Elderly Nutrition and Health Survey in Taiwan (1999-2000): research design, methodology and content.

The purpose of the Elderly Nutrition and Health Survey in Taiwan (1999-2000) was to assess the diet, nutrition and health of persons aged 65 and above in Taiwan. A multi-staged, stratified, clustered probability sampling scheme was used in the survey. The survey population was stratified into a total of 13 strata. The four strata of "Hakka areas", "Mountain areas", " Eastern areas", and "PengHu islands" were unique in their ethnicity or geographic locations. The remaining areas of Taiwan were stratified into "Northern", "Central", and "Southern" parts with these 3 strata, then each subdivided into a further 3 strata based on population density. The household interview of the survey was arranged such that effect of seasonal variation was taken into account. A total of 1,937 persons completed the interview and 2,432 persons completed the health exam. The following data were collected: (1) Interview data : household information, basic demographics, 24 hour dietary recall, food frequency and habit, knowledge, attitudes and practice, medical history, 36-item Short Form for generic health status, and physical activity. (2) Health exam data: blood sample for measurement of nutritional biochemical indicators and complete clinical chemistry profile, urine sample for urinary electrolytes, anthropometric measurements, ECG, blood pressure, body temperature, pulmonary function, and an osteoporosis assessment. Data from the survey were analyzed using SUDAAN to adjust for the design effect and to obtain unbiased estimates of the mean, standard error and confidence intervals. Survey respondents were slightly younger compared to non-respondents; however, after weighting and adjustment with SUDAAN, the education levels and ethnicity of respondents and non-respondents were similar indicating lack of bias. We anticipate that the results of this survey will be of benefit in understanding the nutritional status of the elderly, the relationship between nutrition and health, and factors influencing elderly persons' nutritional status. Furthermore, this information could be used in the development of public health nutrition policy aimed at improving the nutrition and health of the elderly in Taiwan.