Comparison of standard methods for assessing dietary intake of benzo[a]pyrene

Inconsistent presence and strength of associations between dietary benzo[a]pyrene (BaP) exposure and cancers may be due to differences in exposure assessment methods. Thus, we determined correlations of usual meat and BaP intake among three methods: food frequency questionnaires (FFQ), diet diaries, and a biomarker.

Thirty-six nonsmokers were recruited in Baltimore, MD during 2004-2005. Meat and BaP intake estimated from baseline and follow-up FFQs combined with a BaP residue database (FFQ-RD), mean meat and BaP intake estimated from three diet diaries coupled with the residue database (Diary-RD), and mean of three urinary 1-hydroxypyrene glucuronide (1-OHPG) measurements were compared using Spearman correlations. Collections spanned approximately nine months.

BaP intakes from meat from the baseline [median = 6.4, interquartile range (IQR) = 13.9 ng/d] and follow-up FFQ-RD (median = 7.3, IQR = 35.7 ng/d) were higher than the Diary-RD (median = 1.1, IQR = 7.4 ng/d). Mean 1-OHPG concentration was weakly correlated with mean meat intake (r = 0.33, P = 0.05) and BaP intake from meat (r = 0.27, P = 0.11) from the Diary-RD. Mean BaP intake estimated from the Diary-RD was positively correlated with the follow-up (r = 0.35, P = 0.04) but not baseline (r = 0.20, P = 0.24) FFQ; the converse was true for meat intake.

Diary-RD estimates were supported by biomarker measurements, but considerable unexplained variability remained. Limited correlation among the dietary BaP exposure assessment methods could be due to differences in timeframes covered by the assessments, interpersonal variability in metabolism, deficiencies in the residue database, or nondietary exposures to BaP.

Limited correlation in estimated BaP intake among standard methods may contribute to inconsistent epidemiology of BaP and cancer.