SHORT-TERM AND LONG-TERM REPRODUCIBILITY OF DIETARY HISTORY INTERVIEWDATA

This study gives results for comparisons between dietary history inter views repeated at short-term (4-8 months) and long-term (4-7 years) in tervals in conjunction with the Finnish Mobile Clinic Health Examinati on Survey. Interviews surveying the whole range of consumable foods ov er the preceding year were completed in 1967-1976. Short-term study wa s accomplished among 93 adults, and long-term study among 1844 adults. Comparisons were made for intakes of 32 food groups and 32 nutrient i ndices. In the short term, the intraclass correlation coefficients for nutrient indices ranged from 0.16 to 0.80, with 90% of values higher than 0.5. The corresponding figures for repeated measurements at long- term interval were generally poorer, being in the range 0.12-0.60, wit h 45% of values >0.5. When studied in population subgroups, long-term agreement in dietary data was not found to be affected by sex, age, bo dy mass index or smoking status, but it may be reduced among heavier d rinkers (greater-than-or-equal-to 20 g alcohol per day). The intraclas s correlation coefficients for separate nutrients tended to be higher than those for different food groups. In conclusion, we suggest that t he reproducibility of the dietary history method used was acceptable, and that the dietary patterns of examinees were sufficiently stable to be compatible with the needs of epidemiological follow-up studies.