Socioeconomic Disparities in Colorectal Cancer Screening in Korea: A Nationwide Cross-Sectional Study

Factors Affecting Adherence to National Colorectal Cancer Screening: A 12-Year Longitudinal Study Using Multi-Institutional Pooled Data in Korea

BACKGROUND

Consistent uptake of colorectal cancer (CRC) screening is important to reduce the incidence and mortality from advanced-stage CRC and increase the survival rate of the patients. We conducted a longitudinal study to determine the factors affecting CRC screening compliance in Korean adults using individual-level linked data from the Korean National Health and Nutrition Examination Survey, Korean National Health Insurance Service, and Korean Health Insurance Review and Assessment Service.

METHODS

We selected 3,464 adults aged 50-79 years as the study population and followed them for 12 years (January 2007-December 2018). The outcome variable was the level of adherence to CRC screening, categorized as nonadherent, intermittently adherent, and consistently adherent. An ordinal logistic regression model was designed to determine the socioeconomic factors, family history of CRC, and medical conditions that could facilitate the consistent uptake of CRC screening.

RESULTS

The results showed a significant and positive association between consistent uptake of CRC screening and the 100-150% income category (odds ratio [OR], 1.710; 95% confidence interval [CI], 1.401-2.088); clerical, sales and service job category (OR, 1.962; 95% CI, 1.582-2.433); residency at medium-sized cities (OR, 1.295; 95% CI, 1.094-1.532); high-school graduation (OR, 1.440; 95% CI, 1.210-1.713); married status (OR, 2.281; 95% CI, 1.946-2.674); use of employment-based national health insurance (OR, 1.820; 95% CI, 1.261-2.626); use of private insurance (OR, 2.259; 95% CI, 1.970-2.589); no disability (OR, 1.428; 95% CI, 1.175-1.737); family history of CRC (OR, 2.027; 95% CI, 1.514-2.714); and history of colorectal neoplasm (OR, 1.216; 95% CI; 1.039-1.422).

CONCLUSION

The lack of regular participation in CRC screening programs in the Republic of Korea was found to be an issue that requires attention. Policies on CRC screening must place increased emphasis on strengthening educational and public relations initiatives.

Socioeconomic inequality in organized and opportunistic screening for colorectal cancer: results from the Korean National Cancer Screening Survey, 2009-2021

OBJECTIVES

This study aimed to investigate socioeconomic status (SES)-based inequality in colorectal cancer (CRC) screening in Korea. We assessed whether the rates of opportunistic and organized CRC screening differed according to income and education levels.

METHODS

We analyzed data from the Korean National Cancer Screening Survey of 27,654 cancer-free individuals, aged 50-74 years, from 2009 to 2021. The weighted cancer screening rates with trends were estimated with the average annual percentage change using joinpoint regression. Inequality was calculated in both relative and absolute terms, based on a Poisson regression model.

RESULTS

The organized screening rate increased significantly from 22.1% in 2009 to 53.1% in 2020 and 50.6% in 2021, with an average annual change of 8.6% (95% confidence interval [CI], 4.9 to 12.5). In contrast, no significant trend was observed for opportunistic screening. The SES inequality in opportunistic screening uptake was indicated by a slope index of inequality (SII) of 9.74% (95% CI, 6.36 to 13.12), relative index of inequality (RII) of 2.18 (95% CI, 1.75 to 2.70) in terms of education level; and an SII of 7.03% (95% CI, 4.09 to 9.98), RII of 1.81 (95% CI, 1.41 to 2.31) in terms of measured income. Although there was an increasing trend in income inequality, no significant SES inequalities were observed in the overall estimates for organized screening.

CONCLUSIONS

Organized CRC screening is effective in improving the participation rate, regardless of SES. However, significant inequalities were found in opportunistic screening, suggesting room for improvement in the overall equity of CRC screening.

