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.

Proportions of long-chain ω-3 fatty acids in erythrocyte membranes of Canadian adults: Results from the Canadian Health Measures Survey 2012-2015.

BACKGROUND: The Omega-3 Index (OI) is a proposed marker of coronary artery disease (CAD) risk. Another index, the EPA/arachidonic acid (AA) ratio has also been proposed as a possible risk marker for CAD. OBJECTIVE: Our primary objective was to characterize the Canadian population subgroups that have an undesirable OI (<4%, associated with high CAD risk) and to identify the participants' characteristics most strongly associated with the OI. Our secondary objective was to identify the characteristics most strongly associated with the EPA/AA ratio. DESIGN: Data from 4025 adult participants of cycles 3 and 4 (2012-2015) of the cross-sectional Canadian Health Measures Survey were pooled. Adjusted mean proportions of erythrocyte membrane ω-3 (n-3) fatty acids, total ω-6 fatty acids, and ratios were analyzed by sociodemographic, health, and lifestyle characteristics using covariate-adjusted models. RESULTS: The mean OI was 4.5%. Almost 40% of Canadians had an undesirable (<4%) OI. ω-3 supplement use, fish intake, and race were the variables most strongly associated with OI scores. The prevalence of undesirable OI was significantly higher among participants consuming fish less than twice a week (43.8%; 95% CI: 39.0%, 48.6%) than among those consuming more fish (12.7%; 95% CI: 7.8%, 19.9%), among smokers (62.7%; 95% CI: 52.9%, 71.7%) than nonsmokers (33.4%; 95% CI: 29.4%, 37.7%), in whites (42.7%; 95% CI: 38.2%, 47.4%) than in Asians (23.0%; 95% CI: 15.4%, 33.0%), and in adults aged 20-39 y (49.6%; 95% CI: 42.3%, 56.9%) than in those aged 60-79 y (24.4%; 95% CI: 21.0%, 28.1%). ω-3 supplement intake and fish intake were the characteristics most strongly associated with EPA/AA. All P ≤ 0.05. CONCLUSIONS: An important proportion of Canadian adults has an undesirable (<4%) OI, with higher prevalence in some subgroups. Further assessment is required to determine the value and feasibility of an increase in the population's OI to the currently proposed target of ≥8% as a potential public health objective.

A report of activities related to the Dietary Reference Intakes from the Joint Canada-US Dietary Reference Intakes Working Group.

The governments of the United States and Canada have jointly undertaken the development of the Dietary Reference Intakes (DRIs) since the mid-1990s. The Federal DRI committees from each country work collaboratively to identify DRI needs, prioritize nutrient reviews, advance work to resolve methodological issues that is necessary for new reviews, and sponsor DRI-related committees through the National Academies of Sciences, Engineering and Medicine. In recent years, the Joint Canada-US DRI Working Group, consisting of members from both Federal DRI committees, developed an open and transparent nomination process for prioritizing nutrients for DRI review, by which sodium, the omega-3 (n-3) fatty acids, vitamin E, and magnesium were identified. In addition, discussions during the nutrient nomination process prompted the Federal DRI committees to address previously identified issues related to the use of chronic disease endpoints when setting DRIs. The development of guiding principles for setting DRIs based on chronic disease risk reduction will be applied for the first time during the DRI review of sodium and potassium. In summary, the US and Canadian governments have worked collaboratively to adapt our approach to prioritizing nutrients for DRI review and to broaden the scope of the DRIs to better incorporate the concept of chronic disease risk reduction in order to improve public health.

Overweight and obesity are associated with lower vitamin D status in Canadian children and adolescents.

INTRODUCTION: There is evidence that 25-hydroxyvitamin D levels are lower in overweight and obese youth. This study examined the relationship between weight status and 25-hydroxyvitamin D, while controlling for confounders, in Canadian youth. METHODS: Plasma 25-hydroxyvitamin D from subjects aged 6 to 17 years from the Canadian Health Measures Survey cycles 1 (2007 to 2009) and 2 (2009 to 2011) was used. Sex-specific multiple linear regression and logistic regressions examined the relationship of overweight and obesity (body mass index ≥ 85th percentile) with 25-hydroxyvitamin D levels and the odds of 25-hydroxyvitamin D <40 nmol/L and <50 nmol/L. RESULTS: The prevalence of risk of vitamin D deficiency (25-hydroxyvitamin D < 30 nmol/L) was 6% (95% confidence interval [CI] 3.26% to 10.12%). Vitamin D inadequacy, estimated by levels <40 nmol/L, was 15% (95% CI 10.34% to 20.39%; 19% [95% CI 13.1 to 25.6] for teenagers). Seventy per cent (95% CI 63.59 to 75.17) had levels >50 nmol/L, consistent with achieving the Recommended Dietary Allowance. In adjusted analyses, overweight/obesity (1/3 of subjects) was independently associated with lower 25-hydroxyvitamin D for both sexes after adjustment for age, race, income, season, vitamin D supplementation and daily milk consumption. For 25-hydroxyvitamin D <40 nmol/L, the overweight/obese odds ratio for males was 2.63 (95% CI 1.34 to 5.18). For 25-hydroxyvitamin D <50 nmol/L, overweight/obese odds ratios were 2.19 (95% CI 1.46 to 3.28) for males and 1.39 (95% CI 1.05 to 1.84) for females. CONCLUSIONS: This study confirms the inverse association between adiposity and serum concentrations of 25-hydroxyvitamin D in Canadian youth and the independent association of overweight/obesity to 25-hydroxyvitamin D level and vitamin D status after adjustment for other factors.

