The Reliability of Dietary History From the Distant Past1

Abstract

A major barrier to the conduct and interpretation of retrospective studies of diet and cancer has been uncertainty about the reliability of retrospective measures of diet from the distant past. The authors therefore conducted a study to assess the reliability of retrospective dietary reports and to determine whether the retrospective report or the report of current diet is the better indicator of past diet. Persons (n = 323) originally interviewed regarding their diets in 1975-1979 were retrospectively reinterviewed in 1984-1985. There was little difference between the retrospective reports and the reports of current diet when group means were examined as indicators of past diet. The retrospective reports tended to overestimate the past frequency of consumption for most foods, whereas the reports of current diet tended to yield underestimates. Because food frequency-based dietary history data are more useful for ranking study subjects than for generating estimates of group means, correlation analysis was used as the principal assessment of the reliability of the two indicators of past diet. The retrospective reports more closely correlated with the diet reported at the original interview than did the report of current diet (for 37 of 47 foods). Nutrient indices based on the retrospective history were also more highly correlated with those of the original diet than were indices based on the current diet. No differences were noted in the reliability of retrospective reports according to age or sex. Subjects accurately reported perceptions of changes in their consumption of most foods, yet an estimate of past diet created by adjusting current diet for perceived change did not correlate more highly with the original diet than did the retrospective report. The authors conclude that assessing current diet to make inference about diet from the distant past does not yield more reliable estimates of past diet than does the retrospective dietary history. The best estimate of diet from several years in the past may be derived directly from a retrospective dietary history which focuses on that past period of time.

Validation of a short food frequency questionnaire to assess consumption of cereal foods, fruit and vegetables in Chinese Singaporeans

“…For all food groups, there were no signi®cant differences between repeated measurements except for a signi®cant but small difference between measurements when fruit and vegetables were combined. Most previous studies have assessed repeatability for reported frequencies of individual foods at intervals of between three months and two years, mainly using correlation coef®cients (Nomura et al, 1976;Colditz et al, 1987;Byers et al, 1987;Salvini et al, 1989). For reasons explained earlier, correlation coef®cients for repeated FFQ administrations are presented here only for purposes of comparisonÐPearson's correlations were 0.85 for cereal foods and 0.90 for total fruit and vegetables.…”

Potential early-life predictors of dietary behaviour in adulthood: a retrospective study

“…Various studies indicate that retrospective measures of diet are not only reliable 46 but are also typically better than assessments of current diet at predicting diet in the distant past 47,48 (for a review see Friedenreich et al 49 ). Inevitably, some studies show that current diet may influence the reporting of a recalled diet.…”

Modifying Effect of N‐Acetyltransferase 2 Genotype on the Association Between Systemic Lupus Erythematosus and Consumption of Alcohol and Caffeine‐Rich Beverages

“…The possibility of recall bias in reporting consumption of alcoholic and nonalcoholic beverages may be minimized because SLE patients are unlikely to be aware that these habits may be associated with SLE risk. In addition, it has been reported that the report of remote (3-20 years ago) diet correlated more closely with original dietary report than did the report of current diet (61)(62)(63). The observations suggest that if diet from several years past is thought to be relevant to SLE risk, we may generate a more reliable estimate of the past beverage consumption by questioning subjects directly about past beverage consumption rather than current beverage consumption.…”