Risk of fracture among patients with spinal cord injury: A nationwide cohort study in South Korea

BACKGROUND

Clinical concerns about preventing and managing fractures after spinal cord injury (SCI) have been growing.

OBJECTIVE

This study investigates the risk of fractures among SCI patients according to the presence of disability, disease severity, and level of injury.

METHODS

We performed a retrospective cohort study using the Korean National Health Insurance Service (KNHIS 2010-2018) database. We included 5190 SCI patients and 1:3 age- and sex-matched control participants. The primary outcome was fracture, and the cohort was followed until December 31, 2019.

RESULTS

SCI patients had a higher fracture risk than the matched controls (adjusted hazard ratio [aHR] 1.33, 95 % CI 1.16-1.54). The risk of fracture was higher in the presence of disability (aHR 1.57, 95 % CI 1.19-2.07), especially among patients with severe disability (aHR 1.65, 95 % CI 1.05-2.60). Higher fracture risks were observed among SCI patients regardless of injury level, but statistical significance was found only with cervical-level injury. When we considered site-specific fractures, vertebral (aHR 1.31, 95 % CI 1.04-1.64) and hip fracture risks (aHR 2.04, 95 % CI 1.39-2.98) were both higher among SCI patients than the controls. SCI patients with disability and cervical-level injury showed the highest hip fracture risk (aHR 3.67, 95 % CI 1.90-7.07).

CONCLUSIONS

Compared with the controls, SCI patients were at higher risk of any fracture, particularly hip fracture, especially those with disability and cervical-level injury. Clinicians should be aware of the fracture risk among SCI patients to provide proper management.

Risk of Heart Disease in Patients With Amputation: A Nationwide Cohort Study in South Korea

BACKGROUND

Amputation confers disabilities upon patients and is linked to substantial morbidity and death attributed to heart disease. While some studies have focused on traumatic amputees in veterans, few studies have focused on traumatic amputees within the general population. Therefore, the present study aimed to assess the risk of heart disease in patients with traumatic amputation with disability within the general population using a large-scale nationwide population-based cohort.

METHODS AND RESULTS

We used data from the Korean National Health Insurance System. A total of 22 950 participants with amputation were selected with 1:3 age, sex-matched controls between 2010 and 2018. We used Cox proportional hazard models to calculate the risk of myocardial infarction, heart failure, and atrial fibrillation among amputees. Participants with amputation had a higher risk of myocardial infarction (adjusted hazard ratio [aHR], 1.30 [95% CI, 1.14-1.47]), heart failure (aHR, 1.27 [95% CI, 1.17-1.38]), and atrial fibrillation (aHR, 1.17 [95% CI, 1.03-1.33]). The risks of myocardial infarction and heart failure were further increased by the presence of disability (aHR, 1.43 [95% CI, 1.04-1.95]; and aHR, 1.38 [95% CI, 1.13-1.67], respectively).

CONCLUSIONS

We demonstrate an increased risk of myocardial infarction, heart failure, and atrial fibrillation among individuals with amputation, and the risk further increased in those with disabilities. Clinicians should pay attention to the increased risk for heart disease in patients with amputation.

Fracture Risk Among Stroke Survivors According to Poststroke Disability Status and Stroke Type

BACKGROUND

Stroke survivors face physical and cognitive challenges, leading to an increased dependency and a higher fall risk. We aimed to investigate the impact of poststroke disability and stroke type on fracture risk at various sites compared with matched controls.

METHODS

This retrospective cohort study used data from the Korean National Health Insurance System database (2010-2018), including patients with stroke and 1:1 matched controls. Stroke survivors were grouped based on the presence and severity of their poststroke disability and stroke type. The primary outcome was a newly diagnosed fracture, analyzed by Cox proportional hazard regression analyses adjusting for potential confounders.

RESULTS

Among 223 358 stroke survivors (mean age, 64.8±10.9 years; 61.2% men), 16 344 fractures occurred during a mean follow-up of 3.7±2.5 years. In matched controls (n=322 161; mean age, 65.4±11.2 years; 61.3% men), 20 398 fractures were identified. Stroke survivors had increased overall fracture risk compared with matched controls (adjusted hazard ratio [aHR], 1.40 [95% CI, 1.37-1.43]). Specifically, hip fracture risk was even greater in stroke survivors (incidence rate per 1000 person-years, 4.7 [95% CI, 4.5-4.8]; aHR, 2.42 [95% CI, 2.30-2.55]) than controls (incidence rate, 2.2 [95% CI, 2.1-2.3]). The risk of vertebral fractures (aHR, 1.29 [95% CI, 1.25-1.34]) and other fractures (aHR, 1.19 [95% CI, 1.15-1.23]) was also higher than that of the control group. Hip fracture risk was the highest among stroke survivors with severe poststroke disability (aHR, 4.82 [95% CI, 4.28-5.42]), although vertebral or other fracture risk was the highest among those with mild poststroke disability. No significant difference in fracture risk was found between hemorrhagic and ischemic stroke survivors when stratified by disability status.

CONCLUSIONS

Our findings showed increased subsequent fracture risk among stroke survivors, particularly those with poststroke disability and for hip fracture. Bone health assessment and treatment should be emphasized as an essential part of stroke management.

Tuberculosis and osteoporotic fracture risk: development of individualized fracture risk estimation prediction model using a nationwide cohort study

Purpose

Tuberculosis (TB) is linked to sustained inflammation even after treatment, and fracture risk is higher in TB survivors than in the general population. However, no individualized fracture risk prediction model exists for TB survivors. We aimed to estimate fracture risk, identify fracture-related factors, and develop an individualized risk prediction model for TB survivors.

Methods

TB survivors (n = 44,453) between 2010 and 2017 and 1:1 age- and sex-matched controls were enrolled. One year after TB diagnosis, the participants were followed-up until the date of fracture, death, or end of the study period (December 2018). Cox proportional hazard regression analyses were performed to compare the fracture risk between TB survivors and controls and to identify fracture-related factors among TB survivors.

Results

During median 3.4 (interquartile range, 1.6-5.3) follow-up years, the incident fracture rate was significantly higher in TB survivors than in the matched controls (19.3 vs. 14.6 per 1,000 person-years, p < 0.001). Even after adjusting for potential confounders, TB survivors had a higher risk for all fractures (adjusted hazard ratio 1.27 [95% confidence interval 1.20-1.34]), including hip (1.65 [1.39-1.96]) and vertebral (1.35 [1.25-1.46]) fractures, than matched controls. Fracture-related factors included pulmonary TB, female sex, older age, heavy alcohol consumption, reduced exercise, and a higher Charlson Comorbidity Index (p < 0.05). The individualized fracture risk model showed good discrimination (concordance statistic = 0.678).

Conclusion

TB survivors have a higher fracture risk than matched controls. An individualized prediction model may help prevent fractures in TB survivors, especially in high-risk groups.

Association between dental diseases and oral hygiene care and the risk of vertebral fracture: a nationwide cohort study

Periodontal disease and increased missing teeth were associated with incident vertebral fractures. In contrast, professional dental cleaning and frequent tooth brushing, was associated with a lower risk of vertebral fracture. Better oral hygiene care attenuated the risk associated with dental diseases.

PURPOSE

To investigate the association between oral health and the risk of vertebral fractures.

METHODS

We included 2,532,253 individuals aged ≥40 years who underwent the Korean National Health Insurance Service health examinations in 2008 and followed up until December 31, 2017. We performed multivariable Cox proportional hazard regression analyses to evaluate the association between dental diseases and oral hygiene care and the risk of vertebral fractures.

RESULTS

Over the 9.3-year median follow-up, 1.46% (n = 36,857) experienced vertebral fractures. Individuals with dental diseases had a higher risk of vertebral fracture than those without (hazard ratio [HR] 1.04, 95% confidence interval [CI]: 1.02-1.07 for periodontal diseases; 1.02, 1.00-1.05 for dental caries; 1.12, 1.05-1.20 for ≥15 missing teeth). Good oral hygiene care was associated with a lower vertebral fracture risk (HR 0.89, 95% CI: 0.86-0.91 for ≥1 time/year [vs. <1 time/year] of professional dental cleaning; 0.90, 0.87-0.93 for ≥2 times/day [vs. 0-1 time/day] of toothbrushing). The combined dental diseases was significantly associated with an increased vertebral fracture risk, whereas combined oral hygiene care was associated with further risk reduction. Better oral hygiene care reduced vertebral fracture risk associated with dental diseases (all P <0.001).

CONCLUSION

Periodontal disease, dental caries, and an increased number of missing teeth were independently associated with higher risks for vertebral fractures. Conversely, improved oral hygiene care, such as personal dental cleaning and frequent tooth brushing, may modify vertebral fracture risks associated with dental disease.

Increased Risk of Myocardial Infarction, Heart Failure, and Atrial Fibrillation After Spinal Cord Injury

BACKGROUND

Heart diseases are a growing concern for the spinal cord injury (SCI) population.

OBJECTIVES

This study aims to compare the incidence of heart diseases between SCI survivors and the general non-SCI population.

METHODS

We identified 5,083 SCI survivors and 1:3 age- and sex-matched non-SCI controls. Study outcomes were myocardial infarction (MI), heart failure (HF), and atrial fibrillation (AF). The cohort was followed up from the index date (diagnosis date for SCI or corresponding date for matched controls) until 2019.

RESULTS

SCI survivors showed a higher risk for MI (adjusted HR [aHR]: 2.41; 95% CI: 1.93-3.00), HF (aHR: 2.24; 95% CI: 1.95-2.56), and AF (aHR: 1.84; 95% CI: 1.49-2.28) compared to controls. The risks were further increased for those who were registered in the National Disability Registry within 1 year from the index date (SCI survivors with disability): SCI survivors with severe disability had the highest risks of MI (aHR: 3.74; 95% CI: 2.43-5.76), HF (aHR: 3.96; 95% CI: 3.05-5.14), and AF (aHR: 3.32; 95% CI: 2.18-5.05). Cervical and lumbar SCI survivors had an increased risk of heart disease regardless of disability compared to matched controls; these risks were slightly higher in those with disability. Thoracic SCI survivors with disability had significantly increased risk of heart disease compared to matched controls.

