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Background
Keywords
Findings
Authors

Background

Iron deficiency is the most common nutritional deficiency in the world, but little is known about the iron status of people in Canada, where the last estimates are from 1970-1972.

Data and Methods

The data are from cycle 2 (2009 to 2011) of the Canadian Health Measures Survey, which collected blood samples from a nationally representative sample of Canadians aged 3 to 79. Descriptive statistics (percentages, arithmetic means, geometric means) were used to estimate hemoglobin and serum ferritin concentrations, and other markers of iron status. Analyses were performed by age/sex group, household income, self-perceived health, diet, and use of iron supplements. World Health Organization reference values (2001) were used to estimate the prevalence of iron sufficiency and anemia.

Results

The overall prevalence of anemia was low in the 2009-to-2011 period—97% of Canadians had sufficient hemoglobin levels. Generally, hemoglobin concentration increased compared with 1970-1972; however, at ages 65 to 79, rates of anemia were higher than in 1970-1972. Depleted iron stores were found in 13% of females aged 12 to 19 and 9% of females aged 20 to 49. Lower household income was associated with a lower prevalence of hemoglobin sufficiency, but was not related to lower serum ferritin sufficiency. Self-perceived health and diet were not significantly associated with hemoglobin and serum ferritin levels.

Interpretation

The lack of a relationship between iron status and diet may be attributable to the use of questions about food consumption frequency that were not specifically designed to estimate dietary iron intake.  Factors other than iron intake might have contributed to the increase in the prevalence of anemia among seniors.

Keywords

Anemia, dietary supplements, ferritin, hemoglobin, nutritional status

Findings

Iron is essential for biochemical functions in the body at every stage of life. The physiological manifestations of iron-deficiency anemia include reduced immune function and resistance to infection, impaired cognitive performance and behaviour, decreased thermoregulatory performance and energy metabolism, diminished exercise or work capacity, and increased incidence of preterm deliveries and low birthweight infants. In developed countries, iron deficiency and iron-deficiency anemia may be caused by inadequate intake of dietary iron, consumption of poorly available forms of iron, or diminished iron absorption due to dietary inhibitors. Increased demands for iron because of growth, menstrual losses, or pregnancy may also be factors. [Full Text]

Author

Marcia Cooper is with the Nutrition Research Division and Hélène Lowell is with the Office of Nutrition Policy and Promotion at Health Canada.  Linda Greene-Finestone is with the Health Promotion and Chronic Disease Prevention Branch at the Public Health Agency of Canada.  Johanne Levesque and Stacey Robinson are with the Health Statistics Division at Statistics Canada.

What is already known on this subject?

  • Iron deficiency is associated with health risks, such as reduced immune function and diminished exercise or work capacity.
  • Although iron deficiency is common in the world population, the 1970-1972 Nutrition Canada Survey reported a low risk of iron-deficient anemia among Canadians.
  • More recent smaller-scale studies have indicated some Canadian subgroups are at a greater risk of low iron status.

What does this study add?

  • The prevalence of anemia remains low in the Canadian population overall.
  • Compared with 40 years ago, higher rates of anemia were found among seniors.
  • Self-perceived health and selected dietary items were not significantly associated with hemoglobin and serum ferritin levels.