development (smoking, alcohol consumption, obesity, and insulin resistance) had a statistically significant effect on survival among male cancer patients.

Coinfection of hepatitis B and C viruses and risk of hepatocellular carcinoma: Systematic review and meta‐analysis

A subadditive effect of hepatitis B virus (HBV) and hepatitis C virus (HCV) coinfection is possible because superinfection of one virus tends to inhibit infection of the other virus. However, studies have reported inconsistent findings, and two meta‐analyses of studies from various countries (1998) and China (2005) reported a supraadditive effect for hepatocellular carcinoma (HCC) risk. Thus, we reevaluate HBV/HCV monoinfection and coinfection. Of 411 reports, we included 59 studies that assessed the association between HBV/HCV monoinfection and coinfection for HCC risk. HCC risk because of high/detectable HBV DNA and HBeAg infection was higher than HBsAg infection, whereas anti‐HCV vs anti‐HCV/HCV RNA was not different. Geographically, HCC risk was significantly higher in nonendemic than in HBV or HCV endemic areas. Subadditive effect for HCC risk was presented in recently published studies, cohort studies and studies conducted in HBV/HCV nonendemic areas; an additive effect was presented in studies conducted in HBV endemic areas; a supraadditive effect was presented in previously published studies, case‐control studies and studies conducted in HCV endemic areas. Our results suggest HBV/HCV coinfection for HCC risk is not significantly greater than HBV/HCV monoinfection, and HCC risk due to HBV or HCV is higher in nonendemic than endemic areas. The p‐heterogeneity was significant for most analyses, except HBV(+)/HCV(+) and HBV biomarker analyses. Prevention strategies targeted toward HBV or HCV monoinfected patients are needed. In addition, tailored prevention to reduce infectivity such as HBV markers (HBeAg, HBV DNA) is needed.

Prediagnosis Smoking, Obesity, Insulin Resistance, and Second Primary Cancer Risk in Male Cancer Survivors: National Health Insurance Corporation Study

PURPOSE Smoking, obesity, and insulin resistance are well-known risk factors for cancer, yet few epidemiology studies evaluate their role as risk factors for a second primary cancer (SPC). PATIENTS AND METHODS We identified 14,181 men with a first cancer from the National Health Insurance Corporation Study cohort. We obtained data on fasting glucose level, body mass index (BMI), and smoking history from an enrollment interview (1996). We obtained SPC incidence data for 1996 through 2002 from the Korean Central Cancer Registry. We used the standard Poisson regression model to estimate the age- and multivariate-adjusted relative risk (RR) for SPCs in relation to smoking history, BMI, and insulin resistance before diagnosis. RESULTS We observed 204 patients with SPC. The overall age-standardized incidence rate of SPC was 603.2 occurrences per 100,000 person-years, which was about 2.3 times higher than that of first cancer in the general male population. Multivariate regression revealed that lung (RR, 3.69; 95% CI, 1.35 to 10.09) and smoking-related (RR, 2.02; 95% CI, 1.02 to 4.03) SPCs were significantly associated with smoking. Obese patients (BMI > or = 25 kg/m2) had significantly elevated RRs for colorectal (RR, 3.45; 95% CI, 1.50 to 7.93) and genitourinary (RR, 3.61; 95% CI, 1.36 to 9.54) SPCs. Patients with a fasting serum glucose concentration > or = 126 mg/dL had a higher RR for hepatopancreatobiliary (RR, 3.33; 95% CI, 1.33 to 8.37) and smoking-related (1.93; 95% CI, 1.01 to 3.68) SPCs. CONCLUSION Prediagnosis smoking history, obesity, and insulin resistance were risk factors for several SPCs. These findings suggest that more thorough surveillance and screening for SPCs is needed for the cancer survivors with these risk factors.