CONCLUSIONS

SCI survivors at all levels were at significantly greater risk for heart disease than non-SCI controls, particularly those with severe disability. Clinicians must be aware of the importance of heart disease in SCI survivors.

Rheumatoid Arthritis and Risk of Lung Cancer: A Nationwide Cohort Study

INTRODUCTION

There has been an increasing interest in the risk of lung cancer related to rheumatoid arthritis (RA). We investigated the association between RA and the risk of lung cancer with consideration of key confounding factors, including RA serostatus and smoking status.

METHODS

Using a nationwide database, we identified 51,899 patients with newly diagnosed RA between 2010 and 2017, which were matched by sex and age at a 1:5 ratio with 259,495 non-RA population. The association of lung cancer and RA was investigated using Cox regression analyses. Stratified analyses by smoking status, sex, age, and comorbidity of interstitial lung disease were conducted using the same Cox modeling.

RESULTS

During 4.5 years of follow-up, the adjusted hazard ratio of lung cancer in the patients with RA was 1.49 (95% confidence interval: 1.34-1.66). Compared with the patients with seronegative RA, an increased risk of lung cancer was not considerable in the patients with seropositive RA. In the stratified analyses, the increased risk of lung cancer was more prominent in current or previous heavy smokers with RA (interaction p value of 0.046) and male patients (interaction p < 0.001), whereas there was no substantial effect associated with age or interstitial lung disease status.

CONCLUSIONS

Patients with RA had an increased risk of lung cancer compared with the non-RA group, and the risk did not differ by RA serostatus. There is a need for increased awareness of smoking cessation and potentially for regular lung cancer screening with proper risk stratification in patients with RA.

Risk of dementia in survivors of active tuberculosis in Korea: A nationwide cohort study

BACKGROUND

Concern has been growing regarding post-tuberculosis (TB) morbidities, including neurologic and vascular comorbidities. However, the association between post-TB status and the risk of dementia has been evaluated in only few studies. Therefore, in the present study, the risk of dementia was investigated in a nationwide population-based cohort.

METHODS

Using the Korean National Health Insurance Service (KNHIS) database, this study included TB survivors (n = 50,182) and matched controls (n = 50,182) for age, sex, and year of index date. The risk of dementia was estimated using Cox proportional hazards regression, and stratified analyses for related factors were performed.

RESULTS

During a mean 3.5 years of follow-up, the incidence of dementia was 9.32 for Alzheimer disease and 1.17 for vascular dementia per 1000 person-years for TB survivors and 7.21 and 0.67, respectively, for matched controls. The overall risk of Alzheimer disease was 1.11 (95% confidence interval (CI) 1.03-1.20)-fold higher in TB survivors than in matched controls. For vascular dementia, 1.48 (95% CI 1.16-1.89)-fold higher risk was found in TB survivors than in matched controls. The strength of the association between TB and dementia was higher in CNS TB (aHR 1.76, 95% CI 1.18 -2.64) than non-CNS TB (aHR 1.11, 95% CI 1.05-1.19) compared to controls, especially for patients with vascular dementia (3.33, 95% CI 1.06-10.49).

CONCLUSION

TB survivors had a significantly higher risk of dementia than the general population.

Smoking Behavior Change and the Risk of Heart Failure in Patients With Type 2 Diabetes: Nationwide Retrospective Cohort Study

BACKGROUND

Heart failure (HF) is one of the most common initial manifestations of cardiovascular disease in patients with type 2 diabetes. Although smoking is an independent risk factor for HF, there is a lack of data for the incidence of HF according to changes in smoking behaviors in patients with type 2 diabetes.

OBJECTIVE

We aimed to examine the association between interval changes in smoking behavior and the risk of HF among patients with type 2 diabetes.

METHODS

We conducted a retrospective cohort study using the National Health Insurance Service database. We identified 365,352 current smokers with type 2 diabetes who had 2 consecutive health screenings (2009-2012) and followed them until December 31, 2018, for the incident HF. Based on smoking behavior changes between 2 consecutive health screenings, participants were categorized into quitter, reducer I (≥50% reduction) and II (<50% reduction), sustainer (reference group), and increaser groups.

RESULTS

During a median follow-up of 5.1 (IQR 4.0-6.1) years, there were 13,879 HF cases (7.8 per 1000 person-years). Compared to sustainers, smoking cessation was associated with lower risks of HF (adjusted hazard ratio [aHR] 0.90, 95% CI0.86-0.95), whereas increasers showed higher risks of HF than sustainers; heavy smokers who increased their level of smoking had a higher risk of HF (aHR 1.13, 95% CI 1.04-1.24). In the case of reducers, the risk of HF was not reduced but rather increased slightly (reducer I: aHR 1.14, 95% CI 1.08-1.21; reducer II: aHR 1.03, 95% CI 0.98-1.09). Consistent results were noted for subgroup analyses including type 2 diabetes severity, age, and sex.

CONCLUSIONS

Smoking cessation was associated with a lower risk of HF among patients with type 2 diabetes, while increasing smoking amount was associated with a higher risk for HF than in those sustaining their smoking amount. There was no benefit from reduction in smoking amount.

Association between Dental Diseases and Oral Hygiene Care and the Risk of Dementia: A Retrospective Cohort Study

OBJECTIVES

To investigate the associations of dental diseases and oral hygiene care with the risk of dementia.

DESIGN

Retrospective longitudinal cohort study.

SETTING AND PARTICIPANTS

We conducted a population-based study of individuals in the Korean National Health Insurance System. A total of 2,555,618 participants who underwent cardiovascular and dental screenings in 2008 were included.

METHODS

Dental diseases including periodontal diseases, dental caries, and tooth loss were assessed by dentists. Information on oral hygiene care, including professional dental cleaning and the frequency of tooth brushing, was collected using a self-administered questionnaire. Study outcomes were all-cause dementia, Alzheimer's disease (AD), and vascular dementia (VaD).

RESULTS

Periodontal diseases [adjusted hazard ratio (aHR) 1.07, 95% CI 1.04-1.09], dental caries (aHR 1.03, 95% CI 1.00-1.05), and 8-14 missing teeth (aHR 1.07, 95% CI 1.02-1.12) were associated with an increased risk of all-cause dementia. In contrast, either professional dental cleaning or frequent tooth brushing were associated with decreased risks of all-cause dementia (aHR 0.91, 95% CI 0.89-0.93 each; aHR 0.83, 95% CI 0.80-0.86 for both). The increased risks by dental diseases were reduced by oral hygiene care: periodontal diseases with professional dental cleaning (aHR 0.94, 95% CI 0.91-0.98) or tooth brushing ≥2 times/day (aHR 0.97, 95% CI 0.94-1.00) and 1 to 7 missing teeth with professional dental cleaning (aHR 0.94, 95% CI 0.89-0.98) or tooth brushing ≥2 times/day (aHR 0.92, 95% CI 0.89-0.95). Consistent results were noted for AD and VaD and in various subgroup analyses.

CONCLUSION AND IMPLICATIONS

Periodontal disease, dental caries, and a high number of missing teeth were independently associated with a higher risk of dementia. Conversely, improved oral hygiene care, such as professional dental cleaning and frequent tooth brushing, may modify the risk of dementia associated with dental diseases.

Changes in smoking, alcohol consumption, and the risk of Parkinson's disease

Objective

There have been no studies on the association between changes in smoking and alcohol consumption or combined changes in smoking and alcohol consumption frequencies and PD risk. To assess the influence of changes in smoking and alcohol consumption on the risk of Parkinson's disease (PD).

Methods

National Health Insurance Service (NHIS) database between January 2009 to December 2011 was analyzed. A total of 3,931,741 patients were included. Study participants were followed up for the incidence of PD until December 2017.

Results

Compared to the sustained non-smokers, sustained light smokers (adjusted hazard ratio [aHR] 0.80, 95% confidence interval [CI] 0.75-0.85), sustained moderate smokers (aHR 0.54, 95% CI 0.47-0.61), and sustained heavy smokers (aHR 0.49, 95% CI 0.44-0.55) had a lower risk of PD. Compared to those who sustained non-drinking, sustained light drinkers (aHR 0.85 95% CI 0.89-0.91), sustained moderate drinkers (aHR 0.68, 95% CI 0.60-0.78), and sustained heavy drinkers (aHR 0.77, 95% CI 0.68-0.87) showed decreased risk of PD. Among non-drinkers, those who started drinking to a light level were at decreased risk of PD (aHR 0.84, 95% CI 0.77-0.91). Among non-smoking and non-drinking participants, those who initiated smoking only (aHR 0.78, 95% CI 0.70-0.86), drinking only (aHR 0.77, 95% CI 0.68-0.87), and both smoking and drinking (aHR 0.69, 95% CI 0.58-0.82) showed decreased risk of PD.

Conclusion

Smoking is associated with decreased risk of PD with a dose-response relationship. Alcohol consumption at a light level may also be associated with decreased risk of PD. Further studies are warranted to find the possible mechanisms for the protective effects of smoking and drinking on PD, which may present insights into the etiology of PD.

Association of Dental Diseases and Oral Hygiene Care With the Risk of Heart Failure in Patients With Type 2 Diabetes: A Nationwide Cohort Study

Background To evaluate the association of dental diseases and oral hygiene care with incidence of heart failure (HF) among patients with type 2 diabetes. Methods and Results This study included 173 927 patients with type 2 diabetes aged ≥40 years, who underwent Korean National Health Insurance Service health examinations in 2008 and were followed up until the end of 2017. Hazard ratios (HRs) and 95% CIs for HF were estimated using multivariable Cox proportional hazards regression analysis. During a median follow-up of 9.3 years, 1.94% of participants developed HF. An increased number of missing teeth was associated with a higher risk of HF (P<0.001). HRs of HF increased among individuals with ≥15 missing teeth (HR, 1.37 [95% CI, 1.14-1.64]) compared with those without missing teeth. Decreased risk of HF was observed in individuals with ≥1 time/year of professional dental cleaning (HR, 0.93 [95% CI, 0.87-0.99]) and in those with ≥2 times/d of toothbrushing (HR, 0.90 [95% CI, 0.82-0.98]) compared with those without these practices. While combined presence of missing teeth and periodontal disease (P=0.004) or dental caries (P=0.007) increased HF risk, combined oral hygiene care was associated with further HF risk reduction (P=0.024). Better oral hygiene care was associated with decreased HF risk, even as the number of missing teeth increased (P<0.001). Conclusions Among patients with type 2 diabetes, dental diseases and oral hygiene care are important determinants of HF development. Dental disease management and good oral care may prevent HF in patients with type 2 diabetes.

