ABSTRACT
Background
Insomnia is a common clinical symptom that significantly impairs quality of life (QOL) and it frequently occurs in cancer patients. However, the risk of insomnia in Japanese cancer patients compared with cancer‐free patients has not yet been studied.
Aims
This study evaluated the association between cancer diagnosis and the risk of insomnia disorder in the Japanese health insurance claims database.
Methods
A population‐based matched cohort study was performed comparing cancer patients with cancer‐free patients. The primary outcome was the time to onset of insomnia disorder in cancer and cancer‐free patients. Multivariate analyses were performed to determine hazard ratio (HR) for all patients and for each cancer type.
Results
A total of 36,230 cancer patients and 362,300 cancer‐free patients were enrolled in this study. The median age was 53 years. Among cancer patients, the time to onset of insomnia disorder was significantly shorter than that of cancer‐free patients (stratified log‐rank testing; p < 0.001). In the multivariate analysis, the HR of cancer status (HR 3.39; 95% CI 3.28–3.49) was largest. In the subgroup analysis, the insomnia disorder risk was highest in patients with esophageal cancer, multiple cancers, gallbladder/biliary tract cancer, and bone and articular cartilage cancer.
Conclusions
This study shows that Japanese cancer patients have a higher risk of developing insomnia disorder compared with cancer‐free patients. The risk was especially high in cancer types which have a poor prognosis or impair the QOL of patients. These findings highlight the importance of assessing insomnia disorder frequently in cancer patients and providing interventions when it is needed.
Keywords: cancer, insomnia, nationwide claims database, oncology
1. Background
Sleep disorders are a group of conditions that disrupt normal sleep patterns [1]. Insomnia, a condition of unsatisfactory quantity or quality of sleep, is the most common sleep disorder that significantly impairs quality of life (QOL) [2].
Among cancer patients, questionnaire‐based assessments have revealed various sleep disorders such as restlessness in the legs and excessive daytime sleepiness. However, insomnia has consistently been identified as one of the most prevalent symptoms [3]. In a prospective questionnaire survey conducted in an Irish tertiary care center, 33% (98/294) of cancer patients developed insomnia symptoms after cancer diagnosis, among which only 34% (33/98) had a history of insomnia before their cancer diagnosis [4]. Similarly, the studies from China and the United States have reported insomnia symptoms prevalence rates of 35.6% [5] and 21% [6] respectively, consistently highlighting the high global prevalence of insomnia symptoms among cancer patients. Moreover, a meta‐analysis comparing cancer patients with healthy controls revealed a significantly higher proportion of cancer patients experiencing poor sleep quality, suggesting a greater burden of insomnia symptoms [7]. Previous studies have also examined whether the incidence of insomnia symptoms varies across cancer types. For example, a Canadian study suggested that patients with breast cancer had the highest risk of insomnia symptoms compared with other cancer types [3]. The pathophysiology of cancer‐related insomnia symptoms is considered multifactorial, involving psychological stress associated with diagnosis, cancer‐related pain, and adverse events related to treatment [8]. Despite growing evidence linking cancer and insomnia symptoms, it has been reported that only 50% of cancer patients with insomnia symptoms receive treatment interventions, indicating that insomnia symptoms remain under‐recognized by physicians and pose a significant challenge in clinical practice [9]. A study in China reported that insomnia symptoms were strongly correlated with satisfaction with QOL among cancer patients [10], suggesting the importance of early identification of insomnia symptoms and early intervention.
Although international studies have advanced our understanding of cancer‐related insomnia, evidence from Japan remains limited. A Japanese survey among breast cancer survivors reported a 37.5% prevalence of insomnia symptoms [11]. Another study found that 45% of Japanese cancer patients undergoing chemotherapy experienced insomnia symptoms [12]. However, these studies merely assessed prevalence and did not examine whether cancer itself increases the risk of developing insomnia compared with healthy individuals in Japan. Furthermore, whether the differences in insomnia risk across cancer types observed internationally also apply to Japanese patients, and what patient‐related factors contribute to insomnia onset among cancer patients remain unexplored due to insufficient sample sizes.