Population-Based Data Reveal Factors Associated with Organised and Non-Organised Colorectal Cancer Screening: An Important Step towards Improving Coverage

We investigated factors associated with organised and non-organised colorectal cancer screening using faecal occult blood tests, based on data from 308 municipalities in Flanders (6.6 million residents, 57% of Belgium) during 2015-2017. Logistic regression with generalized estimating equations was used to assess the associations between municipal characteristics and organised and non-organised screening coverages. Factors associated negatively with both organised and non-organised screening: percentage of people aged 70-74 in the target population [OR (odds ratios) = 0.98, 95%CI (confidence interval): 0.97-0.99 and OR = 0.98, 95%CI: 0.96-0.999, respectively]; negatively with organised screening: average income [OR = 0.97, 95%CI: 0.96-0.98], percentage of people with a non-Belgian/Dutch nationality [OR = 0.962, 95%CI: 0.957-0.967]; positively with organised screening: percentages of men in the target population [OR = 1.13, 95%CI: 1.11-1.14], jobseekers [OR = 1.12, 95%CI: 1.09-1.15] and people with at least one general practitioner (GP) visit in the last year [OR = 1.04, 95%CI: 1.03-1.05]; positively with non-organised screening: number of patients per GP [OR = 1.021, 95%CI: 1.016-1.026], percentage of people with a global medical dossier handled by a preferred GP [OR = 1.025, 95%CI: 1.018-1.031]. This study helps to identify the hard-to-reach subpopulations in CRC screening, and highlights the important role of GPs in the process of promoting screening among non-participants and encouraging non-organised participants to switch to organised screening.

Colorectal cancer and potential predictors of never screened for faecal occult blood test: a narrative review

Colorectal cancer (CRC) is a major public health threat. Therefore, CRC screening uptake has been a focus with the established precancerous lesion and the strong association of early detection with staging and survival of the disease. However, CRC screening is relatively low in many countries. This article briefly discussed the current situation of CRC, recommendations, and current uptake of CRC screening in various countries. Besides that, this article also highlights the potential factors that help to predict the CRC screening uptake worldwide. Identification of those factors could guide policymakers to develop an effective strategy to improve the CRC screening uptake and ultimately improve the health outcome of the population.

Intentions to undergo primary screening with colonoscopy under the National Cancer Screening Program in Korea

BACKGROUND

We sought to investigate intentions to undergo primary screening with colonoscopy in an attempt to predict future colorectal cancer screening behaviors and the feasibility of implementing colonoscopy as the primary screening modality for colorectal cancer in the National Cancer Screening Program (NCSP) of Korea.

METHODS

Data were obtained from a nationwide online survey conducted in 2018. The survey included a total of 800 eligible adults aged over 45 years. Study measures included the history of screening colonoscopy within the past 10 years and intentions to undergo primary screening with colonoscopy under the NCSP based on the five constructs of the Health Belief Model. Logistic regression analysis was conducted to examine factors associated with intentions to undergo primary screening with colonoscopy.

RESULTS

Approximately 77% of the participants expressed strong willingness to undergo primary screening with colonoscopy under the NCSP. Higher perceived severity and perceived benefits were significantly associated with stronger intentions to undergo screening with colonoscopy (adjusted odds ratio [aOR], 1.53; 95% confidence interval [CI], 1.10-2.14 and aOR, 2.74; 95% CI, 1.76-4.28, respectively). Greater perceived barriers (aOR, 0.65; 95% CI, 0.45-0.93) were significantly associated with weaker intentions. Cues to action elicited the strongest screening intentions (aOR, 8.28; 95% CI, 5.23-13.12).

CONCLUSION

The current study findings highlight the need for increasing awareness of the severity of CRC and the benefits of colonoscopy screening. Family-orientated recommendation strategies and reducing complications may boost an individual's intentions to undergo colonoscopy.

