Warning: mkdir(): Permission denied in /home/virtual/lib/view_data.php on line 81

Warning: fopen(upload/ip_log/ip_log_2024-09.txt): failed to open stream: No such file or directory in /home/virtual/lib/view_data.php on line 83

Warning: fwrite() expects parameter 1 to be resource, boolean given in /home/virtual/lib/view_data.php on line 84
Risk factors including night shift work of colorectal polyp
Skip Navigation
Skip to contents

Ann Occup Environ Med : Annals of Occupational and Environmental Medicine

OPEN ACCESS
SEARCH
Search

Articles

Page Path
HOME > Ann Occup Environ Med > Volume 32; 2020 > Article
Research Article Risk factors including night shift work of colorectal polyp
Kanghyun Um1orcid, Chung-soo Park1orcid, Cheolin Yoo2orcid, Yeon-Soon Ahn3orcid, Moonchan Kim4orcid, Kyoung Sook Jeong5orcid
Annals of Occupational and Environmental Medicine 2020;32:e26.
DOI: https://doi.org/10.35371/aoem.2020.32.e26
Published online: July 13, 2020

1Department of Occupational and Environmental Medicine, Ajou University Hospital, Suwon, Korea.

2Department of Occupational and Environmental Medicine, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan, Korea.

3Department of Preventive Medicine and Genomic Cohort Institute, Yonsei University Wonju College of Medicine, Wonju, Korea.

4Department of Family Medicine, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan, Korea.

5Department of Occupational and Environmental Medicine, Wonju Severance Christian Hospital, Wonju, Korea.

Correspondence: Kyoung Sook Jeong. Department of Occupational and Environmental Medicine, Wonju Severance Christian Hospital, 20 Ilsan-ro, Wonju 26426, Korea. jeongks@yonsei.ac.kr
• Received: May 13, 2020   • Accepted: June 26, 2020

Copyright © 2020 Korean Society of Occupational & Environmental Medicine

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (https://creativecommons.org/licenses/by-nc/4.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

  • 54 Views
  • 0 Download
  • 5 Web of Science
  • 5 Crossref
  • 6 Scopus
prev next
  • Background
    The destruction of circadian rhythms by night shift work affects major circadian genes, which are known to play a role in advancing or killing the cell cycle through tumor suppressor genes. To find out whether night shift work affects the incidence of colorectal cancer, which was found to be associated with long-term night shift work in previous studies, we surveyed effect of night shift work on colorectal polyps that have a higher incidence than colorectal cancer and can progress to colorectal cancer.
  • Methods
    To examine the correlation between rotating night shifts and colorectal polyps, a survey was conducted with 299 men aged 40–60 years from two university hospitals. We examined lifestyle, work history, work patterns, and colonoscopy results. The differences in prevalence among the groups was compared, and prevalence ratio (PR) was calculated via generalized linear modeling.
  • Results
    The prevalence of colorectal polyps in night shift and non-shift workers were 53.0% and 33.5%, respectively. After adjusting for age, smoking status, dietary habits, family history of colorectal cancer, obesity, job type, night shift work (PR: 1.13, 95% CI: 1.02–1.25) was a risk factor of colorectal polyps.
  • Conclusions
    The risk of colorectal polyps was greater in night shift workers than non-shift workers. Also risk of colorectal polyp was higher in older group. Our study investigated colorectal polyp instead of colorectal cancer and lacks information about types and gene mutations of colorectal polyps. Further study is needed to clarify effect of night shift work on development of colorectal cancer.
The incidence of colorectal cancer has recently increased in Korea. In 2017, the incidence of colorectal cancer was 30.8 per 100,000 people - the second most common cancer following stomach cancer. There were 28,111 cases of colorectal cancer; of these, 16,653 cases were men. Compared with other countries, the age-standardized incidence rate of all cancers in men was 291.3 in Korea, 285.9 in Japan, 393.2 in the US, and 344.7 in the United Kingdom. Specifically, Korea had a higher incidence of colorectal cancer (38.8) than other countries except Japan (49.1), including the US (28.8) and the United Kingdom (37.8). In women, the age-standardized incidence rate of all cancers was 251.5 in Korea, 220.5 in Japan, 321.2 in the US, and 299.8 in the UK. Specifically, the incidence of colorectal cancer was 21.8 in Korea, 29.6 in Japan, 22.6 in the US, and 27.0 in the UK, showing that females in Korea had a relatively lower incidence of colorectal cancer compared to other countries [1,2].
The relative risk of colorectal cancer was 1.35 (95% CI: 1.03–1.77) in the group with more than 15 years of shift work experience compared to the group with under 1 year of shift work experience in a cohort study of US female nurses [3]. Further, in a 24-year follow-up cohort study from 1988–2012 and from 1989–2013, the risk of colorectal cancer was 1.15 (95% CI: 0.95–1.39) and the risk of rectal cancer was 1.60 (95% CI: 1.09–2.34) in the group with more than 15 years of shift work experience [4].
Light exposure from night shifts reduces serum melatonin levels, and melatonin increases the expression of p53, a tumor suppressor gene [5]. Therefore, light exposure during night shifts may reduce the expression of tumor suppressor genes by decreasing serum melatonin production and may affect the circadian genes itself. Night shift working increases the risk of breast cancer owing to abnormalities in the hypothalamic-pituitary-gonadal axis by the effects of melatonin, a hormone that is secreted and suppressed under the influence of light [6]. Melatonin is also involved in the development of cancer by inducing cell proliferation and apoptosis through circadian genes in peripheral tissues through the hypothalamic-pituitary-adrenal and hypothalamic-pituitary-gonadal axes [7]. In addition, two circadian regulatory genes, Per2 and Per1 regulate β-catenin and cell proliferation in colon and non-colon cancer cells, and Per2 mutations make intestinal β-catenin and colorectal polyp formation increase [8]. There has been ample research concerning breast cancer and circadian rhythm genes [9,10].
According to the 2017 Korean Working Conditions Survey, since 2006, the proportion of workers working in shifts has been steadily increasing. According to the 5th Working Environment Survey, the proportion of shift workers accounted for 9.7%; of which 10.0% were men and 9.3% were women [11]. Further, based on the results of epidemiological studies and animal studies on breast cancer from the World Health Organization's International Agency for Research on Cancer (WHO IARC), it was concluded that shift work that disrupts the circadian rhythm is risk factor for developing cancer [12]. In 2019, though there was debate on effect of night shiftwork on risk of colorectal cancer, IARC maintained night shift work as probable carcinogen of breast, prostate and colorectal cancer [13].
Compared with other countries, the incidence of colorectal cancer in men is higher in Korea. In addition, Korean male workers have a higher rate of shift work. Therefore, we choose the group exposed to the risk of night work and colorectal cancer as the target of our study. Since night shift work could affect the incidence of colorectal cancer, we tried to indirectly determine whether night shift work is a risk factor for colorectal cancer by comparing the prevalence of colorectal polyp with other known risk factors of colorectal cancer [14], which is higher than colorectal cancer and is a precancerous lesion of colorectal cancer.
Study setting and participants
The study protocol was reviewed and approved by the institutional Review Board of the Dongguk University Ilsan Hospital (approved No 2011-61) and Ulsan University Hospital (approved No 2011076). We examined the questionnaires and colonoscopy results of 476 men those who took informed consent among all the people who received a colonoscopy and 40–60 years old men during a health promotion examination in 2011 and 2012 at 2 University hospitals. Total 476 men were surveyed in our study. We excluded 177 individuals with answers including missing variables. As a result, data from total 299 participants was analyzed in this study.
Variables and instruments