The present study aimed to evaluate the association between cancer diagnosis, defined by ICD‐10 diagnosis codes C00–C96, and the risk of insomnia disorder, defined by the ICD‐10 diagnosis code G47.0, in Japan using a nationwide claims database provided by JMDC Inc [13]. The primary objective was to determine whether Japanese cancer patients are at a higher risk of insomnia disorder compared with cancer‐free patients, consistent with findings from international studies. Secondary objectives included an assessment of the risk of insomnia disorder by cancer type and the identification of patient characteristics associated with insomnia disorder onset among cancer patients.
2. Methods
2.1. Data Source
This cohort study utilized the Japanese health insurance claims database developed by JMDC Inc [13]. In March 2024, the database included records of approximately 16 million working‐age individuals and their dependents, all of whom were under 75 years old and insured through corporate health insurance societies. Insured employees could enroll dependents, such as spouses and children with annual incomes of less than 1.3 million yen, under the same health insurance plan.
The JMDC database contains patient demographics, disease diagnoses classified by ICD‐10 code, prescriptions, medical procedures, and health checkup data, including information on body mass index (BMI), alcohol consumption, and other lifestyle habits. Patients and their dependents were followed longitudinally as long as they remained enrolled in the health insurance society.
Eligible participants for the present study were identified between January 2005 and March 2024, based on the eligibility criteria detailed below. All data were fully anonymized before use, with personally identifiable information (e.g., names and addresses) removed. Researchers had no access to personal identifiers, and data were managed and provided by a third‐party organization. The study was conducted in accordance with the Ethical Guidelines for Medical and Biological Research Involving Human Subjects established by the Ministry of Health, Labour and Welfare of Japan. Because only anonymized secondary data were used, ethical review and informed consent were deemed unnecessary.
2.2. Study Design, Study Population, and Exposure
We conducted a population‐based matched cohort study comparing cancer patients (exposed group) and those without it (unexposed group).
Exposure was defined as follows:
Study period: October 2017 to September 2022. An inclusion period was set to ensure a minimum follow‐up period of 180 days, unless patients were censored due to dropout or outcome occurrence.
Cancer diagnosis: Patients were identified as having cancer if they had two ICD‐10 diagnoses of C00–C96 recorded within three months.
The second cancer diagnosis month was defined as the index month (exposure onset), and the first cancer diagnosis month as the first diagnosis month.
For each cancer patient, we randomly selected 10 cancer‐free patients from a risk set that met the eligibility criteria at the time of the index month. Matching was performed on sex (male/female), age (same age), and working status (working/non‐working). Cancer‐free patients were assigned the same index month as their matched cancer patient, and follow‐up commenced from that date.
The 1:10 matching ratio was determined based on the number of cancer patients (~30,000) and the availability of appropriately matched controls, consistent with the ratio used in a prior cohort study evaluating the risk of major depressive disorder among cancer patients [14].
The eligibility criteria were as follows:
Age ≥ 18 years.
Availability of at least 12 months of continuous data before the index month in the JMDC database.
The exclusion criteria were as follows:
Insomnia disorder (G47.0), narcolepsy, or cataplexy (G47.4) diagnoses within the 12 months preceding the index month.
For cancer patients: any diagnosis of C00–C96 before the first diagnosis month.
For cancer‐free patients: any diagnosis of C00–C96 before the index month.
2.3. Study Outcomes and Follow‐Up
The primary outcome was the time to onset of insomnia disorder in cancer and cancer‐free patients. Insomnia disorder was defined as the first recorded diagnosis of ICD‐10 code G47.0 after the index month. The observation period began at the index month and continued until the insomnia diagnosis. Patients were censored at the end of their observation period if the outcome did not occur.
Baseline variables collected from the JMDC database included site of cancer occurrence (classified as “multiple categories” if multiple cancer sites were diagnosed at baseline), sex, age, insurance membership category: working status. From the most recent health checkup data before the index date, we extracted information on BMI, smoking status, alcohol consumption, sleep quality, and physical activity. The definitions of cancer site classifications are provided in Table S1.
