Handbook of Vitamin C Research

270Alan M. Preston, Luis Vázquez Quiñones, Cynthia M. Pérez et al.Figure 7. Vitamin C intake per snack by smoke exposure group.Table 3. Vitamin C Intake: Summary of Food Choices and Meal Patterns of Childrenwith Low and High Exposure to ETSFood Category – Vitamin C Content Mg Vitamin C/day RatioLEX HEX LEX-HEXLow 5.6 31.4 0.2Moderate 9.9 8.6 1.2Medium 33.8 26.2 1.3High 74.1 36.2 2.1Mean Total/day 123.4 102.4Meal Category – Vitamin C ContentBreakfast 37.8 36.4 1.0Lunch 25.6 25.5 1.0Dinner 27.9 25.2 1.1Snacks 32.1 15.3 2.1Mean Total/day 123.4 102.4DiscussionAs with any research study, the method of data collection is an important consideration.In the present study, results were obtained using one 24-hour recall questionnaire per subject.This approach raises concern as to how representative is the data for a typical day. However,most large-scale nutritional surveys are conducted in this exact or similar manner, andinformation is deemed appropriate for generalizations to groups as a whole [96, 97].It should be noted that in this presentation smoke exposure is classified according to abiomarker, urinary cotinine. This is a departure from the more typical method used which isbased upon self-reported smoke exposure [70, 72-82]. We prefer using cotinine asdeterminant for the following reason. Several investigators in this area have made theobservation that self-reports are subject to errors such as poor recall or under-reported