Antiplatelet agents for the secondary prevention of ischaemic stroke in patients with or without renal dysfunction.

BACKGROUND AND PURPOSE: Studies on using antiplatelet agents for secondary prevention in ischaemic stroke patients with renal dysfunction are limited. The Taiwan Stroke Registry database was used to compare the efficacy of antiplatelet agents. METHODS: From the Taiwan Stroke Registry data, 39 174 acute ischaemic stroke patients were identified and were classified into three groups by antiplatelet agent: aspirin, clopidogrel and dual antiplatelet therapy (DAPT) with a combination of aspirin and clopidogrel. The re-stroke incidence and 1-year mortality were stratified by estimated glomerular filtration rate (eGFR) levels at admission: ≥90, 60-89 and <60 ml/min/1.73 m2 or on dialysis. RESULTS: Compared to the aspirin group, the re-stroke differences were not statistically significant for the clopidogrel group [adjusted subhazard ratio 0.95, 95% confidence interval (CI) 0.84-1.08] and the DAPT group (adjusted subhazard ratio 1.03, 95% CI 0.77-1.39) after controlling for the competing risk of death. The mortality rate increased as the eGFR level declined. In addition, compared to patients taking aspirin, there was no statistically significant difference in overall 1-year mortality for the clopidogrel group (adjusted hazard ratio 1.11, 95% CI 0.95-1.29) and for the DAPT group (adjusted hazard ratio 1.01, 95% CI 0.67-1.54). The results were consistent in different subgroups stratified by eGFR levels. CONCLUSIONS: There was no difference in the risks of recurrent stroke and 1-year mortality amongst ischaemic stroke patients with or without renal dysfunction receiving antiplatelet agents with aspirin, clopidogrel or dual agents with a combination of aspirin and clopidogrel, regardless of their renal dysfunction status.

Risk of hypertension after hysterectomy: a population-based study.

OBJECTIVE: Hysterectomy is the second most common surgery performed mainly for benign uterine pathologies in females. The association between hysterectomy and the subsequent risk of hypertension remains controversial. This study investigated the risk of developing hypertension in women who had a hysterectomy. DESIGN: Population-based retrospective cohort study. SETTING: We used the Taiwan National Health Insurance Research Database with claims data of 1 million randomly selected insured individuals. POPULATION: Women with and without hysterectomy and bilateral salpingo-oophorectomy, aged 30-49 years, were identified in 2000-2013 from the insurance data. METHODS: From the claims data, we identified 6674 women with hysterectomy without hypertension at the time of the surgery. The comparison cohort were 26 696 women randomly selected from women without hysterectomy and hypertension, matched by age and the year hysterectomy was performed. Adjusted hazard ratio (aHR) of hypertension was estimated after controlling for comorbidities. MAIN OUTCOME MEASURE: Prediction for hypertension following hysterectomy for benign disease. RESULTS: Both cohorts had a median age of 43.9 years. After a median follow up of 6.4 years, the incident hypertension was higher in the hysterectomy cohort than in the comparison cohort, with an adjusted hazard ratio (aHR) of 1.35 [95% confidence interval (CI) 1.27-1.44]. The incidence increased with age, with a higher aHR in hysterectomised women aged 40-49 years (aHR 1.37, 95% CI 1.06-1.83) than in those aged 30-39 years (aHR 1.22, 95% CI 1.02-1.46). CONCLUSION: Findings in this study suggest that women with hysterectomy are more likely to be diagnosed with hypertension in the follow-up period. TWEETABLE ABSTRACT: Women with hysterectomy before 50 years of age are at an increased risk of developing subsequent hypertension. PLAIN LANGUAGE SUMMARY: Hysterectomy is one of the most common surgeries for women with benign uterine disease. Hysterectomy may lead to a sudden decline in the production of sex hormone (estrogen and progesterone), which is responsible for vessel wall endothelial dysfunction leading to hardening of arteries and subsequent hypertension. However, the association between hysterectomy and risk of hypertension remains controversial. This study investigated whether premenopausal women have an elevated risk of hypertension after hysterectomy. This study employed the Taiwan National Health Insurance Research Database to identify 6674 women 30-49 years old who had a hysterectomy between 2000 and 2013, and a comparison group of 26 696 women who did not have a hysterectomy matched by age. Women in both the groups had no hypertension at baseline (recruiting date or within 1 year after recruiting date). By the end of 2013, we found that 1196 (17.9%) and 3613 (13.5%) women had developed hypertension in the hysterectomy and the comparison groups, respectively. The hypertension incidence was 1.4-fold greater in the hysterectomy group than in the control group (27.8 versus 20.2/1000 person-years).