2.4. Statistical Analysis
The cumulative incidence of insomnia disorder was estimated using the Kaplan–Meier method. Comparisons of the survival functions between cancer and cancer‐free patients were performed using stratified log‐rank tests stratified by matching variables (age, sex, and working status) with a two‐sided significance level of 5%.
To estimate hazard ratios (HR) for insomnia disorder onset in cancer versus cancer‐free patients, we used the stratified Cox proportional hazards models stratified by matching variables. Both univariate and multivariate analyses were conducted. Covariates in the multivariate model included cancer status (yes/no), smoking status (yes/no), alcohol consumption (yes/no), sleep quality (high/low), physical activity (yes/no), and obesity (BMI ≥ 25 vs.< 25). Exploratory subgroup analyses were also performed by cancer type using the same multivariate stratified Cox models.
To estimate HRs for insomnia disorder onset associated with background factors in cancer patients, Cox proportional hazards models were also applied. Covariates included age, sex, working status, smoking status, alcohol consumption, sleep quality, physical activity, and obesity.
Because certain covariates from the health checkup data (i.e., smoking, alcohol consumption, sleep quality, physical activity, and obesity) contained missing values, with missingness of approximately 20%–30% across variables, we performed multiple imputations using the mice package in R. Five imputed datasets were generated under the assumption of missing at random. These estimates and their standard errors were combined using Rubin's rules. All statistical analyses were conducted using R (version 4.3.0).
3. Results
3.1. Demographic and Baseline Clinical Characteristics
During the study period (October 2017 to September 2022), a total of 36,230 patients were newly diagnosed with cancer with no recent history of insomnia disorder (Figure S1). For each patient with cancer, 10 matched cancer‐free patients were selected, resulting in 362,300 cancer‐ free controls.
The baseline patient characteristics are summarized in Table 1. The median age was 53 years, with 72.4% aged 40–64 years. Males accounted for 46.6% of the cohort, indicating a slightly lower proportion compared with females. 70% of patients were working.
TABLE 1.
Demographic and baseline clinical characteristics of study participants.
| Characteristic | Cancer patients (n = 36,230) | Cancer‐free patients (n = 362,300) |
|---|---|---|
| Male sex, n (%) | 16,877 (46.6%) | 168,770 (46.6%) |
| Female sex, n (%) | 19,353 (53.4%) | 193,530 (53.4%) |
| Age, median (IQR), years | 53 (45–60) | 53 (45–60) |
| 18–39 years, n (%) | 4719 (13.0%) | 47,190 (13.0%) |
| 40–64 years, n (%) | 26,239 (72.4%) | 262,390 (72.4%) |
| 65–74 years, n (%) | 5272 (14.6%) | 52,720 (14.6%) |
| Working, n (%) | 25,368 (70.0%) | 253,680 (70.0%) |
| BMI, median (IQR) | 22.7 (20.5–25.3) | 22.7 (20.5–25.2) |
| Non‐obese (BMI: < 25.0), n (%) | 56.01% | 58.15% |
| Obese (BMI: ≥ 25.0), n (%) | 21.61% | 21.66% |
| BMI: Missing, n (%) | 22.38% | 20.18% |
| Smoking: | ||
| Yes, n (%) | 20.22% | 17.25% |
| No, n (%) | 55.67% | 60.67% |
| Missing, n (%) | 24.11% | 22.08% |
| Alcohol: | ||
| Daily, n (%) | 20.74% | 19.07% |
| Sometimes, n (%) | 22.99% | 24.16% |
| Rarely, n (%) | 28.10% | 30.85% |
| Missing, n (%) | 28.17% | 25.92% |
| Physical activity: | ||
| ≥ 30 min | 16.08% | 17.55% |
| None | 54.73% | 55.51% |
| Missing | 29.19% | 26.94% |
| Restful sleep: | ||
| Yes | 45.66% | 46.79% |
| No | 25.15% | 26.19% |
| Missing | 29.19% | 27.02% |
In both the cancer and cancer‐free groups, more than half of the patients were classified as non‐obese (56.01% and 58.15%, respectively). Questionnaire‐based measures also revealed similar patterns in both groups: more than half of patients were non‐smokers (55.67% vs. 60.67%), more than half reported low alcohol consumption frequency (51.09% vs. 55.01%), and more than half lacked regular physical activity (54.73% vs. 55.51%). Approximately 25% of both groups reported poor restorative sleep (25.15% vs. 26.19%).
