Study | Design | Sampling period | Population | % with blood Hg concentration above guidance value (8 μg/L) |
---|---|---|---|---|
Nunavik Health Survey16 | Representative survey | 2004 | Inuit women aged 18–39 yr in Nunavik (northern Quebec) | 53.3 |
NCDS8 | Birth cohort | 2005–10 | Inuit school-aged children in Nunavik | 16.9* |
Canadian Health Measures Survey17 | Representative survey† | 2007–09 | Women aged 16–49 yr; Canada-wide study | 2.2 |
Geometric mean‡ ± SD or (95% CI) for blood Hg concentration, μg/L | ||||
NCDS8 | Birth cohort | 1995–01 | Pregnant Inuit women from Hudson Bay, Nunavik§ | 10.4 ± 0.4 |
Maternal biomonitoring study18 | Convenience sample | 2005–07 | Pregnant Inuit women in Baffin region | 4.0 (3.4–4.7) |
Pregnant Inuit women in Inuvik | 1.1 (0.85–1.5) | |||
Pregnant Dene and Metis women in Inuvik | 0.70 (0.45–1.1) | |||
Canadian Health Measures Survey17 | Representative survey | 2007–09 | Women aged 16–49 yr; Canada-wide study | 0.72 (0.50–0.94) |
MIREC study19 | Birth cohort | 2008–11 | Pregnant women in 10 Canadian urban regions | 0.86 ± 2.84 |
Note: CI = confidence interval, Hg = mercury, MIREC = Maternal–Infant Research on Environmental Chemicals study, NCDS = Nunavik Child Development Study, SD = standard deviation.
↵* Not published; proportion calculated directly from the NCDS mercury results.
↵† The study does not obtain samples from Canadians residing on Crown land, in Indian reserves or in remote regions, such as northern Quebec.
↵‡ Distributions of environmental concentrations are often skewed to the right and log-normally distributed. Consequently, many studies use geometric means to estimate central tendency, although this measure may be biased low.
↵§ The contemporary NCDS contains more than 1 birth cohort. These estimates come from one of the cohorts, and the sample comprises pregnant women recruited from the 3 largest communities in the Hudson Bay region of Nunavik.