Early Experience Analyzing Dietary Intake Data from the Canadian Community Health Survey-Nutrition Using the National Cancer Institute (NCI) Method.

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.

Modeled changes in US sodium intake from reducing sodium concentrations of commercially processed and prepared foods to meet voluntary standards established in North America: NHANES.

Background: Approximately 2 in 3 US adults have prehypertension or hypertension that increases their risk of cardiovascular disease. Reducing sodium intake can decrease blood pressure and prevent hypertension. Approximately 9 in 10 Americans consume excess sodium (≥2300 mg/d). Voluntary sodium standards for commercially processed and prepared foods were established in North America, but their impact on sodium intake is unclear.Objective: We modelled the potential impact on US sodium intake of applying voluntary sodium standards for foods.Design: We used NHANES 2007-2010 data for 17,933 participants aged ≥1 y to model predicted US daily mean sodium intake and the prevalence of excess sodium intake with the use of the standards of the New York City's National Salt Reduction Initiative (NSRI) and Health Canada for commercially processed and prepared foods. The Food and Nutrient Database for Dietary Studies food codes corresponding to foods reported by NHANES participants were matched to NSRI and Health Canada food categories, and the published sales-weighted mean percent reductions were applied.Results: The US population aged ≥1 y could have reduced their usual daily mean sodium intake of 3417 mg by 698 mg (95% CI: 683, 714 mg) by applying NSRI 2014 targets and by 615 mg (95% CI: 597, 634 mg) by applying Health Canada's 2016 benchmarks. Significant reductions could have occurred, regardless of age, sex, race/ethnicity, income, education, or hypertension status, up to a mean reduction in sodium intake of 850 mg/d in men aged ≥19 y by applying NSRI targets. The proportion of adults aged ≥19 y who consume ≥2300 mg/d would decline from 88% (95% CI: 86%, 91%) to 71% (95% CI: 68%, 73%) by applying NSRI targets and to 74% (95% CI: 71%, 76%) by applying Health Canada benchmarks.Conclusion: If established sodium standards are applied to commercially processed and prepared foods, a significant reduction of US sodium intake could occur.

Rankings of iron, vitamin D, and calcium intakes in relation to maternal characteristics of pregnant Canadian women.

Iron, vitamin D, and calcium intakes in the prenatal period are important determinants of maternal and fetal health. The objective of this study was to examine iron, vitamin D, and calcium intakes from diet and supplements in relation to maternal characteristics. Data were collected in a subsample of 1186 pregnant women from the Maternal-Infant Research on Environmental Chemicals (MIREC) Study, a cohort study including pregnant women recruited from 10 Canadian sites between 2008 and 2011. A food frequency questionnaire was administered to obtain rankings of iron, calcium, and vitamin D intake (16-21 weeks of pregnancy). Intakes from supplements were obtained from a separate questionnaire (6-13 weeks of pregnancy). Women were divided into 2 groups according to the median total intake of each nutrient. Supplement intake was an important contributor to total iron intake (median 74%, interquartile range (IQR) 0%-81%) and total vitamin D intake (median 60%, IQR 0%-73%), while the opposite was observed for calcium (median 18%, IQR 0%-27%). Being born outside of Canada was significantly associated with lower total intakes of iron, vitamin D, and calcium (p ≤ 0.01 for all). Consistent positive indicators of supplement use (iron, vitamin D, and calcium) were maternal age over 30 years and holding a university degree. In conclusion, among Canadian women, the probability of having lower iron, vitamin D, and calcium intakes is higher among those born outside Canada; supplement intake is a major contributor to total iron and vitamin D intakes; and higher education level and age over 30 years are associated with supplement intake.

Sodium food sources in the Canadian diet.

The purpose of this study is to provide information on the current sources of dietary sodium in the Canadian food supply to provide a baseline to measure against the effectiveness of strategies to reduce salt consumption. Such strategies are being developed by a Health Canada-led multistakeholder Working Group. Data from the 2004 Canadian Community Health Survey (CCHS) 2.2, Nutrition, were used to determine the leading food group contributors of sodium in the diet. The total sample size was more than 35,000 respondents. The results from this study were reported for 4 age and sex groups, namely, youths aged 1 to 8 years, youths aged 9 to 18 years, males aged 19 years and older, and females aged 19 years and older. Average daily intakes of sodium for these groups were 2388 mg, 3412 mg, 3587 mg, and 2684 mg, respectively. In all cases these intakes exceeded the tolerable upper intake level (UL) established by the Institute of Medicine, as well as targets set by the governments of the United Kingdom and the United States and the World Health Organization. The contribution of sodium to the food supply by the top 40 food groups is presented for each of the age and sex groups. The key food group contributors of sodium are breads (13.88%), processed meats (8.90%), and pasta dishes (5.67%). Although breads are found to be major contributors of sodium, this is mainly because of the large consumption, rather than a high concentration of sodium. Higher-sodium foods, such as processed meats, are eaten in smaller quantities but, because of their sodium density, contribute significant amounts of sodium to the diet of Canadians. Some very high sodium foods, such as frozen dinners, are eaten by only a small proportion of the population, but for those consuming these, the sodium could contribute a significant proportion of the UL just from a single meal.

Eating well with Canada's Food Guide (2007): development of the food intake pattern.

A food intake pattern specifying amounts and types of food was created for Canada's revised food guide, Eating Well with Canada's Food Guide (2007), using a two-step modeling process. In step one, food composites were manipulated to develop a food intake pattern. The second step used the step one food intake pattern to create 500 simulated diets for each of 16 age and gender groups. The resulting nutrient content distributions were evaluated relative to Dietary Reference Intake reference values. The modeling cycled between these two steps until a satisfactory pattern was achieved. The final pattern reflects modeling, a review of associations between foods and chronic disease, and input received during consultation.