Assessment of a modified household food weighing method in a study of bone health in China.

OBJECTIVE

A 'modified' household dietary method to estimate individual intakes from total household intakes was evaluated in comparison to the individual food weighing method, i.e. direct weighing of foods consumed by individuals.

DESIGN

Foods consumed by the household were weighed and recorded over a 3 day period and were proportionally allocated to a specific person in the household by using energy conversion factors based on age, gender and physical activity. The individual dietary intakes were standardized by body weight (ratio of individual body weight to reference body weight from Chinese Recommended Daily Allowances (Acta Nutr. Sin. 12, 1-9), and were compared with the estimates from the individual food weighing method for both accuracy and associations with bone density.

SETTING

The subjects were randomly selected from five rural countries in China, characterized by different dietary patterns.

SUBJECTS

A total of 712 women aged 35-75 years participated in the dietary and bone measurements.

RESULTS

Nutrient intakes estimated by the modified household method (adjusting for body weight were very similar to those obtained by the individual method (r = 0.53-0.78, P < 0.001), except for sodium which had the largest deviation from the individual methods (r = 0.23, P < 0.001). Calcium intakes were 405 +/- 271 and 409 +/- 323 mg/day, respectively, as estimated by the individual and modified household methods. A very similar degree of correlation with radial bone density also was obtained for both calcium estimates.

CONCLUSION

The results indicate that the modified household method is appropriate for assessing food intakes of individuals in large nutritional studies.