Sociodemographic and work-related characteristics

We surveyed General characteristics and known risk factors of colorectal cancer included height, weight, age, sex, smoking, drinking habits, dietary habits, exercise habits, sleeping habits, and sleep disorders, family history of colon cancer by self-reporting questionnaires. We also investigated the presence of shift work, number of nightshifts, the type of shift work, and the level of activity at work. When men worked shift work, sleeping habits according to the work type were included in the survey. Abdominal obesity was defined as the waist circumference of more than 90 cm. Obesity was classified when their body mass index (BMI) was greater than 25 kg/m2.
We defined night shift work group as a group where the number of night work (work performed at least 2 hours between 10 pm and 5 am) exceeded 3 times per month. The definition of night work in the Working Conditions Survey Report in Korea was used [11]. Cut-off value of night work was previously used for a study on the link between breast cancer and night shift work in Germany in the past [15]. Day worker and those who do night shift work less than 4 times per month were classified no night shift work group.
Average daily sleeping time was calculated via individual's sleeping time when working daytime shifts and sleeping time when working nighttime shifts.

Colonoscopy results

Participants' colonoscopy results were collected after health examination and classified as normal, colorectal polyp, colorectal cancer, and other (including hemorrhoids, colitis, diverticulum).
Statistical analyses
A frequency analysis was performed using IBM SPSS Statistics software 25.0 (IBM, Armonk, NY, USA). Chi-square tests were used to determine the differences in prevalence among the groups, and t-tests were used for mean comparisons. In addition, due to high prevalence of colorectal polyp among current study population, Poisson regression model with robust error variance was used to determine the crude and adjusted prevalence ratio (PR) of colorectal polyps [16].
We compared the general characteristics of participants by night shift work in Table 1. The group with (vs. without) night shift work was older and active during work but did less exercise and the group without (vs. with) the night shift work was more likely to be mainly vegetarian. Also night shift work group had a shorter average daily sleeping time (5.9 hours vs. 6.6 hours). There was no significant difference between the groups concerning smoking rate, obesity, family history of colorectal cancer.
Table 1

Comparison of participants' general characteristics per night shift work

Characteristics No night shift work Night shift worka p-valueb
Age group (years) < 0.001
40–49 171 (73.4) 28 (42.4)
50–60 62 (26.6) 38 (57.6)
Current smoking status 0.607
Non-smoker 49 (21.0) 11 (16.7)
Ex-smoker 112 (48.1) 36 (54.6)
Current smoker 72 (30.9) 19 (28.8)
Abdominal obesity 0.225
Normal 192 (82.4) 50 (75.8)
Abdominal obesityc 41 (17.6) 16 (24.2)
Obese 0.714
No 140 (60.1) 38 (57.6)
Yesd 93 (39.9) 28 (42.4)
Dietary habits < 0.001
Mainly vegetarians 181 (77.7) 22 (33.3)
Omnivores 40 (17.2) 39 (59.1)
Mainly meat-eaters 12 (5.1) 5 (7.6)
Family history of colorectal cancer 0.112e
No 228 (97.9) 62 (93.9)
Yes 5 (2.1) 4 (6.1)
Job type < 0.001
Sedentary 142 (61.0) 18 (27.3)
Non-sedentary 91 (39.1) 48 (72.3)
Exercise 0.014
No 23 (9.9) 14 (21.2)
Yes 210 (90.1) 52 (78.8)
Average daily sleeping time (hours) 6.6 ± 0.8 5.9 ± 1.1 < 0.001f
Values are presented as number (%) or mean ± standard deviation.
aNight shift work more than 4 times per month; bchi-square test; cwaist circumference ≥ 90 cm; dbody mass index (kg/m2) ≥ 25.0.; eFisher's exact test; ft-test.
Table 2 shows colonoscopy result of our study population. There were no participants with colorectal cancer confirmed in the colonoscopy. All cases classified as other were hemorrhoids.
Table 2