High-dose compared with low-dose vitamin B-12 supplement use is not associated with higher vitamin B-12 status in children, adolescents, and older adults.

Over-the-counter vitamin supplements on the Canadian market are permitted to contain a daily vitamin B-12 dose of up to 1000 µg. Our objective was to determine the association between total daily vitamin B-12 supplement dose and markers of vitamin B-12 status in Canadians. Blood collected from a nationally representative sample aged 6-79 y (n = ∼5600) in the Canadian Health Measures Survey (2007-2009) was analyzed for serum vitamin B-12 and plasma total homocysteine (tHcy). Total daily intake of vitamin B-12 from single and multivitamin supplements was calculated. Individuals that indicated proton pump inhibitor or vitamin B-12 injection treatment were excluded from the supplement dose and tHcy analyses; folate-deficient individuals were also excluded from the tHcy analysis. Twenty-three percent of children, 12.3% of adolescents, and 25.5% of adults consumed a vitamin B-12-containing supplement. Supplement users had 33% higher serum vitamin B-12 and 4.2% higher prevalence of adequacy than did non-supplement users. Children and adolescents consuming >10 µg/d supplemental vitamin B-12 did not demonstrate higher serum vitamin B-12, higher prevalence of serum vitamin B-12 adequacy, or lower tHcy than did those consuming >0-10 µg/d. The association between serum vitamin B-12 reached a plateau at doses of >25 and >10-25 µg/d in adults aged 46-59 and 60-79 y, respectively. The prevalences of serum vitamin B-12 adequacy and normal tHcy, and tHcy did not differ by vitamin B-12 supplement dose in adults >45 y. In this cross-sectional study, vitamin B-12 supplement doses >10-25 µg/d were not associated with higher vitamin B-12 status in children, adolescents, or older adults compared with lower doses.

Characteristics of users of supplements containing vitamin D in Canada and associations between dose and 25-hydroxvitamin D.

Canadians using supplements containing vitamin D are more likely to have 25-hydroxyvitamin D (25(OH)D) levels consistent with the Recommended Dietary Allowance, particularly with the low UVB exposure during the winter. This study aimed to determine these users' characteristics and to examine the relationship between dosage and 25(OH)D using the 2007-2009 Canadian Health Measures Survey (n = 5604, 6-79 years of age). Logistic regression models examined the odds of supplement use within the preceding 30 days. Thirty-one percent used vitamin D supplements; 58.5% were female. In adjusted analyses, females' odds of supplement use were lower for those 12-19 years old (odds ratio (OR), 0.63; 95% CI, 0.41-0.96) and higher for those 60-79 years old (OR, 4.19; 95% CI, 2.69-6.64) and 40-59 years old (OR, 1.56; 95% CI, 1.10-2.20) compared with those 20-39 years old; their odds of supplement use were also higher for those of higher income (OR, 2.29; 95% CI, 1.26-4.16) and middle income (OR, 1.59; 95% CI, 1.03-2.46), those reporting ≥1 chronic disease (OR, 1.48; 95% CI, 1.06-2.06), and those consuming milk ≥1 time·day(-1) (OR, 1.35; 95% CI, 1.14-1.60). For males, increased use was associated with age 60-79 years (OR, 2.41; 95% CI, 1.54-3.77) and 6-11 years (OR, 1.77; 95% CI, 1.19-2.64) and higher income (OR, 2.12; 95% CI, 1.49-3.00) and middle income (OR, 1.55; 95% CI, 1.04-2.31). Use did not vary significantly by race, education, season, body mass index, health, or physical activity. A total of 35.7% of Canadians >50 years old took ≥400 IU of vitamin D; 25(OH)D increased with increasing supplement dosage (r = 0.33) in winter, but differences between 1-399 IU and 400-999 IU were not significant. Usage and nonusage patterns are important to consider as ways of improving vitamin D intake are pursued.

Temporal trends and determinants of longitudinal change in 25-hydroxyvitamin D and parathyroid hormone levels.

