Impact of identifying plausible respondents on the under-reporting of energy intake in the Canadian Community Health Survey

by Didier Garriguet

Abstract

Background

Under-reporting is common in nutrition surveys. The identification of plausible respondents is a way of measuring the impact of under-reporting on the relationship between energy intake and body mass index (BMI).

Data and methods

A 24-hour dietary recall from 16,190 respondents aged 12 or older to the Canadian Community Health Survey (CCHS) - Nutrition was used to determine energy and nutrient intake. To identify plausible respondents, a confidence interval was applied to total energy expenditure derived from equations developed by the Institute of Medicine. Estimates of energy and nutrient intake for plausible respondents were compared with estimates for all respondents. Linear regression was used to demonstrate the impact of under-reporting on the relationship between reported energy intake and weight. Logistic regression was used to determine the impact of under-reporting on modelling the characteristics of obese people.

Results

With a confidence interval of 70% to 142% around energy expenditure, 57% of CCHS respondents were identified as "plausible respondents." Nutrient under-reporting varied between 1% and 10%. Analysis based only on plausible respondents re-establishes the theoretical relationship between energy intake and body weight, a relationship that is lost when analysis is based on the full sample.

Interpretation

Identifying plausible respondents is an effective way of measuring the impact of under-reporting food intake. Conclusions based on plausible respondents, rather than on all respondents, are more in line with theoretical expectations, such as a positive association between high energy intake and obesity.

Keywords

Caloric intake, diet, food habits, energy expenditure, energy metabolism, nutrition surveys, obesity, twenty-four-hour recall, under-reporting

Findings

The 2004 Canadian Community Health Survey (CCHS)–Nutrition was the first national survey of the eating habits of the Canadian population since the early 1970s. One of the objectives of the 2004 CCHS was to determine the intake of energy (calories), macronutrients (fats, proteins and carbohydrates) and micronutrients (vitamins and minerals) for different groups. [Full text]

Author

Didier Garriguet (1-613-951-7187; didier.garriguet@statcan.gc.ca) is with the Health Information and Research Division at Statistics Canada, Ottawa, Ontario,K1A 0T6.