Nationwide Population-based Cohort Study Research Articles

Obstetric anal sphincter injury in the second birth after perineal wound complication in the first birth: A nationwide register cohort study.

To investigate whether perineal wound complications in the first birth, alone or in conjunction with obstetric anal sphincter injury (OASI), is associated with an increased risk of OASI in the second birth. Nationwide population-based cohort study. Sweden. Women (n = 411 317) with first and second singleton vaginal births in Sweden, 2001-2019. Data on diagnostic codes and surgical procedures were retrieved from the Swedish Medical Birth Register and the Swedish Patient Register. A perineal wound complication was defined as wound infection, dehiscence or perineal haematoma within 2 months of childbirth. Associations between wound complications in the first birth and OASI in the second birth were investigated with logistic regression and presented as adjusted odds ratios (aORs) with 95% confidence intervals (95% CIs). In total, 2619 (0.6%) women had a wound complication in the first birth, and 5318 (1.3%) had an OASI in the second birth. Women with a wound complication but no OASI in the first birth had more than doubled odds of OASI in the second birth (aOR 2.73, 95% CI 2.11-3.53). Women with OASI and a wound complication in the first birth had almost tenfold odds (aOR 9.97, 95% CI 6.53-15.24) of recurrent OASI. Perineal wound complication in the first birth increases the likelihood of OASI in a subsequent birth.

50835 Air Quality Index (AQI) and atopic dermatitis risk in Taiwan: A nationwide population-based cohort study

50835 Air Quality Index (AQI) and atopic dermatitis risk in Taiwan: A nationwide population-based cohort study

Earnings and work loss after colon and rectal cancer: a Swedish nationwide matched cohort study

Colorectal cancer is common and prognosis is improving. The conditions of survivors of treatment, including financial consequences, are thus important. The aim of this study was to quantify loss of earnings and work loss in working-age patients with colon and rectal cancer relative to matched comparators. The study utilised data from the CRCBaSe database that is generated from the nationwide Swedish ColoRectal Cancer Register and includes data from several Swedish nationwide registers. The study period was 1995-2020 for rectal cancer patients and 2007-2020 for colon cancer patients. A retrospective population-based nationwide cohort study on earnings, disposable income, and work loss, in survivors of stage I-III colorectal cancer treatment was undertaken. Median regression was used to analyse earnings and disposable income, and logistic regression to analyse the probability of work loss. A cohort of 8863 colorectal cancer survivors diagnosed before 2017 and 52,514 comparators matched on birth year, legal sex, and county of residence, was analysed. There was a clear reduction in earnings between the calendar year prior to and the calendar year after diagnosis, from € 31,319 to € 23,924 for colon cancer patients and from € 32,636 to € 22,647 for rectal cancer patients, and earnings never fully recovered during the 5-year follow-up. Disposable income was practically unaltered. The probability of work loss increased in the calendar year of diagnosis, from 29.8% to 25.3% the previous year to 83.3% and 84.4% for colon and rectal cancer patients respectively, and never fully recovered. The probability of work loss was similar between colon and rectal cancer survivors, but was higher among patients with rectal cancer who had received neoadjuvant therapy. This study shows that despite an extensive welfare system providing maintained disposable income, there is a financial burden in the form of increased risk of work loss and a reduction in earnings among survivors of colorectal cancer. The study was supported by the Swedish Cancer Society, the Swedish Cancer and Allergy Foundation, and the Stockholm Cancer Society, and supported by grants provided by the Regional Agreement on Medical Training and Clinical Research (ALF) between the Stockholm County Council and Karolinska Institutet.