3.2. Time to Insomnia Disorder Onset
The cumulative incidence of insomnia disorder in the cancer and cancer‐free groups is shown in Figure 1. Stratified log‐rank testing demonstrated a significantly higher incidence of insomnia disorder events in cancer patients compared with the cancer‐free controls (p < 0.01).
FIGURE 1.
Kaplan–Meier curves for cumulative incidence of insomnia in cancer and cancer‐free patients.
The results of univariate and multivariate Cox proportional hazards analyses, using cancer status, smoking, alcohol consumption, sleep quality, physical activity, and obesity as covariates, are presented in Table 2. In the multivariate model, significant risk factors for insomnia disorder onset included cancer status, smoking, alcohol consumption, poor sleep quality, and lack of physical activity. Notably, cancer status exhibited the largest HR (3.39; 95% CI 3.28–3.49; p < 0.001), exceeding that of other factors.
TABLE 2.
Univariate and multivariate cox regression analyses of risk factors for insomnia onset in cancer vs. cancer‐free patients.
| Variable | Univariate HR (95% CI) | P * | Multivariate HR (95% CI) | P * |
|---|---|---|---|---|
| Cancer (yes vs. no) | 3.39 (3.28–3.50) | < 0.01 | 3.39 (3.28–3.49) | < 0.01 |
| Smoking (yes vs. no) | 1.13 (1.09–1.18) | < 0.01 | 1.09 (1.05–1.14) | < 0.01 |
| Alcohol (yes vs. no) | 1.06 (1.03–1.1) | < 0.01 | 1.05 (1.01–1.09) | 0.025 |
| Low sleep quality (yes vs. no) | 1.41 (1.37–1.45) | < 0.01 | 1.42 (1.38–1.46) | < 0.01 |
| Lack of physical activity (yes vs. no) | 1.00 (0.96–1.03) | 0.932 | 0.95 (0.92–0.98) | < 0.01 |
| Obesity (BMI ≥ 25) (yes vs. no) | 1.01 (0.98–1.05) | 0.573 | 1.00 (0.96–1.04) | 0.997 |
Statistically significant at p < 0.05.
The multivariate stratified Cox proportional hazards analyses by cancer type in cancer patients are presented in Figure 2. Compared with cancer‐free patients, almost all cancer types demonstrated increased risk of insomnia disorder. Cancer types with the highest HRs included esophageal cancer (HR 6.82; 95% CI 6.34–7.32), multiple cancers (HR 6.31; 95% CI 6.16–6.47), gallbladder/biliary tract cancer (HR 6.23; 95% CI 5.54–7.01), and bone and articular cartilage cancer (HR 5.54; 95% CI 4.59–6.69).
FIGURE 2.
Hazard ratios for insomnia onset among patients by cancer type. HR, hazard ratio.
The results of univariate and multivariate analyses for patient background factors in cancer patients are presented in Table 3. In the multivariate model, significant risk factors for insomnia disorder onset included sex, age, smoking status, alcohol consumption, and sleep quality.
TABLE 3.
Univariate and multivariate cox regression analyses of factors associated with insomnia onset among cancer patients.
