To compare various food-frequency questionnaires (FFQs) used in nutritional studies in China for various purposes.

In Study 1, a simplified FFQ with 17 questions on food was used in a large rural study. In Study 2, a questionnaire consisting of 84 questions on food consumption of 16 food categories was used in a study comparing dietary consumption data and various health indicators of elderly people in four geographical areas in China. In Study 3, a questionnaire with 149 items in 17 food categories is being validated by comparison with data obtained by repeated 24-hour recalls.

Study 1 was carried out in one southern site and a northern site in 1996 to 1997. Study 2 was conducted in four different geographical sites in 1998. The on-going study, Study 3, has been carried out in Jiangsu and Beijing since 1999.

Study 1 included 12 234 rural Chinese adults aged 40 years. There were 546 elderly people in Study 2. Study 3 is collecting data from 300 healthy adults.

The results of food consumption and nutrient intakes from Study 1 were comparable with those obtained from a previous household dietary survey, in which sensible correlations between diet and diseases were also found. In Study 2, the dietary data from the four geographical areas showed significant differences in food and nutrient intakes among the different areas. The validation of the new FFQ in Study 3 is still going on.

The FFQ is a useful method for the collection of individual food consumption information. The above FFQ forms could be used in studies with different purposes, especially in studying the relationship between diet, nutrition and chronic diseases.