Risk of empyema in patients with end-stage renal disease: a nationwide propensity-matched cohort study.

BACKGROUND: Empyema is a rare but important complication among patients with end-stage renal disease (ESRD). However, a nationwide, propensity-matched cohort study has never been performed. METHODS: We conducted a retrospective cohort study using data from the National Health Insurance Research Database of Taiwan. The ESRD group consisted of 82 765 patients diagnosed between 2000 and 2008. The comparison group consisted of individuals without kidney disease selected at a 1:1 ratio matched by propensity score estimated with age, gender, year of diagnosis and comorbidities. The occurrence of empyema was monitored until the end of 2011. The hazard ratios (HRs) of empyema were estimated using the Cox proportional hazards model. RESULTS: The incidence of empyema was 2.76-fold higher in the ESRD group than in the comparison group (23.7 vs. 8.19/10 000 person-years, P <0.001), with an adjusted HR of 3.01 [95% confidence interval (CI) = 2.67-3.39]. There was no difference of the incidence of empyema between hemodialysis (HD) and peritoneal dialysis (PD) (adjusted HR = 0.96, 95% CI = 0.75-1.23). In addition, 30-day mortality rate since empyema diagnosis was significantly higher in ESRD group than the comparison group (15.9% vs. 10.9%), with an adjusted OR of 1.69 (95% CI = 1.17-2.44). CONCLUSION: The risk of empyema was significantly higher in patients with ESRD than in those without kidney disease. The occurrence of empyema was without difference in patients undergoing HD compared to those undergoing PD. The 30-day mortality rate since empyema diagnosis was also significantly higher in patients with ESRD.

A nation-wide population-based study of inguinal hernia repair incidence and age-stratified recurrence in an Asian population.

PURPOSE: It has been estimated in the UK that 27 % of men and 3 % of women will undergo an inguinal hernia repair (IHR) during their lifetimes. However, no epidemiologic study investigating IHR has been performed to date in an Asian population. The present study explored the incidence and recurrence of IHR in an Asian population using a nation-wide population-based dataset in Taiwan. METHODS: Based on the National Health Insurance Database, we identified 5806 patients who underwent an IHR between 2000 and 2010 and followed them until they had a recurrence, died during hospitalization, left the program, or the study ended. We calculated the age-stratified recurrence rates and used Cox proportional hazards to explore the influence of demographic and clinical factors on recurrence. We also plotted IHR occurrence over the study period. RESULTS: Among the 5806 sampled subjects who had an IHR, 565 (9.73 %) had an IHR recurrence yielding an overall incidence of 18.23 per 1000 person-years. The hazard ratios for recurrence increased with age, and were greater among men and blue collar workers. The incidence of IHR decreased from 168.21 to 92.10 per 100,000 person-years over the study period. Surgical complication rates ranged between 0.16 and 2.57 %. CONCLUSIONS: On account of the increased risk of recurrence with age, young hernia patients may not want to delay surgery. This study detected a decreasing trend in initial IHR rates, confirming similar trends reported in Western countries. However, the incidence of initial IHR is lower in Taiwan than it is in the West.

5α-Reductase inhibitors increase acute coronary syndrome risk in patients with benign prostate hyperplasia.