Acceptance on colorectal cancer screening upper age limit in South Korea

BACKGROUND

The Korea National Cancer Screening Program currently provides screening for colorectal cancer (CRC) for adults older than 50 years with no upper age limit. In general, people are likely to only pay attention to the benefits of cancer screening and to neglect its risks. Most consider the benefits of cancer screening as being far greater than the risks and are unaware that any potential benefits and harms can vary with age.

AIM

To report acceptance of an upper age limit for CRC screening and factors associated therewith among cancer-free individuals in Korea.

METHODS

The present study analyzed data from the Korea National Cancer Screening Survey 2017, a nationally representative random sample of 4500 Korean individuals targeted for screening for the five most common types of cancer. A total of 1922 participants were included in the final analysis. The baseline characteristics of the study population are presented as unweighted numbers and weighted proportions. Both univariate and multivariate logistic regression models were developed to examine factors related with acceptance of an upper age limit for CRC screening; subgroup analysis was also applied.

RESULTS

About 80% (1554/1922) of the respondents agreed that CRC screening should not be offered for individuals older than 80 years. Specifically, those who had never been screened for CRC had the highest acceptance rate (91%). Overall, screening history for CRC [screened by both fecal occult blood test and colonoscopy, adjusted odds ratio (aOR) = 0.33, 95%CI: 0.22-0.50] and other cancers (aOR = 0.55, 95%CI: 0.34-0.87), as well as a family history of cancer (aOR = 0.66, 95%CI: 0.50-0.87), were negatively associated with acceptance of an upper age limit for CRC screening. In contrast, metropolitan residents (aOR = 1.86, 95%CI: 1.29-2.68) and people who exercised regularly (aOR = 1.42, 95%CI: 1.07-1.89) were more likely to accept an upper age limit. After subgrouping, we found gender, marital status, and lifetime smoking history among never-screened individuals and residential region, family history of cancer, and physical activity among never-screened individuals to be associated with acceptance of an upper age limit.

CONCLUSION

This study describes acceptance of an upper age limit for CRC screening and factors associated with it, and provides perspectives that should be considered, in addition to scientific evidence, when developing population-based cancer screening policies and programs.

Cancer Incidence by Occupation in Korea: Longitudinal Analysis of a Nationwide Cohort

Background

We performed this study to investigate the inequalities in site-specific cancer incidences among workers across different occupations in Korea.

Methods

Subjects included members of the national employment insurance. Incident cancers among 8,744,603 workers were followed from 1995 to 2007. Occupational groups were classified according to the Korean Standard Occupational Classification. Age-standardized incidence rate ratios were calculated.

Results

We found that men in service/sales and blue-collar occupations had elevated rates of esophageal, liver, laryngeal, and lung cancer. Among women, service/sales workers had elevated incidences of cervical cancer. Male prostate cancer, female breast, corpus uteri, and ovarian cancers, as well as male and female colorectal, kidney, and thyroid cancer showed lower incidences among workers in lower socioeconomic occupations.

Conclusions

Substantial differences in cancer incidences were found depending on occupation reflecting socioeconomic position, in the Korean working population. Cancer prevention policy should focus on addressing these socioeconomic inequalities.

Factors related to quality of life among middle-aged and older korean adults in 2006 and 2014: A nationally representative study

Factors related to quality of life (QoL) were investigated using data from middle-aged and older Korean respondents to the 2006 and 2014 Korean Longitudinal Study of Ageing. Respondents' QoL score in 2014 (6.03 ± 1.69) was lower than in 2006 (6.20 ± 2.12). All socio-demographic and health-related variables seemed to influence QoL in 2006 (R² = 0.238) and 2014 (R² = 0.234). Four factors significantly associated with QoL in both years were health, household income, depression, and regular exercise. Rural and mid-sized city dwellers were more likely to have a better QoL than residents of metropolitan areas; residential area had a greater influence on QoL in 2014.

