Blood lead levels in the general population and vulnerable sub-populations and related risk factors for lead exposure in Canada

Lead is an environmental contaminant that is considered a major public health concern due to its effects on various body systems, such as the neurological, cardiovascular, immune and renal systems. Scientific evidence indicates that health effects occur in people at blood lead levels (BLLs) lower than those previously established as levels of concern; no safe level of lead exposure has been established. Lead has been monitored as part of various national and international biomonitoring programs. The aims of this study were: (1) to examine BLLs in the Canadian general population and vulnerable sub-populations between 2007 and 2013 using data from the Canadian Health Measures Survey (CHMS); and (2) to assess factors that are associated with elevated BLLs in these populations. BLLs in Canadians were in a decreasing trend over the study period. BLLs in Canadians varied by age and sex. Those aged 60 to 79 years had the highest BLLs, while the 12 to 19 years age group had the lowest BLLs. Males exhibited significantly higher BLLs than females. In young children aged 3 to 5 years, 99.9 % had BLLs below 5 µg/dL (blood lead reference level for children). BLLs in pregnant women were lower than those in non-pregnant women in the same age range. Multivariable regression analysis suggested that factors such as immigration status, household income, educational level, age of dwelling, smoking status, second-hand smoke exposure, alcohol consumption, and fish and shellfish consumption, were significantly associated with BLLs. This study presents the first robust analysis of BLLs in the Canadian vulnerable populations and assessment of factors associated with elevated BLLs. This information may be useful to identify population subgroups who are differentially exposed to lead based on various exposure factors and are at risk for lead exposure in Canada.