Day-to-day variability in dietary intake makes it difficult to measure accurately the "usual" intake of foods and nutrients. The objectives of the present study were to estimate within- and between-subject variability for foods and nutrients by adjusted and unadjusted models and to assess the number of days required to assess nutrient and food group intakes accurately by two different methods. Adult men and women aged 18-65 y (n = 1543) in the Food Habits of Canadians Study provided a 24-h recall. A repeat interview was conducted in a subsample to estimate components of variability. Within- and between-subject variability were determined by mixed model procedure (crude and adjusted for age, gender, education, smoking, family size and season). The number of days required to obtain various degrees of accuracy was ascertained by two methods, one that uses the variance ratio for groups and one that considers within-subject variability alone for individuals. Variance ratios were higher using the adjusted compared with the unadjusted method (e.g., for men, energy 1.07 vs. 0.49). More days were required to reflect usual intake with accuracy using the adjusted model (energy 5 vs. 2 d), indicating the need to control for confounders to obtain reliable estimates of intakes.
The number of individuals and families accessing food assistance programs has continued to grow throughout the 1990s. Despite the increased health risk among low-income people, few studies have addressed nutrient intake throughout the month or at the end of the month when food and financial resources are thought to be compromised, and no study has described dietary status of a random sample of food bank users. Nutrient intakes of adult female and male food bank users in metropolitan Montreal, Quebec, Canada, were monitored week-by-week over a month by dietitian-administered 24-h recall interviews. A total of 428 participants from a stratified random sample of 57 urban area food banks completed all four interviews. Mean energy intake, as an indicator of diet quantity, was similar to other adult populations (10.2 +/- 4.8 and 7.9 +/- 3.6 MJ for men and women, respectively, age 18-49 y) and not related to sociodemographic variables except the expected biological variation of age and sex. Macronutrient intake was stable throughout the month. Overall median intakes of calcium, vitamin A, and zinc were below recommended levels for all age and sex groups. Intakes of several micronutrients were related to frequency of food bank use, household size, smoking, education, and country of birth. High nutrient intake variability characterized these adult food bank users.
Understanding differences in dietary patterns by smoking status is important for nutritionists and health educators involved in helping individuals to make healthy dietary and lifestyle choices. Although smokers have a poor quality diet compared with nonsmokers, no study has examined nutritional adequacy and variability in the nutrient intake of smokers. The aim of this study was to compare dietary habits of smokers with nonsmokers in terms of nutrient intake, food groups contributing to nutrient intake, nutritional adequacy and day-to-day variation in nutrient intake. Noninstitutionalized adults aged 18--65 y (n = 1543) who participated in the Food Habits of Canadians Survey (1997--1998) were studied. Subjects, selected from across Canada using a multistage, random-sampling strategy, completed an in-home 24-h dietary recall. Repeat interviews were conducted in a subsample to estimate variability in nutrient intake. Smokers had higher intakes of total and saturated fat, and lower intakes of folate, vitamin C and fiber than nonsmokers. There were no significant differences in calcium, zinc and vitamin A intakes or day-to-day variation in nutrient intake by smoking status. Smokers consumed significantly fewer fruits and vegetables than nonsmokers, leading to lower intakes of folate and vitamin C. In conclusion, smokers have a less healthy diet than nonsmokers, placing them at higher risk for chronic disease as a result of both dietary and smoking habits. Diet may act as a confounder in smoking-disease relationships.
The iron status and diet of Inuit infants living in northern Quebec who were part of a prospective cohort study was described. The prevalence of anemia (hemoglobin values > 2 SD below the reference mean) was 21.1% (23/109), 47.4% (55/116) and 37.7% (46/122) at 2, 6 and 12 months, respectively. The corresponding prevalence of microcytic anemia was 0.0%, 4.3% and 21.3%. At 2, 6 and 12 months, iron-deficiency anemia (serum ferritin