Arsenic association with circulating oxidized low-density lipoprotein in a Native American community

More than 500 abandoned uranium (U) mines within the Navajo Nation contribute U, arsenic (As) and other metals to groundwater, soil and potentially air through airborne transport. The adverse cardiovascular health effects attributed to cumulative exposure to these metals remains uncertain. The aim of this study was to examine whether environmental exposure to these metals may promote or exacerbate the oxidation of low-density lipoprotein (LDL) cholesterol in this Native American population. The correlation of cardiovascular biomarkers (oxidized LDL (oxLDL) and C-reactive protein (CRP)) from a Navajo cohort (n = 252) with mean annual As and U intakes from water and urine metals was estimated using linear regression. Proof-of-concept assays were performed to investigate whether As and U directly oxidize human LDL. Mean annual As intake from water was positively and significantly associated with oxLDL, but not CRP in this study population, while U intake estimates were negatively associated with oxLDL. In an acellular system, As, but not U, directly oxidized the apolipoprotein B-100 component of purified human LDL. Neither metal promoted lipid peroxidation of the LDL particle. Both the population and lab results are consistent with the hypothesis that As promotes oxidation of LDL, a crucial step in vascular inflammation and chronic vascular disease. Conversely, for outcomes related to U, negative associations were observed between U intake and oxLDL, and U only minimally altered human LDL in direct exposure experiments. Only urine U was correlated with CRP, whereas no other metals in water or urine were apparently reliable predictors of this inflammatory marker.     

Ethnoracial differences in cannabis use among native-born and foreign-born high school students in Ontario

The objective of this study was to examine the association of ethnoracial background and immigrant status to cannabis use among students in Ontario, Canada. Data were derived from the Ontario Student Drug Use and Health Survey, a school-based, province-wide survey of students in Grades 7–12. The survey utilized a stratified two-stage cluster design. Analyses were based on a pooled subsample of 12,527 students in Grades 9–12 during the 2011 and 2013 survey cycles and included adjustments for the complex sample design. Results indicate that youth who were of South Asian or East/Southeast Asian background were at lower odds of cannabis use than those who were White, Black, or mixed-race backgrounds. Youth who were of mixed-race background (i.e., White and another group) were at higher odds of cannabis use than youth who were of White background. The association between ethnoracial background and cannabis use also varied for some foreign-born and native-born youth. These findings suggest that ethnoracial background should be an important consideration in investigations of cannabis use among foreign- relative to native-born youth.