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

Risk and Status of Gastrointestinal Cancer According to the International Standard Industrial Classification in Korean Workers

Simple Summary

The risk of developing cancers varies depending on occupation, which is a well-known fact. It is crucial to investigate the risk of developing gastrointestinal (GI) cancer in the entire industry. In this study, we calculated the standardized incidence ratios (SIRs) of GI cancer by all industrial sectors as classified in the Korean Standard Industrial Classification (KSIC). There were noticeable differences among industries in the risk of GI cancer. The SIR of all GI cancer was highest among miners and quarriers, and second highest among transportation workers. These results suggest that further research is required to identify the risk factors present in each industry that contribute to the development of GI cancers. We believe this study can help to create tailored cancer prevention strategies for different industrial sectors.

Abstract

To compare the risk of developing gastrointestinal (GI) cancer according to industrial groups, we performed a retrospective cohort study using the database of the Korea National Health Insurance Service (NHIS). We calculated the age-standardized incidence ratios (SIRs) and 95% confidence intervals (95% CIs) for the types of GI cancers according to the Korean Standard Industrial Classification (KSIC) compared with the whole employee population. The highest SIR for all GI cancer was found in the “Mining and quarrying” section (SIR, 1.30; 95% CI, 1.14–1.47), followed by the “Transportation and storage” section (SIR, 1.27; 95% CI, 1.24–1.30). Miners and quarriers had the highest risk of developing gastric cancer (SIR, 1.29; 95% CI, 1.06–1.55) and cancer of the liver and intrahepatic bile ducts (SIR, 1.48; 95% CI, 1.17–1.86). Transportation workers had the highest SIR of cancer of the lip, oral cavity, and pharynx (SIR, 1.27; 95% CI, 1.13–1.43) and cancers of the rectum, anus, and anal canal (SIR, 1.27; 95% CI, 1.19–1.35). There were distinct GI cancers with an elevated risk in each industry group. Our findings imply that distinct cancer prevention programs should be developed for each industrial sector.

Role of Occupation in Shaping Cancer Disparities

Simple Summary

The investigation of cancer disparities is of major importance. In this paper, we address this issue through the occupational point of view, trying to capture how work and its related factors impact on cancer inequalities. The data we provide may increase awareness relevant to cancer control, and stimulate further studies aimed at the identification of the occupational determinants of cancer disparities and the quantification of their role.

Abstract

Cancer occurrence is characterized globally by profound socioeconomic differences. Occupation is a fundamental component of socioeconomic status. In this review, we discuss the role of occupation as a determinant of cancer disparities. First, we address the issue of participation in cancer screening programs based on income, health insurance, occupational status and job title. Second, we review the role of occupation in contributing to disparities by acting as a mediator between cancer and (i) education and (ii) race/ethnicity. Lastly, we analyze data from a multicenter case−control study of lung cancer to calculate the mediating role of occupational exposure to diesel exhaust, silica and welding fumes in the association between education and lung cancer. By addressing the complex paths from occupation to cancer inequalities from multiple points of view, we provide evidence that occupational-related characteristics, such as income, health insurance, unemployment and hazardous exposures impinge on cancer control and outcomes. The increasing awareness of these aspects is fundamental and should lead to public health interventions to avoid inequalities rising from occupational factors.

Breast Cancer Incidence among Female Workers by Different Occupations and Industries: A Longitudinal Population-Based Matched Case-Control Study in Taiwan

BACKGROUND

Breast cancer is the leading cause of cancer incidence worldwide and in Taiwan. The relationship between breast cancer and occupational types remains unclear. This study aimed to investigate lifetime breast cancer incidence by different occupational industries among female workers in Taiwan.

METHODS

A population-based retrospective case-control study was conducted using three nationwide population-based databases. Matched case and control groups were identified with 1-to-4 exact matching among 103,047 female workers with breast cancer diagnosed in 2008-2017 and those without breast cancer. Their lifetime labor enrollment records were tracked using the National Labor Insurance Database, 1950-2017. Conditional logistic regression was used to analyze the association between types of occupational industries and risk of incident breast cancer.

RESULTS

Our study found slightly significant breast cancer risk among the following major occupational classifications: manufacturing (OR: 1.027, 95% CI: 1.011-1.043); wholesale and retail trade (OR: 1.068, 95% CI: 1.052-1.084); information and communication (OR: 1.074, 95% CI: 1.043-1.105); financial and insurance activities (OR: 1.109, 95% CI: 1.086-1.133); real estate activities (OR: 1.050, 95% CI: 1.016-1.085); professional, scientific, and technical activities (OR: 1.118, 95% CI: 1.091-1.145); public administration, defense, and social security (OR: 1.054, 95% CI: 1.023-1.087), education (OR: 1.199, 95% CI: 1.168-1.230); and human health and social work activities (OR: 1.125, 95% CI: 1.096-1.156).

CONCLUSIONS

Greater percentages of industrial occupations (i.e., manufacturing, wholesale and retail, or health professionals) were associated with slightly increased breast cancer risk. Further studies should investigate the possible risk factors among female workers in those industries with slightly higher incidence of breast cancer.