Result of colonoscopy

Result of colonoscopy No. (%)
Normal 143 (47.8)
Colorectal polyp 113 (37.8)
Colorectal cancer 0 (0)
Other 43 (14.4)
Table 3 shows participants' characteristics by the prevalence of colorectal polyps. The prevalence of colorectal polyps was significantly higher in those who work in night shift more than 4 times per month than those who work in night shift less than 4 times per month. The prevalence of colorectal polyps was significantly higher among older group. The other relationships were non-significant.
Table 3

Participants' characteristics according to prevalence of colorectal polyps

Characteristics Presence of colorectal polyps p-valuea
No Yes
Total 186 (62.2) 113 (37.8) -
Age group (years) 0.001
40–49 137 (68.8) 62 (31.2)
50–60 49 (49.0) 51 (51.0)
Current smoking status 0.219
Non-smoker 43 (71.7) 17 (28.3)
Ex-smoker 87 (58.8) 61 (41.2)
Current smoker 56 (61.5) 35 (38.5)
Abdominal obesity 0.889
Normal 151 (62.4) 91 (37.6)
Abdominal obesityb 35 (61.4) 22 (38.6)
Obese 0.674
No 109 (61.2) 69 (38.8)
Yesc 77 (63.6) 44 (36.4)
Dietary habits 0.142
Mainly vegetarians 134 (66.0) 69 (34.0)
Omnivores 43 (54.4) 36 (45.6)
Mainly meat-eaters 9 (52.9) 8 (47.1)
Family history of colorectal cancer 0.728
No 180 (62.1) 110 (37.9)
Yes 6 (66.7) 3 (33.3)
Job type 0.398
Sedentary 96 (60.0) 64 (40.0)
Non-sedentary 90 (64.8) 49 (35.2)
Exercise 0.473
No 26 (66.7) 13 (33.3)
Yes 163 (61.5) 102 (38.5)
Night shift workd 0.004
No 155 (66.5) 78 (33.5)
Yes 31 (47.0) 35 (53.0)
achi-square test; bwaist circumference ≥ 90 cm; cbody mass index (kg/m2) ≥ 25.0; dnight shift work more than 4 times per month.
The PRs for the risk of colorectal polyps are shown in Table 4 with both crude ratios and ratios adjusted for age group, smoking status, dietary habits, family history of colorectal cancer, obesity, job type, and night shift work. In the analysis of individual variables, age (PR: 1.15, 95% CI: 1.06–1.25) and night shift work (PR: 1.15, 95% CI: 1.05–1.26) was significantly associated with elevated risk of colorectal polyps while other variables including smoking history, eating habits, family history of colorectal cancer, obese and job type was not significant. In the multivariable analysis including whole variables above, age (PR: 1.12, 95% CI: 1.02–1.22) and night shift work (PR: 1.13, 95% CI: 1.02–1.25) remained associated with the elevated risk of colorectal polyps.
Table 4

Prevalence ratios for the risk of colorectal polyps after adjusting for confounder variables