Socioeconomic Inequalities in Colorectal Cancer Screening in Korea, 2005-2015: After the Introduction of the National Cancer Screening Program

PURPOSE

This study aimed to investigate inequalities in colorectal cancer (CRC) screening rates in Korea and trends therein using the slope index of inequality (SII) and relative index of inequality (RII) across income and education groups.

MATERIALS AND METHODS

Data from the Korean National Cancer Screening Survey, an annually conducted, nationwide cross-sectional survey, were utilized. A total of 17174 men and women aged 50 to 74 years were included for analysis. Prior experience with CRC screening was defined as having either a fecal occult blood test within the past year or a lifetime colonoscopy. CRC screening rates and annual percentage changes (APCs) were evaluated. Then, SII and RII were calculated to assess inequality in CRC screening for each survey year.

RESULTS

CRC screening rates increased from 23.4% in 2005 to 50.9% in 2015 (APC, 7.8%; 95% CI, 6.0 to 9.6). Upward trends in CRC screening rates were observed for all age, education, and household income groups. Education inequalities were noted in 2009, 2014, and overall pooled estimates in both indices. Income inequalities were inconsistent among survey years, and overall estimates did not reach statistical significance.

CONCLUSION

Education inequalities in CRC screening among men and women aged 50 to 74 years were observed in Korea. No apparent pattern, however, was found for income inequalities. Further studies are needed to thoroughly outline socio-economic inequalities in CRC screening.

Gender Differences in Factors Associated With Colorectal Cancer Screening: A National Cross-Sectional Study in Korea

The rate of and factors influencing colorectal cancer screening differs by gender. We aimed to determine the behaviors for and predict the factors influencing self-reported colorectal cancer screening in Korean adults. Secondary analysis was performed with data from the cross-sectional 2012 Community Health Survey. We examined the relationship between gender and self-reported screening using data for 115 045 adults aged ≥50 years; 62.4% of men and 65.5% of women underwent colorectal cancer screening. In the multivariate logistic regression analysis, men with private insurance and who attended regular health checkups were more likely to undergo screening; men who were employed, ate salty food, were older, or smoked were less likely. Women with private insurance, who lived with a spouse, were more educated, were housewives, or attended regular health checkups were more likely, and older women were less likely to undergo screening. Therefore, gender-specific interventions are needed to encourage colorectal cancer screening.

Stages of Adoption for Fecal Occult Blood Test and Colonoscopy Tests for Colorectal Cancer Screening in Korea

Purpose

While colorectal cancer (CRC) is common in Asian countries, screening for CRC is not. Moreover, CRC screening behaviors in Asian populations remain largely unknown. The present study aimed to investigate the stages of adopting CRC screening in Korea according to screening modality.

Materials and Methods

Data were obtained from the 2014 Korean National Cancer Screening Survey, a cross-sectional survey that utilized nationally representative random sampling to investigate cancer screening rates. A total of 2,066 participants aged 50-74 years were included in this study. Chi-square test and multinomial logistic regressionwere applied to determine stages of adoption for fecal occult blood test (FOBT) and colonoscopy and factors associated with each stage.

Results

Of 1,593 participants included in an analysis of stage of adoption for FOBT, 36% were in action/maintenance stages, while 18%, 40%, and 6% were in precontemplation, contemplation, and relapse/relapse risk stages, respectively. Of 1,371 subjects included in an analysis of stage of adoption for colonoscopy, 48% were in action/maintenance stages, with 21% in precontemplation, 21% in contemplation, and 11% in relapse/relapse risk stages. Multinomial logistic regression highlighted sex, household income, place of residency, family history of cancer, having private cancer insurance, smoking status, alcohol use, and regular exercise as being associated with stages of adoption for FOBT and colonoscopy.

Conclusion

This study outlines the distributions of stages of adoption for CRC screening by screening modality. Interventions to improve screening rates should be tailored to individuals in particular stages of adoption for CRC screening by modality.

