N-Nitroso Compounds: Assessing Agreement between Food Frequency Questionnaires and 7-day Food Records

摘要

N-nitroso compounds are recognized as important dietary carcinogens. Accurate assessment of N-nitroso intake is fundamental to advancing research regarding its role with cancer. Previous studies have not used a quantitative database to estimate their intake. To address this gap a database of N-nitroso values was developed in conjunction with an existing food frequency questionnaire (FFQ). The purpose of this paper is to report on the relative validity of the FFQ instrument modified to estimate N-nitroso compounds. Intake estimates of 23 N-nitroso compounds from FFQ were compared with those from seven days of food records (7DFR) in a cross-sectional study conducted from January 2005 through June 2006. A sample of 98 healthy adult subjects (50.42 ± 12.84 years) completed a FFQ and then recorded foods and beverages consumed (7DFR). Crude and energy-adjusted N-nitroso compounds intakes were significantly higher in the FFQ than the 7DFR(P < 0.001). Spearman correlations for crude and energy-adjusted N-nitroso intakes ranged from 0.004 to 0.48. By tertiles of N-ntiroso compounds, there was moderate agreement (Kappa >0.30) for five compounds. Higher estimates of N-nitroso compounds by FFQ was explained by a greater proportion of subjects who reported eating foods high in N-nitroso compounds on FFQ than reported on 7DFR. The modified FFQ with N-nitroso values is a useful tool for assessing N-nitroso intakes relative to a group, and captures all food items with N-nitroso compounds including those foods with high concentrations and eaten sporadically.