Factors associated with the blood and urinary selenium concentrations in the Canadian population: Results of the Canadian Health Measures Survey (2007-2011).

Abstract

The objective of the present work is to assess the factors associated with whole blood and urinary selenium (Se) concentrations in Canadians aged 6-79 years old, and to interpret the data in the context of exposure guidance values. Whole blood Se concentrations data collected from 10740 participants as part of the Canadian Health Measures Survey (CHMS) Cycle 1 (2007-09) and Cycle 2 (2010-11) were analyzed for associations with the demographic and dietary characteristics of the Canadian population; whereas the urinary Se concentrations were only assessed for their association with the demographic variables. Whole blood and urinary Se concentrations were compared to biomonitoring equivalents established for exposure guidance values. The geometric means of whole blood Se concentrations (μg/L) were 197.42 (95% CI: 194.79, 200.08) and 192.35 (95% CI: 189.68, 195.06) for males and females, respectively. The corresponding urinary Se concentrations (μg/L) were 56.91 (95% CI: 54.81, 59.10) and 44.10 (95% CI: 41.89, 46.43) respectively. Males, participants born in Asia, older individuals, and participants who frequently consumed nuts and vegetables had higher whole blood Se, whereas current smokers, residents of Quebec and Ontario, participants who frequently consumed meat, fruits or dairy products were associated with lower whole blood Se. Sociodemographic factors were also significantly associated with urinary Se although the direction of association sometimes differed from those observed with blood Se. More than 99.9% of the Canadian population covered by the survey had whole blood Se concentrations within the range from the lower (100 μg/L) and higher (400 μg/L) biomonitoring equivalents set for the protection from deficiency and selenosis, respectively. The CHMS data provide a baseline for Se exposure among Canadians and indicated that the population is generally not at risk of deficiency or toxicity.