Smoking behavior change and risk of cardiovascular disease incidence and mortality in patients with type 2 diabetes mellitus

BACKGROUND

We aimed to examine the association between smoking behavior change and risk of cardiovascular disease (CVD) incidence and mortality in patients with type 2 diabetes mellitus (T2DM).

METHODS

This study used nationwide data from the Korean National Health Insurance System and included 349,137 T2DM patients who smoked. Smoking behavior changes were defined with five groups: quitters, reducers I (≥ 50% reduction), reducers II (20-50% reduction), sustainers (± 20%), and increasers (≥ 20% increase) from the number of cigarettes/day at the baseline.

RESULTS

During a median follow-up of 5.1 years, 6,514 cases of myocardial infarction (MI) (1.9%), 7,837 cases of ischemic stroke (IS) (2.2%), and 14,932 deaths (4.3%) were identified. Quitters had a significantly decreased risk of MI (adjusted hazard ratio [aHR] 0.80, 95% CI 0.75-0.86) and IS (aHR 0.80, 95% CI 0.75-0.85) compared to sustainers, whereas reducers did not have a significant association with the risk of MI (aHR 1.03, 95% CI 0.94-1.13) and IS (aHR 1.00, 95% CI 0.92-1.08) in reducer I. Quitters also had a lower all-cause and CVD mortality than sustainers.

CONCLUSIONS

Smoking cessation was associated with decreased CVD incidence, and all-cause and CVD mortality among T2DM patients. However, smoking reduction was not associated with decreased risks for these.

Blood pressure and dementia risk by physical frailty in the elderly: a nationwide cohort study

BACKGROUND

Midlife hypertension has been recognized as a modifiable risk factor for dementia, but association between blood pressure (BP) in late life and dementia has been inconclusive. In addition, few studies have investigated effects of BP control on dementia incidence in the frail elderly. Thus, this study aimed to investigate the association of BP and dementia incidence with concomitant consideration of physical frailty in the young elderly population.

METHODS

Using the Korean National Health Information Database, we identified 804,024 subjects without history of dementia at age 66. Dementia diagnosis was defined with prescription records of anti-dementia drugs and dementia-related diagnostic codes. Physical frailty was measured using the Timed Up and Go test. Association of BP and dementia incidence with concomitant consideration of physical frailty was investigated using Cox hazards analyses.

RESULTS

The risks of Alzheimer's and vascular dementia increased from systolic BP ≥ 160 and 130-139 mmHg, respectively; a significant association of dementia incidence with low BP was not observed. In the analyses stratified by the physical frailty status, low BP was not associated with increased risks of dementia within the groups both with and without physical frailty.

CONCLUSIONS

High BP was associated with increased risks of dementia, especially for vascular dementia, while low BP was not associated with increased risks of any type of dementia in young elderly people, even in those with physical frailty. This study suggests the need for tight BP control in young elderly people, irrespective of frailty status, to prevent dementia and supports the current clinical guidelines of hypertension treatment.

Smoking Cessation Reduces the Risk of Heart Failure: A Nationwide Cohort Study

BACKGROUND

There is a lack of data for the incidence of heart failure (HF) according to changes in smoking behaviors.

OBJECTIVES

The authors aimed to investigate the effects of smoking behavior change on development of HF.

METHODS

In this population-based, retrospective cohort study using the Korean National Health Insurance System database, the authors identified 778,608 current smokers who participated in a health screening program in 2009 and in a follow-up screening in 2011. Participants were categorized into quitters, reducers I (≥50% reduction) and II (<50% reduction), sustainers, and increasers.

RESULTS

During a median follow-up of 6.3 years, there were 23,329 HF events (4.8 per 1,000 person-years). Compared with sustainers, the risk of HF was increased among increasers (adjusted hazard ratio [aHR]: 1.06 [95% CI: 1.02-1.10]). By contrast, quitters had a reduced risk for HF (aHR: 0.86 [95% CI: 0.83-0.90]). Even heavy smokers who quit smoking had a lower risk for HF than those who sustained heavy smoking (aHR: 0.90 [95% CI: 0.85-0.95]). In reducers, the risk of HF was not reduced but rather increased slightly (≥50% reduction, aHR: 1.06 [95% CI: 1.01-1.11]; <50% reduction, aHR: 1.04 [95% CI: 1.00-1.08]).

CONCLUSIONS

Current smokers who increased their smoking amount were associated with a higher risk for HF development compared to sustainers, whereas self-reported smoking cessation was associated with a lower risk of HF. There was no benefit from reduction in smoking amount. Self-reported smoking cessation should be reinforced whenever possible to prevent HF.

Associations of reproductive factors with incidence of myocardial infarction and ischemic stroke in postmenopausal women: a cohort study

BACKGROUND

To assess the association between the reproductive factors of age at menarche, age at menopause, and reproductive span and the incidence of myocardial infarction (MI) and ischemic stroke (IS).

METHODS

We used a population-based retrospective cohort study from the National Health Insurance Service database of Korea including a total of 1,224,547 postmenopausal women. Associations between age at menarche (≤ 12, 13-14 [reference], 15, 16, and ≥ 17 years), age at menopause (< 40, 40-45, 46-50, 51-54 [reference], and ≥ 55 years), and reproductive span (< 30, 30-33, 34-36, 37-40 [reference], and ≥ 41 years) and the incidence of MI and IS were assessed by Cox proportional hazard models with adjustment for traditional cardiovascular risk factors and various reproductive factors.

RESULTS

During a median follow-up of 8.4 years, 25,181 MI and 38,996 IS cases were identified. Late menarche (≥ 16 years), early menopause (≤ 50 years), and short reproductive span (≤ 36 years) were linearly associated with a 6%, 12-40%, and 12-32% higher risk of MI, respectively. Meanwhile, a U-shaped association between age at menarche and risk of IS was found, with a 16% higher risk in early menarche (≤ 12 years) and a 7-9% higher risk in late menarche (≥ 16 years). Short reproductive span was linearly associated with an increased risk of MI, whereas both shorter and longer reproductive spans were associated with an increased risk of IS.

CONCLUSIONS

This study demonstrated different patterns of association between age at menarche and incidence of MI and IS: a linear association for MI versus a U-shaped association for IS. Female reproductive factors in addition to traditional cardiovascular risk factors should be considered when assessing overall cardiovascular risk in postmenopausal women.

Association of reproductive factors with cardiovascular disease risk in pre-menopausal women: nationwide population-based cohort study

BACKGROUND

Although the morbidity and mortality of cardiovascular diseases (CVD) are rising in young women, the risk factors of CVD among Korean pre-menopausal women have not been intensively investigated.

AIMS

To determine how age at menarche and other female reproductive factors are associated with the risk of CVD in pre-menopausal women.

METHODS AND RESULTS

A total of 1 088 992 pre-menopausal women who participated in health screening in 2009 were included. The study outcomes were myocardial infarction (MI) and ischaemic stroke. Cox proportional hazards regression analysis was conducted with adjustment of traditional CVD risk factors and reproductive factors.

RESULTS

Mean age was 43.8 ± 5.3 years (98.9%, < 55 years), 3.5% were current smokers, and 1.2% were heavy drinkers. During a mean follow-up of 8.3years [9 032 685.9 person-years (PY)], there were 10 876 CVD events (1.0 per 1000 PY).With later menarche, the risk of CVD increased; ≤12 years [adjusted hazard ratio (HR) 1.04, 95% confidence interval 0.93-1.16], 13 years (reference), 14 years (1.06, 0.98-1.14), 15 years (1.15, 1.07-1.24), 16 years (1.23, 1.14-1.34), and ≥17 years (1.33, 1.24-1.44). Compared with non-users, oral contraceptives (OC) users (≥1 year) had an increased risk of CVD (1.11, 1.01-1.22) (P for trend = 0.007).

CONCLUSIONS

Later menarche than the mean age at menarche (13 years old) and the use of OC (≥1 year) were associated with a higher risk of CVD, after adjusting for traditional cardiovascular risk factors. This study suggests that female reproductive factors could be unique risk factors for CVD in pre-menopausal women.

Changes in Alcohol Consumption and Risk of Dementia in a Nationwide Cohort in South Korea

IMPORTANCE

The impact of serial changes in alcohol consumption on dementia risk has rarely been investigated to date.

OBJECTIVE

To investigate the association of comprehensive patterns of changes in alcohol consumption with the incidence of all-cause dementia, Alzheimer disease (AD), and vascular dementia (VaD).

DESIGN, SETTING, AND PARTICIPANTS

This is a retrospective cohort study. Data were obtained from the Korean National Health Insurance Service database. Adults aged 40 years and older underwent 2 health examinations in 2009 and 2011. The cohort was assessed until December 31, 2018, and statistical analysis was performed in December 2021.

EXPOSURES

Alcohol consumption level was categorized into none (0 g per day), mild (<15 g per day), moderate (15-29.9 g per day), and heavy (≥30 g per day) drinking. On the basis of changes in alcohol consumption level from 2009 to 2011, participants were categorized into the following groups: nondrinker, quitter, reducer, sustainer, and increaser.

MAIN OUTCOMES AND MEASURES

The primary outcome was newly diagnosed AD, VaD, or other dementia.