Epidemiology of Elderly-Onset IBD: A Nationwide Population-based Cohort Study

We examined the incidence and natural history of patients with very elderly-onset (herein, referred to as very late-onset) inflammatory bowel diseases (IBD) (age ≥70y at diagnosis), compared with patients diagnosed between ages 60-69y in Denmark. In the Danish National Patient Register, between 1980-2018, we identified all individuals ≥60y with newly diagnosed Crohn's disease (CD) and ulcerative colitis (UC) and examined trends in incidence, cumulative risk of hospitalization, treatment patterns, IBD-related surgery, serious infection, cancer and cardiovascular and venous thromboembolic risks among very late-onset (70-79y or 80+ years) vs. late-onset (60-69y) IBD, using non-parametric competing risk analysis treating death as competing risk. We identified 3,459 patients with onset of CD at age ≥60y (47% ≥70y) and 10,774 patients with onset of UC aged ≥60y (51% ≥70y). Over the last three decades, incidence changes for very late-onset and late-onset IBD have followed the same patterns. Also, both for CD and UC, cumulative incidence of IBD-related hospitalization and corticosteroid use was comparable in very late-onset vs. late-onset patients. However, the burden of disease-modifying therapy, either immunomodulator or TNF antagonist use, and major IBD-related surgery was significantly lower in patients with very late-onset than in late-onset IBD. On the other hand, 5-year risk of serious infections and cardiovascular events was higher in patients with very late-onset IBD. This nationwide cohort study shows that patients diagnosed with very late-onset (≥70y) IBD have a higher relative burden of disease- and aging-related complications, with limited use of steroid-sparing strategies and surgery, compared with late-onset IBD.

Association of Uterine Leiomyoma with Type 2 Diabetes Mellitus in Young Women: A Population-Based Cohort Study.

We investigated the association between uterine leiomyoma (UL) and incident type 2 diabetes mellitus (T2DM) in young women. A nationwide population-based cohort study of 2,541,550 women aged between 20 and 40 years was performed using the National Health Information Database. Cox proportional hazards models were used to analyze the risk of incident T2DM according to the presence of UL and myomectomy. The mean age was 29.70 years, and mean body mass index was 21.31 kg/m2. Among 2,541,550 participants, 18,375 (0.72%) women had UL. During a median 7.45 years of follow-up, 23,829 women (0.94%) were diagnosed with T2DM. The incidence of T2DM in women with UL (1.805/1,000 person-years) was higher than in those without UL (1.289/1,000 person-years). Compared with women without UL, women with UL had a higher risk of incident T2DM (hazard ratio, 1.216; 95% confidence interval [CI], 1.071 to 1.382). Women with UL who did not undergo myomectomy had a 1.505 times (95% CI, 1.297 to 1.748) higher risk for incident T2DM than women without UL. However, women with UL who underwent myomectomy did not have increased risk for incident T2DM. Young women with UL were associated with a high risk of incident T2DM. In addition, myomectomy seemed to attenuate the risk for incident T2DM in young women with UL.

Prevalence, Risk Factors, and Postoperative Infection Rates of Blood Transfusion in Lumbar Spinal Fusion Surgery: A Nationwide Population-Based Study.

Study Design: Retrospective cohort study. Objectives: Effects of blood loss that requires blood transfusion after lumbar spinal fusion remain an important issue. Blood transfusions are used commonly in cases of significant blood loss in lumbar spinal fusion but are associated with adverse effects. The objective was to assess the rate of blood transfusion and the associated risk after lumbar spinal fusion from 2013 to 2018. Methods: In this nationwide population-based cohort study, the Korean Health Insurance Review and Assessment Service database was reviewed retrospectively from 2013 to 2018. Data were extracted from patients who underwent lumbar spinal fusion without history of lumbar spinal surgery in the preceding year. The primary outcome was the rate of blood transfusion within 1 week of surgery. In addition, the risk factors for blood transfusion and the rate of postoperative infection were evaluated. Results: A total of 188,581 patients underwent lumbar spinal fusion between 2013 and 2018. A significant decline in blood transfusions was observed during the study period (56.38-47.51%). The presence of comorbidities was associated with an increased risk of blood transfusion. Patients who underwent the posterior approach were more likely to receive blood transfusion than patients who underwent the anterior or anterior and posterior approach. Receiving blood transfusion was associated with postoperative infection. Conclusions: In the present study, the prevalence, risk factors, and postoperative infection rates associated with blood transfusion in lumbar spinal fusion were identified. Spine surgeons should consider these risk factors in patients at high risk of blood transfusion.

