Risk of cancer and longest-held occupations in Japanese workers: A multicenter hospital-based case-control study

Statistical Analysis of the Factors that Affect Postoperative Length of Hospital Stay after Unruptured Intracranial Aneurysm Treatment in Japan: A 20-year Nationwide Multicenter Study

Treatment strategies for unruptured intracranial aneurysms (UIAs) should be carefully considered with reference to rupture and complication rates. It is also important to minimize the length of hospital stay (LOS) and to ensure a high quality of medical care. In this study, we aim to clarify the factors that affect the LOS of patients treated for UIAs using the Inpatient Clinico-Occupational Database of the Rosai Hospital Group (ICOD-R). This was a nationwide-multicenter study based on ICOD-R data from 2000 to 2019. Patients diagnosed with UIAs who were treated with clipping or coiling were included in the study. Multivariate analysis was performed to identify the factors affecting LOS. LOS was also compared between groups classified by surgical procedure or treatment period. We identified 3294 patients on the database who underwent clipping or coiling of UIAs during the study period. Multivariate analysis revealed hospital admission during the early 2000s and the late 2010s, age, and treating institution to be significantly correlated with LOS (p < 0.05). There was a significant difference between the mean LOS of the clipping group (20.3 days) and the coiling group (9.65 days) (p < 0.001). Compared by treatment period, LOS significantly shortened over time. Our results suggest that the type of treatment, time of treatment, patient age, and the treating institution affect postoperative LOS for UIAs. Although coiling was found to lead to a lower average LOS than clipping, treatment selection should take the characteristics of each patient's aneurysm into consideration.

A Genome-Wide Association Study of Prostate Cancer Susceptibility Using Occupational and Environmental Factors as Confounding Factors

Background In addition to genetic predisposition, occupational and environmental factors are important for the risk of prostate cancer. We investigated the effect of single nucleotide polymorphisms (SNPs) on the development of prostate cancer in Japan, including occupational and industrial history as confounding factors in addition to age, smoking, and alcohol drinking. Methods We enrolled 210 prostate cancer patients and 504 male control patients. We conducted four genome-wide association study (GWAS) patterns for prostate cancer development. In the association test, logistic regression models incorporated age, smoking history, alcohol consumption history, and each pattern of industrial/occupational classification. Results No SNPs satisfying the genome-wide significance level of 5×10-8 were detected in GWAS. SNPs with a suggestive association level of 1×10-6 were found near the long intergenic non-protein coding RNA 1824 (LINC01824) and tripartite motif family like 2 (TRIML2) genes in the GWAS using occupational history as a confounder and near the ribosomal protein S2 pseudogene 25 (RPS2P25) gene in the GWAS using industrial history as a confounder. No SNPs that met the suggestive association level were observed in the GWAS that did not include occupational and industrial history. Conclusion By adding occupational and industrial history to the confounding factors, there were SNPs detected in the GWAS for prostate cancer development. The consideration of occupational and industrial history may increase the usefulness of GWAS.

Length of employment in workplaces handling hazardous chemicals and risk of cancer among Japanese men

OBJECTIVES

In Japan, the risk of developing cancer among workers employed in workplaces where chemical substances are handled is unclear. This study aimed to assess the association between cancer risk and employment in workplaces handling hazardous chemicals.

METHODS

The Inpatient Clinico-Occupational Survey of the Rosai Hospital Group data of 120 278 male patients with incident cancer and 217 605 hospital controls matched for 5-year age group, hospital (34 hospitals) and year of admission (2005-2019) were analysed. Cancer risk in relation to lifetime employment in workplaces using regulated chemicals was assessed while controlling for age, region and year of diagnosis, smoking, alcohol consumption and occupation. Further analysis stratified by smoking history was performed to examine interaction effects.

