Reproducibility and validity of dietary patterns identified using factor analysis among Chinese populations

Abstract

In the present study, we evaluated the reproducibility and validity of dietary patterns among Chinese adult populations. A random subsample of 203 participants (aged 31-80 years) from a community-based nutrition and health survey was enrolled. An eighty-seven-item FFQ was administered twice (FFQ1 and FFQ2) 1 year apart; four 3 consecutive day, 24-h dietary recalls (24-HDR, as a reference method) were performed between the administrations of the two FFQ every 3 months. Dietary patterns from three separate dietary sources were derived using factor analysis based on twenty-eight predefined food groups. Comparisons between dietary pattern scores were made by using Pearson's or intraclass correlation coefficients (ICC), cross-classification analysis, weighted κ statistic and Bland-Altman plots; the four major dietary patterns identified from FFQ1, FFQ2 and 24-HDR were similar. Regarding reproducibility, ICC for z-scores between FFQ1 and FFQ2 were all >0·6 for dietary patterns. The 'animal and plant protein' pattern had the highest ICC of 0·870. For validity, the adjusted Pearson's correlation coefficients for dietary pattern z-scores between two FFQ and the mean of four 3 consecutive day 24-HDR ranged from 0·387 for the 'Chinese traditional' pattern to 0·838 for the 'animal and plant protein' pattern. More than 75 % of the participants were classified into the same or adjacent quartile, and <5 % were misclassified into opposite quartiles. The weighted κ ranged from 0·259 to 0·680. Bland-Altman plots indicated that no significant deviation was found between two dietary assessment methods. Our findings indicate a good reasonable reproducibility and a reasonable validity of dietary patterns derived by factor analysis in China.

The reliability and relative validity of predefined dietary patterns were higher than that of exploratory dietary patterns in the European Prospective Investigation into Cancer and Nutrition (EPIC)-Potsdam population

“…A possible explanation for the weak correlations of the exploratory DP, in comparison with other studies, could be the rather low explained variance in the food groups. While the two DP derived with data from the FFQ 1 explained in total 18•8 % of variance, DP from other studies explained 22-84 % (25,27,29,30) , resulting partly in moderate to good reliability and validity (25) . However, explained variance is highly dependent on the number of DP scores to be retained and also on the number of food groups, included in the analysis.…”

“…A potential influence of weight changes during the study period on the stability of the DP scores could be ruled out, because weight remains stable in both men and women. Correlation coefficients in most previous studies ranged between 0•63 and 0•87 (24)(25)(26)(27) , pointing towards a moderate to good reliability. However, Nanri et al showed a comparable reliability of DP scores (r 0•55-0•56) to our results (28) .…”

“…In other studies, the validity of exploratory DP was assessed with diverse reference instruments, using either 24HDR (24,25) or dietary records covering different numbers of days (26)(27)(28)(29)(30) . Studies using the same reference instrument as in our analysis showed a wide range of correlation coefficients (r 0•30-0•70) (24,25) , which cover our results (first DP score: r 0•30; second DP score: r 0•70). While the validity of the two DP in the Health Professional Follow-Up Study (26) was moderate to good (r 0•52-0•74), Nanri et al (28) reported rather low to moderate correlations (r 0•32-0•49 in men; r 0•36-0•63 in women).…”

Identification and reproducibility of dietary patterns assessed with a FFQ among women planning pregnancy

“…Strengths of the current study include having a relatively large sample size (n 289) as compared with other dietary validation studies with sample sizes ranging from 92 to 203 participants (9,13,14,(40)(41)(42) and the reproducibility of these patterns was examined using CFA, giving additional credence to the results (43) . However, several limitations are worth noting.…”

Association of major cardiovascular risk factors, risk factor clustering with cardiovascular diseases from eastern China A population-based cross-sectional study

“…The three variables were defined and categorized elsewhere [24]. Habitual dietary intakes over the previous year were estimated by the validated semi-quantitative food frequency questionnaire (FFQ) [25]. Subjects were defined as adopting unhealthy dietary habits if they had 3 or more of the following: insufficient intake of vegetables and fruits (<400g/day), insufficient intake of dairy products (<300g/day), insufficient intake of bean products (e.g., tofu, dry beans, bean sprouts, soy chicken, bean curd sheet, <25g/day), excessive intake of red meat (e.g., pork, beef and mutton, >100g/day) and excessive intake of salt (>6g/day) [26][27].…”