BACKGROUND: This study explored the possible association between the use of two typical 5ARIs (finasteride and dutasteride) and the risk of acute coronary syndrome (ACS) in patients with benign prostate hyperplasia (BPH). METHODS: From the claims data of the Taiwan National Health Insurance (NHI) Taiwan, we identified 1843 ACS cases among BPH patients and randomly selected 7330 controls without ACS, with a similar mean age of 73 years. Multivariate logistic regression analysis estimated the odds ratio (OR) and 95 % confidence interval (CI) for the relationship between the 5ARIs medications and ACS risk. RESULTS: We found that BPH patients who had received treatment with both finasteride and dutasteride were at a higher risk of ACS with an OR of 3.47 (95 % CI 1.05-11.5), compared to patients without 5ARIs treatment. Furthermore, the dosage analysis showed that there were no significant associations between ACS risk and uses of a single drug medication regardless the dosages. The ORs for those who took only dutasteride were 1.07 (95 % CI 0.39-2.99) with low dose and 0.73 (95 % CI 0.38-1.44) with high dose. The ORs for those who took only finasteride were 1.30 (95 % CI 0.89-1.92) with low dose and 0.98 (95 % CI 0.19-5.13) with high dose. CONCLUSION: This population-based nested case-control study suggests that 5ARI use may increase ACS risk among patients with BPH when patients were exposed to both finasteride and dutasteride.

Mortality and cost of radiation therapy for oesophageal cancer according to hospital accreditation level: a nationwide population-based study.

This study examined and analysed the relationship between the cost-effectiveness and outcome of radiotherapy for oesophageal cancer among hospitals with varying accreditation levels. We selected 428 oesophageal cancer patients from medical and non-medical centres using the National Health Insurance Research Database, which is maintained by the Taiwanese National Health Research Institutes, and compared their medical expenditure and the outcome of their radiotherapy treatment. In this study cohort of patients with oesophageal cancer, 278 patients were treated in medical centres (mean age: 60.1 years) and 150 patients were treated in non-medical centres (mean age: 62.0 years, P = 0.16). The medical centre group exhibited significantly lower medical expenses, mortality and risk of death compared with the non-medical centre group (adjusted hazard ratio = 1.38, 95% confidence interval = 1.11-1.71). Our study determined that radiotherapy for oesophageal cancer costs significantly less, and medical centres had lower mortality rates than non-medical centres. These findings could provide professional organisations and healthcare policy makers with essential information for allocation of resources.

Survival outcome of patients with nasopharyngeal carcinoma: a nationwide analysis of 13 407 patients in Taiwan.

OBJECTIVES: We reported the contemporary survival outcome of patients with nasopharyngeal carcinoma (NPC) and analysed the factors affecting survival. DESIGN: A retrospective cohort study. SETTING: A nationwide population-based study in Taiwan. PARTICIPANTS: We identified 13 407 patients with newly diagnosed NPC from 2002 to 2010. MATERIAL AND METHODS: The multivariate Cox proportional hazards model was performed to measure the mortality-association risk factor in patients with NPC after adjusting for NPC treatment and socio-demographic characteristics. RESULTS: The 1-, 2-, 5- and 8-year overall survival (OS) rates were 89.6%, 80.4%, 65.2% and 56.5%, respectively. The factors associated with mortality risk were sex (men versus women, HR = 1.45), age (>60 versus ≤ 40 years, HR = 3.61), geographic region of residence (eastern Taiwan versus northern Taiwan HR = 1.39), income (<15 840 versus >25 000, HR = 1.87) and treatment modality (chemotherapy alone versus radiotherapy alone, HR = 2.25). CONCLUSION: The contemporary 5-year OS rate was 65.2% in Taiwan. Male patients, old age, residing in eastern Taiwan, low income and receiving chemotherapy alone were independent predictors for poor OS.

Correlation between use of simvastatin and lovastatin and female lung cancer risk: a nationwide case-control study.

BACKGROUND: The objective of this study was to determine the association between statin use and female lung cancer in Taiwan. METHODS: In this case-control study, we used information from the Taiwan National Health Institute Research Database on 17,329 patients (cases) aged 20 years or older recently diagnosed with lung cancer between 2005 and 2010 and 17,329 patients without lung cancer to assess the association between female lung cancer and statin use, even adjustment for its comorbidities. RESULTS: After adjusting for age and associated risk factors, we determined that women who engaged in long-term use of simvastatin at a defined daily dose (DDD) of over 150 have a reduced risk of lung cancer compared with those who did not use statins (odds ratio: 0.77, 95% confidence interval: 0.62-0.97) in women. However, lovastatin was not significantly associated with lung cancer in women. Among female patients with pre-existing comorbidities of respiratory diseases such as chronic obstructive pulmonary disease, hypertension, stroke and pulmonary tuberculosis, statins reduced the risk of lung cancer. CONCLUSIONS: Simvastatin use at a DDD of more than 150 is correlated with an approximately 20% reduction in the risk of lung cancer in women.

