Hyperpigmentation, hyperkeratoses, and Bowen's disease are hallmarks of chronic arsenic exposure. The association between arsenic-induced skin lesions and subsequent internal cancers is examined by using a community-based prospective study. The cohort was enrolled from an arseniasis-endemic area in southwestern Taiwan, where 2,447 residents participated in skin examinations during the late 1980s. The number of participants diagnosed with hyperpigmentation was 673; with hyperkeratosis, 243; and with skin cancer (Bowen's disease or non–melanoma skin cancer), 378. Newly diagnosed internal cancers were ascertained through linkage with National Cancer Registry profiles. Cox regression was performed to estimate hazard ratios with 95% confidence intervals for potential risk predictors. Compared with participants without skin lesions, patients affected with skin cancers had a significantly increased risk of lung cancer (hazard ratio = 4.64, 95% confidence interval: 2.92, 7.38) and urothelial carcinoma (hazard ratio = 2.02, 95% confidence interval: 1.23, 3.30) after adjustment for potential confounders and cumulative arsenic exposure. Hyperkeratosis is significantly associated with an increased lung cancer risk (hazard ratio = 2.76, 95% confidence interval: 1.35, 5.67). A significant interactive effect on lung cancer risk between hyperkeratosis and cigarette smoking was identified, which suggests that patients with hyperkeratosis who have been exposed to arsenic should cease smoking.

Similarities in the symptoms of chronic fatigue syndrome (CFS) and inflammatory bowel disease (IBD) have been observed as follows: severe disease activity in IBD correlates with severe fatigue, major psychiatric signs, the common use of medication, and bacterial translocation. One of several hypotheses for explaining the mechanisms underlying CFS suggests a similarity to the impaired intestinal mucosa of IBD. “This study investigated the risk of incident CFS among patients with IBD”. We conducted a population-based retrospective cohort study by using Taiwan’s National Health Insurance Research Database to evaluate the subsequent risk of CFS in patients with IBD, according to demographic characteristics and comorbidities. The exposure cohort comprised 2163 patients with new diagnoses of IBD. Each patient was randomly selected and frequency matching according to gender and age with four participants from the general population who had no history of CFS at the index date (control cohort). Cox proportional hazards regression analysis was conducted to estimate the relationship between IBD and the subsequent risk of CFS. The exposure cohort had a significantly higher overall risk of subsequent CFS than that of the control group [adjusted hazard ratio (Christophi in Inflamm Bowel Dis 18(12):2342–2356, 2012 ) = 2.25, 95%, confidence interval (Aaron and Buchwald in Ann Intern Med 134(9 Pt 2):868–881, 2001 ; Farraye et al. in Am J Gastroenterol 112:241, 2017 ) 1.70–2.99]. Further analysis indicated a significantly higher risk of CFS in patients who were male (HR = 3.23, 95% CI 2.12–4.91), were older than 35 years, and had IBD but without comorbidity status, e.g. Cancers, diabetes, obesity, depression, anxiety, sleep disorder, renal disease (HR = 2.50, 95% CI 1.63–3.84) after adjustment. The findings from this population-based retrospective cohort study suggest that IBD, especially Crohn’s disease, is associated with an increased risk of subsequent CFS.

The risk of herpes zoster (HZ) between patients with psoriasis receiving and not receiving systemic therapy has received increasing attention. This study investigated the association of psoriasis with the risk of HZ. We conducted a population-based retrospective cohort study by using the Taiwan National Health Insurance Research Database. The psoriasis cohort consisted of 4077 patients with newly diagnosed psoriasis between 2000 and 2006. Each patient with psoriasis was frequency-matched with four people without psoriasis, by sex, age and index year. (nonpsoriasis cohort; 16308 subjects). Patients who received systemic therapy were classified as having severe psoriasis, whereas those who did not receive systemic therapy were classified as having mild psoriasis. The Cox proportional hazards regression analysis was conducted to estimate the association between psoriasis and HZ risk. The overall incidence density rate of HZ in the psoriasis cohort than in the nonpsoriasis cohort (4.50 vs. 3.44 per 1,000 person-years), with a multivariable Cox proportional hazards model measured adjusted HR of 1.29 [95% confidence interval (CI) = 1.07–1.56]. In additional, compared with the nonpsoriasis cohort, the risk of HZ was higher in the severe psoriasis cohort than in the nonpsoriasis cohort (adjusted hazard ratio [HR], 1.61; 95% confidence interval [CI], 1.15–2.27). The comparison between psoriasis and nonpsoriasis cohorts revealed a greatest magnitude risk of HZ in women (adjusted HR, 1.36; 95% CI, 1.04–1.79), study participants in the age group of 20–39 years (adjusted HR, 1.77; 95% CI, 1.17–2.66), and study participants without any comorbidities (adjusted HR, 1.37; 95% CI, 1.02–1.84). Our results suggest that psoriasis is associated with an increased risk of HZ, which involves differences in sex and age. Although systemic therapy may have a major role in the risk of HZ, the intrinsic factors of psoriasis cannot be excluded.