Occupational disparities in tumor grade and cytosolic HMGB1 expression in renal cell cancer

Objectives

We sought to examine occupational disparities in tumor grade and cytosolic expression of high‐mobility group box‐1 (HMGB1) among renal cell cancer (RCC) patients.

Methods

This retrospective study included 318 RCC patients with complete information on occupation and pathology in Kanagawa Cancer Registry (KCR). Longest‐held occupations were grouped into manual workers (e.g., manufacturing, construction) versus “others.” Odds ratios (OR) and 95% confidence intervals (CI) for high‐grade histology were estimated by logistic regression, adjusted for age and sex. We also examined a sub‐sample of 74 low‐grade RCC inpatients to estimate the OR for positive cytosolic HMGB1 expression in manual workers, adjusting for age, sex, and other available covariates.

Results

High‐grade tumors were more prevalent in manual workers compared to other occupations: 23.0% (14/61) versus 10.9% (28/257, p = .01) with an adjusted OR of 2.28 (95% CI, 1.11–4.69). In the sub‐sample of low‐grade RCCs, positive cytosolic HMGB1 expression was more prevalent in manual workers compared to other occupations: 71.4% (10/14) versus 38.3% (23/60, p = .03) with a sex‐ and age‐adjusted OR of 3.76 (95% CI, 1.03–13.7).

Conclusions

Manual workers are associated with increased risks of high‐grade renal cell tumors and cytosolic HMGB1 expression.

Cancer incidence in agricultural workers: Findings from an international consortium of agricultural cohort studies (AGRICOH)

BACKGROUND

Agricultural work can expose workers to potentially hazardous agents including known and suspected carcinogens. This study aimed to evaluate cancer incidence in male and female agricultural workers in an international consortium, AGRICOH, relative to their respective general populations.

METHODS

The analysis included eight cohorts that were linked to their respective cancer registries: France (AGRICAN: n = 128,101), the US (AHS: n = 51,165, MESA: n = 2,177), Norway (CNAP: n = 43,834), Australia (2 cohorts combined, Australian Pesticide Exposed Workers: n = 12,215 and Victorian Grain Farmers: n = 919), Republic of Korea (KMCC: n = 8,432), and Denmark (SUS: n = 1,899). For various cancer sites and all cancers combined, standardized incidence ratios (SIR) and 95% confidence intervals (CIs) were calculated for each cohort using national or regional rates as reference rates and were combined by random-effects meta-analysis.

RESULTS

During nearly 2,800,000 person-years, a total of 23,188 cancers were observed. Elevated risks were observed for melanoma of the skin (number of cohorts = 3, meta-SIR = 1.18, CI: 1.01-1.38) and multiple myeloma (n = 4, meta-SIR = 1.27, CI: 1.04-1.54) in women and prostate cancer (n = 6, meta-SIR = 1.06, CI: 1.01-1.12), compared to the general population. In contrast, a deficit was observed for the incidence of several cancers, including cancers of the bladder, breast (female), colorectum, esophagus, larynx, lung, and pancreas and all cancers combined (n = 7, meta-SIR for all cancers combined = 0.83, 95% CI: 0.77-0.90). The direction of risk was largely consistent across cohorts although we observed large between-cohort variations in SIR for cancers of the liver and lung in men and women, and stomach, colorectum, and skin in men.

CONCLUSION

The results suggest that agricultural workers have a lower risk of various cancers and an elevated risk of prostate cancer, multiple myeloma (female), and melanoma of skin (female) compared to the general population. Those differences and the between-cohort variations may be due to underlying differences in risk factors and warrant further investigation of agricultural exposures.

Secondhand smoke exposure, diabetes, and high BMI are risk factors for uterine cervical cancer: a cross-sectional study from the Korea national health and nutrition examination survey (2010-2018)

Background

Human papilloma virus infection and tobacco smoking are the major risk factors for cervical cancer. There are limited studies searching other risk factors for cervical cancer and the results are not consistent. This study investigated the relations between cervical cancer and possible risk factors, including secondhand cigarette smoke exposure, diabetes, body mass index (BMI), and work schedule.

Methods

In this cross-sectional study, 29,557 women completed a cervical cancer questionnaire and were selected using 2010–2018 data from the Korea National Health and Nutrition Examination Survey. Details in secondhand smoke exposure, diabetes, BMI, and work schedule were assessed with participants’ health interviews and health-related surveys.

Results

Two hundred sixty-two women (0.89%) in the sample were diagnosed with cervical cancer. Domestic secondhand smoke exposure, diabetes, and high BMI significantly increased cervical cancer risk. Respective odds ratios and 95% confidence intervals were: 1.547 (1.042–2.297), 2.156 (1.535–3.027), and 1.036 (1.006–1.067). Weekly work hours, and work schedule were not significantly related to cervical cancer incidence.

Conclusion

Among Korean women, passive exposure to cigarette smoke at home, diabetes, and high BMI increase risk for cervical cancer.

Occupational disparities in survival in Korean women with cancer: a nationwide registry linkage study

OBJECTIVES

We sought to examine occupational disparities in survival among Korean women diagnosed with cancer.