RESULTS

In the longest group of employment in tertiles, ORs were increased for all cancers (OR=1.13; 95% CI: 1.07 to 1.19) and lung (OR=1.82; 95% CI: 1.56 to 2.13), oesophageal (OR=1.73; 95% CI: 1.18 to 2.55), pancreatic (OR=2.03; 95% CI: 1.40 to 2.94) and bladder (OR=1.40; 95% CI: 1.12 to 1.74) cancers. Employment of 1+ years was associated with risk for lung cancer; 11+ years for pancreatic and bladder cancers; and 21+ years for all cancers and oesophageal cancer. These positive relationships were particularly obvious among patients with a history of smoking; however, no significant interaction between smoking and length of employment was observed.

CONCLUSIONS

There is a high risk of cancer among workers, especially smokers, employed in workplaces handling regulated chemicals in Japan. Thus, future measures for chemical management in workplaces are needed to prevent avoidable cancers.

Occupational class and risk of hepatitis B and C viral infections: A case-control study-based data from a nationwide hospital group in Japan

BACKGROUND

Occupational class, a proxy for socio-economic status, is a known factor for health disparities. However, no study has reported the association between occupational class and the risk of viral hepatitis B and C (HBV/HCV) infections. We investigated the effects of occupational class on the prevalence of HBV/HCV infections.

METHODS

This is an unmatched hospital-based case-control study that included 12,101 patients who were diagnosed with HBV infection (ICD-10, B16.0, B16.1, B16.2, B16.9, B17.0, B18.0, B18.1) or HCV infection (ICD-10, B17.1, B18.2) and 698,168 controls (those with non-HBV/HCV-related diseases) aged ≥ 20 years who were initially hospitalized between 2005 and 2019. Patients were categorized according to occupational class (blue-collar, service, professional, and manager) and industrial sector (blue-collar, service, and white-collar). Managers in the blue-collar industry were set as the reference group, and the odds ratios (ORs) for the risk of HBV and HCV infections were calculated.

RESULTS

Occupational class was significantly associated with only HCV infection risk. Professionals in all industrial sectors showed the lowest risk for HCV (OR (95% confidence intervals [CIs]) = 0.69 [0.58-0.82] in the blue-collar industry, 0.52 [0.38-0.73] in the service industry, and 0.60 [0.52-0.70] in the white-collar industry). Further, after adjusting for sex, age, and region of admitting hospital, all occupational classes in the white-collar industry showed lower risks of HCV than those in the other industries (ORs= 0.58 [0.47-0.71] in blue-collar workers, 0.74 [0.64-0.84] in service workers, 0.60 [0.52-0.70] in professionals, and 0.81 [0.64-1.02] in managers in white-collar industry).

CONCLUSIONS

Occupational class was closely associated with HCV infection risk only. Considering that blue-collar workers in the white-collar industry also showed a low risk, adequate measures should be taken against hepatitis, possibly because of the screening tests and cure implemented in that population.

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.

Modifiable risk factors for prostate cancer in low- and lower-middle-income countries: a systematic review and meta-analysis

BACKGROUND

Most of the epidemiological data on prostate cancer risk factors come from high-income countries (HIC). Reducing exposure to prostate cancer modifiable risk factors may significantly lower PCa morbidity and mortality in LIC and MIC. The objective of this study was to summarize the evidence on modifiable risk factors (RFs) for PCa in LIC and lower-middle-income countries (LMIC).

METHODS

We conducted a systematic search on MEDLINE, EMBASE, and Global Health databases. We selected case-control and cohort studies from 2010 onwards that studied modifiable RFs for PCa in LIC and LMIC with a population of 30 million or more, as defined by the World Bank in January 2021. Risk of bias was assessed by the Ottawa-Newcastle tool. Individual study estimates were pooled when estimates were available for at least two studies.

RESULTS

5740 studies were initially identified; 16 studies met inclusion criteria. All were case-control studies except one retrospective cohort study. Higher fat intake was associated with a higher risk of PCa incidence with an odds ratio (OR) of 3.13 (95% CI 1.33-7.33). Higher vegetable intake (OR 0.48, 95% CI 0.24-0.97) and tea consumption (OR 0.51, 95% CI 0.32-0.83) were associated with a lower risk for PCa. There was no association between fruits, fish, and chicken consumption and risk of PCa. Alcohol consumption, smoking, red meat intake, and a BMI ≥ 25-30 kg/m² showed a trend towards an increased risk, although these were not statistically significant.