Variables Category Crude PR (95% CI) Adjusted PR (95% CI)a
Age (years) 40–49 1 (Reference) 1 (Reference)
50–60 1.15 (1.06–1.25) 1.12 (1.02–1.22)
Smoking history Never smoker 1 (Reference) 1 (Reference)
Ex- or current smoker 1.09 (0.99–1.21) 1.07 (0.96–1.18)
Eating habits Mainly vegetarians 1 (Reference) 1 (Reference)
Omnivores 1.09 (0.99–1.19) 1.00 (0.91–1.10)
Mainly meat-eaters 1.10 (0.93–1.30) 1.05 (0.87–1.25)
Family history of colorectal cancer No 1 (Reference) 1 (Reference)
Yes 0.97 (0.76–1.22) 0.92 (0.73–1.16)
Obese No 1 (Reference) 1 (Reference)
Yesb 0.98 (0.91–1.07) 0.98 (0.91–1.06)
Job type Sedentary 1 (Reference) 1 (Reference)
Non-sedentary 0.97 (0.89–1.05) 0.94 (0.87–1.02)
Night shift work No 1 (Reference) 1 (Reference)
Yesc 1.15 (1.05–1.26) 1.13 (1.02–1.25)
PR: prevalence ratio, CI: confidence interval.
aAdjusting for age, smoking history, eating habits, family history of colorectal cancer, obese, job style, night shift work; bbody mass index (kg/m2) ≥ 25.0; cnight shift work more than 4 times per month.
The purpose of this study was to investigate the relationship between night shift work and colorectal polyps using a survey and the colonoscopy results of men aged 40–60 years. The group that worked night shifts more than 4 times per month was more likely to have colorectal polyps after correcting for other risk factors such as age, smoking status, dietary habits, family history of colorectal cancer, BMI, and activity level at work. And old age was also a risk factor of colorectal polyps.
The prevalence of colorectal polyps varies widely by race and country. Previous study of asymptomatic average-risk Koreans showed that the prevalence of colorectal adenoma in age group of 40s and 50s was 28.1% and 38.1% [17]. Another study found that the prevalence of colorectal adenoma in asymptomatic Korean men with average risk was 27.9 in 40s and 36.8 in 50s [18]. In our study, the overall prevalence of colorectal polyp was 37.8% and according to age, the prevalence was 31.2% in 40s and 51.0% in 50s which is consistent with findings of former studies.
The prevalence of colorectal cancer increases with age. Because the risk of colorectal cancer begins to increase when people are in their 50s, the United States Preventive Service Task Force (2016) strongly recommends screening when individuals are aged 50–75 years [19]. The Canadian Task Force on Preventive Health Care (2016) and the Asia Pacific Working Group in Colorectal Cancer (2015) also recommend screening for colorectal cancer in asymptomatic adults aged 50–75 years [20,21]. Hawkins and Ward report that polyps with microsatellite instability can cause colorectal cancer and that methylation of human mut-L homologue 1 (hMLH1) promoter is a crucial step in the progression to cancer [22]. Kim et al. [23] found that k-ras mutations were found in 31.1% of the 45 polyps analysis in Korea and that methylation of hMLH1 occurred in 64.4% of polyps, which may become precancerous lesions of colorectal cancer. In a study on the influence of lifestyle factors of colorectal cancer, the odds ratio of colorectal cancers according to age, after adjusting for family history, BMI, smoking, and drinking, was 1.12 (95% CI: 1.02–1.22), and the prevalence of colorectal polyps also increased with age [24]. In this study, the group with colorectal polyps was significantly older than the group without colorectal polyps. After adjusting for smoking, eating habits, family history of colorectal cancer, obesity, job style, and night shift work, aging was a significant risk factor for colorectal polyps.
Smoking is also a risk factor for colorectal polyps [25,26,27]. In a previous meta-analysis, compared to non-smokers the risk of colorectal polyps in current smokers was higher [28]; and Kim et al. [29] showed that the risk of colorectal polyps was 2.12 (95% CI: 1.23–3.66) in ex-smokers and 2.22 (95% CI: 1.29–3.83) in current smokers compared to non-smokers after adjusting for age, calories, calcium level, alcohol, BMI, and physical activity. In current study adjusted PRs were 1.07 (95% CI: 0.96–1.18) in ever smokers compared to non-smokers, which was non-significant. In our study, the average age of the current smoker group was 47.0 years old, significantly lower than that of the past smokers and non-smokers 48.8 and 47.6 (p = 0.006). It is thought that the effect of smoking was reduced due to this difference in age among these groups which was shown above to increase risk of colorectal polyps.
A meta-analysis about obesity and colorectal cancer found that risk of colorectal cancer of overweight men (BMI: 25–29.9) was 1.26 (95% CI: 1.04–1.52) compared to the normal-weight men and risk of those that were extremely obese (BMI ≥ 30 kg/m2) was 1.71 (95% CI: 1.33–2.19) [30]. In a study of Koreans, the risk of colorectal cancer higher for the obese group compared to the normal group, showing obesity as a risk factor for colorectal cancer [31]. In addition, Kim et al. [32] found that the risk of colorectal polyps was higher for both men and women with abdominal obesity to their counterparts. The risk of colorectal polyps was for obese was higher compared to those in normal weight, suggesting that obesity is associated with an increased risk of colorectal polyps. In this study, the prevalence of colorectal polyps was slightly higher in those with abdominal obesity and obesity; however, this was non-significant, and the mean BMI of the group with and without polyps was the same. In both the obese and non-obese groups, the rate of usual exercise was 89.3% and 86.5%, respectively. It is possible that exercise had reduced the effect of obesity.
Wolin et al. [33] reviewed and meta-analyzed studies about physical activity and exercise in relation to the risk of colorectal polyps, and they found that the risk of colorectal polyps owing to physical activity in men was 0.81 (95% CI: 0.67–0.98); i.e., increased exercise led to a lower risk of colorectal polyps. In this study, the prevalence of colorectal polyps was lower in the group with a work environment that involved physical activity compared to those with sedentary tasks; however, this was non-significant. There is a possibility that the effect of night shift work may have reduced the protective effect of physical activity in workplace, as the proportion of night shift workers working on sedentary task is significantly lower than the proportion of non-night shift workers working on sedentary task.
Koushik et al. [34] analyzed 14 cohort studies and found that there was no significant correlation between vegetable-rich diet and risk of colorectal cancer nor between fruit-rich diet and risk of colorectal cancer. The meta-analysis by Johnson et al. [35] showed that the risk of colorectal cancer was higher in the group that consumed meat 5 times a week, lower when fruits were consumed more than three times a, and also lower when vegetables were eaten more than five times a day; thus, they identified the protective effects against colorectal cancer when fruits and vegetables were regularly consumed. In this study, eating habit was not a significant factor.
A family history of colorectal cancer is a risk factor colorectal cancer and colorectal polyps. In a prospective cohort study, the age-adjusted relative risk of colorectal cancer was higher for those with a family history than those without family history; and, for those aged younger than 45 years, the relative risk was much higher, suggesting that, especially with younger age, family history of colorectal cancer increases the risk of colorectal cancer [36]. In this study, family history was not a significant factor; this could be owing to the small sample size that had a family history of colorectal cancer.
Lastly, concerning whether night shift work is a risk factor for colorectal polyps, Papantoniou et al. [4] completed a 24-year follow-up cohort study from 1988 to 2012 and from 1989 to 2013. They found that the risk of colorectal cancer was the risk of colorectal cancer was 1.15 (95% CI: 0.95–1.39) and the risk of rectal cancer was 1.60 (95% CI: 1.09–2.34 in the group with more than 15 years of shift work experience compared to those without it. There was a meta-analysis conducted by Xiao et al. [37] that showed significant association between night shift work and increased risk of colorectal cancer. A case-control study in Spain found increased risk of colorectal cancer in ever performed rotating shift work group compared to day workers [38]. However, a study of Australian women workers showed that the risk of colorectal cancer in those that worked night shifts for over 7.5 years compared with those with no exposure to night shiftwork was 0.95 (95% CI: 0.57–1.58), indicating no significant relationship between shift work and colorectal cancer [39]. In our study, the prevalence of colorectal polyps in the group with and without night shift work was 53.0% and 33.5%, respectively. The risk of colorectal polyps after adjusting for age group, smoking, eating habits, family history of colorectal cancer, obesity, and job style was significantly higher for the group with night shift work. One study found those who sleep less than 6 hours per night had a increased risk of colorectal adenomas [40]. This is consistent with the results of the current study because short sleep time appeared in the night shift work group of our study (5.9 hours vs 6.6 hours, respectively). Patel et al. [41] found shorter duration of sleep was associated with increase in tumor necrosis factor alpha (TNF-α). and Kim et al. [42] found that increased plasma levels of TNF-α is associated with increased risk of colorectal adenoma. This increased risk of colorectal polyps in night shift workers could be explained by the decrease in melatonin due to night light exposure to night time workers and the mutations in circadian regulatory genes, PER2 related colonic polyp formation caused by circadian disruption [8]. and by increase of circulating inflammatory cytokine like TNF-α [42] due to shorter sleep duration [41].
Since this study employed a cross-sectional design, it has a limitation about causality which cannot be identified. In addition, although night shift work experience was identified, we failed to identify participants' total amount of night shift work and the type of night shift work. Moreover, small sample size of this study would be another limitation. Because of the small sample size, we investigated association between night shift work and colorectal cancer indirectly through colon polyps rather than directly through colon cancer. Our data is also lacking information about history of colorectal polyp removal, which is also a risk factor of development of subsequent colorectal cancer [43]. Furthermore, colon polyps differ in the probability of developing colorectal cancer according to the types of polyps such as adenomatous polyps and non-adenomatous polyps [44] and regarding previous studies that showed a link between night shifts and an increased risk of certain subsite colorectal cancers, our study has limitations in not examining the types of colorectal polyps and subsites. Also, there are known changes in genes are associated with the development of colorectal cancer, and the lack of investigation on these genes in our study will also be a limitation. However, our study has a strength that it is the first study on night shift work experience and colorectal polyps in Korea. In addition, the survey and the actual patients' colonoscopy results were linked throughout the study. Since the diagnostic test was conducted at the time of the study, the prevalence of colon polyps in study participants could be identified more accurately than by a simple survey. This is another strength of our research.
The risk of colorectal polyps was greater in night shift workers than non-shift workers. Risk of colorectal polyp was higher in older group. Considering the recent large-scale studies that show an increased risk of colorectal cancer in long-term shift workers, further studies which conducted in large-scale cohort design with detailed information about individual's night shift work and colon cancer's characteristics including types, subsites and gene mutations are essential to elucidate the relationship between night shift work and risk of colorectal polyps and risk of colorectal cancer.