| Variable | Univariate HR (95% CI) | P * | Multivariate HR (95% CI) | P * |
|---|---|---|---|---|
| Male (vs. female) | 0.90 (0.85–0.95) | < 0.01 | 0.86 (0.8–0.93) | < 0.01 |
| Working (vs. non‐working) | 0.89 (0.84–0.94) | < 0.01 | 0.93 (0.87–1.01) | 0.085 |
| Age 40–64 years (vs. < 40) | 1.13 (1.04–1.22) | < 0.01 | 1.10 (0.99–1.22) | 0.091 |
| Age ≥ 65 years (vs. < 40) | 1.35 (1.22–1.51) | < 0.01 | 1.36 (1.18–1.56) | < 0.01 |
| Smoking (yes vs. no) | 1.23 (1.14–1.33) | < 0.01 | 1.26 (1.15–1.39) | < 0.01 |
| Alcohol (yes vs. no) | 1.09 (1.02–1.17) | < 0.01 | 1.09 (1.01–1.17) | 0.028 |
| Low sleep quality (yes vs. no) | 1.21 (1.12–1.30) | < 0.01 | 1.22 (1.12–1.32) | < 0.01 |
| Lack of physical activity (yes vs. no) | 1.01 (0.94–1.10) | 0.714 | 0.99 (0.92–1.07) | 0.820 |
| Obesity (BMI ≥ 25) (yes vs. no) | 0.97 (0.91–1.04) | 0.452 | 0.99 (0.92–1.06) | 0.768 |
Statistically significant at p < 0.05.
4. Discussion
This study represents the first large‐scale matched cohort study to demonstrate that cancer patients have a significantly higher risk of developing insomnia disorder compared with cancer‐free patients in Japan. To our knowledge, this is the first large‐scale Japanese cohort study to estimate the risk for insomnia disorder in cancer patients compared with matched cancer‐free patients, while adjusting for relevant covariates.
The large sample size allowed us to conduct subgroup analyses by cancer type, including types for which insomnia risk had not been previously studied, and to evaluate the impact of patient characteristics (e.g., sex, smoking status, alcohol consumption) on insomnia disorder onset among cancer patients. These findings highlight the elevated risk of insomnia disorder in almost all type of cancer patients and underscore the need for physicians to carefully inquire about sleep disturbances in this clinical population.
Previous studies have shown that cancer patients experiencing poor sleep quality compared with the healthy population, suggesting a greater burden of insomnia symptoms [7]. Consistent with these findings, our analysis demonstrated that cancer patients had a significantly higher cumulative incidence of insomnia disorder than cancer‐free patients matched for age, sex, and working status. The HR for insomnia disorder onset was 3.39 (95% CI 3.28–3.50; p < 0.001) in univariate analyses and remained high at 3.39 (95% CI 3.28–3.49; p < 0.001) in multivariate analyses, suggesting a strong association between cancer and insomnia disorder independent of lifestyle factors, such as smoking, alcohol consumption, sleep quality, and physical activity.
In the cancer type–specific analyses, the highest HRs for insomnia disorder were observed in esophageal cancer (HR 6.82; 95% CI 6.34–7.32), multiple cancers (HR 6.31; 95% CI 6.16–6.47), gallbladder/biliary tract cancer (HR 6.23; 95% CI 5.54–7.01), and bone and articular cartilage cancer (HR 5.54; 95% CI 4.59–6.69). Previous studies have reported breast cancer as the cancer type most strongly associated with insomnia symptoms [3]; however, those analyses grouped cancer into six broad categories. In contrast, our study classified over 30 cancer types, providing more detailed risk estimates, which may explain the discrepancy in findings. Cancer types with higher HRs in our study are known to be associated with poor prognosis or substantial impairment of QOL. For example, esophageal cancer frequently causes dysphagia and swallowing difficulties, which severely impair QOL [15]. Bone and articular cartilage cancers often cause severe pain, contributing to poor QOL [16]. Patients with multiple cancers generally have poorer prognoses compared with those with single cancers [17, 18]. Gallbladder/biliary tract cancer has a 5‐year survival rate of only 5%–15%, indicating poor prognosis and significant psychological burden [19, 20]. Collectively, these findings suggest that both physical suffering (e.g., pain and impaired function) and psychological distress associated with poor prognosis may contribute to the heightened risk of insomnia disorder in these cancer types. It should be noted, however, that for some rare cancers, the small number of cases precluded precise estimation of HRs.
Factors identified as being associated with insomnia disorder onset in cancer patients included sex, age, smoking, alcohol consumption, and poor sleep quality. These are consistent with previously reported risk factors for insomnia in the general population [21, 22, 23, 24, 25], indicating that the same factors remain relevant among cancer patients.