Increased risk of chronic obstructive pulmonary disease in patients with rheumatoid arthritis: a population-based cohort study.

BACKGROUND: The role of autoimmune pathology in development and progression of chronic obstructive pulmonary disease (COPD) is becoming increasingly popular. Our aim was to assess the association between patients with rheumatoid arthritis (RA) and subsequent COPD risk in a nationwide population. METHOD: We conducted a retrospective cohort study using data from the National Health Insurance system of Taiwan. The RA cohort included patients who were newly diagnosed and recruited between 1998 and 2008. Each patient was randomly frequency-matched for age, sex and the year of index date with people without RA from the general population. The newly diagnosed COPD was followed up until the end of 2010. The relative risks of COPD were estimated using Cox proportional hazard models after adjusting for age, sex, index year and comorbidities. RESULT: The overall incidence rate of COPD was 1.74-fold higher in the RA cohort than in the non-RA cohort (5.25 vs. 3.01 per 1000 person-years, 95% confidence interval (CI) = 1.68-1.81). Age-related risk analysis showed an increased incidence of COPD with age in both RA and non-RA cohorts. However, adjusted hazard ratio (HR) maximum was witnessed in the age range of 20-34 years (adjusted HR: 7.67, 95% CI=1.94-30.3), whereas adjusted HR minimum was observed in the oldest age group (>65 years). CONCLUSION: Patients with RA have a significantly higher risk of developing COPD than that of the control population. Further, age-related risk analysis indicated much higher adjusted HR in younger patients although COPD incidence increased with age. It can be hypothesized that in addition to cigarette smoke, RA may be a determining factor for COPD incidence and/or facilitates shortening of the time course for developing COPD. However, further investigation is needed to corroborate this hypothesis.

Paediatric head CT scan and subsequent risk of malignancy and benign brain tumour: a nation-wide population-based cohort study.

BACKGROUND: To evaluate the possible association between paediatric head computed tomography (CT) examination and increased subsequent risk of malignancy and benign brain tumour. METHODS: In the exposed cohort, 24 418 participants under 18 years of age, who underwent head CT examination between 1998 and 2006, were identified from the Taiwan National Health Insurance Research Database (NHIRD). Patients were followed up until a diagnosis of malignant disease or benign brain tumour, withdrawal from the National Health Insurance (NHI) system, or at the end of 2008. RESULTS: The overall risk was not significantly different in the two cohorts (incidence rate=36.72 per 100 000 person-years in the exposed cohort, 28.48 per 100 000 person-years in the unexposed cohort, hazard ratio (HR)=1.29, 95% confidence interval (CI)=0.90-1.85). The risk of benign brain tumour was significantly higher in the exposed cohort than in the unexposed cohort (HR=2.97, 95% CI=1.49-5.93). The frequency of CT examination showed strong correlation with the subsequent overall risk of malignancy and benign brain tumour. CONCLUSIONS: We found that paediatric head CT examination was associated with an increased incidence of benign brain tumour. A large-scale study with longer follow-up is necessary to confirm this result.

Increased risk of cancer for patients with ankylosing spondylitis: a nationwide population-based retrospective cohort study.

OBJECTIVES: Few studies have investigated the relationship between ankylosing spondylitis (AS) and other inflammatory spondyloarthritis and subsequent cancer. The aim of this study was to determine whether AS is associated with cancer risk. METHOD: We used data from the National Health Insurance (NHI) system of Taiwan to investigate this association. The AS cohort included 4133 patients, and each patient was randomly frequency matched with four persons without AS based on sex, age, and entry year (control cohort). We conducted a Cox proportional hazards regression analysis to estimate the influence of AS on cancer risk. RESULTS: Among patients with AS, the overall risk of developing cancer was 38% higher than that of people without AS, and the difference was significant [adjusted hazard ratio (HR) 1.38, 95% confidence interval (CI) 1.18-1.60]. This phenomenon held true even when we analysed males and females separately. The risk of developing lung or head and neck cancer among patients with AS was significantly higher; and risks for liver, bladder, and uterus cancers were marginally significantly higher. CONCLUSIONS: This nationwide population-based cohort study shows that Taiwanese patients with AS have a higher risk of developing cancer, particularly lung or head and neck cancer.