Insurance Types and All-Cause Mortality in Korean Cancer Patients: A Nationwide Population-Based Cohort Study.

Economic deprivation is expected to influence cancer mortality due to its impact on screening and treatment options, as well as healthy lifestyle. However, the relationship between insurance type, premiums, and mortality rates remains unclear. This study investigated the relationship between insurance type and mortality in patients with newly diagnosed cancer using data from the Korean National Health Insurance Database. this retrospective cohort study included 111,941 cancer patients diagnosed between 1 January 2007 and 31 December 2008, with a median follow-up period of 13.41 years. The insurance types were categorized as regional and workplace subscribers and income-based insurance premiums were divided into tertiles (T1, T2, and T3). Cox proportional hazards regression analysis adjusted for age, lifestyle factors, health metrics, and comorbidities showed workplace subscribers (n = 76,944) had a lower all-cause mortality hazard ratio (HR) (95% confidence interval [CI]: 0.940 [0.919-0.961]) compared to regional subscribers (n = 34,997). Higher income tertiles (T2, T3) were associated with lower mortality compared to the T1 group, notably in male regional and workplace subscribers, and female regional subscribers. The study identified that insurance types and premiums significantly influence mortality in cancer patients, highlighting the necessity for individualized insurance policies for cancer patients.

Patient characteristics, treatment patterns, and survival outcomes for patients with malignant pleural mesothelioma in Denmark between 2011 and 2018: a nationwide population-based cohort study.

Malignant pleural mesothelioma (MPM) is a rare thoracic malignancy with poor prognosis and limited treatment options. Immunotherapy shows potential for improved outcomes; however, real-world evidence on its use will take time to accumulate. This study examined patient characteristics, treatment patterns, overall survival (OS), and predictors of mortality among patients diagnosed with MPM in Denmark prior to the introduction of newer treatments. This historical cohort study based on routinely collected Danish National Registry data included adults newly diagnosed with MPM between 01 January 2011 and 31 May 2018. Summary statistics were used to describe patient characteristics and initial treatment. OS was estimated using Kaplan-Meier methods; Cox regression was used to compare patient mortality against the (age/sex-matched) general population and to investigate mortality predictors. Overall, 880 patients were included; 44% had advanced MPM, 37% had non-advanced MPM, and 19% had unknown MPM stage. Median age at diagnosis was 71.9 years, and 82% of the patients were male. Within 180 days of diagnosis, no treatment was recorded for 215 patients (54%) with advanced MPM and 150 (46%) with non-advanced MPM. Median time-to-initial treatment (interquartile range) was 47 days (31-111) overall, 40 days (28-77) in patients with advanced MPM, and 53 days (35-121) with non-advanced MPM. Median OS was 13.7 months overall (non-advanced MPM: 18.0 months vs. advanced MPM: 10.0 months). Predictors of higher mortality were older age at diagnosis, histology, and advanced MPM stage. These findings provide a baseline upon which to evaluate MPM epidemiology as newer treatments are adopted in routine practice.

Improved Proteinuria May Attenuate the Risk of Atrial Fibrillation: A Nationwide Population-Based Cohort Study.

