Total serum magnesium (Mg) concentration (SMC) is commonly used to assess Mg status. This study reports current SMCs of Canadians and their associations with demographic factors, diabetes, and measures of glycemic control and insulin resistance using results from the Canadian Health Measures Survey cycle 3 (2012–2013). Associations were examined in adults aged 20–79 years using linear mixed models. Mean SMCs and percentile distributions for 11 sex-age groups between 3 and 79 years (n = 5561) are reported. SMCs were normally distributed and differences (p < 0.05) among sex and age groups were small. Between 9.5% and 16.6% of adult sex-age groups had a SMC below the lower cut-off of a population-based reference interval (0.75–0.955 mmol·L−1) established in the United States population as part of the NHANES I conducted in 1971–1974. Having diabetes was associated with 0.04 to 0.07 mmol·L−1 lower SMC compared to not having diabetes in the various models. Body mass index, glycated hemoglobin, serum glucose and insulin concentrations, and homeostatic model assessment of insulin resistance were negatively associated with SMC. This is the first study to report SMCs in a nationally representative sample of the Canadian population. A substantial proportion of Canadians are hypomagnesaemic in relation to a population-based reference interval, and SMC was negatively associated with diabetes and indices of glycemic control and insulin resistance.

Background: One of the underpinning elements to support evidence-based decision-making in food and nutrition is the usual dietary intake of a population. It represents the long-run average consumption of a particular dietary component (i.e., food or nutrient). Variations in individual eating habits are observed from day-to-day and between individuals. The National Cancer Institute (NCI) method uses statistical modeling to account for these variations in estimation of usual intakes. This method was originally developed for nutrition survey data in the United States. The main objective of this study was to apply the NCI method in the analysis of Canadian nutrition surveys. Methods: Data from two surveys, the 2004 and 2015 Canadian Community Health Survey—Nutrition were used to estimate usual dietary intake distributions from food sources using the NCI method. The effect of different statistical considerations such as choice of the model, covariates, stratification compared to pooling, and exclusion of outliers were assessed, along with the computational time to convergence. Results: A flowchart to aid in model selection was developed. Different covariates (e.g., age/sex groups, cycle, weekday/weekend of the recall) were used to adjust the estimates of usual intakes. Moreover, larger differences in the ratio of within to between variation for a stratified analysis or a pooled analysis resulted in noticeable differences, particularly in the tails of the distribution of usual intake estimates. Outliers were subsequently removed when the ratio was larger than 10. For an individual age/sex group, the NCI method took 1 h–5 h to obtain results depending on the dietary component. Conclusion: Early experience in using the NCI method with Canadian nutrition surveys data led to the development of a flowchart to facilitate the choice of the NCI model to use. The ability of the NCI method to include covariates permits comparisons between both 2004 and 2015. This study shows that the improper application of pooling and stratification as well as the outlier detection can lead to biased results. This early experience can provide guidance to other researchers and ensures consistency in the analysis of usual dietary intake in the Canadian context.

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Background: In September 2018, the prohibition of partially hydrogenated oils (PHO) came into effect in Canada to reduce industrially produced trans fats (TFA) in the food supply to the lowest level possible. Canada’s public health objective is that ≥90% of the population consume <1% of total energy (1%En) as TFA (WHO recommendation). Objective: Estimate the intakes of TFA by Canadians before the PHO prohibition. Methods: Data from 19,670 participants of the cross-sectional Canadian Community Health Survey (CCHS)–Nutrition 2015 was analyzed. Foods were classified based on the source of TFA (industrially produced only (i-TFA), naturally occurring only (n-TFA), or a mix of both). Food content in TFA originated from 2016 label information and the 2015 Canadian Nutrient File. Mean usual intakes of total TFA and TFA from different sources were estimated for Canadians aged 1-75y. Results: For the overall population, the mean intake of total TFA represented 0.57%En (SE:0.001), with the 95 percentile at 0.93%En (SE:0.005). All age-sex groups had mean TFA intakes <1%E, ranging from 0.52 to 0.71%En. On average, foods containing only n-TFA provided >1/2 of total TFA intake (0.32%En, SE:0.005). Foods containing only i-TFA provided <1/3 of total TFA intake (0.19%En, SE:0.005). The target of ≥90% of the population consuming <1%En as TFA had already been achieved before the PHO prohibition in all age-sex groups, except children 1-3 years old, with 86% within target. In that group, foods containing only n-TFA provided >2/3 of total TFA intake (0.48%En, SE:0.02).Conclusions: Total TFA intakes in Canada before the PHO prohibition were relatively low, likely due to previous initiatives to reduce industrially produced TFA in foods, starting with labelling of the amount of TFA on most pre-packaged foods, which became mandatory in 2007. These analyses will be repeated using post-PHO prohibition data to continue monitoring progress after the prohibition.