CONCLUSIONS

In LIC and LMIC, high fat intake was associated with higher risk of PCa while a diet rich in vegetables and tea intake was associated with a lower risk. Future prospective studies will be important to elucidate whether other modifiable risk factors for PCa specific to LIC and LMIC can be identified to inform impactful and cost-effective preventive strategies in these countries.

Genome-Wide Association Study Adjusted for Occupational and Environmental Factors for Bladder Cancer Susceptibility

This study examined the effects of single-nucleotide polymorphisms (SNPs) on the development of bladder cancer, adding longest-held occupational and industrial history as regulators. The genome purified from blood was genotyped, followed by SNP imputation. In the genome-wide association study (GWAS), several patterns of industrial/occupational classifications were added to logistic regression models. The association test between bladder cancer development and the calculated genetic score for each gene region was evaluated (gene-wise analysis). In the GWAS and gene-wise analysis, the gliomedin gene satisfied both suggestive association levels of 10⁻⁵ in the GWAS and 10⁻⁴ in the gene-wise analysis for male bladder cancer. The expression of the gliomedin protein in the nucleus of bladder cancer cells decreased in cancers with a tendency to infiltrate and those with strong cell atypia. It is hypothesized that gliomedin is involved in the development of bladder cancer.

Occupation and prostate Cancer risk: results from the epidemiological study of prostate cancer (EPICAP)

Background

Although prostate cancer (PCa) is the most frequent male cancer in industrialized countries, little is known about its aetiology. The literature has suggested an influence of the environment, including occupational exposures, but results are inconsistent. In this context, we investigated PCa risk associated to employment among several occupations using data from EPICAP study.

Methods

EPICAP is a French population-based case-control study including 819 PCa incident cases and 879 controls frequency-matched on age. In-person interviews gathered data on potential risk factors and lifetime occupational histories for each job held at least 6 months. Then, occupations were coded using ISCO 68. Unconditional logistic regressions were performed to assess the association between occupations (ever occupied and by duration) and PCa risk, whether all and aggressive, after adjusting for potential confounders.

Results

For ≥10 years of employment, we found positive associations with PCa, whether overall and aggressive, among Medical, Dental and Veterinary workers (OR (odds ratios) =5.01 [95% confidence interval] [1.27; 19.77]), Members of the armed forces (OR = 5.14 [0.99; 26.71]) and Fishermen, hunters and related workers (OR = 4.58 [1.33; 15.78]); whether overall and non-aggressive PCa, among Legislative officials and Government administrators (OR = 3.30 [1.10; 9.84]) or Managers (OR = 1.68 [1.18; 2.41]); however a negative association, whether overall and non-aggressive PCa, among Material-Handling and Related Equipment Operators, Dockers and Freight Handlers (OR = 0.40 [0.17; 0.97]).

Conclusion

Excess PCa risks were observed in the EPICAP study mostly among white collar workers exposed to several factors in their work environment. These emerging associations can be used to lead future research investigating specific occupational exposures.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12995-022-00346-2.

Occupational physical activity differentially affects the risk for developing later-onset Crohn's disease and ulcerative colitis among middle-aged and older populations

BACKGROUND

A person's occupation may increase his/her risk for developing inflammatory bowel disease (IBD). This study investigated the association between risk for later-onset of IBD and both specific occupations and occupational physical activity (OPA) levels.

MATERIALS AND METHODS

A multicenter hospital-based matched case-control study was conducted using the Inpatient Clinico-Occupational Survey database. Cases were patients with Crohn's disease (CD) and ulcerative colitis (UC) patients admitted for the first time between 2005 and 2015. Four controls matched by age, sex, admission year and hospital were selected for each case. Cases and controls were grouped into the longest-held occupations as classified by the Japanese Standard Occupational Classification and OPA levels. We conducted conditional logistic regressions to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for IBD, CD and UC adjusted for alcohol consumption and smoking status.