Background/Objectives: Proteinuria is documented as a risk factor for atrial fibrillation (AF) and can manifest in either reversible or continued forms. Our objective was to examine the relationship between the change in status for proteinuria and the risk of AF in a longitudinal cohort study on the general population nationwide. Methods: We included participants (n = 1,708,103) who underwent repetitive health examinations. The presence of proteinuria was determined by dipstick urinalysis results. The outcome was the occurrence of AF (International Classification of Diseases-10 code: I48). Results: All included participants, 1,666,111 (97.5%), 17,659 (1.0%), 19,696 (1.2%), and 4637 (0.3%), were categorized into groups of proteinuria-free, improved, progressed, and persistent, respectively. During a median follow-up of 14.5 years, 41,190 (2.4%) cases of AF occurred. In the multivariable analysis, the risk of AF was increased as the initial severity was more severe in the proteinuria-improved and proteinuria-persistent groups (p for trend < 0.001). In a further pairwise comparison, the proteinuria-improved group had a relatively lower risk of AF compared to the proteinuria-persistent group (HR: 0.751, 95% CI: 0.652-0.865, p < 0.001). Conclusions: Our study showed that the risk of AF can change according to alterations in proteinuria status. Notably, recovering from proteinuria can also be considered a modifiable risk factor for AF.

Relationship between smoking experience and risk of suicide mortality in South Korean adults: A nationwide population-based retrospective cohort study

Relationship between smoking experience and risk of suicide mortality in South Korean adults: A nationwide population-based retrospective cohort study

Risk and prognosis of cancer in patients with obstructive uropathy compared with the general Danish population.

To examine whether obstructive uropathy is associated with increased risk of cancer and whether mortality differs between cancer patients with and without obstructive uropathy. In a nationwide population-based Danish cohort study including 37,275 adult patients with a first-time hospital-related diagnosis of obstructive uropathy in 1996-2022, we assessed cumulative cancer incidence (risk) and standardized incidence ratios (SIRs). Furthermore, we compared the mortality of 7,485 patients diagnosed with cancer after obstructive uropathy diagnosis with that of 69,785 cancer patients without obstructive uropathy matched by age, sex, cancer site, stage, and calendar year of cancer diagnosis. The 3-month risk of cancer after an obstructive uropathy diagnosis was 9.6%. The 3-month SIR was 34.2 (95% confidence interval [CI], 33.1-35.4) while the 1-<5 year SIR was 1.2 (95% CI, 1.1-1.3). The 3-month SIRs were 82.7 (95% CI, 79.3-86.2) for urological cancer, 88.8 (95% CI, 79.8-98.5) for gynecological cancer, and 13.9 (95% CI, 12.0-15.9) for colorectal cancer. After 1 year of follow-up, the excess number of urological cancers decreased to 0.1 per 100 person-years, whereas we observed no excess risk of gynecological and colorectal cancers. The 5-year all-cause mortality following cancer was 64.1% (95% CI, 62.9-65.2) in patients with an obstructive uropathy diagnosis before cancer diagnosis and 53.2% (95% CI, 52.9-53.6) in those without. A first-time diagnosis of obstructive uropathy can be a clinical marker of underlying undiagnosed cancer and elevated mortality in relation to any cancer diagnosed after obstructive uropathy. These findings can inform the follow-up recommendations for obstructive uropathy.

Risk factors of acute pancreatitis in young adults: a Nationwide population-based cohort study in South Korea.

This study aimed to identify the risk factors for acute pancreatitis (AP) in young adults in their 20s based on data from the nationwide cohort in South Korea. From the 2009 national health examination database of South Korea, total 471,098 individuals between the ages of 20 and 29 were analyzed. To identify the newly developed AP, the linked claims database was used. The incidence rates of AP were 18.8 and 9.8 per 100,000 person-years in male and female participants, respectively. Alcohol consumption and smoking were associated with the heightened risk of AP. The risk of AP development was increased as daily alcohol consumption increased. Also, ex-smokers and current smokers showed higher AP risk than never smokers. Hypertriglyceridemia and obesity were associated with the increased AP risk as well. Compared to female participants, male participants showed a higher risk of AP in univariate analysis, but showed a lower risk of AP in multivariate analysis. In the young adult population, alcohol consumption, smoking, hypertriglyceridemia, and obesity were associated with an elevated risk of developing AP. It is important to identify and manage the modifiable AP risk factors in young adults to minimize the socioeconomic burden of AP.