RESULTS

Among 3 933 382 participants (mean [SD] age, 55.0 [9.6] years; 2 037 948 men [51.8%]), during a mean (SD) follow-up of 6.3 (0.7) years, there were 100 282 cases of all-cause dementia, 79 982 cases of AD, and 11 085 cases of VaD. Compared with sustained nondrinking, sustained mild (adjusted hazard ratio [aHR], 0.79; 95% CI, 0.77-0.81) and moderate (aHR, 0.83; 95% CI, 0.79-0.88) drinking were associated with a decreased risk of all-cause dementia, whereas sustained heavy drinking was associated with an increased risk of all-cause dementia (aHR, 1.08; 95% CI, 1.03-1.12). Compared with sustained levels of drinking, reducing alcohol consumption from a heavy to a moderate level (aHR, 0.92; 95% CI, 0.86-0.99) and the initiation of mild alcohol consumption (aHR, 0.93; 95% CI, 0.90-0.96) were associated with a decreased risk of all-cause dementia. Increasers and quitters exhibited an increased risk of all-cause dementia compared with sustainers. The trends in AD and VaD remained consistent.

CONCLUSIONS AND RELEVANCE

In this cohort study of a Korean population, decreased risk of dementia was associated with maintaining mild to moderate alcohol consumption, reducing alcohol consumption from a heavy to a moderate level, and the initiation of mild alcohol consumption, suggesting that the threshold of alcohol consumption for dementia risk reduction is low.

Body mass index, waist circumference and cardiovascular diseases in transitional ages (40 and 66 years)

BACKGROUND

There is lack of data on effect modification by age on the association between body mass index (BMI) or waist circumference (WC) and cardiovascular diseases (CVDs). We aimed to investigate the impact of BMI and WC on incident CVDs in individuals aged 40 and 66 years.

METHODS

Overall, 2 430 510 participants who underwent a national health screening for transitional ages provided by the Korean National Health Insurance Service between 2009 and 2012 were included. The adjusted hazard ratios and 95% confidence intervals for myocardial infarction (MI), ischaemic stroke and CVDs as a composite outcome of MI and ischaemic stroke were calculated using multivariable Cox proportional hazard regression analysis.

RESULTS

During a mean follow-up of 7.7 years, 24 884 MI and 29 415 ischaemic stroke events occurred. Among participants aged 40 years, there was a J-shaped association of BMI with incident CVDs, MI and ischaemic stroke with nadir at BMI 18.5-22.9 kg/m² (P for trend < 0.001 for all). Among those aged 66 years, there were significant U-shaped associations of BMI with CVDs and MI with nadir at a BMI of 23.0-24.9 kg/m² (P for trend 0.013 and 0.017, respectively). WC was linearly associated with all study outcomes in both age groups (P for trend <&nbsp;0.001). The impact of general and abdominal obesity on both study outcomes was more prominent in those aged 40 years than in those aged 66 years (P for interaction < 0.001).

CONCLUSIONS

To prevent cardiovascular risk, weight loss intervention should be cautiously implemented and individualized according to age. The maintenance of muscle mass may be essential in managing weight loss particularly in older population.

Association of Changes in Smoking Intensity With Risk of Dementia in Korea

IMPORTANCE

Several observational studies have reported that smoking cessation is associated with a lower risk of dementia. However, no studies have examined the association between change in smoking intensity and risk of dementia.

OBJECTIVE

To investigate the association between a change in smoking intensity, including smoking reduction and smoking cessation, and risk of all dementia.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study used data from the National Health Insurance Service database of Korea. The cohort included participants 40 years or older who underwent biennial health examinations (2009 and 2011) and had current smoking status at the first health examination. The cohort was followed up until December 31, 2018, and statistical analysis was performed between July and December 2021.

EXPOSURES

Change in smoking intensity from baseline was defined operationally as follows: quitters (stopped smoking), reducers I (decreased number of cigarettes smoked per day by ≥50%), reducers II (decreased number of cigarettes smoked per day by 20%-50%), sustainers (maintained [decreased or increased] number of cigarettes smoked per day by less than 20%), or increasers (increased number of cigarettes smoked per day by ≥20%).

MAIN OUTCOMES AND MEASURES

The primary outcome was newly diagnosed dementia, which was identified by prescribed antidementia medications with concomitant International Statistical Classification of Diseases and Related Health Problems, Tenth Revision diagnosis codes for dementia. Adjusted hazard ratios and 95% CIs were used to determine the association between change in smoking intensity and incidence of dementia, including Alzheimer disease (AD) and vascular dementia (VaD).

RESULTS

A total of 789 532 participants (756 469 males [95.8%]; mean [SD] age, 52.2 [8.5] years) were included. During a median (IQR) follow-up period of 6.3 (6.1-6.6) years, 11 912 dementia events, including 8800 AD and 1889 VaD events, were identified. Overall, participants in the quitter group had a significantly lower risk of all dementia (adjusted hazard ratio [aHR], 0.92; 95% CI, 0.87-0.97) compared with those in the sustainer group. Those in the reducer I (aHR, 1.25; 95% CI, 1.18-1.33) and increaser (aHR, 1.12; 95% CI, 1.06-1.18) groups had a significantly higher risk of all dementia compared with those in the sustainer group.The patterns for AD and VaD remained consistent with patterns for all dementia.

CONCLUSIONS AND RELEVANCE

The results of this study showed that smoking cessation was associated with a lower risk of dementia compared with sustained smoking intensity, while smoking reduction was associated with a higher risk. Smoking cessation should be emphasized in efforts to reduce the disease burden of dementia.

Increased Risk of Developing Depression in Disability after Stroke: A Korean Nationwide Study

Stroke is a leading cause of mortality and a major cause of disability worldwide. A significant number of stroke survivors suffer from depression, impeding the activities of daily living and rehabilitation. Here, we examined the risk of depression among stroke survivors according to the severity of disabilities and compared its incidence with a matched control group. We included data from the Korean National Health Insurance Service of 207,678 stroke survivors. Cox proportional hazard models were used to calculate the risk of depression among stroke survivors. Stroke survivors had a greater risk of developing depression than the matched control group with an adjusted hazard ratio of 2.12 (95% confidence interval 2.09-2.15). Stroke survivors with more severe disabilities were associated with a higher risk of depression than those with mild disabilities. The risk of developing depression was prominently high within the first year after a stroke. Males and younger people (<65 years) were independent risk factors for depression in stroke survivors. This study demonstrated an increased risk of developing depression in stroke survivors compared to control subjects, and a higher risk of depression was associated with a more severe degree of disability. Clinicians should be aware of the risk of depression developing in stroke survivors, especially those with disabilities.

Fracture risk in Parkinson's disease according to its severity and duration

Fracture risk was elevated in Parkinson's disease (PD) patients compared with controls in this nationwide study. Among PD patients, the risk of fracture increased linearly with PD severity, whereas no difference in fracture risk was observed according to PD duration.

INTRODUCTION

Parkinson's disease (PD) is reported to be associated with a high risk of fractures. Several studies found an association between severity and duration of PD and falls or bone mineral density, but those factors have not been considered in most previous research. The aim of this study was to determine the fracture risk in PD patients according to their disease severity and duration.

METHODS

This population-based, retrospective cohort study used data from the Korean National Health Insurance Service database. The study population included 10,333 patients with prevalent PD and 6,501,464 comparison cohort. Fracture risks according to the prevalence, severity, and duration of PD were evaluated using Cox proportional hazard methods.

RESULTS

Fracture risk was elevated in PD patients at all sites compared with controls (adjusted hazard ratio [aHR] 1.49, 95% confidence interval [CI] 1.44-1.56 for any fracture). When comparing fracture sites, hip fractures showed the largest risk increase in PD patients (aHR 2.16, 95% CI 1.95-2.38). Among PD patients, the risk of any fracture increased linearly with PD severity and was highest in patients with severe disease (aHR 1.65, 95% CI 1.53-1.79 compared with controls). Meanwhile, no significant association was observed between PD duration and fracture risk.

CONCLUSIONS

The prevalence of PD was related to an increased risk of fractures in this nationwide study, and PD severity was linearly associated with fracture risk. PD prevalence and severity should be considered when evaluating the risk factors of fracture in clinical practice.

Tuberculosis and the Risk of Ischemic Heart Disease: A Nationwide Cohort Study

Background

Little is known about the risk of ischemic heart disease (IHD) in tuberculosis (TB) survivors.

Methods

We performed a population-based retrospective cohort study using the Korean National Health Insurance Service database. TB survivors (n = 60,602) and their 1:1 age- and sex-matched controls (n = 60,602) were enrolled. Eligible participants were followed up from 1 year after their TB diagnosis to the date of an IHD event, date of death, or the end of the study period (December 31, 2018), whichever came first. The risk of IHD was estimated using a Cox proportional hazards regression, and stratified analyses were performed for related factors. Among IHD events, we additionally analyzed for myocardial infarction (MI).

Results

During a median of 3.9 years of follow-up, 2.7% of TB survivors (1,633/60,602) and 2.0% of the matched controls (1,228/60,602) developed IHD, and 0.6% of TB patients (341/60,602) and 0.4% of the matched controls (223/60,602) developed MI. The overall risk of developing IHD and MI was higher in TB patients (adjusted hazard [aHR] 1.21, 95% CI 1.12–1.32 for IHD and aHR 1.48, 95% CI 1.23–1.78 for MI) than in the matched controls. Stratified analyses showed that TB survivors have an increased risk of IHD and MI regardless of income, place of residence, smoking status, alcohol consumption, physical activity, body mass index, and Charlson comorbidity index.

Conclusions

TB survivors have a higher risk of IHD than matched controls. Strategies are needed to reduce the burden of IHD in TB survivors.

