Methodology of the 1997 New Zealand National Nutrition Survey

Aims: To describe the development and use of the methodologies in the 1997 New Zealand National Nutrition Survey (NNS97).

Methods: NNS97 was a voluntary cross-sectional population survey conducted over a twelve month period on 4,636 non-institutionalized urban and rural New Zealand residents aged fifteen years and older. Survey data were collected in the participants' home and included: a self-administered qualitative food frequency questionnaire, including questions on food preparation habits; a three-pass 24-hour diet recall; interviewer-administered questions on diet supplement use, barriers to dietary change and participant perception of household food security; physical measurements including weight, height, three circumferences, two skinfolds and elbow breadth; blood pressure; and a blood sample to determine cholesterol and iron status.

Results: New methodologies developed for NNS97 included a computer based interview system, probability analyses for estimating prevalence of inadequate intake of selected nutrients, determination of iron status by both dietary and biochemical assessment, assessments of dietary supplement use and food security. A full range of quality control procedures at each stage of the data collection were also initiated.

Conclusion: NNS97 has improved on previous New Zealand national nutrition survey methodologies, particularly with direct data capture and rigorous quality control procedures used in the collection of survey data.