Funding: This study was supported by Korea Medical Institute.

Competing interests: The authors declare that they have no competing interests.

Author Contributions:

  • Conceptualization: Jeong KS, Yoo C, Ahn Y, Kim M.

  • Data curation: Um K, Park C.

  • Investigation: Yoo C, Kim M.

  • Writing - original draft: Um K, Park C.

  • Writing - review & editing: Um K, Park C, Jeong K.

BMI

body mass index

CI

confidence interval

OR

odds ratio

PR

prevalence ratio

SD

standard deviation

TNF-α

tumor necrosis factor alpha
  • 1. Korea Central Cancer Registry, National Cancer Center. Annual report of cancer statistics in Korea in 2017. Sejong: Ministry of Health and Welfare; 2020.
  • 2. Ferlay J, Ervik M, Lam F, Colombet M, Mery L, Piñeros M, et al. Global cancer observatory: cancer today. 2018;https://gco.iarc.fr/today.
  • 3. Schernhammer ES, Laden F, Speizer FE, Willett WC, Hunter DJ, Kawachi I, et al. Night-shift work and risk of colorectal cancer in the nurses' health study. J Natl Cancer Inst 2003;95(11):825–828. 12783938.ArticlePubMed
  • 4. Papantoniou K, Devore EE, Massa J, Strohmaier S, Vetter C, Yang L, et al. Rotating night shift work and colorectal cancer risk in the nurses' health studies. Int J Cancer 2018;143(11):2709–2717. 29978466.ArticlePubMedPMCPDF
  • 5. Schernhammer ES, Schulmeister K. Melatonin and cancer risk: does light at night compromise physiologic cancer protection by lowering serum melatonin levels? Br J Cancer 2004;90(5):941–943. 14997186.ArticlePubMedPMCPDF
  • 6. Stevens RG. Circadian disruption and breast cancer: from melatonin to clock genes. Epidemiology 2005;16(2):254–258. 15703542.ArticlePubMed
  • 7. Fu L, Lee CC. The circadian clock: pacemaker and tumour suppressor. Nat Rev Cancer 2003;3(5):350–361. 12724733.ArticlePubMedPDF
  • 8. Wood PA, Yang X, Hrushesky WJ. Clock genes and cancer. Integr Cancer Ther 2009;8(4):303–308. 20042409.ArticlePubMedPDF
  • 9. Chen ST, Choo KB, Hou MF, Yeh KT, Kuo SJ, Chang JG. Deregulated expression of the PER1, PER2 and PER3 genes in breast cancers. Carcinogenesis 2005;26(7):1241–1246. 15790588.ArticlePubMed
  • 10. Kuo SJ, Chen ST, Yeh KT, Hou MF, Chang YS, Hsu NC, et al. Disturbance of circadian gene expression in breast cancer. Virchows Arch 2009;454(4):467–474. 19296127.ArticlePubMedPDF
  • 11. Korea Occupational Safety and Health. Working conditions survey report. Ulsan: Korea Occupational Safety and Health; 2017.
  • 12. Straif K, Baan R, Grosse Y, Secretan B, El Ghissassi F, Bouvard V, et al. Carcinogenicity of shift-work, painting, and fire-fighting. Lancet Oncol 2007;8(12):1065–1066. 19271347.ArticlePubMed
  • 13. Ward EM, Germolec D, Kogevinas M, McCormick D, Vermeulen R, Anisimov VN, et al. Carcinogenicity of night shift work. Lancet Oncol 2019;20(8):1058–1059. 31281097.PubMed
  • 14. Øines M, Helsingen LM, Bretthauer M, Emilsson L. Epidemiology and risk factors of colorectal polyps. Best Pract Res Clin Gastroenterol 2017;31(4):419–424. 28842051.ArticlePubMed
  • 15. Rabstein S, Harth V, Pesch B, Pallapies D, Lotz A, Justenhoven C, et al. Night work and breast cancer estrogen receptor status--results from the German GENICA study. Scand J Work Environ Health 2013;39(5):448–455. 23543199.ArticlePubMed
  • 16. Coutinho LM, Scazufca M, Menezes PR. Methods for estimating prevalence ratios in cross-sectional studies. Rev Saude Publica 2008;42(6):992–998. 19009156.PubMed
  • 17. Park HW, Byeon JS, Yang SK, Kim HS, Kim WH, Kim TI, et al. Colorectal neoplasm in asymptomatic average-risk Koreans: the KASID prospective multicenter colonoscopy survey. Gut Liver 2009;3(1):35–40. 20479899.ArticlePubMedPMC
  • 18. Yang MH, Rampal S, Sung J, Choi YH, Son HJ, Lee JH, et al. The prevalence of colorectal adenomas in asymptomatic Korean men and women. Cancer Epidemiol Biomarkers Prev 2014;23(3):499–507. 24443404.ArticlePubMedPDF
  • 19. Bibbins-Domingo K, Grossman DC, Curry SJ, Davidson KW, Epling JW Jr, García FA, et al. Screening for colorectal cancer: US preventive services task force recommendation statement. JAMA 2016;315(23):2564–2575. 27304597.ArticlePubMed
  • 20. Canadian Task Force on Preventive Health Care. Recommendations on screening for colorectal cancer in primary care. CMAJ 2016;188(5):340–348. 26903355.Article
  • 21. Sung JJ, Ng SC, Chan FK, Chiu HM, Kim HS, Matsuda T, et al. An updated Asia Pacific Consensus Recommendations on colorectal cancer screening. Gut 2015;64(1):121–132. 24647008.ArticlePubMed
  • 22. Hawkins NJ, Ward RL. Sporadic colorectal cancers with microsatellite instability and their possible origin in hyperplastic polyps and serrated adenomas. J Natl Cancer Inst 2001;93(17):1307–1313. 11535705.ArticlePubMed