Fenofibrate and risk of end-stage renal disease: A nationwide cohort study.

Previous studies have shown that fenofibrate improves outcomes such as albuminuria and estimated glomerular filtration rate decline. We hypothesize that fenofibrate has renoprotective effects and prevents or delays the development of end-stage renal disease. The objective of this study is to investigate the risk of incident end-stage renal disease in relation to fenofibrate treatment in patients who are already taking statins. We performed a nationwide population-based cohort study using data from the Korea National Health Information Database from 2010 to 2017. Among adults using statins, 413 715 fenofibrate users were compared with 413 715 fenofibrate non-users after 1:1 age, sex and triglyceride matching. The endpoint of this study was incident end-stage renal disease. During a median 3.96-year follow-up, the incidence per 1000 person years of end-stage renal disease was lower in fenofibrate users than in fenofibrate non-users (0.885 vs. 0.960, p < 0.0001). The hazard ratio for end-stage renal disease was lower (0.763, 95% confidence interval 0.710-0.821) in fenofibrate users. This association was significant in patients with hypertension, proteinuria and an estimated glomerular filtration rate <60 mL/min/1.732. Fenofibrate use in patients taking statins with either hypertension, proteinuria, or decreased estimated glomerular filtration rate is associated with a low risk of incident end-stage renal disease. To confirm the renoprotective effect of fenofibrate in chronic kidney disease, a randomized controlled trial is warranted.

Association between Air Quality Index and the risk of rosacea: A Nationwide population-based Cohort Study.

Air pollution is associated with several inflammatory skin disorders. However, the association between air quality and rosacea remains unclear. To investigate the association between air quality index and incidence of rosacea. Overall, 21,709,479 participants without rosacea before 2008 were recruited from the Taiwan National Health Insurance Research Database. The long-term average air quality index (AQI) value for each participant was acquired from the Taiwan Air Quality Monitoring System Network and calculated from 2008/1/1 until the diagnosis of rosacea, withdrawal from the National Health Insurance, or December 31, 2018. We observed a significant association between AQI and the incidence of rosacea, with each unit elevation in AQI increasing the risk of rosacea by 5 %. Compared with the Q1 group, the Q2, Q3, and Q4 cohorts exhibited 1.82-fold, 4.48-fold and 7.22-fold increased risk of rosacea, respectively. Additionally, exposure to PM2.5, SO2 and CO increased the risk of rosacea, whereas exposure to PM10 was associated with a lower risk. This study supported a significant dose-response relationship between AQI and the incidence of rosacea.

Epidemiology of uveitis after tuberculosis in Taiwan – A nationwide population-based cohort study

Abstract: PURPOSE: Current reports on the risk of uveitis of all causes after tuberculosis (TB) diagnosis are lacking. Therefore, we sought to investigate the association between the diagnosis of TB and the subsequent risk of uveitis in Taiwan. MATERIALS AND METHODS: Data from the Taiwan National Health Insurance system were retrieved and patients with newly diagnosed TB between 2000 and 2012 were recruited. The endpoint of interest was the occurrence of uveitis. Patients without TB were randomly matched 4:1 to TB cases based on age, gender, index date, outpatient clinic visit, and index year. Univariate and multivariable Cox proportional regression analyses were performed to analyze the risk of uveitis among TB patients. RESULTS: A total of 6139 patients with TB and corresponding 24,555 matched control participants were recruited. The mean age was 52.9 ± 22.1 years old and 32.1% were male. The medium follow-up period was 5.81 ± 4.37 years and 7.16 ± 3.95 years in the TB and matched control cohorts. Our results showed that patients with TB had no significantly increased incidence of uveitis. After stratification by gender, age, and comorbidities, the relationship between TB and uveitis was found to be not significant. The cumulative incidence of uveitis was also found to be not significantly higher among the TB group (log-rank P = 0.84). CONCLUSION: Our nationwide population-based cohort retrospective study showed that the incidence of uveitis was not significantly higher among patients with TB. Future prospective and multicenter studies are warranted to confirm our findings.

