The Dunedin Multidisciplinary Health and Development Study: are its findings consistent with the overall New Zealand population?

AIMS: To compare the health of the Dunedin Multidisciplinary Health and Development Study members with people of the same age in the nationally representative New Zealand Health and National Nutrition Surveys.
METHOD: Where similar information was obtained, means or proportions and confidence intervals were generated for both the age 26 assessment of the Dunedin sample and for the 25-26 year old participants in the national surveys. The populations were considered to differ when confidence intervals did not overlap.
RESULTS: For smoking habit, body mass index, waist-hip ratio, general practitioner and medical specialist consultations, and hospital admissions, the findings of the Dunedin Study were not significantly different to the nationally representative surveys. The Dunedin Study members also did not differ from their national counterparts on SF-36 subscales measuring physical functioning, bodily pain, general health, vitality, and mental health. They had better scores on the three interference subscales of the SF-36 compared to the national sample, and men in the Dunedin Study spent a little more time doing vigorous physical activity. DISCUSSION: For most outcomes, the Dunedin Study members were very similar to the nationally representative samples. There was little evidence that the repeated assessments in the Dunedin Study had significantly altered the Study members' health, either in terms of responses to questionnaires or on physiological measures of health status. Findings from the Dunedin Study are likely to be generalisable to most young New Zealanders. However, the Dunedin Study is under-representative of Maori and Pacific peoples, so these findings need to be interpreted with caution in this context. Implications for the proposed national Longitudinal Study of New Zealand Children and Families are discussed.