Associations of perceived risk and cancer worry for colorectal cancer with screening behaviour

We investigated the associations of perceived risk and cancer worry with colorectal cancer screening by the faecal occult blood test, colonoscopy or both. This study was based on the 2013 Korean National Cancer Screening Survey, including 2154 randomly selected, cancer-free and over 50-year-old adults. Individuals with higher cancer worry were 1.53 times more likely to undergo colorectal cancer screening, influenced by emotional reaction; individuals with greater perceived risk were 1.61 times more, affected by subjective awareness. However, cancer worry was only associated with the faecal occult blood test. Better understanding of cancer worry and perceived risk on screening behaviours may help to increase colorectal cancer screening rates.

Why Do Some People Choose Opportunistic Rather Than Organized Cancer Screening? The Korean National Health and Nutrition Examination Survey (KNHANES) 2010-2012

Purpose

Although the Korean government has implemented a universal screening program for common cancers, some individuals choose to participate in opportunistic screening programs. Therefore, this study was conducted to identify factors contributing to the selection of organized versus opportunistic screening by the Korean general population.

Materials and Methods

Data from 11,189 participants aged ≥ 40 yearswho participated in the fifth Korean National Health and Nutrition Examination Survey (2010-2012) were analyzed in this study.

Results

A total of 6,843 of the participants (58.6%) underwent cancer screening, of which 6,019 (51.1%) participated in organized and 824 (7.5%) participated in opportunistic screening programs. Being female, older, highly educated, in the upper quartile of income, an ex-smoker, and a light drinker as well as having supplementary private health insurance and more comorbid conditions and engaging in moderate physical activity 1-4 days per week were related to participation in both types of screening programs. Being at least a high school graduate, in the upper quartile for income, and a light drinker, as well as having more comorbid conditions and engaging in moderate physical activities 1-4 days per week had a stronger effect on those undergoing opportunistic than organized screening.

Conclusion

The results of this study suggest that socioeconomic factors such as education and income, as well as health status factors such as health-related quality of life and number of comorbid conditions and health behaviors such as drinking and engaging in moderate physical activity 1-4 days per week had a stronger influence on participation in an opportunistic than in an organized screening program for cancer.

Income Disparities in the Use of Health Screening Services Among University Students in Korea: A Cross-Sectional Study of 2479 Participants in a University

Public health insurance coverage for preventive care in young adults is incomplete in Korea. Few studies have focused on young adults' socioeconomic disparities in preventive care utilization. We aimed to explore household income disparities in the use of different types of health screening services among university students in Korea.This cross-sectional study used a web-based self-administered survey of students at a university in Korea from January to February 2013. To examine the associations between household income levels and health screening service use within the past 2 years, odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using logistic regression with adjustment for various covariables.Of 2479 participants, 45.5% reported using health screening services within 2 years (university-provided screening 32.9%, private sector screening 16.7%, and both 4.1%). Household income levels were not significantly associated with overall rates of health screening service use with a multivariable-adjusted OR (95% CI) in the lowest versus highest income group of 1.12 (0.87-1.45, Ptrend = 0.35). However, we found significantly different associations in specific types of utilized screening services by household income levels. The multivariable-adjusted OR (95% CI) of university-provided health screening service use in the lowest versus highest income level was 1.74 (1.30-2.34; Ptrend < 0.001), whereas the multivariable-adjusted OR (95% CI) of private sector service use in the lowest versus highest income level was 0.45 (0.31-0.66; Ptrend < 0.001).This study demonstrated significant disparities in the types of utilized health screening services by income groups among university students in Korea, although overall rates of health screening service use were similar across income levels. Low-income students were more likely to use university-provided health screening services, and less likely to use private sector screening services. To ensure appropriate preventive care delivery for young adults and to address disparities in disadvantaged groups, the expansion of medical insurance coverage for preventive health care, establishment of a usual source of care, focusing on vulnerable groups, and the development of evidence-based standardized health screening guidelines for young adults are needed.