RESULTS

There were 564 cases (172 CD, 392 UC) and 2086 controls. The risk for UC was higher among sales workers and carrying, cleaning and packing workers (ORs 2.62 [95%CIs 1.18-5.82], 2.52 [1.04-6.09]). There was no association between occupation type and CD risk. Higher OPA level decreased CD risk (OR 0.51 [95%CIs 0.26-1.00]) and increased UC risk (OR 1.53 [95%CIs 1.02-2.30]).

CONCLUSIONS

Our study revealed that the risk for later-onset of UC, but not CD, was associated with longest-held 'service' and 'manufacture' work. The risk by OPA levels was inversely associated between CD and UC. Further studies are needed by follow-up method for long-term effects of physical activity.

A case control study of occupation and cardiovascular disease risk in Japanese men and women

We aimed to investigate the risks of cardiovascular diseases associated with specific occupations, using a nation-wide, multicentre, hospital-based registry data from the Inpatient Clinico-Occupational Survey. The analysis included 539,110 controls (non-circulatory disease) and 23,792 cases (cerebral infarction, intracerebral/subarachnoid hemorrhage, acute myocardial infarction) aged ≥ 20 years who were initially hospitalized during 2005–2015. The participants’ occupational and clinical histories were collected by interviewers and medical doctors. Occupations were coded into 81 categories according to the Japanese standard occupation classification. Multivariable logistic regression analysis adjusted for age, admission year and hospital, smoking, alcohol consumption, hypertension, and shift-work was conducted by sex using general clerical workers as the reference. Increased risks of cerebral infarction, intracerebral hemorrhage, subarachnoid hemorrhage, and acute myocardial infarction, were observed in 15, 20, 25, and 1 occupation(s) in men, and 9, 2, 2, and 10 occupations in women. Motor vehicle drivers, food and drink preparatory workers, fishery workers, cargo workers, civil engineer workers, and other manual workers in men and other manual workers in women faced increased risks of all three stroke subtypes. Our findings demonstrate associations between specific occupations and the risk of cardiovascular disease incidence and suggest that the risk may vary by occupation.

Occupation, occupational exposures and mammographic density in Spanish women

INTRODUCTION

Mammographic density (MD), the proportion of radiologically dense breast tissue, is a strong risk factor for breast cancer. Our objective is to investigate the influence of occupations and occupational exposure to physical, chemical, and microbiological agents on MD in Spanish premenopausal women.

METHODS

This is a cross-sectional study based on 1362 premenopausal workers, aged 39-50, who attended a gynecological screening in a breast radiodiagnosis unit of Madrid City Council. The work history was compiled through a personal interview. Exposure to occupational agents was evaluated using the Spanish job-exposure matrix MatEmESp. MD percentage was assessed using the validated semi-automated computer tool DM-Scan. The association between occupation, occupational exposures, and MD was quantified using multiple linear regression models, adjusted for age, educational level, body mass index, parity, previous breast biopsies, family history of breast cancer, energy intake, use of oral contraceptives, smoking, and alcohol consumption.

RESULTS

Although no occupation was statistically significantly associated with MD, a borderline significant inverse association was mainly observed in orchard, greenhouse, nursery, and garden workers (β = -6.60; 95% confidence interval (95%CI) = -14.27; 1.07) and information and communication technology technicians (β = -7.27; 95%CI = -15.37; 0.84). On the contrary, a positive association was found among technicians in art galleries, museums, and libraries (β = 8.47; 95%CI = -0.65; 17.60). Women occupationally exposed to fungicides, herbicides, and insecticides tended to have lower MD. The percentage of density decreased by almost 2% for every 5 years spent in occupations exposed to the mentioned agents.

CONCLUSIONS

Although our findings point to a lack of association with the occupations and exposures analyzed, this study supports a deeper exploration of the role of certain occupational agents in MD, such as pesticides.