The role of co-occurring conditions and genetics in the associations of eating disorders with attention-deficit/hyperactivity disorder and autism spectrum disorder.

Eating disorders (EDs) commonly co-occur with other psychiatric and neurodevelopmental disorders including attention-deficit/hyperactivity disorder (ADHD) and autism spectrum disorder (ASD); however, the pattern of family history and genetic overlap among them requires clarification. This study investigated the diagnostic, familial, and genetic associations of EDs with ADHD and ASD. The nationwide population-based cohort study included all individuals born in Denmark, 1981-2008, linked to their siblings and cousins. Cox regression was used to estimate associations between EDs and ADHD or ASD, and mediation analysis was used to assess the effects of intermediate mood or anxiety disorders. Polygenic scores (PGSs) were used to investigate the genetic association between anorexia nervosa (AN) and ADHD or ASD. Significantly increased risk for any ED was observed following an ADHD [hazard ratio = 1.97, 95% confidence interval = 1.75-2.22] or ASD diagnosis [2.82, 2.48-3.19]. Mediation analysis suggested that intermediate mood or anxiety disorders could account for 44-100% of the association between ADHD or ASD and ED. Individuals with a full sibling or maternal halfsibling with ASD had increased risk of AN [1.54, 1.33-1.78; 1.45, 1.08-1.94] compared to those with siblings without ASD. A positive association was found between ASD-PGS and AN risk [1.06, 1.02-1.09]. In this study, positive phenotypic associations between EDs and ADHD or ASD, mediation by mood or anxiety disorder, and a genetic association between ASD-PGS and AN were observed. These findings could guide future research in the development of new treatments that can mitigate the development of EDs among individuals with ADHD or ASD.

Estimating vaccine effectiveness against COVID-19 using cause-specific sick leave as an indicator: a nationwide population-based cohort study, Norway, July 2021 – December 2022

BackgroundDue to changes in testing policy and increased use of rapid tests, other indicators for SARS-CoV-2 infections are needed to monitor vaccine effectiveness (VE). We aimed to estimate VE against COVID-19 sick leave (> 3 days, certified by a medical professional) among employed individuals (25–64-years-old) in Norway.MethodsWe performed a nationwide cohort study by collating data from the Emergency preparedness register for COVID-19. We used adjusted Cox proportional hazard models with vaccine status as a time-varying covariate and presented results as adjusted hazard ratios (aHRs) with corresponding 95% confidence intervals. Separate models were run against sick leave and against SARS-CoV-2 infections during the Delta period (June-December 2021), and against sick leave during the Omicron period (January-December 2022) when SARS-CoV-2 PCR-testing was replaced by rapid self-tests and infections were underreported.ResultsWe included 2,236,419 individuals during the Delta period, of whom 73,776 (3.3%) had a reported infection and 54,334 (2.4%) were registered with sick leave. Of the 2,206,952 included individuals in the Omicron period, 300,140 (13.6%) were registered with sick leave. During the Delta period, 55% (26,611) of individuals who had registered sick leave also had a positive test, compared to 32% (96,445) during the Omicron period. The VE against sick leave during the Delta period followed a similar waning pattern to that against SARS-CoV-2 infections. After the second and third dose, the lowest aHRs were estimated for 2–7 days after vaccination for both sick leave (0.25; 95%CI 0.24–0.26 and 0.26; 95% CI 0.24–0.29) and infection ( 0.16; 95% CI 0.15–0.17 and 0.18; 95% CI 0.16–0.19) respectively. During the Omicron period, aHRs for sick leave were higher than during the Delta period, but the lowest aHRs were still found in 2–7 weeks after receiving the second (0.61; 95% CI 0.59–0.64) or third dose (0.63; 95% CI 0.62–0.64).ConclusionOur results showed that sick leave could be a relevant indicator for VE in the surveillance of COVID-19 and a finding that may be important in the surveillance of other respiratory infection.