  • 23. Kim KM, Lee EJ, Ha S, Kang SY, Jang KT, Park CK, et al. Molecular features of colorectal hyperplastic polyps and sessile serrated adenoma/polyps from Korea. Am J Surg Pathol 2011;35(9):1274–1286. 21836485.ArticlePubMed
  • 24. Hassan C, Pickhardt PJ, Marmo R, Choi JR. Impact of lifestyle factors on colorectal polyp detection in the screening setting. Dis Colon Rectum 2010;53(9):1328–1333. 20706078.ArticlePubMed
  • 25. Zahm SH, Cocco P, Blair A. Tobacco smoking as a risk factor for colon polyps. Am J Public Health 1991;81(7):846–849. 2053658.ArticlePubMedPMC
  • 26. Lee WC, Neugut AI, Garbowski GC, Forde KA, Treat MR, Waye JD, et al. Cigarettes, alcohol, coffee, and caffeine as risk factors for colorectal adenomatous polyps. Ann Epidemiol 1993;3(3):239–244. 8275195.ArticlePubMed
  • 27. Todoroki I, Kono S, Shinchi K, Honjo S, Sakurai Y, Wakabayashi K, et al. Relationship of cigarette smoking, alcohol use, and dietary habits with sigmoid colon adenomas. Ann Epidemiol 1995;5(6):478–483. 8680611.ArticlePubMed
  • 28. Botteri E, Iodice S, Raimondi S, Maisonneuve P, Lowenfels AB. Cigarette smoking and adenomatous polyps: a meta-analysis. Gastroenterology 2008;134(2):388–395. 18242207.ArticlePubMed
  • 29. Kim MC, Kim CS, Jeong TH, Kim YS. Prevalence and risk factors for adenomatous polyp in Koreans (a cross-sectional study). J Korean Acad Fam Med 2006;27(7):549–555.
  • 30. Dai Z, Xu YC, Niu L. Obesity and colorectal cancer risk: a meta-analysis of cohort studies. World J Gastroenterol 2007;13(31):4199–4206. 17696248.ArticlePubMedPMC
  • 31. Shin CM, Han K, Lee DH, Choi YJ, Kim N, Park YS, et al. Association among obesity, metabolic health, and the risk for colorectal cancer in the general population in Korea using the National Health Insurance Service-National Sample Cohort. Dis Colon Rectum 2017;60(11):1192–1200. 28991084.ArticlePubMed
  • 32. Kim Y, Kim Y, Lee S. An association between colonic adenoma and abdominal obesity: a cross-sectional study. BMC Gastroenterol 2009;9(1):4. 19144203.ArticlePubMedPMCPDF
  • 33. Wolin KY, Yan Y, Colditz GA. Physical activity and risk of colon adenoma: a meta-analysis. Br J Cancer 2011;104(5):882–885. 21304525.ArticlePubMedPMCPDF
  • 34. Koushik A, Hunter DJ, Spiegelman D, Beeson WL, van den Brandt PA, Buring JE, et al. Fruits, vegetables, and colon cancer risk in a pooled analysis of 14 cohort studies. J Natl Cancer Inst 2007;99(19):1471–1483. 17895473.ArticlePubMed
  • 35. Johnson CM, Wei C, Ensor JE, Smolenski DJ, Amos CI, Levin B, et al. Meta-analyses of colorectal cancer risk factors. Cancer Causes Control 2013;24(6):1207–1222. 23563998.ArticlePubMedPMCPDF
  • 36. Fuchs CS, Giovannucci EL, Colditz GA, Hunter DJ, Speizer FE, Willett WC. A prospective study of family history and the risk of colorectal cancer. N Engl J Med 1994;331(25):1669–1674. 7969357.ArticlePubMed
  • 37. Wang X, Ji A, Zhu Y, Liang Z, Wu J, Li S, et al. A meta-analysis including dose-response relationship between night shift work and the risk of colorectal. Oncotarget 2015;6(28):25046–25060. 26208480.ArticlePubMedPMC
  • 38. Papantoniou K, Castaño-Vinyals G, Espinosa A, Turner MC, Alonso-Aguado MH, Martin V, et al. Shift work and colorectal cancer risk in the MCC-Spain case-control study. Scand J Work Environ Health 2017;43(3):250–259. 28251241.ArticlePubMed
  • 39. Walasa WM, Carey RN, Si S, Fritschi L, Heyworth JS, Fernandez RC, et al. Association between shiftwork and the risk of colorectal cancer in females: a population-based case-control study. Occup Environ Med 2018;75(5):344–350. 29438001.ArticlePubMed
  • 40. Thompson CL, Larkin EK, Patel S, Berger NA, Redline S, Li L. Short duration of sleep increases risk of colorectal adenoma. Cancer 2011;117(4):841–847. 20936662.Article
  • 41. Patel SR, Zhu X, Storfer-Isser A, Mehra R, Jenny NS, Tracy R, et al. Sleep duration and biomarkers of inflammation. Sleep 2009;32(2):200–204. 19238807.ArticlePubMedPMC
  • 42. Kim S, Keku TO, Martin C, Galanko J, Woosley JT, Schroeder JC, et al. Circulating levels of inflammatory cytokines and risk of colorectal adenomas. Cancer Res 2008;68(1):323–328. 18172326.ArticlePubMedPMCPDF
  • 43. Cottet V, Jooste V, Fournel I, Bouvier AM, Faivre J, Bonithon-Kopp C. Long-term risk of colorectal cancer after adenoma removal: a population-based cohort study. Gut 2012;61(8):1180–1186. 22110052.ArticlePubMed
  • 44. Tanaka T. Colorectal carcinogenesis: Review of human and experimental animal studies. J Carcinog 2009;8(1):5. 19332896.ArticlePubMedPMC

