Background: This study aimed to assess the effects of iodine intake, thyroid function, and their combined effect on the risk of papillary thyroid cancer (PTC) and papillary thyroid microcarcinoma (PTMC).Methods: A case-control study was conducted including 500 community-based controls who had undergone a health check-up, and 446 overall PTC cases (209 PTC and 237 PTMC) from the Thyroid Cancer Longitudinal Study. Urinary iodine concentration (UIC), was used as an indicator of iodine intake, and serum for thyroid function. The risk of PTC and PTMC was estimated using unconditional logistic regression.Results: Excessive iodine intake (UIC ≥220 μg/gCr) was associated with both PTC (odds ratio [OR], 18.13 95% confidence interval [CI], 8.87 to 37.04) and PTMC (OR, 8.02; 95% CI, 4.64 to 13.87), compared to adequate iodine intake (UIC, 85 to 219 μg/gCr). Free thyroxine (T4) levels ≥1.25 ng/dL were associated with PTC (OR, 1.97; 95% CI, 1.36 to 2.87) and PTMC (OR, 2.98; 95% CI, 2.01 to 4.41), compared to free T4 levels of 0.7 to 1.24 ng/dL. Individuals with excessive iodine intake and high free T4 levels had a greatly increased OR of PTC (OR, 43.48; 95% CI, 12.63 to 149.62), and PTMC (OR, 26.96; 95% CI, 10.26 to 70.89), compared to individuals with adequate iodine intake and low free T4 levels.Conclusion: Excessive iodine intake using creatinine-adjusted UIC and high free T4 levels may have a synergistic effect on PTC and PTMC. Considering both iodine intake and thyroid function is important to assess PTC and PTMC risk.

Objectives: This study aimed to identify the social and policy determinants of coronavirus disease 2019 (COVID-19) infection across 23 countries.Methods: COVID-19 indicators (incidence, mortality, and fatality) for each country were calculated by direct and indirect standardization. Multivariable regression analyses were used to identify the social and policy determinants of COVID-19 infection.Results: A higher number of doctors per population was related to lower incidence, mortality, and fatality rates of COVID-19 in 23 countries (β=-0.672, -0.445, and -0.564, respectively). The number of nurses/midwives per population was associated with lower mortality and fatality rates of COVID-19 in 23 countries (β=-0.215 and -0.372, respectively). Strengthening of policy restriction indicators, such as restrictions of public gatherings, was related to lower COVID-19 incidence (β=-0.423). A national Bacillus Calmette–Guérin vaccination policy conducted among special groups or in the past was associated with a higher incidence of COVID-19 in 23 countries (β=0.341). The proportion of the elderly population (aged over 70 years) was related to higher mortality and fatality rates (β=0.209 and 0.350, respectively), and income support was associated with mortality and fatality rates (β=-0.362 and -0.449, respectively).Conclusions: These findings do not imply causality because this was a country-based correlation study. However, COVID-19 transmission can be influenced by social and policy determinants such as integrated health systems and policy responses to COVID-19. Various social and policy determinants should be considered when planning responses to COVID-19.

(1) Background: In the semiconductor industry, female workers were identified as having an increased risk of spontaneous abortion (SA). To date, the association between semiconductor work and SA is controversial. We aimed to assess the association between semiconductor work and specific processes and SA, in the semiconductor industry. (2) Methods: A literature search was conducted using databases such as PubMed, Embase, Cochrane library, and other core databases, from the date of inception of these databases to 31 July 2019. Studies that identified SA risk in female workers in the semiconductor industry were included. (3) Results: We identified 529 studies, of which six studies were included in the meta-analysis. During 1980–1993, the risk of SA in fabrication (Fab) workers was significantly higher than non-Fab workers (RR, 1.29; 95% CI, 1.05–1.57). Photolithography workers had a higher SA risk than non-process and office workers (RR, 1.41; 95% CI, 1.13–1.77). (4) Conclusion: Meta-analysis indicates a statistically significant association between Fab-work and SA. Specific process and chemical exposure meta-analyses need to be interpreted carefully considering bias. Because of the rapid change in the semiconductor industry, it is necessary to conduct an elaborate cohort study taking into consideration the current working environment.

BackgroundIodine is an intrinsic element of thyroid hormone, which is essential for childhood growth and development. The Ideal Breast Milk (IBM) cohort study aims to evaluate the effects of maternal iodine status during pregnancy and lactation on maternal thyroid function, offspring growth and development, and offspring thyroid function.MethodsThe IBM cohort study recruited pregnant women from Seoul National University Hospital between June 2016 and August 2017, followed by enrollment of their offspring after delivery. For the maternal participants, iodine status is evaluated by urinary iodine concentration (UIC) and dietary records in the third trimester and at 3 to 4 weeks and 12 to 15 months postpartum. For the child participants, cord blood sampling and UIC measurements are performed at birth. At 3 to 4 weeks of age, UIC and breastmilk iodine concentrations are measured. At 12 to 15 months of age, growth and development are assessed and measurements of UIC, a thyroid function test, and ultrasonography are performed.ResultsA total of 198 pregnant women in their third trimester were recruited. Their mean age was 35.1±3.5 years, and 78 (39.4%) of them were pregnant with twins. Thirty-three (16.7%) of them had a previous history of thyroid disease.ConclusionKorea is an iodine-replete area. In particular, lactating women in Korea are commonly exposed to excess iodine due to the traditional practice of consuming brown seaweed soup postpartum. The study of the IBM cohort is expected to contribute to developing guidelines for optimal iodine nutrition in pregnant or lactating women.

Identifying the predisposing factors to chronic or end-stage kidney disease is essential to preventing or slowing kidney function decline. Therefore, here, we investigated the genetic variants related to a rapid decline in the estimated glomerular filtration rate (eGFR) (i.e., a loss of >5 mL/min/1.73 m2 per year) and verified the relationships between variant-related diseases and metabolic pathway signaling in patients with chronic kidney disease. We conducted a genome-wide association study that included participants with diabetes, hypertension, and rapid eGFR decline from two Korean data sources (N = 115 and 69 for the discovery and the validation cohorts, respectively). We identified a novel susceptibility locus: 4q32.3 (rs10009742 in the MARCHF1 gene, beta = −3.540, P = 4.11 × 10−8). Fine-mapping revealed 19 credible, causal single-nucleotide polymorphisms, including rs10009742. The pimelylcarnitine and octadecenoyl carnitine serum concentrations were associated with rs10009742 (beta = 0.030, P = 7.10 × 10−5, false discovery rate (FDR) = 0.01; beta = 0.167, P = 8.11 × 10−4, FDR = 0.08). Our results suggest that MARCHF1 is associated with a rapid eGFR decline in patients with hypertension and diabetes. Furthermore, MARCHF1 affects the pimelylcarnitine metabolite concentration, which may mediate chronic kidney disease progression by inducing oxidative stress in the endoplasmic reticulum.