131I treatment for thyroid cancer and risk of developing primary hyperparathyroidism: a cohort study.

PURPOSE: To evaluate the association between (131)I therapy for thyroid cancer and risk of developing primary hyperparathyroidism. METHODS: This was a nationwide population-based cohort study of patients with thyroid cancer diagnosed during the period 1997-2008. The data were obtained from the Taiwan National Health Insurance Research dataset. The cumulative (131)I dose in each patient was calculated. Hazard ratios (HRs) were calculated using a proportional hazards model to estimate the effect of (131)I therapy on the risk of developing primary hyperparathyroidism in the cohort. RESULTS: A total of 8,946 patients with thyroid cancer were eligible for the final analysis. Among these patients, 8 developed primary hyperparathyroidism during the follow-up period that represented 38,248 person-years giving an incidence rate of 20.9 per 10(5) person-years. (131)I was used in the treatment of 6,153 patients (68.8%) with a median cumulative dose of 3.7 GBq. The adjusted HRs were 0.21 (95% CI 0.02-1.86) and 0.46 (95% CI 0.10-2.10) for those receiving a cumulative (131)I dose of 0.1-3.6 GBq and ≥3.7 GBq, respectively, compared to no therapy. The risk of developing primary hyperparathyroidism did not increase with increasing (131)I dose (test for trend p = 0.51). No interaction was found between (131)I dose and age (p = 0.94) or (131)I dose and sex (p = 0.99). CONCLUSION: (131)I treatment for thyroid cancer did not increase risk of primary hyperparathyroidism during a 10-year follow-up in this study population. Further research with a longer follow-up period is needed to assess late adverse effects beyond 10 years.

In utero exposure to environmental lead and manganese and neurodevelopment at 2 years of age.

BACKGROUND AND OBJECTIVE: Manganese, lead, arsenic and mercury are common neurotoxic metals in the environment. Nonetheless, the relationship between prenatal exposure to low doses of neurotoxic metals and neurodevelopment in children is not clear. The objective of this study was to explore the relationship between in utero exposure to environmental neurotoxic metals and neurodevelopment at 2 years of age. METHODS: The population of this study came from the Taiwan Birth Panel Study. We included 230 pairs of non-smoking mothers without any occupational exposure and their singleton full-term children. The information about exposure during pregnancy was obtained using a structured questionnaire, and the manganese, lead, arsenic and mercury levels in umbilical cord blood samples were analyzed using inductively coupled plasma mass spectrometry. We used the Comprehensive Developmental Inventory for Infants and Toddlers (CDIIT) to evaluate the developmental status of each child at 2 years of age, and we examined the association of in utero exposure to environmental metals and neurodevelopment using linear regression models. RESULTS: The median concentrations of manganese, lead, arsenic and mercury in the cord blood samples in this study were 47.90 µg/L (range, 17.88-106.85 µg/L), 11.41 µg/L (range 0.16-43.22 µg/L), 4.05 µg/L (range, 1.50-12.88 µg/L) and 12.17 µg/L (range, 1.53-64.87 µg/L), respectively. After adjusting for maternal age, infant gender, environmental tobacco smoke during pregnancy and after delivery, Home Observation for Measurement of the Environment Inventory results, and arsenic and mercury levels in cord blood, we found that manganese and lead levels above the 75th percentile had a significant adverse association with the overall (ß=-7.03, SE=2.65, P=0.0085), cognitive (ß=-8.19, SE=3.17, P=0.0105), and language quotients (ß=-6.81, SE=2.73, P=0.0133) of the CDIIT. CONCLUSIONS: In utero exposure to environmental manganese and lead may have an adverse association with neurodevelopment at 2 years of age, and there is an interaction effect between the manganese and lead levels in the cord blood that could aggravate the effect.

Aristolochic acid and the risk of cancers in patients with type 2 diabetes: Nationwide population-based cohort study.

BACKGROUND: Both aristolochic acid (AA) exposure and diabetic can increase risk of certain cancers,whetherAAexposureincreases cancer risk in diabetic patientsisunknown. The purpose of this study was to investigate the association between the use of Chinese herbal products containing AA and the risk of cancer in diabetic patients. METHODS: A cohort study was conducted using the National Health Insurance Research Database in Taiwan. Patients older than 18 years who were diagnosed with diabetes between 1997 and 2010 were enrolled in our cohort. The use of Chinese herbal products containing AA was recorded from the beginning of 1997 until the ban of herbs containing AA in November 2003. Patients were individually tracked to identify cancer incidence between 1997 and 2013. Only patients who visited traditional Chinese medicine clinics between 1997 and 1 year before the end of follow-up were included in the cohort to ensure comparability. Cox proportional hazards regression was used to calculate the hazard ratio for the association between the use of Chinese herbal products containing AA and the occurrence of cancer. RESULTS: Among the 430 377 male and 431 956 female patients with diabetes enrolled in our cohort, 37 554 and 31 535 cancer diagnoses were recorded during the study period, respectively. The use of AA-containing herbal products was associated with a significantly higher risk of liver, colorectum, kidney, bladder, prostate, pelvis, and ureter cancer in a dose-dependent manner. An increased risk of extrahepatic bile duct cancer in women was also associated with AA exposure at doses of more than 500 mg. CONCLUSIONS: Association between AA exposure and the risk of some cancers were found in this study. AA exposure might increase risk of kidney,bladder,pelvis, ureter,liver,colorectum,andprostatecancer in all patientsandextrahepatic bile duct cancerin women.