A major strength of this study is the use of a large nationwide health insurance database, enabling robust follow‐up across different medical institutions. The large sample size allowed for detailed analyses by cancer type and for multivariable adjustments. Furthermore, using a high matching ratio (1:10) of cancer‐free controls to cancer patients, potential bias was minimized.
4.1. Study Limitations
This study has some limitations. First, detailed clinical information, such as cancer stage at diagnosis, laboratory values, performance status, and overall survival, was not available in the database. Second, the JMDC database mainly includes employees of medium‐to‐large companies and their dependents, who are generally younger and have a higher socioeconomic status than the general Japanese population. Therefore, our findings have limited generalizability to the entire Japanese population. As older individuals and those with lower socioeconomic status typically have a higher risk of insomnia [22, 26], our findings should be interpreted with caution when generalizing to the entire population. Third, insomnia disorder was defined based on ICD‐10 diagnostic codes, which means that only patients recognized and documented as having insomnia disorder by a physician were identified. Epidemiological studies have shown that the prevalence of insomnia symptoms is substantially higher than clinically diagnosed insomnia disorder [27]. Previous studies have suggested that approximately only 50% of cancer patients with insomnia symptoms receive treatment [9]. Therefore, the actual prevalence and risk of insomnia may have been underestimated in this study. In addition, because the covariates in this study were limited to those available from the health checkup data, we were unable to capture important risk factors for insomnia disorders, such as psychiatric comorbidities (e.g., depression and anxiety), chronic pain, and other sleep disorders. The inability to adjust for these variables was a limitation of our multivariate analysis. Finally, because follow‐up began at the point of cancer diagnosis to avoid immortal time bias, insomnia diagnoses occurring immediately before could not be captured. As insomnia may arise or worsen shortly before a cancer diagnosis [3], this limitation should be considered when interpreting our findings.
4.2. Clinical Implications
This study demonstrated that cancer patients in Japan are at increased risk of developing insomnia disorder compared with cancer‐free individuals. Insomnia is known to reduce QOL [2], yet approximately half of cancer patients with insomnia symptoms reportedly do not receive appropriate therapeutic interventions [9]. Healthcare providers should be aware that insomnia symptoms are particularly common among cancer patients associated with poor prognosis or substantial physical suffering, such as esophageal, gallbladder/biliary tract, or bone cancers, as well as multiple cancers. Physicians should actively inquire about sleep problems in cancer patients and provide appropriate interventions when necessary to alleviate symptoms and improve QOL. As first‐line symptom management, cognitive‐behavioral therapy for insomnia (CBT‐I) is recommended for cancer patients [28].
5. Conclusion
This study shows that Japanese cancer patients have a higher risk of developing insomnia disorder compared with cancer‐free patients. The risk was especially high in cancer types which have a poor prognosis or impair the QOL of patients. These findings highlight the importance of assessing insomnia symptoms frequently in cancer patients and providing interventions when it is needed.
Author Contributions
Risa Murakami: writing – original draft, conceptualization, data curation, formal analysis, investigation. Hiroyuki Sato: writing – review and editing, supervision. Akihiro Hirakawa: supervision, writing – review and editing.
Ethics Statement
The study was conducted in accordance with the Ethical Guidelines for Medical and Biological Research Involving Human Subjects established by the Ministry of Health, Labour and Welfare of Japan. Because only anonymized secondary data were used, ethical review and informed consent were deemed unnecessary.
Conflicts of Interest
R.M. is an employee of Novartis Pharma K.K. This work was carried out without any involvement of Novartis products, services, or business activities.
Supporting information
Figure S1: Flowchart of participant selection.
Table S1: Definitions of cancer site classifications.
Acknowledgements
We would like to thank Editage (www.editage.com) for English language editing. All authors were investigators in the study and participated in the study design, interpretation of the study results, and in the drafting, critical revision, and approval of the final version of the manuscript. No funding was received for conducting this study.
Data Availability Statement
The data are available for purchase from JMDC Inc. Restrictions apply to the availability of the data used in this study because of contractual agreements between JMDC Inc. and the health insurance associations. For inquiries regarding the accessibility of the dataset, please contact JMDC Inc. (https://www.jmdc.co.jp/en/).
