Population Iron Status in Canada: Results from the Canadian Health Measures Survey 2012-2019.

BACKGROUND: In Canada, population iron status estimates are dated (2009-2011) and did not consider the presence of inflammation. OBJECTIVES: This study aimed to update iron status estimates in Canada using serum ferrin (SF) and evaluate different correction methods for inflammation based on c-reactive protein (CRP). METHODS: Data from the Canadian Health Measures Survey cycles 3-6 (2012-2019) formed a multiyear, cross-sectional, nationally representative sample (3-79 y) (n = 21,453). WHO cutoffs for SF and hemoglobin were used to estimate iron deficiency (ID), iron deficiency anemia (IDA), anemia, and elevated iron stores. ID was first estimated without considering inflammation. Correction approaches evaluated were excluding individuals with CRP >5 mg/L, using modified SF cutoffs, and regression correction. RESULTS: Total population uncorrected prevalence estimates were 7% (95% CI: 6.2, 7.9) ID, 6.1% (95% CI: 5.2, 7.0) anemia, and 2.0% (95% CI: 1.6, 2.4) IDA. The uncorrected prevalence of ID was the highest among females of reproductive age with 21.3% (95% CI: 17.6, 25.0) and 18.2% (95% CI: 15.4, 21.1) in 14-18 y and 19-50 y, respectively. Corrected ID estimates were higher than the uncorrected values, independent of the correction approach. Regression correction led to a moderate increase in the prevalence to 10.5% for the total population, whereas applying the higher modified SF cutoffs (70 µg/L for those older than 5 y) led to the largest increases in the prevalence, to 12.6%. Applying modified cutoffs led to implausibly high ID estimates among those with inflammation. Elevated iron stores were identified in 17.2% (95% CI: 16.2, 18.2) of the population, mostly in adult males. CONCLUSIONS: Correction methods for estimating population iron status need further research. Considering the fundamental drawbacks of each method, uncorrected and regression-corrected estimates provide a reasonable range for ID in the Canadian population. Important sex-based differences in iron status and a public health ID problem of moderate magnitude among females of reproductive age are evident in Canada.

Vitamin D Status of People 3 to 79 Years of Age from the Canadian Health Measures Survey 2012-2019.

BACKGROUND: Vitamin D is recognized in bone health and the prevention of rickets and osteomalacia. OBJECTIVE: This study aimed to assess vitamin D status of people in Canada and to identify factors associated with vitamin D inadequacy and deficiency. METHODS: Serum 25-hydroxyvitamin D (25(OH)D) from the Canadian Health Measures Survey (cycles 3-6, n = 21,770, 3-79 y) were evaluated for geometric means and proportions <40 (inadequate) and <30 (risk of deficiency) nmol/L. Factors associated with inadequacy or deficiency were tested using logistic regression. RESULTS: Mean serum 25(OH)D was 57.9 (95% CI: 55.4, 60.5) nmol/L; the prevalence of inadequacy was 19.0% (95% CI: 15.7, 22.3) and risk of deficiency was 8.4% (95% CI: 6.5, 10.3). Prominent dietary factors associated with inadequacy in adults included: not consuming fish compared with ≥1/wk (adjusted ORadj: 1.60; 95% CI: 1.21, 2.11), none compared with ≥1/d for cow's milk (ORadj: 1.41; 95% CI: 1.02, 1.94) or margarine (ORadj: 1.42; 95% CI: 1.08, 1.88); or nonuser compared with user of vitamin D supplements (ORadj: 5.21; 95% CI: 3.88, 7.01). Notable demographic factors included: younger adults compared with 71 to 79 y (19-30 y ORadj: 2.33; 95% CI: 1.66, 3.29); BMI ≥30 compared with <25 kg/m2 (ORadj: 2.30; 95% CI: 1.79, 2.95); lower household income quartile 1 compared with 4 (ORadj: 1.46; 95% CI: 1.00, 2.15); and self-reported Black (ORadj: 8.06; 95% CI: 4.71, 13.81), East/Southeast Asian (ORadj: 3.83; 95% CI: 2.14, 6.85), Middle Eastern (ORadj: 4.57; 95% CI: 3.02, 6.92), and South Asian (ORadj: 4.63; 95% CI: 2.62, 8.19) race compared with White. Similar factors were observed in children and for deficiency. CONCLUSIONS: Most people in Canada have adequate vitamin D status; nonetheless, racialized groups have an elevated prevalence of inadequacy. Further research is required to evaluate if current strategies to improve vitamin D status, including increasing vitamin D in fortified foods and supplements, and dietary guidance to include a source of vitamin D every day help to reduce health inequality in Canada.