Figure & Data

REFERENCES

    Citations

    Citations to this article as recorded by  
    • Spatial clustering of colorectal cancer in Malaysia
      Sharifah Saffinas Syed Soffian, Azmawati Mohammed Nawi, Rozita Hod, Khairul Nizam Abdul Maulud, Ahmad Tarmizi Mohd Azmi, Mohd Hazrin Hasim Hashim, Huan-Keat Chan, Muhammad Radzi Abu Hassan
      Geospatial Health.2023;[Epub]     CrossRef
    • Circadian regulation of digestive and metabolic tissues
      Zainab Taleb, Phillip Karpowicz
      American Journal of Physiology-Cell Physiology.2022; 323(2): C306.     CrossRef
    • Do sleep quality and psychological factors link precancerous conditions of colorectal cancer? A retrospective case-control study
      Wei Liu, Huijie Zhang
      Expert Review of Gastroenterology & Hepatology.2022; 16(2): 173.     CrossRef
    • Prevalence of Colorectal Polyps Based on Cardiorespiratory Fitness, Muscle Strength, Health Behavior, and Abdominal Obesity in Asymptomatic Elderly
      Shiyu Zhang, Junyong Zhang, Yonghwan Kim, Wangyang Zhang
      Healthcare.2021; 9(10): 1400.     CrossRef
    • The Circadian Clock Gene, Bmal1, Regulates Intestinal Stem Cell Signaling and Represses Tumor Initiation
      Kyle Stokes, Malika Nunes, Chantelle Trombley, Danilo E.F. L. Flôres, Gang Wu, Zainab Taleb, Abedalrhman Alkhateeb, Suhrid Banskota, Chris Harris, Oliver P. Love, Waliul I. Khan, Luis Rueda, John B. Hogenesch, Phillip Karpowicz
      Cellular and Molecular Gastroenterology and Hepatology.2021; 12(5): 1847.     CrossRef

    • PubReader PubReader
    • ePub LinkePub Link
    • Cite
      CITE
      export Copy Download
      Close
      Download Citation
      Download a citation file in RIS format that can be imported by all major citation management software, including EndNote, ProCite, RefWorks, and Reference Manager.

