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.

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.

A scoping review shows that no single existing risk of bias assessment tool considers all sources of bias for cross-sectional studies.

OBJECTIVES: Different tools to assess the potential risk of bias (RoB) for cross-sectional studies have been developed, but it is unclear whether all pertinent bias concepts are addressed. We aimed to identify RoB concepts applicable to cross-sectional research validity and to explore coverage for each in existing appraisal tools. STUDY DESIGN AND SETTING: This scoping review followed the Joanna Briggs Institute methodology. We included records of any study design describing or reporting methods, concepts or tools used to consider RoB in health research reported to be descriptive/prevalence survey or analytic/association (cross-sectional) study designs. Synthesis included quantitative and qualitative analysis. RESULTS: Of the 4556 records screened, 90 were selected for inclusion; 67 (74%) described the development of, or validation process for, appraisal tools, 15 (17%) described methodological content or theory relevant to RoB for cross-sectional studies and 8 (9%) records of methodological systematic reviews. Review of methodological reports identified important RoB concepts for both descriptive/prevalence and analytic/association studies. Tools identified (n = 64 unique tools) were either intended to appraise quality or assess RoB in multiple study designs including cross-sectional studies (n = 21; 33%) or cross-sectional designs alone (n = 43; 67%). Several existing tools were modified (n = 17; 27%) for application to cross-sectional studies. The RoB items most frequently addressed in the RoB tools were validity and reliability of the exposure (53%) or outcome (65%) measurement and representativeness of the study population (59%). Most tools did not consider nonresponse or missingness appropriately or at all. CONCLUSION: Assessing cross-sectional studies involve unique RoB considerations. We identified RoB tools designed for broad applicability across various study designs as well as those specifically tailored for cross-sectional studies. However, none of the identified tools comprehensively address all potential biases pertinent to cross-sectional studies. Our findings indicate a need for continued improvement of RoB tools and suggest that the development of context-specific or more precise tools for this study design may be necessary.

Risk of bias in cross-sectional studies: Protocol for a scoping review of concepts and tools.

Cross-sectional studies are commonly used to study human health and disease, but are especially susceptible to bias. This scoping review aims to identify and describe available tools to assess the risk of bias (RoB) in cross-sectional studies and to compile the key bias concepts relevant to cross-sectional studies into an item bank. Using the JBI scoping review methodology, the strategy to locate relevant RoB concepts and tools is a combination of database searches, prospective review of PROSPERO registry records; and consultation with knowledge users and content experts. English language records will be included if they describe tools, checklists, or instruments which describe or permit assessment of RoB for cross-sectional studies. Systematic reviews will be included if they consider eligible RoB tools or use RoB tools for RoB of cross-sectional studies. All records will be independently screened, selected, and extracted by one researcher and checked by a second. An analytic framework will be used to structure the extraction of data. Results for the scoping review are pending. Results from this scoping review will be used to inform future selection of RoB tools and to consider whether development of a new RoB tool for cross-sectional studies is needed.

NUQUEST-NUtrition QUality Evaluation Strengthening Tools: development of tools for the evaluation of risk of bias in nutrition studies.

BACKGROUND: Dietary exposure assessments are a critical issue in evaluating human nutrition studies; however, nutrition-specific criteria are not consistently included in existing bias assessment tools. OBJECTIVES: Our objective was to develop a set of risk of bias (RoB) tools that integrated nutrition-specific criteria into validated generic assessment tools to address RoB issues, including those specific to dietary exposure assessment. METHODS: The Nutrition QUality Evaluation Strengthening Tools (NUQUEST) development and validation process included 8 steps. The first steps identified 1) a development strategy; 2) generic assessment tools with demonstrated validity; and 3) nutrition-specific appraisal issues. This was followed by 4) generation of nutrition-specific items and 5) development of guidance to aid users of NUQUEST. The final steps used established ratings of selected studies and feedback from independent raters to 6) assess reliability and validity; 7) assess formatting and usability; and 8) finalize NUQUEST. RESULTS: NUQUEST is based on the Scottish Intercollegiate Guidelines Network checklists for randomized controlled trials, cohort studies, and case-control studies. Using a purposive sample of 45 studies representing the 3 study designs, interrater reliability was high (Cohen's κ: 0.73; 95% CI: 0.52, 0.93) across all tools and at least moderate for individual tools (range: 0.57-1.00). The use of a worksheet improved usability and consistency of overall interrater agreement across all study designs (40% without worksheet, 80%-100% with worksheet). When compared to published ratings, NUQUEST ratings for evaluated studies demonstrated high concurrent validity (93% perfect or near-perfect agreement). Where there was disagreement, the nutrition-specific component was a contributing factor in discerning exposure methodological issues. CONCLUSIONS: NUQUEST integrates nutrition-specific criteria with generic criteria from assessment tools with demonstrated reliability and validity. NUQUEST represents a consistent and transparent approach for evaluating RoB issues related to dietary exposure assessment commonly encountered in human nutrition studies.