Changes in Alcohol Consumption and Risk of Heart Failure: A Nationwide Population-Based Study in Korea

Background: The association between alcohol intake and newly developed heart failure remains unclear. We aimed to measure the change in alcohol intake between two timepoints to evaluate the association of alcohol consumption with incident heart failure using a population-based study in Korea. Methods: Using the Korean National Health Insurance database, participants who underwent two subsequent national health examinations in 2009 and 2011 were included. Participants were classified into four groups according to total alcohol intake (none: 0 g alcohol/day; light: <15 g alcohol/day; moderate: 15−30 g alcohol/day; and heavy: ≥30 g alcohol/day), and changes in alcohol consumption between the two health exams were grouped into the following five categories: abstainers, sustainers (those who maintained their first examination drinking level), increasers, reducers, and quitters. After adjustment for age, sex, smoking status, regular exercise, socioeconomic information, and comorbidities, the Charlson Comorbidity Index, systolic blood pressure, and laboratory results, a Cox proportional hazards model was used to find the risk of newly diagnosed heart failure (according to ICD-10 code I50 from claims for the first hospitalization) as the primary endpoint. A subgroup analysis among those with a third examination was conducted to reflect further changes in alcohol consumption. Results: Among 3,842,850 subjects, 106,611 (3.0%) were diagnosed with heart failure during the mean follow-up period of 6.3 years. Increasers to a light level of drinking had a lower HF risk compared with abstainers (aHR = 0.91, 95% CI: 0.89−0.94). Those who increased their alcohol intake to a heavy level had a higher HF risk (from light to heavy (aHR = 1.19, 95% CI: 1.12−1.26) and from a moderate to heavy level (aHR = 1.13, 95% CI: 1.07−1.19). Reducing alcohol from a heavy to moderate level was associated with lower HF risk (aHR = 0.90, 95% CI: 0.86−0.95). Conclusion: This study found that light and moderate sustainers had lower incident heart failure risk compared with abstainers. Increased alcohol consumption from light to moderate to heavy was associated with a higher incident heart failure risk.

The Association of Smoking Status and Clustering of Obesity and Depression on the Risk of Early-Onset Cardiovascular Disease in Young Adults: A Nationwide Cohort Study

BACKGROUND AND OBJECTIVES

To evaluate the impact of smoking in young adults on the risk of cardiovascular disease (CVD) and the clustering effect of behavioral risk factors such as smoking, obesity, and depression.

METHODS

A Korean nationwide population-based cohort of a total of 3,280,826 participants aged 20-39 years old who underwent 2 consecutive health examinations were included. They were followed up until the date of CVD (myocardial infarction [MI] or stroke), or December 2018 (median, 6 years).

RESULTS

Current smoking, early age of smoking initiation, and smoking intensity were associated with an increased risk of CVD incidence. Even after quitting smoking, the risk of MI was still high in quitters compared with non-smokers. Cigarette smoking, obesity, and depression were independently associated with a 1.3-1.7 times increased risk of CVD, and clustering of 2 or more of these behavioral risk factors was associated with a 2-3 times increased risk of CVD in young adults.

CONCLUSIONS

In young adults, cigarette smoking was associated with the risk of CVD, and the clustering of 2 or more behavioral risk factors showed an additive risk of CVD.

The Association between Duration of Noise Exposure in the Workplace and Glucose Metabolism Status: Evidence from the Korea National Health and Nutrition Examination Survey

BACKGROUND

This study aimed to evaluate the association between the duration of workplace noise exposure and glucose metabolism status in a nationally representative Korean sample.

METHODS

This cross-sectional study included 3,534 participants aged ≥40 years without tinnitus or hearing loss from the Korea National Health and Nutrition Examination Survey (2018). The primary exposure was noise in the workplace and its duration. We divided the noise exposure group into four groups according to the duration of noise exposure (<3 years, 3-10 years, 10-20 years, and ≥20 years). The primary outcomes were fasting blood sugar (FBS), hemoglobin A1c (HbA1c), and pre-diabetes and diabetes diagnosed using FBS. Logistic and linear regression analyses were used to test the association between noise exposure and glycemic status.

RESULTS

After adjustment, HbA1c levels were significantly higher in the noise exposure than in the non-noise exposure group. HbA1c levels were significantly higher in those exposed to occupational noise for more than 20 years than in others. In the subgroup analysis among those who had been exposed to noise for >20 years, the non-aerobic physical activity group had significantly higher HbA1c levels than the physical activity group. Furthermore, among those who had been exposed to noise for >20 years, the without hearing protection group had significantly higher HbA1c levels than those using hearing protection.

CONCLUSION

The association between noise exposure and the prevalence of diabetes is unclear. However, our study clearly suggests that there is a relationship between elevated HbA1c levels and workplace noise exposure and that a long period of workplace noise exposure, no physical activity, and not wearing a hearing protection device could increase the risk of diabetes.

Tuberculosis and Risk of Ischemic Stroke: A Nationwide Cohort Study

BACKGROUND

Conflicting results exist regarding the risk of ischemic stroke in tuberculosis survivors. We aimed to estimate the risk of ischemic stroke using a nationwide population-based retrospective cohort.

METHODS

We gathered data from the Korean National Health Insurance Service on tuberculosis survivors and 1:1 age- and sex-matched non-tuberculosis cases. Eligible participants were followed up from 1 year after tuberculosis diagnosis to the date of ischemic stroke event, date of death, or until the end of the study period (December 31, 2018), whichever came first. Cox proportional hazard regression and stratified analyses were performed to identify any related factors.

RESULTS

During follow-up periods of 3.8 years for patients with tuberculosis and matched non-tuberculosis cases, 1.3% of patients with tuberculosis (941/72 863) and 1.0% of matched non-tuberculosis cases (707/72 863) developed ischemic stroke. The overall risk of ischemic stroke was higher in tuberculosis patients (adjusted hazard ratio: 1.22 [95% CI, 1.10-1.36]) compared with the matched non-tuberculosis cases. A stratified analysis showed that patients with tuberculosis had increased risk of ischemic stroke regardless of age, sex, smoking status, alcohol consumption, physical activity, body mass index, and Charlson Comorbidity Index score.

CONCLUSIONS

Tuberculosis survivors had a higher risk of ischemic stroke than their matched non-tuberculosis cases. The results of this study suggest that tuberculosis is a crucial infectious factor associated with increased incidence of ischemic stroke.

Association Between Changes in Alcohol Consumption and Cancer Risk

IMPORTANCE

Although numerous studies have shown an association between alcohol consumption and cancer, how changes in drinking behavior increase or decrease the incidence of cancer is not well understood.

OBJECTIVE

To investigate the association between the reduction, cessation, or increase of alcohol consumption and the development of alcohol-related cancers and all cancers.

DESIGN, SETTING, AND PARTICIPANTS

This population-based cohort study analyzed adult beneficiaries in the Korean National Health Insurance Service. Participants (aged ≥40 years) included those who underwent a national health screening in both 2009 and 2011 and had available data on their drinking status. Data were analyzed from April 16 to July 6, 2020.

EXPOSURES

Alcohol consumption level, which was self-reported by participants in health screening questionnaires, was categorized into none (0 g/d), mild (<15 g/d), moderate (15-29.9 g/d), and heavy (≥30 g/d) drinking. Based on changes in alcohol consumption level from 2009 to 2011, participants were categorized into the following groups: nondrinker, sustainer, increaser, quitter, and reducer.

MAIN OUTCOMES AND MEASURES

The primary outcome was newly diagnosed alcohol-related cancers (including cancers of the head and neck, esophagus, colorectum, liver, larynx, and female breast), and the secondary outcome was all newly diagnosed cancers (except for thyroid cancer).

RESULTS

Among the 4 513 746 participants (mean [SD] age, 53.6 [9.6] years; 2 324 172 [51.5%] men), the incidence rate of cancer was 7.7 per 1000 person-years during a median (IQR) follow-up of 6.4 (6.1-6.6) years. Compared with the sustainer groups at each drinking level, the increaser groups had a higher risk of alcohol-related cancers and all cancers. The increased alcohol-related cancer incidence was associated with dose; those who changed from nondrinking to mild (adjusted hazard ratio [aHR], 1.03; 95% CI, 1.00-1.06), moderate (aHR, 1.10; 95% CI, 1.02-1.18), or heavy (aHR, 1.34; 95% CI, 1.23-1.45) drinking levels had an associated higher risk than those who did not drink. Those with mild drinking levels who quit drinking had a lower risk of alcohol-related cancer (aHR, 0.96; 95% CI, 0.92-0.99) than those who sustained their drinking levels. Those with moderate (aHR, 1.07; 95% CI, 1.03-1.12) or heavy (aHR, 1.07; 95% CI, 1.02-1.12) drinking levels who quit drinking had a higher all cancer incidence than those who sustained their levels, but when quitting was sustained, this increase in risk disappeared. Compared with sustained heavy drinking, reduced heavy drinking levels to moderate levels (alcohol-related cancer: aHR, 0.91 [95% CI, 0.86-0.97]; all cancers: aHR, 0.96 [95% CI, 0.92-0.99]) or mild levels (alcohol-related cancer: aHR, 0.92 [95% CI, 0.86-0.98]; all cancers: aHR, 0.92 [95% CI, 0.89-0.96]) were associated with decreased cancer risk.

CONCLUSIONS AND RELEVANCE

Results of this study showed that increased alcohol consumption was associated with higher risks for alcohol-related and all cancers, whereas sustained quitting and reduced drinking were associated with lower risks of alcohol-related and all cancers. Alcohol cessation and reduction should be reinforced for the prevention of cancer.

Changes in Physical Activity and the Risk of Dementia in Patients With New-Onset Type 2 Diabetes: A Nationwide Cohort Study

OBJECTIVE

We investigated the association between interval changes in physical activity (PA) and dementia risk among patients with new-onset type 2 diabetes.

RESEARCH DESIGN AND METHODS

We identified 133,751 participants newly diagnosed with type 2 diabetes in a health screening (2009-2012), with a follow-up health screening within 2 years (2010-2015). PA level changes were categorized into continuous lack of PA, decreaser, increaser, and continuous PA groups. Dementia was determined using dementia diagnosis codes and antidementia drug prescriptions.

RESULTS

During the median follow-up of 4.8 years, 3,240 new cases of all-cause dementia developed. Regular PA was associated with lower risks of all-cause dementia (adjusted hazard ratio [aHR] 0.82; 95% CI 0.75-0.90), Alzheimer disease (AD) (aHR 0.85; 95% CI 0.77-0.95), and vascular dementia (VaD) (aHR 0.78; 95% CI 0.61-0.99). Increasers who started to engage in regular PA had a lower risk of all-cause dementia (aHR 0.86; 95% CI 0.77-0.96). Moreover, the risk was further reduced among those with continuous regular PA: all-cause dementia (aHR 0.73; 95% CI 0.62-0.85), AD (aHR 0.74; 95% CI 0.62-0.88), and VaD (aHR 0.62; 95% CI 0.40-0.94). Consistent results were noted in various subgroup analyses.