Hearing loss may be a non-motor feature of Parkinson's disease in older people in Taiwan.

BACKGROUND AND PURPOSE: The aim of this study was to explore whether hearing loss is associated with the risk of Parkinson's disease in the elderly in Taiwan. METHODS: Using claims data of the Taiwan National Health Insurance Program, 4976 patients (aged 65 years or older) with newly diagnosed hearing loss from 2000 to 2010 were identified and 19 904 subjects without hearing loss were randomly selected as comparisons, frequency matched by sex, age and index year of diagnosing hearing loss. The incidence of Parkinson's disease by the end of 2010 and the associated risk factors were investigated. RESULTS: The incidence of Parkinson's disease in the hearing loss group was 1.77-fold higher than that in the non-hearing-loss group (3.11 vs. 1.76 per 1000 person-years). After controlling for confounding factors, the adjusted hazard ratio (HR) of Parkinson's disease was 1.53 (95% CI 1.17, 1.99) for the hearing loss group compared with the non-hearing-loss group. Male sex (HR = 1.33, 95% CI 1.02, 1.74), age (for each year, HR = 1.06, 95% CI 1.04, 1.09), hypertension (HR = 1.70, 95% CI 1.26, 2.30) and cerebrovascular disease (HR = 1.78, 95% CI 1.37, 2.32) were also significantly associated with the risk of Parkinson's disease. CONCLUSIONS: Hearing loss correlates with an increased risk of Parkinson's disease in the elderly. Further studies are needed to confirm whether hearing loss could be a non-motor feature of Parkinson's disease.

Idiopathic venous thromboembolism: a potential surrogate for occult cancer.

BACKGROUND: Several studies have indicated an association between venous thromboembolism (VTE) and a subsequent diagnosis of cancer in Western countries. However, information is scant on subsequent cancer incidence after idiopathic VTE events in Asian people. Through a nationwide cohort study, we evaluated the cancer prevalence of VTE and new cancer incidence in patients after the first episode of idiopathic VTE. METHODS: To conduct a nationwide population cohort study on VTE, we retrieved data from the Taiwan National Health Insurance Database from 1998 to 2008, including a 2-year follow-up period extending to the end of 2010. The occurrence of cancer in the cohort was also determined by accessing the Registry for Catastrophic Illness Patient Database. RESULTS: A total of 45,242 patients had the newly diagnosed VTE from 1998 to 2008. The incidence of VTE increased with age. Among 28,243 idiopathic VTE patients, 1944 patients (6.89%) had a subsequent cancer diagnosis within 2 years of the first idiopathic VTE episode. The three most common newly diagnosed cancers after idiopathic VTE were lung cancer, liver cancer and colorectal cancer (18.3%, 12.3% and 10.9%, respectively). Male sex and advanced age are independent risk factors of having an underlying malignant disorder among patients diagnosed with idiopathic VTE. CONCLUSION: Patients with symptomatic VTE without an identifiable risk factor have a 6.89% incidence of subsequent cancer diagnosis in Taiwan. An extensive screening for an occult cancer in an idiopathic VTE patient may be warranted.

A nationwide population-based retrospective cohort study: increased risk of acute coronary syndrome in patients with ankylosing spondylitis.

OBJECTIVES: To compare the risk of acute coronary syndrome (ACS) between patients with and without ankylosing spondylitis (AS). METHOD: This retrospective cohort study identified all patients with AS aged ≥ 18 years newly diagnosed from 2000 to 2009, registered in the National Health Insurance Research Database (NHIRD) in Taiwan. The non-AS cohort consisted of fourfold randomly selected control patients free of AS, frequency matched by age, sex, and diagnosis year. The incidence of ACS was determined for both AS and non-AS cohorts. RESULTS: We selected 6262 patients with AS and 25 048 patients without AS. The patients with AS were more prevalent than those without, with co-morbidities of hypertension, diabetes mellitus (DM), hyperlipidaemia, stroke, and peripheral vascular diseases. The overall incidence rate of ACS was higher in the AS cohort than in the non-AS cohort (4.4 vs. 2.9 per 1000 person-years), with an adjusted hazard ratio (aHR) of 1.36 [95% confidence interval (CI) 1.16-1.59]. AS patients with co-morbidities of hypertension, DM, and cancer had an aHR of 7.74 for ACS, compared to those without these co-morbidities. CONCLUSIONS: AS patients are at higher risk of ACS compared with non-AS subjects. Management of CV risk factors should be taken into account for the treatment of patients with AS, especially for patients with co-morbidities of hypertension, DM, and cancer.