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.

Examining the diversity of ultra-processed food consumption and associated factors in Canadian adults.

Ultra-processed food (UPF) consumption is increasing globally at an unprecedented rate. We investigated UPF consumption among Canadian adults and associated sociodemographic and health-related factors. This study was a secondary analysis of the Foodbook study (2014-2015), which collected self-reported data on foods consumed by Canadians during a 7-day period. UPF diversity was assessed by summing the different types of UPFs consumed in the previous week to produce a diversity score. Descriptive statistics summarized UPF diversity among subgroups in Canada. Regression models identified significant associations between UPF diversity, body mass index (BMI), and sociodemographic variables. This study included 6062 participants, aged 18 years and older, representing 24.7 million Canadian adults. Almost all Canadian adults (99.0%) consumed UPFs at least once weekly. The most common UPFs consumed were chocolate, chips/pretzels, cold breakfast cereal, and fast foods. UPF diversity was greatest among men, young respondents, those with high income, and those with obesity. When controlling for potential confounders, UPF diversity for men and women was significantly associated with younger age and higher BMI; it was also associated with region for women. This study suggests UPF consumption in Canada varies across sociodemographic subgroups, but ultimately is pervasive. Further research examining potential health risks associated with UPF consumption is encouraged to inform Canadian interventions. Novelty: Almost all Canadians consume at least one type of ultra-processed food weekly. Nearly half or more Canadians consume chocolate, chips/pretzels, cold breakfast cereal, or fast food at least once weekly. Gender, age, and BMI are consistently associated with ultra-processed food diversity.

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.

Options for basing Dietary Reference Intakes (DRIs) on chronic disease endpoints: report from a joint US-/Canadian-sponsored working group.

Dietary Reference Intakes (DRIs) are used in Canada and the United States in planning and assessing diets of apparently healthy individuals and population groups. The approaches used to establish DRIs on the basis of classical nutrient deficiencies and/or toxicities have worked well. However, it has proved to be more challenging to base DRI values on chronic disease endpoints; deviations from the traditional framework were often required, and in some cases, DRI values were not established for intakes that affected chronic disease outcomes despite evidence that supported a relation. The increasing proportions of elderly citizens, the growing prevalence of chronic diseases, and the persistently high prevalence of overweight and obesity, which predispose to chronic disease, highlight the importance of understanding the impact of nutrition on chronic disease prevention and control. A multidisciplinary working group sponsored by the Canadian and US government DRI steering committees met from November 2014 to April 2016 to identify options for addressing key scientific challenges encountered in the use of chronic disease endpoints to establish reference values. The working group focused on 3 key questions: 1) What are the important evidentiary challenges for selecting and using chronic disease endpoints in future DRI reviews, 2) what intake-response models can future DRI committees consider when using chronic disease endpoints, and 3) what are the arguments for and against continuing to include chronic disease endpoints in future DRI reviews? This report outlines the range of options identified by the working group for answering these key questions, as well as the strengths and weaknesses of each option.

Adolescents' low-carbohydrate-density diets are related to poorer dietary intakes.