CONCLUSIONS

Regular PA was independently associated with lower risks of all-cause dementia, AD, and VaD among individuals with new-onset type 2 diabetes. Those with continuous regular PA and, to a lesser extent, those who started to engage in regular PA had a lower risk of dementia. Regular PA should be encouraged to prevent dementia in high-risk populations and those with new-onset type 2 diabetes.

Association of Change in Alcohol Consumption With Risk of Ischemic Stroke

BACKGROUND

The effect of serial change in alcohol consumption on stroke risk has been limitedly evaluated. We investigated the association of change in alcohol consumption with risk of stroke.

METHODS

This study is a population-based retrospective cohort study from National Health Insurance Service database of all Koreans. Four lakh five hundred thirteen thousand seven hundred forty-six participants aged ≥40 years who underwent 2 subsequent national health examinations in both 2009 and 2011. Alcohol consumption was assessed by average alcohol intake (g/day) based on self-questionnaires and categorized into non-, mild, moderate, and heavy drinking. Change in alcohol consumption was defined by shift of category from baseline. Cox proportional hazards model was used with adjustment for age, sex, smoking status, regular exercise, socioeconomic information, and comorbidities, Charlson Comorbidity Index, systolic blood pressure, and laboratory results. Subgroup analysis among those with the third examination was conducted to reflect further change in alcohol consumption.

RESULTS

During 28 424 497 person-years of follow-up, 74 923 ischemic stroke events were identified. Sustained mild drinking was associated with a decreased risk of ischemic stroke (adjusted hazard ratio, 0.88 [95% CI, 0.86-0.90]) compared with sustained nondrinking, whereas sustained heavy drinking was associated with an increased risk of ischemic stroke (adjusted hazard ratio, 1.06 [95% CI, 1.02-1.10]). Increasing alcohol consumption was associated with an increased risk of ischemic stroke (adjusted hazard ratio, 1.11 [95% CI, 1.06-1.17] from mild to moderate; adjusted hazard ratio, 1.28 [95% CI, 1.19-1.38] from mild to heavy) compared with sustained mild drinkers. Reduction of alcohol consumption from heavy to mild level was associated with 17% decreased risk of ischemic stroke through 3× of examinations.

CONCLUSIONS

Light-to-moderate alcohol consumption is associated with a decreased risk of ischemic stroke, although it might be not causal and could be impacted by sick people abstaining from drinking. Reduction of alcohol consumption from heavy drinking is associated with a decreased risk of ischemic stroke.

Blood Pressure Variability and the Risk of Fracture: A Nationwide Cohort Study

CONTEXT

Although blood pressure variability (BPV) is associated with various health outcomes, only 1 study suggested that BPV is correlated with hip fractures. As cardiovascular disease and fractures share similar pathophysiology, there might be a link between BPV and fractures.

OBJECTIVE

To investigate the association between BPV and the incident fractures.

DESIGN

Retrospective cohort study.

SETTING

Population-based, using the Korean National Health Insurance System database.

PATIENTS OR OTHER PARTICIPANTS

A total of 3 256 070 participants aged ≥50 who participated in ≥3 health examinations within the previous 5 years, including the index year (2009-2010), were included. Outcome data were obtained through the end of 2016.

EXPOSURE

BPV was calculated using variability independent of the mean. High variability was defined as the highest quartile of variability.

MAIN OUTCOME MEASURES

Newly diagnosed fractures.

RESULTS

During the median follow-up of 7.0 years, there were 337 045 cases of any fracture (10.4%). After adjusting for age, sex, income, lifestyle factors, and comorbidities, a higher risk of fracture was observed with higher quartiles of BPV than the lowest quartile group: the adjusted hazard ratios (95% CIs) for incident any fracture were 1.07 (1.06-1.08) in the higher quartile of systolic BPV, 1.06 (1.05-1.07) in that of diastolic BPV, and 1.07 (1.06-1.08) in that of both systolic and diastolic BPV. Consistent results were noted for vertebral fractures and hip fractures, as well as in various subgroup analyses.

CONCLUSIONS

A positive association was noted between higher BPV and fracture incidence. BPV is an independent predictor for developing fracture.

Effect of smoking reduction, cessation, and resumption on cancer risk: A nationwide cohort study

BACKGROUND

The objective of this study was to investigate the effects of reduction, cessation, and resumption of smoking on cancer development.

METHODS

The authors identified 893,582 participants who currently smoked, had undergone a health screening in 2009, and had a follow-up screening in 2011. Among them, 682,996 participated in a third screening in 2013. Participants were categorized as quitters, reducers I (≥50% reduction), reducers II (<50% reduction), sustainers (referent), or increasers (≥20% increase). Outcome data were obtained through December 31, 2018.

RESULTS

Reducers I exhibited a decreased risk of all cancers (adjusted hazard ratio [aHR], 0.96; 95% confidence interval [CI], 0.93-0.99), smoking-related cancers (aHR, 0.95; 95% CI, 0.92-0.99), and lung cancer (aHR, 0.83; 95% CI, 0.77-0.88). Quitters had the lowest risk of all cancers (aHR, 0.94; 95% CI, 0.92-0.96), smoking-related cancers (aHR, 0.91; 95% CI, 0.89-0.93), and lung cancer (aHR, 0.79; 95% CI, 0.76-0.83). In further analysis with 3 consecutive screenings, additional smoking reduction (from reducers II to reducers I) lowered the risk of lung cancer (aHR, 0.74; 95% CI, 0.58-0.94) in comparison with sustainers. Quitting among reducers I further decreased the risk of all cancers (aHR, 0.90; 95% CI, 0.80-1.00), smoking-related cancers (aHR, 0.81; 95% CI, 0.81-0.92), and lung cancer (aHR, 0.66; 95% CI, 0.52-0.84) in comparison with sustainers. Smoking resumption after quitting, even at a lower level, increased the risk of smoking-related cancers (aHR, 1.19; 95% CI, 1.06-1.33) and lung cancer (aHR, 1.48; 95% CI, 1.21-1.80) in comparison with sustained quitting.

CONCLUSIONS

Smoking cessation and, to a lesser extent, smoking reduction decreased the risks of cancer. Smoking resumption increased cancer risks in comparison with sustained quitting.

LAY SUMMARY

Worldwide, tobacco use is the single leading preventable risk factor for cancer and cancer death. This study examined the effects of reduction, cessation, and resumption of smoking on cancer development by measuring smoking behavior repetitively. Although smoking reduction has a substantial cancer prevention benefit for those who cannot quit, cessation should be encouraged whenever possible. Quitters should be monitored to ensure that they do not resume smoking.

Female reproductive factors and risk of joint replacement arthroplasty of the knee and hip due to osteoarthritis in postmenopausal women: a nationwide cohort study of 1.13 million women

OBJECTIVES

Previous studies of the relationships between female reproductive factors and osteoarthritis (OA) have shown conflicting results. In this study, we aimed to explore the relationships between reproductive factors and joint replacement arthroplasty of the knee (TKRA) and hip (THRA) in a large nationwide population-based cohort of postmenopausal Korean women.

METHODS

We included 1,134,680 subjects who participated in national health examinations in 2009 in the study. The study outcomes were incident THRA or TKRA due to severe hip or knee OA. The relationships between reproductive factors and THRA or TKRA were evaluated using a multivariable-adjusted proportional hazards model.

RESULTS

During a mean follow-up duration of 8.2 years, 1,610 incident THRA cases and 60,670 incident TKRA cases were observed. Later age at menarche, longer breastfeeding, HRT and OC use were associated with increased risk of TKRA for severe knee OA, while later age at menopause and longer reproductive span were associated with decreased risk. With regard to THRA for severe hip OA, later menarche, longer breastfeeding, HRT more than 5 years, and OC use more than 1 year were associated with higher risk. The associations between reproductive factors and severe OA were more pronounced in underweight and younger subjects.

CONCLUSION

We found that shorter estrogen exposure was associated with higher risk of TKRA due to severe knee OA, and such associations were more pronounced in underweight and younger subjects. The association between shorter estrogen exposure and THRA was not robust.

Associations between alcohol consumption patterns and risk of multiple myeloma: A nationwide cohort study in South Korea

BACKGROUND

Among the potential modifiable risk factors, the association between alcohol consumption and the risk of multiple myeloma (MM) remains controversial. We investigated the effects of weekly average alcohol consumption and drinking pattern on the risk of MM using a nationwide representative database.

METHODS

We identified 11,737,467 subjects who participated in the Korean national health screening program in 2009-2010. Cox regression analyses were performed to calculate the risk of MM according to weekly alcohol consumption, drinking frequency, and amount per session.

RESULTS

During a mean follow-up period of 6.8 years after a one-year time lag, 6,981 subjects (3,921 men and 3,060 women) were diagnosed with MM. Compared with non-drinkers, all drinkers were at a significantly lower risk for MM. The risk of MM was reduced in a dose-dependent manner: mild drinkers, adjusted hazard ratio (aHR) 0.89, 95% confidence interval (CI) 0.84-0.95; moderate drinkers, aHR 0.83, 95% CI 0.76-0.91; and heavy drinkers, aHR 0.76, 95% CI 0.69-0.85. Furthermore, both drinking frequency and amount per drinking session showed inverse association with the risk of MM.

CONCLUSIONS

Our large population-based study suggested an inverse dose-dependent association between total average alcohol consumption and the risk of MM, and drinking frequency and amount per drinking session seemed to not differ in their relative contribution to the risk of MM.

IMPACT

Based on the unprecedently large number of study population analyzed in this study, our study provides solid epidemiologic evidence of alcohol consumption on MM risk.