References
- 1. Karna B., Sankari A., and Tatikonda G., “Sleep Disorder,” in StatPearls [Internet] (StatPearls Publishing, 2023). [PubMed] [Google Scholar]
- 2. Mai E. and Buysse D. J., “Insomnia: Prevalence, Impact, Pathogenesis, Differential Diagnosis, and Evaluation,” Sleep Medicine Clinics 3, no. 2 (2008): 167–174. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 3. Davidson J. R., AW M. L., Brundage M. D., and Schulze K., “Sleep Disturbance in Cancer Patients,” Social Science & Medicine 54, no. 9 (2002): 1309–1321. [DOI] [PubMed] [Google Scholar]
- 4. Harrold E. C., Idris A. F., Keegan N. M., et al., “Prevalence of Insomnia in an Oncology Patient Population: An Irish Tertiary Referral Center Experience,” Journal of the National Comprehensive Cancer Network 18, no. 12 (2020): 1623–1630. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 5. Zhao K., Yu Z., Wang Y., and Feng W., “Prevalence of Insomnia and Related Factors Among Cancer Outpatients in China,” Nature and Science of Sleep 17 (2025): 69–79. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 6. Page J. M., Morgans A. K., Hassett M. J., et al., “Insomnia Prevalence and Correlates in Cancer Patients Undergoing Treatment,” Psycho‐Oncology 34, no. 1 (2025): e70079. [DOI] [PubMed] [Google Scholar]
- 7. Chen M. Y., Zheng W. Y., Liu Y. F., et al., “Global Prevalence of Poor Sleep Quality in Cancer Patients: A Systematic Review and Meta‐Analysis,” General Hospital Psychiatry 87 (2024): 92–102. [DOI] [PubMed] [Google Scholar]
- 8. Saeki Y., Sumi Y., Ozaki Y., et al., “Proposal for Managing Cancer‐Related Insomnia: A Systematic Literature Review of Associated Factors and a Narrative Review of Treatment,” Cancer Medicine 13, no. 22 (2024): e70365. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 9. Siefert M. L., Hong F., Valcarce B., and Berry D. L., “Patient and Clinician Communication of Self‐Reported Insomnia During Ambulatory Cancer Care Clinic Visits,” Cancer Nursing 37, no. 2 (2014): E51–E59. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 10. Li Z., Song L., Leng J., et al., “Relationships Between Insomnia and Quality of Life in Patients With Advanced Liver Cancer: A Secondary Analysis of a Multicenter Cross‐Sectional Study,” Psycho‐Oncology 34, no. 5 (2025): e70157. [DOI] [PubMed] [Google Scholar]
- 11. Ueno T., Ichikawa D., Shimizu Y., et al., “Comorbid Insomnia Among Breast Cancer Survivors and Its Prediction Using Machine Learning: A Nationwide Study in Japan,” Japanese Journal of Clinical Oncology 52, no. 1 (2022): 39–46. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 12. Akui C., Kimura T., and Hirose M., “Associations Between Insomnia and Central Sensitization in Cancer Survivors Undergoing Opioid Therapy for Chronic Cancer Pain: A STROBE‐Compliant Prospective Cohort Study,” Medicine (Baltimore) 101, no. 38 (2022): e30845. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 13. Nagai K., Tanaka T., Kodaira N., Kimura S., Takahashi Y., and Nakayama T., “Data Resource Profile: JMDC Claims Database Sourced From Health Insurance Societies,” Journal of General and Family Medicine 22, no. 3 (2021): 118–127. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 14. Akechi T., Mishiro I., Fujimoto S., and Murase K., “Risk of Major Depressive Disorder in Japanese Cancer Patients: A Matched Cohort Study Using Employer‐Based Health Insurance Claims Data,” Psycho‐Oncology 29, no. 10 (2020): 1686–1694. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 15. Wang Y., Xie Z., Liu Y., Wang J., Liu Z., and Li S., “Symptom Clusters and Impact on Quality of Life in Esophageal Cancer Patients,” Health and Quality of Life Outcomes 20, no. 1 (2022): 168. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 16. Kruiswijk A. A., Dorleijn D. M. J., Marang‐van de Mheen P. J., van de Sande M. A. J., and van Bodegom‐Vos L., “Health‐Related Quality of Life of Bone and Soft‐Tissue Tumor Patients Around the Time of Diagnosis,” Cancers (Basel) 15, no. 10 (2023): 2804. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 17. Sert F., Caner A., and Haydaroglu A., “Trends in the Incidence and Overall Survival of Multiple Primary Cancers in Turkey,” Journal of B.U.ON 25, no. 2 (2020): 1230–1236. [PubMed] [Google Scholar]