This study was undertaken to assess how low-carbohydrate-density diets below the acceptable macronutrient distribution range relate to food and micronutrient intake and sociodemographic and health-related characteristics. The multistage stratified cluster design in the 1990 Ontario Health Survey was used. There were 5,194 subjects, 12 to 18 years of age, in sampled households. Dietary data were collected via a food frequency questionnaire. Low-carbohydrate-density diets were consumed by 27.6% of males and 24.1% of females. Low-carbohydrate-density diets were related (P < .05) to reduced sufficiency of vegetables and fruit and higher consumption of meat and alternatives and added fats. The low-carbohydrate-density diet resulted in intakes lower in vitamin C and fiber and higher in cholesterol and total fat. The low-carbohydrate-density diet was directly associated with being Canadian-born (odds ratio [OR] = 1.78, 95% confidence interval [CI] = 1.27 to 2.50), overweight status (OR = 1.27, 95% CI = 1.02 to 1.57), smoking (OR = 1.53, 95% CI = 1.23 to 1.90), alcohol use (OR = 1.46, 95% CI = 1.21 to 1.75), and poorer self-rated health (OR = 1.47, 95% CI = 1.01 to 2.14). Use of the acceptable macronutrient distribution range identified adolescents with low-carbohydrate-density diets whose food choices and nutrient intake may impact negatively on short- and long-term health.

Measuring longitudinally the metabolic demands of stroke patients: resting energy expenditure is not elevated.

BACKGROUND AND PURPOSE: Little is known of the acute, subacute, and longer-term energy demands of stroke, information essential to appropriate clinical and nutritional management. The goals of this study were to (1) determine the resting energy expenditure (REE) of stroke patients from stroke onset to 3 months, (2) examine relations between stroke size, type, location, severity, and REE, and (3) evaluate whether estimation of REE from the Harris-Benedict equation (HB) requires the addition of a "stress factor" to capture the possible additional REE imposed by stroke. METHODS: The REE of new stroke patients was measured prospectively at hospital admission and on days 7, 11, 14, 21, and 90 by indirect calorimetry. Stroke patients' REEs (Kcal/d) over time and REEs as a percentage of HB were compared with control subjects' single measurements. RESULTS: Mean REE and %HB of stroke patients ranged from 1521+/-290 to 1663+/-268 Kcal/d and from 107+/-14.9 to 114+/-12.9 %HB, respectively. Mean measurements of control subjects were 1665+/-265 Kcal/d and 112.9+/-11.4 %HB (NS). REE was not associated with stroke characteristics (NS). Changes in REE measured longitudinally were not clinically meaningful (4 to 62 Kcal/d) though statistically significant (P=0.004). CONCLUSIONS: The REEs of stroke patients and controls were both approximately 10% higher than those predicted by HB. No hypermetabolic response pattern of energy expenditure was evident after stroke. REE did not vary with stroke characteristics, although confirmation with larger subgroups is required.

Tracking clinical improvement of swallowing disorders after stroke.

GOAL: The goal of this study was to determine recovery rates from swallowing disorders, or dysphagia, at 3 weeks and 3 months poststroke by tracking changes in nutritional management. MATERIALS AND METHODS: Ninety-one newly diagnosed stroke patients were studied. Patients with suspected dysphagia were referred for bedside swallowing assessment, performed by a speech-language pathologist, and, where indicated, a videofluoroscopic modified barium swallow. Patients with confirmed dysphagia were initiated on either an oral dysphagia diet or enteral feeding, and they continued to receive swallowing treatment as both inpatients and out-patients. Recovery from dysphagia, based on the patient's type of diet, was assessed at days 21 and 90 poststroke. FINDINGS: On admission, 48 of 91 (53%) newly diagnosed stroke patients presented with clinical evidence of a swallowing abnormality. Forty-two percent of these patients were managed by enteral tube feedings, and 58% received a dysphagia diet. By day 21 poststoke, 13 (27%) of the initially dysphagic patients were consuming a regular diet. By day 90, 36 (75%) of these patients were consuming a regular diet; 5 patients (10%) remained dysphagic and were nutritionally managed either with a dysphagia diet or enteral feeding. A total of 7 (15%) of the 48 patients were lost to follow-up. CONCLUSIONS: Three quarters of stroke patients initially presenting with dysphagia were consuming their prestroke diet by 3 months. Using assessment-based diet type as a proxy for the ongoing identification of dysphagia poststroke, this study found a substantial recovery rate in patients presenting with swallowing disorders.

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.