Does prenatal cadmium exposure affect fetal and child growth?

OBJECTIVES: Cadmium is known to be a significant health hazard, but most information comes from studies of adults. The effects of exposure to cadmium during fetal life on early growth and development remain uncertain. In this study we investigated the placental transport of cadmium and the effects of prenatal cadmium exposure on fetal and child growth in Taiwan. METHODS: The data in this study were from a birth cohort study in Taiwan which started in 2004. Pregnant women were recruited from four hospitals and interviewed after delivery to collect information on themselves and their infants. Children were followed up to obtain information on growth up to 3years of age. Whole blood cadmium concentrations in maternal and cord blood samples were measured and the relationship with birth size and growth assessed using linear regression and mixed models. RESULTS: 321 maternal blood samples and 402 cord blood samples were eligible for analysis. Among 289 pairs with maternal and cord blood suitable for measurement, the median cadmium concentration in cord blood (0.31µg/l) was less than that in maternal blood (1.05µg/l), with low correlation between the two (r=0.04). An increase in cord blood cadmium was found to be associated with newborn decreased head circumference and to be significantly and consistently associated with a decrease in height, weight and head circumference up to 3 years of age. CONCLUSIONS: Placental transport of cadmium is limited. However, prenatal cadmium exposure may have a detrimental effect on head circumference at birth and child growth in the first 3years of life.

Association Between 131I Treatment for Thyroid Cancer and Risk of Receiving Cataract Surgery: A Cohort Study from Taiwan.

UNLABELLED: The risk of cataracts after (131)I therapy for cancer is unknown. The objective of this study was to evaluate the association between (131)I therapy for thyroid cancer and risk of receiving cataract surgery in Taiwan. METHODS: This was a nationwide population-based cohort study of patients with thyroid cancer diagnosed during the period 1998-2008. The data were obtained from the Taiwan National Health Insurance Research dataset. The cumulative (131)I activity in each patient was calculated. Hazard ratios were calculated using a time-dependent survival analysis to estimate the effect of (131)I therapy on the risk of receiving cataract surgery. RESULTS: A total of 8,221 patients were eligible for the final analysis (mean age, 43.2 y; mean follow-up, 5.9 y); 69% received (131)I with a median cumulative activity of 3.7 GBq. Two hundred patients received cataract surgery. The adjusted hazard ratios were 0.77 (95% confidence interval, 0.54-1.09), 0.92 (95% CI, 0.64-1.31), and 1.06 (95% CI, 0.58-1.94) for cumulative (131)I activities of 0.1-3.6, 3.7-7.3, and 7.4 GBq or more, respectively, compared with a cumulative activity of 0. No trend was noted (P = 0.85). No interaction between (131)I activity and age or between (131)I activity and sex was noted (all P > 0.05). CONCLUSION: (131)I treatment for thyroid cancer did not increase the risk of receiving cataract surgery up to 10 y after treatment. However, further research with direct lens examination and a longer follow-up period is needed to assess subtle and late adverse effects beyond 10 y.

The role of essential metals in the placental transfer of lead from mother to child.

Epidemiological studies have found adverse birth and child health outcomes from prenatal lead exposure, but little is known about factors influencing placental transfer. In this study we describe the placental transfer of lead in a Taiwanese population, and investigate whether three essential metals - zinc, manganese, or selenium - influence transfer. Maternal and cord blood samples (308 pairs) from a birth cohort study were analyzed using multiple linear regression. There was a clear correlation between mother and child lead concentration (r=0.48, p<0.001), although lead concentration in cord blood (mean=1.29, SD=0.72 microg/dL) was lower than that for mothers (mean=1.58, SD=1.11 microg/dL). Cord blood lead was lower where the mother had a higher blood concentration of zinc (p<0.001) or manganese (p=0.02). Thus maternal blood zinc and manganese, but not selenium, appeared to decrease the placental transfer of lead. These findings raise the possibility of reducing placental transfer of lead by increasing zinc levels via nutritional supplementation during pregnancy.