Body Mass Index, Diabetes, and Risk of Tuberculosis: A Retrospective Cohort Study

Although both diabetes mellitus (DM) and underweight are associated with increased risk of tuberculosis (TB), there are limited data evaluating TB risk while considering two factors simultaneously—body mass index (BMI) and DM. A retrospective cohort study was performed with 10,087,903 participants of the Korean National Health Screening Program in 2009. The cohort was followed up to the date of TB incidence, death, or until December 31, 2018. We compared the incidence and risk of TB according to BMI category and DM. During the 7.3-year follow-up duration, the incidence of TB was 0.92 per 1,000 person-years in the normal weight without DM, 2.26 in the normal weight with DM, 1.80 in the underweight without DM, and 5.35 in the underweight with DM. Compared to the normal weight without DM, the normal weight with DM, the underweight without DM, and the underweight with DM showed a 1.51-fold (95% CI, 1.46–1.57), a 2.21-fold (95% CI, 2.14–2.28), and a 3.24-fold (95% CI, 2.95–3.56) increased risk of TB, respectively. However, compared to the normal weight without DM, the severely obese without DM and those with DM showed a 0.37 (95% CI, 0.36–0.38) and a 0.42 (95% CI, 0.36–0.48)-fold decreased risk of TB, respectively. There was no significant joint effect of BMI and DM on the risk of incident TB in the overall population; a synergistic effect of underweight and DM was evident in participants <65 years of age, current smokers, and heavy drinkers. In conclusion, being underweight or DM individually increases the risk of incident TB. Based on our study results, a focused screening of incident TB in patients with DM may be beneficial.

Association between obesity and the risk of gastric cancer in premenopausal and postmenopausal women: A nationwide cohort study

BACKGROUND AND AIM

Obesity was suggested to increase the incidence of gastric cancer (GC) in women, but results from previous studies were inconsistent. We investigated the relationship between obesity and the risk of GC according to menopausal status.

METHODS

We enrolled 1 418 180 premenopausal and 4 854 187 postmenopausal women aged ≥ 40 years using the Korean National Health Insurance System Cohort (2009-2014). We calculated hazard ratios (HRs) and 95% confidence intervals (CIs) for GC incidence according to body mass index (BMI) and waist circumference (WC) using the Cox proportional hazards models.

RESULTS

During the mean follow-up period of 7.2 years, 42 441 women were newly diagnosed with GC. Compared with the group with BMI 18.5-22.9 kg/m² , the adjusted HRs (95% CIs) for GC in the groups with BMI < 18.5, 23-24.9, 25-29.9, and ≥ 30 kg/m² were 1.12 (0.95-1.33), 0.96 (0.89-1.04), 1.02 (0.94-1.11), and 0.99 (0.83-1.18), respectively, for premenopausal women and 1.07 (1.00-1.14), 1.01 (0.99-1.04), 1.03 (1.00-1.05), and 1.11 (1.10-1.16), respectively, for postmenopausal women. Compared with the group with WC 65-74.9 cm, the adjusted HRs (95% CIs) for GC for the groups with WC < 65, 75-84.9, 85-94.9, and ≥ 90 cm were 1.00 (0.88-1.15), 1.03 (0.96-1.11), 1.10 (0.99-1.22), and 1.02 (0.81-1.27), respectively, for premenopausal women and 1.01 (0.94-1.09), 1.01 (0.99-1.04), 1.09 (1.06-1.13), and 1.14 (1.09-1.19), respectively, for postmenopausal women.

CONCLUSIONS

We found a positive association between the highest BMI and WC category and risk of GC in postmenopausal women; however, such an association was not evident in premenopausal women.

Being Underweight Increases the Risk of Non-Cystic Fibrosis Bronchiectasis in the Young Population: A Nationwide Population-Based Study

Although body mass index (BMI) is a potential risk factor for bronchiectasis in young adults, the association between BMI and incident bronchiectasis has not been well elucidated. This study included 6,329,838 individuals aged 20-40 years from the Korean National Health Insurance Service database 2009-2012 who were followed up until the date of the diagnosis of bronchiectasis, death, or 31 December 2018. We evaluated the incidence and risk of bronchiectasis according to the BMI category. The incidence rate of bronchiectasis increased as BMI decreased in a dose-dependent manner (p for trend <0.01). In multivariable Cox regression analysis, being underweight was an independent risk factor for the development of bronchiectasis, with a hazard ratio of 1.24 (95% confidence interval, 1.19-1.30) compared to being normal weight. In subgroup analysis, the effect of being underweight on the development of bronchiectasis was more evident in males and older individuals (30-40 years) than females and younger individuals (20-29 years), respectively (p for interaction <0.01 for both). These results remained significant in subgroup analysis in which subjects with comorbidities related to being underweight were excluded. Being underweight may be a novel risk factor for the development of bronchiectasis in young adults.

Diabetes Status and Association With Risk of Tuberculosis Among Korean Adults

IMPORTANCE

The risk of tuberculosis (TB) associated with diabetes status, considering impaired fasting glucose or duration of diabetes, has not been well established.

OBJECTIVE

To evaluate the association of diabetes status with the development of TB in the general population.

DESIGN, SETTING, AND PARTICIPANTS

This population-based cohort study used data from the Korean National Health Insurance System database. Adult participants without a history of TB who underwent a health screening in 2009 were included. Eligible participants were followed up for incident TB cases from 1 year after the day of health screening until December 31, 2018. Data analysis was performed from September 2019 to September 2020.

EXPOSURES

Five levels of diabetes status were evaluated: normal glucose, impaired fasting glucose (considered as without diabetes), new-onset diabetes, diabetes duration less than 5 years, and diabetes duration 5 years or longer (considered as having diabetes).

MAIN OUTCOMES AND MEASURES

Newly diagnosed TB.

RESULTS

Among 4 423 177 participants, the mean (SD) age was 46.5 (13.9) years, and there were 2 597 142 men (58.7%). A total of 26 458 participants (0.6%) received a diagnosis of TB within a median (interquartile range) of 8.3 (8.1-8.6) years of follow-up. An increased risk of TB was observed in participants with diabetes compared with those without diabetes (adjusted hazard ratio [aHR], 1.48; 95% CI, 1.42-1.53). Although participants with impaired fasting glucose did not show an increased risk of TB incidence (aHR, 0.97; 95% CI, 0.93-1.01), the risk of TB incidence increased with diabetes duration (new-onset diabetes, aHR, 1.32; 95% CI, 1.23-1.42; diabetes duration <5 years, aHR, 1.45; 95% CI, 1.36-1.54; diabetes duration ≥5 years, aHR, 1.57; 95% CI, 1.48-1.66). Among participants with new-onset diabetes, compared with those in the lowest decile (fasting plasma glucose [FPG] level ≥126 but <128 mg/dL), the risk of TB was significantly increased for those in the highest decile (FPG level ≥202 mg/dL, aHR, 1.79; 95% CI, 1.42-2.26).

CONCLUSIONS AND RELEVANCE

These findings suggest that longer diabetes duration is associated with development of TB, showing a dose-response association. Among participants with new-onset diabetes, incident TB was more common among those with FPG levels greater than or equal to 202 mg/dL.

Association of the Frequency and Quantity of Alcohol Consumption With Gastrointestinal Cancer

IMPORTANCE

Although total alcohol consumption is a known risk factor for gastrointestinal (GI) cancers, few studies have attempted to assess the pattern of alcohol drinking in association with GI cancers.

OBJECTIVE

To evaluate the relative association of the frequency of drinking vs the amount of alcohol consumed per occasion with the development of GI cancers.

DESIGN, SETTING, AND PARTICIPANTS

A population-based retrospective cohort study used data from the Korean National Health Insurance System database on 11 737 467 participants without cancer who underwent a national health screening program from January 1, 2009, to December 31, 2010. Participants were followed up from the year after their health screening date until they received a diagnosis of GI cancer, death, or December 31, 2017. The median follow-up duration was 6.4 years (interquartile range, 6.4-7.4 years). Statistical analysis was performed from January 1, 2019, to March 31, 2020.

EXPOSURES

Weekly alcohol consumption (nondrinker [0 g/week], mild drinker [0-104 g/week], moderate drinker [105-209 g/week], and heavy drinker [≥210 g/week]), drinking frequency, and amount per occasion.

MAIN OUTCOMES AND MEASURES

Incident GI cancers at 6 specific sites (esophagus, stomach, colorectal, liver, biliary, and pancreas).

RESULTS

Among 11 737 467 participants (6 124 776 women [52.2%]; mean [SD] age, 54.6 [10.4] years), 319 202 (2.7%) developed GI cancer. Compared with nondrinkers, the risk of GI cancer was higher for mild drinkers (adjusted hazard ratio [aHR], 1.04; 95% CI, 1.03-1.05), moderate drinkers (aHR, 1.14; 95% CI, 1.12-1.15), and heavy drinkers (aHR, 1.28; 95% CI, 1.26-1.29). The risk of GI cancer increased linearly with the frequency of drinking in a dose-dependent manner (aHR, 1.39; 95% CI, 1.36-1.41 for individuals who drink every day). In contrast, the risk of GI cancer appeared to increase with consumption up to 5 to 7 units per occasion (aHR, 1.15; 95% CI, 1.14-1.16), and then the HRs were no higher for those with a higher intake per session than 5 to 7 units (8-14 units per occasion: aHR, 1.11; 95% CI, 1.09-1.12; >14 units per occasion: aHR, 1.11; 95% CI, 1.08-1.14). Given similar weekly alcohol consumption levels, the risk of GI cancer increased with a higher frequency of drinking and decreased with a higher amount per occasion. Risk patterns for 6 specific cancers were generally similar to that of all GI cancers.

CONCLUSIONS AND RELEVANCE

In this cohort study, frequent drinking was a more important risk factor for incident GI cancers than the amount of alcohol consumed per occasion. Individuals should be cautioned about regular consumption of small amounts of alcohol in addition to the total amount of alcohol consumption or amount per occasion.

Anemia, sarcopenia, physical activity, and the risk of tuberculosis in the older population: a nationwide cohort study

Background:

The aim of this study was to investigate whether physical activity, sarcopenia, and anemia are associated an with increased risk of tuberculosis (TB) among the older population.

Methods:

We included 1,245,640 66-year-old subjects who participated in the National Screening Program for Transitional Ages for Koreans from 2009 to 2014. At baseline, we assessed common health problems in the older population, including anemia and sarcopenia. The subjects’ performance in the timed up-and-go (TUG) test was used to predict sarcopenia. The incidence of TB was determined using claims data from the National Health Insurance Service database.