Vitamin D is essential for facilitating calcium absorption and preventing increases in parathyroid hormone (PTH), which can augment bone resorption. Our objectives were to examine serum levels of 25-hydroxyvitamin D [25(OH)D] and PTH, and factors related to longitudinal change in a population-based cohort. This is the first longitudinal population-based study looking at PTH and 25(OH)D levels. We analyzed 3896 blood samples from 1896 women and 829 men in the Canadian Multicentre Osteoporosis Study over a 10-year period starting in 1995 to 1997. We fit hierarchical models with all available data and adjusted for season. Over 10 years, vitamin D supplement intake increased by 317 (95% confidence interval [CI] 277 to 359) IU/day in women and by 193 (135 to 252) IU/day in men. Serum 25(OH)D (without adjustment) increased by 9.3 (7.3 to 11.4) nmol/L in women and by 3.5 (0.6 to 6.4) nmol/L in men but increased by 4.7 (2.4 to 7.0) nmol/L in women and by 2.7 (-0.6 to 6.2) nmol/L in men after adjustment for vitamin D supplements. The percentage of participants with 25(OH)D levels <50 nmol/L was 29.7% (26.2 to 33.2) at baseline and 19.8% (18.0 to 21.6) at year 10 follow-up. PTH decreased over 10 years by 7.9 (5.4 to 11.3) pg/mL in women and by 4.6 (0.2 to 9.0) pg/mL in men. Higher 25(OH)D levels were associated with summer, younger age, lower body mass index (BMI), regular physical activity, sun exposure, and higher total calcium intake. Lower PTH levels were associated with younger age and higher 25(OH)D levels in both women and men and with lower BMI and participation in regular physical activity in women only. We have observed concurrent increasing 25(OH)D levels and decreasing PTH levels over 10 years. Secular increases in supplemental vitamin D intake influenced both changes in serum 25(OH)D and PTH levels.

Vitamin B-12 and homocysteine status in a folate-replete population: results from the Canadian Health Measures Survey.

BACKGROUND: Vitamin B-12 is an important cofactor required for nucleotide and amino acid metabolism. Vitamin B-12 deficiency causes anemia and neurologic abnormalities-a cause for concern for the elderly, who are at increased risk of vitamin B-12 malabsorption. Vitamin B-12 deficiency is also associated with an increased risk of neural tube defects and hyperhomocysteinemia. The metabolism of vitamin B-12 and folate is interdependent, which makes it of public health interest to monitor biomarkers of vitamin B-12, folate, and homocysteine in a folic acid-fortified population. OBJECTIVE: The objective was to determine the vitamin B-12, folate, and homocysteine status of the Canadian population in the period after folic acid fortification was initiated. DESIGN: Blood was collected from a nationally representative sample of ∼5600 participants aged 6-79 y in the Canadian Health Measures Survey during 2007-2009 and was analyzed for serum vitamin B-12, red blood cell folate, and plasma total homocysteine (tHcy). RESULTS: A total of 4.6% of Canadians were vitamin B-12 deficient (<148 pmol/L). Folate deficiency (<320 nmol/L) was essentially nonexistent. Obese individuals were less likely to be vitamin B-12 adequate than were individuals with a normal BMI. A total of 94.9% of Canadians had a normal tHcy status (≤13 µmol/L), and individuals with normal tHcy were more likely to be vitamin B-12 adequate and to have high folate status (>1090 nmol/L). CONCLUSIONS: Approximately 5% of Canadians are vitamin B-12 deficient. One percent of adult Canadians have metabolic vitamin B-12 deficiency, as evidenced by combined vitamin B-12 deficiency and high tHcy status. In a folate-replete population, vitamin B-12 is a major determinant of tHcy.

The vitamin D status of Canadians relative to the 2011 Dietary Reference Intakes: an examination in children and adults with and without supplement use.

BACKGROUND: The 2011 Dietary Reference Intakes (DRIs) for vitamin D use 25-hydroxyvitamin D [25(OH)D] concentrations to define vitamin D deficiency (<30 nmol/L), the Estimated Average Requirement (40 nmol/L), and the Recommended Dietary Allowance (RDA; 50 nmol/L). The Canadian population has not yet been assessed according to these recommendations. OBJECTIVE: We determined the prevalence of meeting DRI recommendations and the role of vitamin D supplement use among Canadians aged 6-79 y. DESIGN: Plasma 25(OH)D from a representative sample of Canadians in the Canadian Health Measures Survey-Cycle 1 (n = 5306) were used. Supplement use was assessed by household interview. Concentrations of 25(OH)D were compared in supplement users and nonusers by season and race. RESULTS: Overall, 5.4%, 12.7%, and 25.7% of the participants had 25(OH)D concentrations below the 30-, 40-, and 50-nmol/L cutoffs, respectively. In white Canadians, plasma 25(OH)D concentrations ranged from an undetectable percentage with concentrations <30 nmol/L in summer to 24.5% with concentrations <50 nmol/L in winter; the corresponding values ranged from 12.5% to 53.1% in nonwhite Canadians. Supplement users had significantly higher 25(OH)D concentrations than did nonusers, and no seasonal differences were found. In nonsupplement users, the prevalence of 25(OH)D concentrations <50 nmol/L in winter was 37.2% overall and was 60.7% in nonwhites. CONCLUSIONS: One-quarter of Canadians did not meet the RDA, but the use of vitamin D supplements contributed to a better 25(OH)D status. Nonwhite Canadians had the highest risk of not achieving DRI recommendations. More than one-third of Canadians not using supplements did not meet the RDA in winter. This suggests that current food choices alone are insufficient to maintain 25(OH)D concentrations of 50 nmol/L in many Canadians, especially in winter.