DESIGN

Population-based, registry-linkage study.

SETTING

South Korea.

PARTICIPANTS

Our study population comprised female workers registered in the Korean national employment insurance programme during 1995-2000 and diagnosed with cancer between 1995 and 2008. A total of 61 110 women with cancer diagnoses was included in analysis. The occupation was categorised into four groups: (1) managers, professionals and technical workers, (2) clerks, (3) service/sales workers and (4) blue-collar workers.

PRIMARY AND SECONDARY OUTCOME MEASURE

Study population were linked to the national death registry until 2009. HRs for mortality adjusting for age and year of diagnosis were calculated in the study sample and subgroups with 10 specific cancer sites including thyroid, breast, stomach, cervix, colon or lung cancer using managers, professionals and technical workers as the reference.

RESULTS

Women in service/sales (HR 1.25, 95% CI 1.15 to 1.35) and blue-collar occupations (HR 1.34, 95% CI 1.25 to 1.44) had poorer survival for all cancer sites combined, while blue-collar workers showed poorer survival for lung (HR 1.41, 95% CI 1.14 to 1.77), breast (HR 1.28, 95% CI 1.06 to 1.54), cervical cancer (HR 1.42, 95% CI 1.02 to 2.06) and non-Hodgkin's lymphoma (HR 1.69, 95% CI 1.09 to 2.77) compared with women in professional and managerial positions.

CONCLUSION

We found substantial and significant inequalities in overall survival by the occupational group among Korean women with cancer, even in the context of universal access to cancer screening and treatment.

Investigating the health disparities in the association between lifestyle behaviors and the risk of head and neck cancer

Many studies have reported a positive association between lower socioeconomic status (SES) and higher head and neck cancer (HNC) risk. Fewer studies have examined the impact of SES on the association between alcohol or cigarette use and HNC risk. The current case‐control study (1104 HNC cases and 1363 controls) investigated the influence of education, a SES indicator, on the association between HNC and the use of alcohol, cigarettes, or betel quids in Taiwan, a country with universal health care. Our results showed a larger increase in HNC risk associated with alcohol among those with lower educational level (odds ratio [OR] = 2.07; 95% confidence interval [CI], 1.53‐2.80) than those with higher educational level (OR = 1.38; 95% CI, 1.04‐1.85) (heterogeneity‐P = .03). Educational level had an influence on the association between alcohol use and HNC risk among those with genetic susceptibility (ALDH2‐deficient) to the carcinogenic effect of alcohol. The association between cigarette or betel quid use and HNC risk was similar between the high and low educational groups. National policies and social interventions have led to the decline in the prevalence of cigarette and betel quid users in Taiwan. In contrast, due to the lack of adequate alcohol control policies, alcohol consumption in Taiwan has continued to rise. A higher impact of alcohol on HNC risk among lower SES individuals even with universal health care could be the result of insufficient alcohol control policies in Taiwan.

Cancer risk in road transportation workers: a national representative cohort study with 600,000 person-years of follow-up

We analysed cancer risk in road transportation workers (RTWs) exposed to traffic air pollution and motor vehicle engine exhaust using the Korean National Health Insurance Service database. RTWs were defined as individuals in the transportation workers group doing road transportation. First admission history of cancer within a 3-year wash-out period was defined as an incident case. The crude incidence, standardised incidence ratio (SIR), and 95% confidence interval (CI) of all cancer risk of RTWs were compared with those of government employees or the whole working population. In total, 3,074 cancer cases were found among RTWs. The respective SIRs and 95% CIs for cancers in RTWs compared with those in the whole population were as follows: liver and intrahepatic bile duct cancers, 1.15 and 1.04-1.27; other digestive organ cancers, 1.28 and 1.04-1.57; trachea, bronchus, and lung cancers, 1.28 and 1.15-1.43; and bladder cancer, 1.26 and 1.03-1.52, respectively. The corresponding SIRs and 95% CIs were also higher in RTWs than in government employees. RTWs have a high risk of developing cancer, including cancer in the liver, intrahepatic bile ducts, other digestive organs, trachea, bronchus, lung, and bladder. Our results can assist in establishing prevention strategies for various cancers in RTWs.

Occupational Class and Cancer Survival in Korean Men: Follow-Up Study of Nation-Wide Working Population

Background: We aimed to describe inequalities in site-specific cancer survival across different occupational classes in Korean men. Methods: Subjects included cancer diagnosed members of the national employment insurance program during 1995-2008. A total of 134,384 male cases were followed by linking their data to the Death registry until 2009. Occupational classes were categorized according to the Korean Standard Occupational Classification (KSOC). Hazard ratio adjusting age and diagnosed year were calculated for each occupation by cancer sites. Results: Men in service/sales and blue-collar occupations had lower survival of all cancer sites combined and esophagus, stomach, colorectal, liver, larynx, lung, prostate, thyroid cancer and non-Hodgkin's lymphoma than men in professional and managerial positions. Cancer sites with good prognosis like prostate cancer showed wider gap across occupational class. Conclusions: Considerable inequalities in cancer survival were found by occupation among Korean men. Cancer control policy should more focus on lower socioeconomic occupational class.