Results:

The median follow-up duration was 6.4 years. There was a significant association between the severity of anemia and TB incidence, with an adjusted hazard ratio (aHR) of 1.28 [95% confidence interval (CI), 1.20–1.36] for mild anemia and 1.69 (95% CI, 1.51–1.88) for moderate to severe anemia. Compared with those who had normal TUG times, participants with slow TUG times (⩾15 s) had a significantly increased risk of TB (aHR 1.19, 95% CI, 1.07–1.33). On the other hand, both irregular (aHR 0.88, 95% CI 0.83–0.93) and regular (aHR 0.84, 95% CI, 0.78–0.92) physical activity reduced the risk of TB. Male sex, lower income, alcohol consumption, smoking, diabetes, and asthma/chronic obstructive pulmonary disease increased the risk of TB.

Conclusion:

The risk of TB among older adults increased with worsening anemia, sarcopenia, and physical inactivity. Physicians should be aware of those modifiable predictors for TB among the older population.

Association between physical performance and incidence of end-stage renal disease in older adults: a national wide cohort study

Background

Physical frailty has previously been associated with adverse clinical outcomes in patients with end-stage renal disease (ESRD). This study aimed to determine whether impaired physical performance at baseline is associated with the incidence of ESRD, using a nationwide database.

Methods

The timed up-and-go (TUG) test was used to assess physical frailty in 1,552,781 66-year-old individuals, using health examination database records from the Korean National Health Insurance Service. As a primary endpoint, incident ESRD was defined operationally using healthcare claims data from the Korean Health Insurance Review and Assessment Service.

Results

Our results showed that baseline kidney function was significantly worse in individuals with TUG results of > 10 s compared to individuals with an intact TUG performance (≤10 s). Kaplan-Meier analysis showed a stepwise dose-response relationship between baseline physical performance and the incidence rate of ESRD (log-rank test P-value of < 0.001). An increasing ESRD incidence rate trend with poor physical performance remained significant after adjusting for characteristics such as baseline glomerular filtration rate and proteinuria.

Conclusion

Poor baseline physical performance was associated with an increased risk of ESRD, suggesting possible interactions between systemic frailty and vascular aging processes.

Conditional Survival of Surgically Treated Patients with Lung Cancer: A Comprehensive Analyses of Overall, Recurrence-free, and Relative Survival

Purpose

Survival probability changes over time in cancer survivors. This study examined conditional survival in patients undergoing curative resection for non-small cell lung cancer (NSCLC).

Materials and Methods

Five-year conditional recurrence-free survival (CRFS), conditional overall survival (COS), and conditional relative survival (CRS) up to 10 years after surgery were calculated in patients who underwent NSCLC resection from 1994 to 2016. These rates were stratified according to age, sex, year of diagnosis, pathological stage, tumor histology, smoking status, comorbidity, and lung function.

Results

Five-year CRFS increased from 65.6% at baseline to 90.9% at 10 years after surgery. Early differences in 5-year CRFS according to stratified patient characteristics disappeared, except for age: older patients exhibited persistently lower 5-year CRFS. Five-year COS increased from 72.7% to 78.3% at 8 years and then decreased to 75.4% at 10 years. Five-year CRS increased from 79.0% at baseline to 86.8% at 10 years. Older age and higher pathologic stage were associated with lower 5-year COS and CRS up to 10 years after surgery. Female patients, those with adenocarcinoma histology, non-smokers, patient without comorbidities and had good lung function showed higher COS and CRS.

Conclusion

CRFS improved over time, but significant risk remained after 5 years. CRS slightly improved over time but did not reach 90%, suggesting significant excess mortality compared to the general population. Age and stage remained significant predictors of conditional survival several years after surgery. Our conditional survival estimates should help clinicians and patients make informed treatment and personal life decisions based on survivorship status.

Association of Female Reproductive Factors With Incidence of Fracture Among Postmenopausal Women in Korea

IMPORTANCE

Although estrogen level is positively associated with bone mineral density, there are limited data on the risk of fractures after menopause.

OBJECTIVE

To investigate whether female reproductive factors are associated with fractures among postmenopausal women.

DESIGN, SETTING, AND PARTICIPANTS

This population-based retrospective cohort study used data from the Korean National Health Insurance Service database on 1 272 115 postmenopausal women without previous fracture who underwent both cardiovascular and breast and/or cervical cancer screening from January 1 to December 31, 2009. Outcome data were obtained through December 31, 2018.

EXPOSURES

Information was obtained about reproductive factors (age at menarche, age at menopause, parity, breastfeeding, and exogenous hormone use) by self-administered questionnaire.

MAIN OUTCOMES AND MEASURES

Incidence of any fractures and site-specific fractures (vertebral, hip, and others).

RESULTS

Among the 1 272 115 participants, mean (SD) age was 61.0 (8.1) years. Compared with earlier age at menarche (≤12 years), later age at menarche (≥17 years) was associated with a higher risk of any fracture (adjusted hazard ratio [aHR], 1.24; 95% CI, 1.17-1.31) and vertebral fracture (aHR, 1.42; 95% CI, 1.28-1.58). Compared with earlier age at menopause (<40 years), later age at menopause (≥55 years) was associated with a lower risk of any fracture (aHR, 0.89; 95% CI, 0.86-0.93), vertebral fracture (aHR, 0.77; 95% CI, 0.73-0.81), and hip fracture (aHR, 0.88; 95% CI, 0.78-1.00). Longer reproductive span (≥40 years) was associated with lower risk of fractures compared with shorter reproductive span (<30 years) (any fracture: aHR, 0.86; 95% CI, 0.84-0.88; vertebral fracture: aHR, 0.73; 95% CI, 0.71-0.76; and hip fracture: aHR, 0.87; 95% CI, 0.80-0.95). Parous women had a lower risk of any fracture than nulliparous women (aHR, 0.96; 95% CI, 0.92-0.99). Although breastfeeding for 12 months or longer was associated with a higher risk of any fractures (aHR, 1.05; 95% CI, 1.03-1.08) and vertebral fractures (aHR, 1.22; 95% CI, 1.17-1.27), it was associated with a lower risk of hip fracture (aHR, 0.84; 95% CI, 0.76-0.93). Hormone therapy for 5 years or longer was associated with lower risk of any factures (aHR, 0.85; 95% CI, 0.83-0.88), while use of oral contraceptives for 1 year or longer was associated with a higher risk of any fractures (aHR, 1.03; 95% CI, 1.01-1.05).

CONCLUSIONS AND RELEVANCE

The findings of this cohort study suggest that female reproductive factors are independent risk factors for fracture, with a higher risk associated with shorter lifetime endogenous estrogen exposure. Interventions to reduce fracture risk may be needed for women at high risk, including those without osteoporosis.

Conditional relative survival and competing mortality in patients who underwent surgery for lung cancer: A nationwide cohort study

We aimed to investigate the conditional relative survival (CRS) and competing mortality in patients who underwent surgery for newly diagnosed lung cancer. Using a nationwide population-based database, we calculated 5-year CRS on 1 to 5 years survival after surgery. These rates were reported according to age, sex, socioeconomic status, comorbidities and treatment received. We also estimated cause-specific mortality with the consideration of competing risk. We identified 34 349 patients newly diagnosed with primary lung cancer from 2007 to 2013. The 5-year CRS after surgery was 71.7% at baseline improving steadily to 85.4% by 5 years, suggesting evidence of persistent excess mortality risk. Throughout the period, lung cancer was the most common cause of death, contributing to 83.6% mortality 1 year after surgery and 66.3% 5 years after surgery. Other causes of death included cardiovascular disease and respiratory disease, which increased continuously with time after surgery. CRS rates for patients with lung cancer improved over time but did not reach the level of the general population even 5 years after surgery. Although the main cause of death continues to be lung cancer, death from noncancer causes increased with time after surgery. Evidence-based decisions could be made on the dynamic risk profiles of the patients.

Obesity Has a Stronger Relationship with Colorectal Cancer in Postmenopausal Women than Premenopausal Women

BACKGROUND

To examine the relationship between obesity measured by waist circumference (WC) and body mass index (BMI) and the incidence of colorectal cancer in premenopausal and postmenopausal women.

METHODS

A total of 1,418,180 premenopausal and 4,854,187 postmenopausal women without cancer at baseline and ages over 40 were identified using the Korean National Health Insurance System Cohort during 2009 to 2014. The hazard ratio (HR) for colorectal cancer incidence was assessed according to menopausal state using Cox proportional hazards models.

RESULTS

During a mean follow-up period of 7.2 years, 7,094 and 57,449 colorectal cancer cases occurred in premenopausal and postmenopausal women, respectively. Compared with the reference group (WC 65-75), the HRs [95% confidence interval (CI)] of colorectal cancer in WC <65, 75-85, 85-95, and >95 groups were 1.01 (0.91-1.11), 1.02 (0.97-1.07), 1.09 (1.00-1.18), and 1.31 (1.12-1.52), respectively, in premenopausal women and 1.01 (0.95-1.17), 1.09 (1.07-1.12), 1.19 (1.00-1.18), and 1.30 (1.25-1.35), respectively, in postmenopausal women. Compared with the reference group (BMI 18.5-22.9), HRs (95% CI) for colorectal cancer in BMI <18.5, 23-25, 25-30, and >30 groups were 0.99 (0.87-1.14), 0.99 (0.94-1.06), 0.98 (0.92-1.04), and 1.06 (0.92-1.20), respectively, in premenopausal women. In postmenopausal women, those values were 0.99 (0.93-1.05), 1.05 (1.03-1.08), 1.11 (1.09-1.13), and 1.20 (1.16-1.25), respectively.

CONCLUSIONS

WC is associated with the risk of colorectal cancer in both groups of women, but this association was stronger in postmenopausal women than in premenopausal women. BMI increased the incidence of colorectal cancer only in postmenopausal women IMPACT: Obesity has a stronger relationship with colorectal cancer in postmenopausal women than in premenopausal women.