Detection of Clonorchis sinensis in stool samples using real-time PCR

Abstract Human clonorchiasis, caused by infection with the trematode Clonorchis sinensis, is a common health problem in East Asia. In an attempt to develop a new, sensitive method for the diagnosis of the disease, the use of a real-time PCR (targeting the internal-transcribed-spacer-2 sequence of the parasite) to detect C. sinensis-specific DNA in faecal samples has recently been evaluated. The PCR-based assay, which included an internal control to detect any inhibition of the amplification by faecal constituents in the sample, was performed on stool samples and on DNA controls representing a wide range of intestinal microorganisms. The assay appeared very specific, only showing positivity with C. sinensis and Opisthorchis felineus. The sensitivity of the assay was explored by testing 170 preselected samples of human faeces, from an endemic area of South Korea, which had known (microscopically-determined) densities of C. sinensis eggs. The sensitivity of the assay was 100% for the 74 samples that each had > 100 eggs/g and 91.4% for the other 70 samples found egg-positive by microcopy (i.e. those that had ≤ 100 eggs/g). Three of the 26 samples that appeared egg-negative by microscopy were found PCR-positive. Encouragingly, the PCR cycle-threshold values, which reflect parasite-specific DNA loads, showed significant correlation with the egg counts. The real-time PCR used in this study therefore appears to be a powerful tool for both the detection and quantification of C. sinensis infections.

Relative and absolute risks of cigarette smoking on major histologic types of lung cancer in Korean men

Objectives: Most prospective cohort studies of lung cancer focus on the relative risk rather than the absolute risk of smoking. Methods: This prospective study included 437,976 Korean men (cohort for the National Health Insurance Cooperation Study), ≥40 years old, who were free of cancer and smoking-related chronic disease at the time of enrollment. Based on new incidence cases, relative risk and excess risk, and their 95% confidence intervals (95% CI), were estimated with the standard Poisson regression model after adjustment for age or other demographic factors and other confounders. Results: During the 6-year follow-up period of 3,142,451 person-years, 1,357 new lung cancer cases were identified. Based on the multivariate-adjusted relative risk for current smokers, the strongest association with smoking was shown for small-cell lung cancer (relative risk, 21.7; 95% CI, 8.0-58.5) followed by squamous cell carcinoma (relative risk, 11.7; 95% CI, 7.1-19.4) and then adenocarcinoma (relative risk, 2.1; 95% CI, 1.6-2.7). In current smokers with ≥40 pack-years of exposure, excess risk was highest for squamous cell carcinoma (excess risk, 33.8; 95% CI, 10.2-109.8) followed by adenocarcinoma (excess risk, 26.7; 95% CI, 10.3-64.4), and then small-cell carcinoma (excess risk, 16.3; 95% CI, 1.8-144.3). Conclusions: In Korean men, cigarette smoking was as important a risk factor for adenocarcinoma as it was for squamous cell and small-cell lung cancer.

Population attributable fraction of infection-related cancers in Korea

BACKGROUND A number of infectious agents have been classified as human carcinogens. The purpose of the current study was to provide an evidence-based assessment of the burden of infection-related cancers in the Korean population. MATERIALS AND METHODS The population attributable fraction was calculated using infection prevalence data from 1990 or earlier, relative risk estimates from meta-analyses using mainly Korean studies and national data on cancer incidence and mortality for the year 2007. RESULTS The fractions of all cancers attributable to infection were 25.1% and 16.8% for cancer incidence in men and women, and 25.8% and 22.7% of cancer mortality in men and women, respectively. Among infection-related cancers, Helicobacter pylori was responsible for 56.5% of cases and 45.1% of deaths, followed by hepatitis B virus (HBV) (23.9% of cases and 37.5% of deaths) and human papillomavirus (HPV) (11.3% of cases and 6% of deaths) and then by hepatitis C virus (HCV) (6% of cases and 9% of deaths). Over 97% of infection-related cancers were attributable to infection with H. pylori, HBV, HCV and HPV. CONCLUSION Up to one-quarter of cancer cases and deaths would be preventable through appropriate control of infectious agents in Korea.

Staphylococcal enterotoxin sensitization in a community‐based population: a potential role in adult‐onset asthma

Recent studies suggest that Staphylococcus aureus enterotoxin sensitization is a risk factor for asthma. However, there is a paucity of epidemiologic evidence on adult‐onset asthma in community‐based populations.

Tobacco control challenges in East Asia: proposals for change in the world's largest epidemic region

East Asia is one of the worlds largest tobacco epidemic regions. Although several international studies have evaluated the status of tobacco control in this region, the findings have not been integrated with knowledge on domestic activities at the national and municipal levels. We analysed the current tobacco control situation in three East Asian countries, Japan, China and the Republic of Korea, using both international and domestic data sources. We collected data between 2008 and 2011 in each country according to the framework of WHOs MPOWER (Monitoring, Protect, Offer, Warn, Enforcement and Raise) approach for guiding implementation of the WHO Framework Convention on Tobacco Control. Analysis revealed that 37–53% of adult men were current smokers and that smoking prevalence among middle-aged men reached 63%. Less than 20% of male smokers plan to quit and the use of nicotine replacement drugs was 14% at maximum. Forty-six percent or more of men and 20% or more of women were exposed to passive smoking at workplaces and at home, respectively. Many tobacco industry activities remain unrestricted and prevalent. Our findings indicate an urgent need for the following set of policies: raise cigarette prices to increase the quit attempt rate, particularly among adult men; develop a multi-component quitting assistance system to provide adequate assistance for smoking cessation; implement effective smoke-free policies in workplaces and public places to reduce exposure to passive smoking; and rebuild the administrative structure to denormalise tobacco industry activities. The importance of these standard approaches should be reaffirmed by all tobacco control policymakers in East Asia.