- 18. Sanli A. N., Sanli D. E. T., Altundag M. K., and Aydogan F., “Prognostic Factors Affecting Survival of Patients With Single Primary Breast Cancer vs Patients With Multiple Primary Cancers in Lifetime, One of Which Is Breast Cancer,” American Surgeon 90, no. 11 (2024): 2745–2755. [DOI] [PubMed] [Google Scholar]
- 19. Miao W., Liu F., Guo Y., Zhang R., Wang Y., and Xu J., “Research Progress on Prognostic Factors of Gallbladder Carcinoma,” Journal of Cancer Research and Clinical Oncology 150, no. 10 (2024): 447. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 20. Çila İ., Oyman A., Işik S., et al., “Prognostic Factors in Resected Biliary Tract Cancers and the Impact of Cytokeratin 20 Expression,” Journal of Oncology Science 7, no. 3 (2021): 125–132. [Google Scholar]
- 21. Zeng L. N., Zong Q. Q., Yang Y., et al., “Gender Difference in the Prevalence of Insomnia: A Meta‐Analysis of Observational Studies,” Frontiers in Psychiatry 11 (2020): 577429. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 22. Brewster G. S., Riegel B., and Gehrman P. R., “Insomnia in the Older Adult,” Sleep Medicine Clinics 17, no. 2 (2022): 233–239. [DOI] [PubMed] [Google Scholar]
- 23. Nuñez A., Rhee J. U., Haynes P., et al., “Smoke at Night and Sleep Worse? The Associations Between Cigarette Smoking With Insomnia Severity and Sleep Duration,” Sleep Health 7, no. 2 (2021): 177–182. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 24. Hu N., Ma Y., He J., Zhu L., and Cao S., “Alcohol Consumption and Incidence of Sleep Disorder: A Systematic Review and Meta‐Analysis of Cohort Studies,” Drug and Alcohol Dependence 217 (2020): 108259. [DOI] [PubMed] [Google Scholar]
- 25. Chen V. Q., “The Comorbidity of Anxiety‐Related Disorders and Insomnia: An Analysis of Mechanisms,” Theoretical and Natural Science 29 (2024): 164–169. [Google Scholar]
- 26. Lallukka T., Sares‐Jäske L., Kronholm E., et al., “Sociodemographic and Socioeconomic Differences in Sleep Duration and Insomnia‐Related Symptoms in Finnish Adults,” BMC Public Health 12 (2012): 565. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 27. Chung K. F., Yeung W. F., Ho F. Y. Y., Yung K. P., Yu Y. M., and Kwok C. W., “Cross‐Cultural and Comparative Epidemiology of Insomnia: The Diagnostic and Statistical Manual (DSM), international Classification of Diseases (ICD) and International Classification of Sleep Disorders (ICSD),” Sleep Medicine 16, no. 4 (2015): 477–482. [DOI] [PubMed] [Google Scholar]
- 28. Grassi L., Zachariae R., Caruso R., et al., “Insomnia in Adult Patients With Cancer: ESMO Clinical Practice Guideline,” ESMO Open 8, no. 6 (2023): 102047. [DOI] [PMC free article] [PubMed] [Google Scholar]
Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Supplementary Materials
Figure S1: Flowchart of participant selection.
Table S1: Definitions of cancer site classifications.
Data Availability Statement
The data are available for purchase from JMDC Inc. Restrictions apply to the availability of the data used in this study because of contractual agreements between JMDC Inc. and the health insurance associations. For inquiries regarding the accessibility of the dataset, please contact JMDC Inc. (https://www.jmdc.co.jp/en/).