Association between global DNA methylation (LINE-1) and occupational particulate matter exposure among informal electronic-waste recyclers in Ghana.

This study examined the associations between PM (2.5 and 10) and global DNA methylation among 100 e-waste workers and 51 non-e-waste workers serving as controls. Long interspersed nucleotide repetitive elements-1 (LINE-1) was measured by pyrosequencing. Personal PM2.5 and PM10 were measured over a 4-hour work-shift using real-time particulate monitors incorporated into a backpack . Linear regression models were used to assess the association between PM and LINE-1 DNA methylation. The concentrations of PM2.5 and PM10 were significantly higher among the e-waste workers than the controls (77.32 vs 34.88, p < 0.001 and 210.21 vs 121.92, p < 0.001, respectively). PM2.5 exposure was associated with increased LINE-1 CpG2 DNA methylation (ß = 0.003; 95% CI; 0.001, 0.006; p = 0.022) but not with the average of all 4 CpG sites of LINE-1. In summary, high levels of PM2.5 exposure was associated with increased levels of global DNA methylation in a site-specific manner.

Micronutrient status and leukocyte telomere length in school-age Colombian children.

PURPOSE: Leukocyte telomere length (LTL) is a biomarker of inflammation and oxidative stress that predicts chronic disease risk. Nutritional factors are related to LTL in adulthood, but these associations are not well characterized in children. We examined whether micronutrient status biomarkers were associated with LTL in school-age children. METHODS: We conducted a cross-sectional study of 330 boys and 393 girls aged 5-12 years from Bogotá, Colombia. We quantified blood concentrations of hemoglobin, ferritin, zinc, vitamin A, folate, and vitamin B-12; and measured LTL using qPCR in DNA extracted from buffy coat. We estimated mean differences in LTL by quartiles of micronutrient status biomarkers and categories of relevant sociodemographic and anthropometric covariates with the use of linear regression. RESULTS: In girls, plasma vitamin B-12 was positively associated with LTL (adjusted LTL difference between extreme vitamin B-12 quartiles = 0.11; P, trend = 0.02). LTL was also positively associated with birth order in girls (P, trend = 0.02). In boys, LTL was not related to the micronutrient status biomarkers but, unexpectedly, it was positively associated with birth weight (P = 0.02), height-for-age Z score (P, trend = 0.01), and serum C-reactive protein (P, trend = 0.01). CONCLUSIONS: LTL is associated with vitamin B-12 status among girls. LTL is also associated with birth weight, height, and C-reactive protein in boys.

Vitamin D intake and survival and recurrence in head and neck cancer patients.

OBJECTIVES/HYPOTHESIS: With an unacceptably low 5-year survival rate and few identified modifiable factors that affect head and neck cancer (HNC) outcomes, HNC survival remains an important public health problem. Vitamin D has been shown to be associated with immune reactivity and improved outcomes for some cancer sites, but findings are mixed, and few studies have examined vitamin D in relation to HNC. This study aimed to assess the association between vitamin D intake and survival outcomes in HNC patients. STUDY DESIGN: Prospective cohort study. METHODS: This study utilized data on 434 HNC patients with valid pretreatment food frequency questionnaire data who participated in the University of Michigan Head and Neck Specialized Program of Research Excellence epidemiology project. Cox proportional hazard models were used to estimate the associations between total, dietary, and supplemental vitamin D intake and HNC outcomes, while adjusting for other known prognostic factors. RESULTS: After multivariable adjustment, we found a statistically significant inverse trend between total vitamin D intake and recurrence (Q4 vs. Q1 hazard ratio: 0.47, 95% confidence interval: 0.20-1.10, P trend = .048). We observed no association with dietary or supplemental intake separately, and no association was observed with all-cause or HNC-specific mortality. CONCLUSIONS: These findings suggest that HNC patients with lower levels of vitamin D intake are at higher risk of recurrence. If borne out in future studies, our results suggest that increased vitamin D intake through dietary intervention or the use of supplements may be a feasible intervention for prevention of recurrence in HNC patients. LEVEL OF EVIDENCE: 2b. Laryngoscope, E371-E376, 2018.

Ethnic disparity in breast cancer survival in southern Thai women.

