An internet-based food frequency questionnaire for a large Chinese population.

BACKGROUND AND OBJECTIVES: National dietary surveys are needed and difficult to conduct in China. The current study aims to develop and validate an internet-based diet questionnaire for Chinese (IDQC) to assess intakes in Northern China. METHODS AND STUDY DESIGN: We recruited 292 city residents by email and telephone in Harbin to obtain the IDQC and 3-day diet diaries. The food group and nutrient intakes from the IDQC were validated against those from the 3-day diet diaries. Paired sample t-tests were used to compare the methodological differences, and repeatability was estimated using Pearson's correlations. Cross-classification was used to calculate the percentage agreement in quartiles for all food groups and nutrients. RESULTS: Positive correlations were found between the IDQC and 3-day diet diaries for all food groups after energy adjustment (from 0.28 for seeds and nuts to 0.63 for dairy products). Positive correlations were observed for all nutrients between the IDQC and 3-day diet diaries, with correlations ranging from 0.37 for folic acid to 0.98 for iodine. The overall agreements for food groups and nutrients were above 69.2%, indicating satisfactory consistency between the IDQC and 3-day diet diaries. CONCLUSIONS: The IDQC can be used to estimate the food and nutrient intakes in a Northern China population for both clinical nutrition epidemiological and public health nutritional purposes. The questionnaire system IDQC (v1.0) is freely available at http://www.yyjy365.org/diet/.

The Ratio of Dietary Branched-Chain Amino Acids is Associated with a Lower Prevalence of Obesity in Young Northern Chinese Adults: An Internet-Based Cross-Sectional Study.

This study aims to examine the association between the ratio of dietary branched chain amino acids (BCAA) and risk of obesity among young northern Chinese adults. A total of 948 randomly recruited participants were asked to finish our internet-based dietary questionnaire for the Chinese (IDQC). Associations between dietary BCAA ratio and prevalence of overweight/obesity and abdominal obesity were analyzed. Furthermore, 90 subjects were randomly selected to explore the possible mechanism. Dietary BCAA ratio in obese participants was significantly lower than non-obese participants. We found negative correlations between the ratio of dietary BCAA and body mass index (BMI) (r = -0.197, p < 0.001) or waist circumference (r = -0.187, p < 0.001). Compared with those in the first quartile, the multivariable-adjusted OR (95% CI) of the 3rd and 4th quartiles of dietary BCAA ratio for overweight/obesity were 0.508 (0.265-0.972) and 0.389 (0.193-0.783), respectively (all p < 0.05). After stratification by gender, the significance still existed in the 3rd and 4th quartile in males and the 4th quartile in females. For abdominal obesity, the multivariable-adjusted OR (95% CI) of the 3rd and 4th quartile of dietary BCAA ratio were 0.351 (0.145-0.845) and 0.376 (0.161-0.876), respectively (all p < 0.05). This significance was stronger in males. Further studies indicated that dietary BCAA ratio was inversely associated with 2-h postprandial glucose (2 h-PG) and status of inflammation. In conclusion, a higher ratio of dietary BCAA is inversely associated with prevalence of obesity, postprandial glucose and status of inflammation in young northern Chinese adults.

Development and Applicability of an Internet-Based Diet and Lifestyle Questionnaire for College Students in China: A Cross-Sectional Study.

Diet contributes to the increasing incidence of chronic diseases. Thus, fast, accurate, and convenient dietary assessment tools are in demand. We designed an internet-based diet and lifestyle questionnaire for Chinese (IDQC). The objective of this study was to validate its applicability and assess the dietary habits of Chinese college students.Six hundred forty-four college students from northern China were recruited and asked to complete the IDQC for the last 4 months (135 food items) and 3-day diet records (3DDRs). Food and nutrient intakes recorded in the IDQC were validated against those in the 3DDRs using the Wilcoxon matched-pairs t test, correlation analysis, and cross-classification. The Student t and χ tests were used in the dietary assessment.There were significantly positive correlations in the dietary intakes of 9 food groups and 23 nutrients between the IDQC and 3DDRs. All participants consumed low levels of fruits, vegetables, legumes, dairy, and certain micronutrients (ie, vitamin A, vitamin B1, vitamin B2, folic acid, vitamin C, calcium, selenium, and iodine), and high levels of iron and manganese. Male students consumed higher intakes of the food groups and nutrients than female students.The IDQC represents an accurate and convenient dietary assessment tool that can be used in large populations. Inadequate and excessive nutrition co-existed in college students, and more fruits, vegetables, legumes, dairy, and various vitamins and minerals were needed in this population's daily diet. The IDQC is free of access at www.yyjy365.org/diet.