Secondary primary cancer in patients with head and neck carcinoma: the differences among hypopharyngeal, laryngeal, and other sites of head and neck cancer.

This paper presents a population-based retrospective cohort study to identify the differences in secondary primary cancer (SPC) among hypopharyngeal, laryngeal, and other sites of head and neck cancer (HNC). Data were collected from the Taiwan National Health Insurance Research Database (NHIRD) for the period 1979-2010. The study cohort comprised 5914 newly diagnosed hypopharyngeal and laryngeal patients from the registry of the Catastrophic Illness Patients Database (CIPD). The comparison cohort comprised 5914 patients with other sites of HNC. We used a multivariate Cox proportional-hazards regression model to assess the risk of developing SPC. The incidence of SPC in the study cohort was 68% higher compared with the comparison cohort (23.9 vs. 14.2 per 1000 person-years, Incident Rate Ratio = 1.68). The study cohort had a higher adjusted hazard ratio (HR) in oesophageal cancer (HR = 3.47) and lung cancer (HR = 1.89). The difference in SPC incidence between the study and comparison cohort was significant.

Increased breast cancer risk for patients with multiple sclerosis: a nationwide population-based cohort study.

BACKGROUND AND PURPOSE: Studies have suggested that multiple sclerosis (MS) might be linked to an overall reduced cancer rate, but a positive relationship is also found for several types of cancer. This study determines whether MS is associated with cancer risk in Taiwan. METHODS: Data from the National Health Insurance System of Taiwan were used to assess this issue. The MS cohort included 1292 patients, and each patient was randomly frequency-matched with four participants without MS, based on their age, sex and index year (control cohort). Cox proportional hazards regression analysis was conducted to estimate the influence of MS on cancer risk. RESULTS: A significantly higher risk of developing overall cancer was found amongst the MS cohort compared with the control cohort [adjusted hazard ratio (HR) 1.85, 95% confidence interval (CI) 1.26-2.74], as well as breast cancer (adjusted HR 2.23, 95% CI 1.11-4.46). CONCLUSIONS: The nationwide population-based cohort study revealed that Taiwanese patients with MS have a higher risk of developing overall cancer types and breast cancer in particular.

Cancer risk in patients with Hashimoto's thyroiditis: a nationwide cohort study.

BACKGROUND: This study examined the risk of cancer in patients with Hashimoto's thyroiditis (HT). METHODS: The Taiwanese National Health Insurance Research Database (NHIRD) was used to identify 1521 newly diagnosed HT patients from 1998-2010, and 6084 frequency-matched non-HT patients. The risk of developing cancer for HT patients was measured using the Cox proportional hazard model. RESULTS: The incidence of developing cancer in the HT cohort was 5.07 per 1000 person-years, which was 1.68-fold higher than that in the comparison cohort (P<0.001). Compared with patients aged 20-34 years, patients in older age groups had a higher risk of developing cancer (35-55 years: hazard ratio (HR)=5.96; >55 years: HR=9.66). After adjusting for sex, age, and comorbidities, the HT cohort had HRs of 4.76 and 11.8 for developing colorectal cancer and thyroid cancer, respectively, compared with non-HT cohort. Furthermore, the HT cohort to non-HT cohort incidence rate ratio (IRR) of thyroid cancer was higher in the first 3 years (48.4, 95% confidence interval (CI)=35.0-66.3), with an adjusted HR of 49.4 (95% CI=6.39-382.4). CONCLUSION: Hashimoto's thyroiditis patients have a higher risk of thyroid cancer and colorectal cancer. The thyroid cancer prevention effort should start soon after HT is diagnosed, while being cautious of colorectal cancer increases with time.

Synergistic interaction of benign prostatic hyperplasia and prostatitis on prostate cancer risk.