Maternal cigarette smoking before or during pregnancy increases the risk of severe neonatal morbidity after delivery: a nationwide population-based retrospective cohort study

BackgroundThe association of maternal cigarette smoking during pregnancy with severe neonatal morbidity (SNM) is still inconclusive. We aimed to examine the associations of the timing and the intensity of maternal...

Incidence of seropositive and seronegative rheumatoid arthritis in Denmark: a nationwide population-based study

Objective To investigate and compare trends in incidence rates (IRs) of seropositive and seronegative rheumatoid arthritis (RA) in Denmark using various data sources for serostatus definition. Method This nationwide population-based cohort study was based on data from Danish healthcare and clinical quality registries between 2000 and 2018. Information on anti-cyclic citrullinated peptide and immunoglobulin M rheumatoid factor was obtained, and definitions of seropositivity according to the number of applied data sources were prespecified. Annual age- and sex-standardized IRs were calculated as the number of incident seropositive and seronegative cases, divided by the number of person-years (PY) in the general population in that given year. Results An increasing temporal trend in IR of seropositive RA and a decreasing trend in seronegative RA were observed. The IRs were higher for seropositive RA than for seronegative RA from 2009 onwards, with a widening of the IR gap between 2009 and 2016 regardless of the definition of seropositivity. When combining laboratory- and physician-reported autoantibody information and ICD-10 codes, the IR of seropositive RA in 2018 was approximately twice that of seronegative RA, at 19.0 and 9.0 per 100 000 PY, respectively. The level of antibody testing increased significantly during the study period. Conclusions The IR of seropositive RA increased over time, whereas the IR of seronegative RA decreased. Temporal IR changes may be caused by a real change in the RA serology subtypes, an increase in autoantibody testing and availability, changes in registration practice over time, or a combination of these factors.

Income dynamics and risk of colorectal cancer in individuals with type 2 diabetes: a nationwide population-based cohort study.

Individuals with type 2 diabetes (T2D) have increased colorectal cancer (CRC) risk, but it is unknown whether income dynamics are associated with CRC risk in these individuals. We examined whether persistent low- or high-income and income changes are associated with CRC risk in non-elderly adults with T2D. Using nationally representative data from the Korean Health Insurance Service database, 1,909,492 adults aged 30 to 64 years with T2D and no history of cancer were included between 2009 and 2012 (median follow-up of 7.8 years). We determined income levels based on health insurance premiums and assessed annual income quartiles for the baseline year and the four preceding years. Hazard ratios(HRs) and 95% confidence intervals(CIs) were estimated after adjusting for sociodemographic factors, CRC risk factors, and diabetes duration and treatment. Persistent low income (i.e., lowest income quartile) was associated with increased CRC risk (HRn=5years vs. n=0years 1.11, 95% CI 1.04-1.18; P for trend=0.004). Income declines (i.e., a decrease≥25% in income quantile) were also associated with increased CRC risk (HR≥2 vs. 0 declines 1.10, 95% CI 1.05-1.16; p for trend=0.001). In contrast, persistent high income (i.e., highest income quartile) was associated with decreased CRC risk (HRn=5years vs. n=0years 0.81, 95% CI 0.73-0.89; p for trend<0.0001), which was more pronounced for rectal cancer (HR 0.64, 95% CI 0.53-0.78) and distal colon cancer (HR 0.70, 95% CI 0.57-0.86). Our findings underscore the need for increased public policy awareness of the association between income dynamics and CRC risk in adults with T2D.