BACKGROUND: Breast cancer has the highest incidence in women of all cancers and its burden is expected to continue to increase worldwide, especially in middle-income countries such as Thailand. The southern region of Thailand is unique in that it is comprised of 30% Muslims, whereas the rest of Thailand is 95% Buddhist. Breast cancer incidence and survival differ between these religious groups, but the association between clinical subtype of breast cancer and survival has not yet been assessed. METHODS: Here we characterized differences in breast cancer survival with consideration to clinical subtype by religious group (Muslim Thai and Buddhist Thai women). We compared distributions of age, stage and clinical subtype and assessed overall survival by religion. RESULTS: Our findings show that Muslim Thai women with breast cancer are diagnosed at a younger age, at later stages and have shorter overall survival times compared to Buddhist Thai women with breast cancer. We also observe a higher proportion of triple negative tumors characterized in Muslim Thai women. CONCLUSIONS: Our findings confirm previous studies that have shown lower survival rates in Muslim Thai women compared to Buddhist women with breast cancer and offer novel information on subtype distribution. To date, this is the first study assessing clinical subtypes in southern Thailand by religious status. IMPACT: Our findings are critical in providing information on the role of clinical subtype in cancer disparities and provide evidence from the Southeast Asian region for global studies on breast cancer survival.

Sociodemographic correlates and family aggregation of leukocyte telomere length in adults and children from Mesoamerica.

OBJECTIVE: Telomere length is a biomarker of cumulative stress and inflammation related to chronic disease risk. We examined the associations of leukocyte telomere length (LTL) with sociodemographic and anthropometric variables and estimated LTL family aggregation in Central America, a region with a high burden of chronic disease where LTL has not been studied. METHODS: We conducted a cross-sectional study of 174 school age children and their parents in the capital cities of Belize, Honduras, Nicaragua, Costa Rica, Panama, and the city of Tuxtla-Gutierrez in Mexico. We measured LTL by quantitative PCR in DNA extracted from whole blood. We compared the distribution of LTL by categories of sociodemographic and anthropometric characteristics using linear regression. Family aggregation was estimated with correlation coefficients and intraclass correlations. RESULTS: In mothers, LTL was inversely associated with age (P, trend < .0001) and positively associated with height (P = .0002). Among fathers, LTL was inversely associated with food insecurity (P, trend = .0004). In children, boys had 0.10 log units shorter LTL than girls (95% CI: -0.17, -0.03; P = .004). LTL was inversely associated with parental education (P, trend = .01) and positively associated with paternal age at birth (P, trend < .0001), maternal LTL (P, trend = .007), and paternal LTL (P, trend = .02). LTL varied significantly by country of origin among all family members. Aggregation was greatest between children and their mothers, and mostly occurred at the country, rather than family, level. CONCLUSION: LTL is associated with age and height in women; food insecurity in men; and sex, parental education, parental LTL, and paternal age at birth among children.

DNA methylation is differentially associated with environmental cadmium exposure based on sex and smoking status.

The adverse health effects of cadmium (Cd) are well known in human populations; however, much of what is known about biological mechanisms of Cd comes from in vitro and animal studies. The adverse health outcomes due to high levels of Cd exposure in the population of Mae Sot, Thailand have been extensively characterized. Here, for the first time, this population is being studied in an epigenetic context. The objective of this study was to characterize the association between DNA methylation markers and Cd exposure, taking into account sex and smoking differences, in an adult population at an increased risk of experiencing adverse health outcomes from high body burden of Cd. One hundred and sixty-nine residents from known exposure areas of Mae Sot, Thailand and one hundred residents from non-exposed areas nearby were surveyed in 2012. Urine and blood samples were collected for measurement of urinary Cd (UCd) and DNA methylation of Cd-related markers (DNMT3B, MGMT, LINE-1, MT2A). UCd levels were 7 times higher in the exposed compared to the unexposed populations (exposed median: 7.4 µg/L, unexposed median: 1.0 µg/L, p < 0.001). MGMT hypomethylation was associated with increasing levels of UCd in the total population. Sex-specific associations included MT2A and DNMT3B hypomethylation in women and LINE-1 hypermethylation in men with increasing UCd. Upon subanalysis, these associations separated by smoking status. In summary, environmental Cd exposure is associated with gene-specific DNA methylation in a sex and smoking dependent manner.