BACKGROUND: The incidence of prostate cancer is much lower in Asian men than in Western men. This study investigated whether prostate cancer is associated with prostatitis, benign prostatic hyperplasia (BPH), and other medical conditions in the low-incidence population. METHODS: From the claims data obtained from the universal National Health Insurance of Taiwan, we identified 1184 patients with prostate cancer diagnosed from 1997 to 2008. Controls comprised 4736 men randomly selected from a cancer-free population. Both groups were 50 years of age or above. Medical histories between the two groups were compared. RESULTS: Multivariate logistic regression analysis showed that prostatitis and BPH had stronger association with prostate cancer than the other medical conditions tested. Compared with men without prostatitis and BPH, a higher odds ratio (OR) for prostate cancer was associated with BPH (26.2, 95% confidence interval (CI) 20.8-33.0) than with prostatitis (10.5, 95% CI=3.36-32.7). Men with both conditions had an OR of 49.2 (95% CI=34.7-69.9). CONCLUSION: Men with prostate cancer have strong association with prostatitis and/or BPH. Prostatitis interacts with BPH, resulting in higher estimated relative risk of prostate cancer in men suffering from both conditions.

Dental diagnostic X-ray exposure and risk of benign and malignant brain tumors.

BACKGROUND: This study evaluates the risk of benign brain tumors (BBTs) and malignant brain tumors (MBTs) associated with dental diagnostic X-ray, using a large population-based case-control study. MATERIALS AND METHODS: We identified 4123 BBT cases and 16 492 controls without BBT (study 1) and 197 MBT cases and 788 controls without MBT (study 2) from Taiwan National Health Insurance claim data. The risks of both types of tumor were estimated in association with the frequency of received dental diagnostic X-ray. RESULTS: The mean ages were ~44.2 years in study 1 and 40.6 years in study 2. Multivariable unconditional logistic regression analysis showed that the risk of BBT increases as the frequency of received dental diagnostic X-ray increases. The BBT odds ratio increased from 1.33 [95% confidence interval (CI) 1.22-1.44] for those with annual mean X-ray examination of less than one to 1.65 (95% CI 1.37-1.98) for those with three or more X-ray examinations, after controlling for comorbidities. No significant association was found between MBTs and dental diagnostic X-ray exposure. CONCLUSIONS: Exposure to dental diagnostic X-rays in oral and maxillofacial care increases the risk of BBTs, but not MBTs.

Young nasopharyngeal cancer patients with radiotherapy and chemotherapy are most prone to ischaemic risk of stroke: a national database, controlled cohort study.

OBJECTIVES: This population-based cohort study investigated the ischaemic stroke risk of patients with nasopharyngeal carcinoma (NPC) by treatment. DESIGN: Controlled cohort study. SETTING: Based on claims data of National Health Research Insurance Database in years 1996-2010. PARTICIPANTS: A total of 4615 patients with nasopharyngeal carcinoma newly diagnosed in 2000-2003 were divided into three subgroups: patients received radiotherapy only, patients received both radiotherapy/chemotherapy and patients received neither radiotherapy nor chemotherapy (non-radio/chemotherapy). They were compared with 36 919 reference persons without stroke and cancer, frequency matched with demographic characteristics. MAIN OUTCOME MEASURES: Study subjects were followed up until 2010 to measure ischaemic stroke incidences. Risks associated with treatment and comorbidity were evaluated using Cox proportional hazards regression analysis incorporated with the competing risk of deaths. RESULTS: Ischaemic stroke incidence rates were ≈2-fold higher in nasopharyngeal carcinoma patients with radiotherapy, radiotherapy/chemotherapy and non-radio/chemotherapy than in references (13.8, 12.8 and 12.6 versus 6.07 per 1000 person-years, respectively). The risk was much higher for 20- to 39-year-old nasopharyngeal carcinoma patients with radiotherapy/chemotherapy [hazard ratio (HR) 14.7, 95% confidence interval 9.24-23.4]. Hypertension, diabetes, hyperlipidaemia and alcoholism also enhanced the risk with hazard ratios ranging from 2.4 to 9.3. The overall adjusted ischaemic stroke risk was higher in nasopharyngeal carcinoma patients with the two types of treatment than those without, but not significant. CONCLUSIONS: Patients with nasopharyngeal carcinoma are at an elevated risk of ischaemic stroke, without significant difference among treatment modalities. The relative risk is more prominent in younger patients. Comorbidity may enhance the risk.