      Format:
      • RIS — For EndNote, ProCite, RefWorks, and most other reference management software
      • BibTeX — For JabRef, BibDesk, and other BibTeX-specific software
      Include:
      • Citation for the content below
      Risk factors including night shift work of colorectal polyp
      Ann Occup Environ Med. 2020;32:e26  Published online July 13, 2020
      Close
    • XML DownloadXML Download
    Risk factors including night shift work of colorectal polyp
    Risk factors including night shift work of colorectal polyp
    CharacteristicsNo night shift workNight shift workap-valueb
    Age group (years)< 0.001
    40–49171 (73.4)28 (42.4)
    50–6062 (26.6)38 (57.6)
    Current smoking status0.607
    Non-smoker49 (21.0)11 (16.7)
    Ex-smoker112 (48.1)36 (54.6)
    Current smoker72 (30.9)19 (28.8)
    Abdominal obesity0.225
    Normal192 (82.4)50 (75.8)
    Abdominal obesityc41 (17.6)16 (24.2)
    Obese0.714
    No140 (60.1)38 (57.6)
    Yesd93 (39.9)28 (42.4)
    Dietary habits< 0.001
    Mainly vegetarians181 (77.7)22 (33.3)
    Omnivores40 (17.2)39 (59.1)
    Mainly meat-eaters12 (5.1)5 (7.6)
    Family history of colorectal cancer0.112e
    No228 (97.9)62 (93.9)
    Yes5 (2.1)4 (6.1)
    Job type< 0.001
    Sedentary142 (61.0)18 (27.3)
    Non-sedentary91 (39.1)48 (72.3)
    Exercise0.014
    No23 (9.9)14 (21.2)
    Yes210 (90.1)52 (78.8)
    Average daily sleeping time (hours)6.6 ± 0.85.9 ± 1.1< 0.001f
    Result of colonoscopyNo. (%)
    Normal143 (47.8)
    Colorectal polyp113 (37.8)
    Colorectal cancer0 (0)
    Other43 (14.4)
    CharacteristicsPresence of colorectal polypsp-valuea
    NoYes
    Total186 (62.2)113 (37.8)-
    Age group (years)0.001
    40–49137 (68.8)62 (31.2)
    50–6049 (49.0)51 (51.0)
    Current smoking status0.219
    Non-smoker43 (71.7)17 (28.3)
    Ex-smoker87 (58.8)61 (41.2)
    Current smoker56 (61.5)35 (38.5)
    Abdominal obesity0.889
    Normal151 (62.4)91 (37.6)
    Abdominal obesityb35 (61.4)22 (38.6)
    Obese0.674
    No109 (61.2)69 (38.8)
    Yesc77 (63.6)44 (36.4)
    Dietary habits0.142
    Mainly vegetarians134 (66.0)69 (34.0)
    Omnivores43 (54.4)36 (45.6)
    Mainly meat-eaters9 (52.9)8 (47.1)
    Family history of colorectal cancer0.728
    No180 (62.1)110 (37.9)
    Yes6 (66.7)3 (33.3)
    Job type0.398
    Sedentary96 (60.0)64 (40.0)
    Non-sedentary90 (64.8)49 (35.2)
    Exercise0.473
    No26 (66.7)13 (33.3)
    Yes163 (61.5)102 (38.5)
    Night shift workd0.004
    No155 (66.5)78 (33.5)
    Yes31 (47.0)35 (53.0)
    VariablesCategoryCrude PR (95% CI)Adjusted PR (95% CI)a
    Age (years)40–491 (Reference)1 (Reference)
    50–601.15 (1.06–1.25)1.12 (1.02–1.22)
    Smoking historyNever smoker1 (Reference)1 (Reference)
    Ex- or current smoker1.09 (0.99–1.21)1.07 (0.96–1.18)
    Eating habitsMainly vegetarians1 (Reference)1 (Reference)
    Omnivores1.09 (0.99–1.19)1.00 (0.91–1.10)
    Mainly meat-eaters1.10 (0.93–1.30)1.05 (0.87–1.25)
    Family history of colorectal cancerNo1 (Reference)1 (Reference)
    Yes0.97 (0.76–1.22)0.92 (0.73–1.16)
    ObeseNo1 (Reference)1 (Reference)
    Yesb0.98 (0.91–1.07)0.98 (0.91–1.06)
    Job typeSedentary1 (Reference)1 (Reference)
    Non-sedentary0.97 (0.89–1.05)0.94 (0.87–1.02)
    Night shift workNo1 (Reference)1 (Reference)
    Yesc1.15 (1.05–1.26)1.13 (1.02–1.25)
    Table 1 Comparison of participants' general characteristics per night shift work

    Values are presented as number (%) or mean ± standard deviation.

    aNight shift work more than 4 times per month; bchi-square test; cwaist circumference ≥ 90 cm; dbody mass index (kg/m2) ≥ 25.0.; eFisher's exact test; ft-test.

    Table 2 Result of colonoscopy

    Table 3 Participants' characteristics according to prevalence of colorectal polyps

    achi-square test; bwaist circumference ≥ 90 cm; cbody mass index (kg/m2) ≥ 25.0; dnight shift work more than 4 times per month.

    Table 4 Prevalence ratios for the risk of colorectal polyps after adjusting for confounder variables

    PR: prevalence ratio, CI: confidence interval.

    aAdjusting for age, smoking history, eating habits, family history of colorectal cancer, obese, job style, night shift work; bbody mass index (kg/m2) ≥ 25.0; cnight shift work more than 4 times per month.


    Ann Occup Environ Med : Annals of Occupational and Environmental Medicine
    Close layer
    TOP