Combined effect of socioeconomic status, viral hepatitis, and lifestyles on hepatocelluar carcinoma risk in Korea

Background:The independent and combined effects of socioeconomic status (SES), viral hepatitis, and other lifestyle factors on hepatocellular carcinoma (HCC) risk have not been investigated among Koreans.Methods:From the National Cancer Center Hospital, 207 HCC cases and 828 age- and gender-matched controls aged 30 years or older were recruited. Socio-demographic and behavioural risk factors were ascertained through personal interview, and infection with hepatitis B and C viruses was determined by their serologic markers. Multivariate logistic regression and synergy index methods were applied for statistical analysis.Results:HB surface antigen (HbsAg) and anti-HCV-positive rates were 149.3 and 185.1 times higher in cases than controls, respectively. Lifetime alcohol consumption (odds ratio: 2.96, 95% CI: 1.29–6.79), cigarette smoking (OR: 3.53, 95% CI: 1.31–9.52), and family income (OR: 17.07, 95% CI: 4.27–68.25) were independently associated with the risk of HCC in subjects with or without viral hepatitis. Synergistic interaction on HCC risk was observed between low income and HBsAg positivity (SI: 3.12, 95% CI: 1.51–6.47) and between low income and heavy alcohol intake (SI: 2.93, 95% CI: 1.24–6.89).Conclusion:The inverse association with SES suggests SES as an independent and synergistic predictor of HCC. Heavy alcohol intake also showed a combined effect with low SES on HCC risk.

Website Quality, Expectation, Confirmation, and End User Satisfaction: The Knowledge-Intensive Website of the Korean National Cancer Information Center

Background The fact that patient satisfaction with primary care clinical practices and physician-patient communications has decreased gradually has brought a new opportunity to the online channel as a supplementary service to provide additional information. Objective In this study, our objectives were to examine the process of cognitive knowledge expectation-confirmation from eHealth users and to recommend the attributes of a “knowledge-intensive website.”. Knowledge expectation can be defined as users’ existing attitudes or beliefs regarding expected levels of knowledge they may gain by accessing the website. Knowledge confirmation is the extent to which user’s knowledge expectation of information systems use is realized during actual use. In our hypothesized research model, perceived information quality, presentation and attractiveness as well as knowledge expectation influence knowledge confirmation, which in turn influences perceived usefulness and end user satisfaction, which feeds back to knowledge expectation. Methods An empirical study was conducted at the National Cancer Center (NCC), Republic of Korea (South Korea), by evaluating its official website. A user survey was administered containing items to measure subjectively perceived website quality and expectation-confirmation attributes. A study sample of 198 usable responses was used for further analysis. We used the structural equation model to test the proposed research model. Results Knowledge expectation exhibited a positive effect on knowledge confirmation (beta = .27, P < .001). The paths from information quality, information presentation, and website attractiveness to knowledge confirmation were also positive and significant (beta = .24, P < .001; beta = .29, P < .001; beta = .18, P < .001, respectively). Moreover, the effect of knowledge confirmation on perceived usefulness was also positively significant (beta = .64, P < .001). Knowledge expectation together with knowledge confirmation and perceived usefulness also significantly affected end user satisfaction (beta = .22 P < .001; beta = .39, P < .001; beta = .25, P < .001, respectively). Conclusions Theoretically, this study has (1) identified knowledge-intensive website attributes, (2) enhanced the theoretical foundation of eHealth from the information systems (IS) perspective by adopting the expectation-confirmation theory (ECT), and (3) examined the importance of information and knowledge attributes and explained their impact on user satisfaction. Practically, our empirical results suggest that perceived website quality (ie, information quality, information presentation, and website attractiveness) is a core requirement for knowledge building. In addition, our study has also shown that knowledge confirmation has a greater effect on satisfaction than both knowledge expectation and perceived usefulness.