The relationship of hospital stay and readmission with employment status

The Inpatient Clinico-Occupational Survey collected data from 3.76 million patients, showing that the average length of stay declined by 16.1 d in FY2008 and by 14.1 d in FY2015. In this study, we assessed the length of hospital stay and readmission, stratified by ICD-10 and employment status. A cross-sectional study was conducted on data from FY2008, including those from 65,806 first hospitalizations and 16,653 readmissions in FY2008, where 62,260 first admissions and 29,242 readmissions in FY 2015. The length of hospital stay was longest in those admitted due to external influences (24.8 d), followed by musculoskeletal disorders (22.5 d). This remained unchanged in FY2015, however, lengths of stay of those were reduced by 20.1 and 20.0 d, respectively. The length of hospital stay for most diseases was longer upon readmission than on first admission, and longer for those who were unemployed. It is necessary to give attention to patients who need to be discharged early due to work, or plan for frequent hospitalization in order to reduce the length of each hospital stay because of the expected increase in the number of elderly workers brought on by a declining birth rate and an aging population.

Mortality risks among blue- and white-collar workers: A time series study among Japanese men aged 25-64 years from 1980 to 2015

OBJECTIVE

We aimed to analyse age-standardised mortality trends in Japan among blue- and white-collar male workers aged 25-64 years, by major causes of mortality from 1980 to 2015.

METHODS

Five-yearly mortality data were extracted from occupation-specific vital statistics maintained by the Japanese Ministry of Health, Labour and Welfare. A time series study was conducted among employed men aged 25-64 years. Age-standardised mortality trends by occupational category were calculated separately for all cancers, ischaemic heart disease, cerebrovascular disease and suicide. Poisson regression analysis was performed to analyse mortality trends by occupational category for each cause.

RESULTS

Mortality rates for all cancers and ischaemic heart disease were higher among white-collar workers than blue-collar workers throughout the 35-year study period. The gap in the mortality rates for all four causes of death among blue- and white-collar workers widened in 2000 after Japan's economic bubble burst in the late 1990s. Simultaneously, suicide mortality rates among white-collar workers increased sharply and have remained higher than among blue-collar workers.

CONCLUSIONS

White-collar male workers in Japan have a higher risk of mortality than male blue-collar workers. However, despite substantial differences, significant progress has been made in recent years in reducing mortality across all occupations in Japan.

Combined effects of occupational exposure to hazardous operations and lifestyle-related factors on cancer incidence

We aimed to examine whether the number of types of hazardous operations at work experienced through a lifetime is associated with cancer incidence, and additionally examined the combined effects with lifestyle‐related factors. Using a nationwide, multicenter, hospital inpatient dataset (2005‐2015), we conducted a matched case‐control study with 1 149 296 study subjects. We classified the participants into those with none, 1, or 2 or more types of hazardous operation experience, based on information of special medical examinations taken, mandatory in Japan for workers engaged in hazardous operations. Using those with no experience as the reference group, we estimated the odds ratios for cancer incidence (all sites, lung, stomach, colon and rectum, liver, pancreas, bile duct, and bladder) by conditional logistic regression with multiple imputations. We also examined the effects of the combination with hazardous operations and lifestyle‐related factors. We observed increased risks for cancer of all sites, and lung, pancreas, and bladder cancer associated with the experience of hazardous operations. Multivariable‐adjusted ORs (95% CIs) of cancer incidence of all sites were 1 (reference), 1.16 (1.12, 1.21), and 1.17 (1.08, 1.27) for none, 1, and 2 or more types of hazardous operation experience, respectively (P for trend <.001). Potential combined associations of hazardous operations with smoking were observed for lung, pancreas, and bladder cancer, and with diabetes for pancreas cancer. Engaging in hazardous operations at work and in combination with lifestyle‐related factors may increase the risk of cancer. We highlight the potential for those engaged in hazardous work to avoid preventable cancers.

Manufacturing Industry Cancer Risk in Japan: A Multicenter Hospital-Based Case Control Study

Background:

It is well known that specific occupations can cause harm in developing malignant neoplasms. Chemical exposure is particularly high in the manufacturing industry and workers in this sector may face a higher occupational risk for cancer. We aimed to estimate inequalities in the risk of cancers related to occupational chemical exposure in various manufacturing categories.