Differences between poststroke drivers and nondrivers: demographic characteristics, medical status, and transportation use.

OBJECTIVE: To determine the demographic, medical, and transportation use characteristics of stroke survivors wanting to drive who resumed or did not resume driving and compare the driving habits of those who drove with those of a nonstroke control group. DESIGN: One hundred and six stroke survivors who underwent a driving evaluation at a rehabilitation center in Ottawa, Canada, between 1995 and 2003, participated in a structured telephone interview 4-5 yrs after the evaluation. Information on driving history and transportation use before the driving assessment was obtained from the driving assessment client database. The nonstroke control group was derived from the literature. RESULTS: After stroke, 66% of subjects had resumed driving. Prestroke driving history was similar for drivers and nondrivers. Drivers were younger than nondrivers (mean age +/- SD, 62.7 +/- 12.7 yrs vs. 69.2 +/- 13.4 yrs; P = 0.02), had less medical comorbidity (mean modified Cumulative Illness Rating Scale score, 3.7 +/- 1.97 vs. 5.0 +/- 2.89; P = 0.01), and were less likely to rely on a walker (1.4% vs. 19.4%, P < 0.001). Self-imposed restrictions were reported by 35.7% of drivers. More nondrivers than drivers relied on family/friends (94.4% vs. 41.4%), public transportation (60.7% vs. 35.3%), or taxis (27.8% vs. 2.9%) (all P < 0.05). Drivers reported fewer driving difficulties (e.g., skill, weather, or traffic related;

Dietary reference intakes for vitamin D: justification for a review of the 1997 values.

Recent Institute of Medicine (IOM) reviews of the process for deriving Dietary Reference Intakes (DRIs) suggest that determining the need for a new nutrient review should be evaluated against criteria set a priori. After selecting the criterion of significant new and relevant research, a working group of US and Canadian government scientists used results from a systematic review and 2 conferences on vitamin D and health to evaluate whether significant new and relevant scientific evidence had become available since the 1997 IOM publication of the DRIs for vitamin D. This working group concluded that there appears to be new research meeting the criteria for 4 key DRI questions. The new research is of larger quantity and quality for the elderly than for other groups, but overall 1) adds to the bone-related and status evidence available to the 1997 DRI Committee for several of the life-stage groups, 2) identifies new outcomes with respect to risk of falls and performance measures in the elderly and potential adverse effects, and 3) provides additional information on dose-response relations between intakes and circulating 25-hydroxyvitamin D concentrations and between 25-hydroxyvitamin D concentrations and several health outcomes (ie, bone-related outcomes for all ages and risk of falls and performance measures in older adults). Members of the working group concluded that significant new and relevant research was available for reviewing the existing DRIs for vitamin D while leaving the decision of whether the new research will result in changes to the current DRIs to a future IOM-convened DRI committee.

Dietary intake among young adolescents in Ontario: associations with vegetarian status and attitude toward health.

BACKGROUND: This study aimed to describe the dietary intakes of adolescent vegetarians and omnivores and determine if, and how, attitude toward personal health related to food consumption. METHODS: Among grade 9 students in Ontario, Canada (n = 630), vegetarian status and estimated consumption of foods and food groups were determined by food frequency questionnaire. Personal health was self-categorized as very important (the "health conscious") or somewhat/not important (the "non-health conscious"). RESULTS: The prevalence of vegetarianism was 6.5% (CI = 4.6-8.4%) among females and 1.0% (CI = 0.2-1.8%) among males. Health-conscious omnivores consumed more grain, vegetables and fruit, and milk product than non-health-conscious omnivores (P < 0.05). Health-conscious vegetarians ingested more grain products, vegetables and fruit, and meat and alternatives than non-health-conscious vegetarians (P < 0.05). Among non-health-conscious vegetarians, none consumed two daily servings of meat and alternatives compared to 60.5% of non-health-conscious omnivores (P < 0.001). Among health-conscious vegetarians, milk product consumption was lower than that of health-conscious omnivores (P = 0.015). CONCLUSIONS: Large proportions of both vegetarian and omnivore adolescents consumed suboptimal diets. Health consciousness had value as an indicator of dietary adequacy and may be useful as a rudimentary screen for problematic dietary consumption patterns.