Methods:

Using nationwide clinical inpatient data (1984−2017) in Japan, we undertook a multicenter, case-control study with regard to risks of developing cancers among various manufacturing industry categories. Using the food manufacturing industry as the reference group, odds ratios and 95% confidence intervals for each industry were estimated by conditional logistic regression, adjusted for sex, age, admission period, and the admitting hospital. Medical record summaries accounting for 89% of industrial categories with high odds ratios were collected to confirm diagnoses made on the basis of histology. We estimated industrial hazards based on the Pollutant Release and Transfer Register.

Results:

A reduced risk for some of common cancers was observed among lumber and wood products industries. Leather tanning, leather products and fur tended to show a higher risk: 2.36 (95% CI 1.15−4.83) for pancreatic cancer, 2.85 (95% CI 1.26−6.47) for liver cancer and 2.00 (95% CI 1.01–3.99) for lung cancer. For the electronics category, observations of high risk ranged from 2.09 (95%CI 1.18–3.70) for ureter cancer, to 2.49 (95% CI 1.79–3.55) for kidney cancer.

Conclusions:

This study revealed industry risk inequalities in manufacturing categories were present with regard to the risk of common cancers in Japan.

Occupation as a predictor of prostate cancer screening behaviour in Canada

OBJECTIVES

If prostate cancer screening practices relate to occupation, this would have important implications when studying the aetiological role of workplace exposures on prostate cancer. We identified variations in screening by occupation among men in Montreal, Canada (2005-2012).

METHODS

Prostate specific antigen testing and digital rectal examination (ever-screened and frequency of screening, previous five years) were examined among population controls from the Prostate Cancer & Environment Study. Face-to-face interviews elicited lifestyle and occupational histories. Multivariable logistic regression was used to estimate the odds of ever-screening for the longest-held occupation, adjusting for potential confounders. Negative binomial models were used to examine relationships with screening frequency.

RESULTS

Among 1989 controls, 81% reported ever having had a prostate specific antigen test, and 77% a digital rectal examination. Approximately 40% of men reported having a prostate specific antigen test once a year, on average. Compared with those in management or administrative jobs, men in primary industry (odds ratio 0.26, 95% confidence interval 0.10-0.65), construction (0.44, 0.25-0.79), machining (0.45, 0.21-0.97), and teaching (0.37, 0.20-0.70) were less likely to have undergone prostate specific antigen screening. Results were similar when considering the most recent job.

CONCLUSIONS

Our findings highlight substantial variations in prostate cancer screening by occupation. Men in occupations where carcinogen exposures are more common are less likely to participate in prostate screening activities. This could be an important source of bias, and occupational studies of prostate cancer should account for screening practices.

Risk of cancer and longest-held occupations in Japanese workers: A multicenter hospital-based case-control study

Objectives

Little is known about the risk of developing various cancers according to occupation and occupational physical activity.

Methods

Using nationwide clinical inpatient data (1984‐2017) in Japan, we undertook a multicentered, matched case‐control study with regard to the risk of developing various cancers according to occupation and using patients admitted with fractures as controls. Using standardized national occupation and industrial classifications, we first identified the longest‐held job for each patient. Using sales workers as the reference group, odds ratios (ORs) and 95% confidence intervals (CIs) were estimated by conditional logistic regression, adjusted for age, admission period, and the admitting hospital, with smoking, alcohol consumption, and lifestyle diseases as covariates. The risk of high and low occupational physical activity was also estimated.

Results

Across all occupations, a reduced risk for all common cancers among males was observed among those occupations associated with high physical activities, such as agriculture. People in these occupations tended to show a lower risk for most cancers, including, for example, prostate cancer (OR 0.58, 95% CI 0.45‐0.75) and lung cancer (OR 0.63, 95% CI 0.51‐0.76). For females, the breast cancer risk was low in women engaged in agriculture (OR 0.58, 95% CI 0.45‐0.75) and in those occupations with high levels of occupational physical activity (OR 0.58, 95% CI 0.52‐0.66).

Conclusions

This study revealed differences in cancer risk among diverse occupations in Japan. Specifically, those occupations associated with high levels of physical activity may be associated with a decreased risk of cancer.