A study was conducted to validate a food frequency questionnaire for a Japanese population. The study examined the validity of the intake of certain nutrients, including β-carotene, β-cryptoxanthin, folate, vitamin D, eicosatetraenoic acid, and docosahexaenoic acid, using the method of triads. The findings of this study were presented at two major conferences, ASN 2022 and Cardiology 2022. This study is important because it provides a valid and efficient tool for assessing the nutrient intake of the Japanese population by use of this questionnaire.

1. Reproducibility and validity of a food
frequency questionnaire to measure
the consumption of β-carotene,
β-cryptoxanthin, folate, vitamin D,
EPA, and DHA
a Department of Nutrition, Harvard T.H. Chan School
of Public Health, Boston, MA
b Department of Epidemiology, Harvard T.H. Chan
School of Public Health, Boston, MA
Dr. Kazuko Yoshizawaa
Dr. Laila Al-Shaar a
Prof. Walter Willetta, b

2. Background

3. Background
modifiable
Diet Disease
Major diet assessment methods: 24-hour recall, diet record, and food
frequency questionnaire, biomarkers
Assessment needs a tool

4. An epidemiologic study using the
Food Frequency Questionnaire
(FFQ)
• The most widely used method in
epidemiologic studies
• Measure long term intake
• Ranks individuals or groups by
nutrient or food intake level
• Low cost
• Low participant burden

5. Objective
To assess the
reproducibility and
validity and of a FFQ
for a Japanese
population

6. Outline
Study population
Design of the FFQ
Data collection
Statistical analyses
Results
Conclusion

7. Methods

8. Study participants
Healthy, free-living men and women in the
western region of Japan
Had lived in urban and rural areas for more
than 5 years in the region
Had not changed their recent habitual diets
due to their health conditions

9. Design of the
FFQ β-carotene
β-cryptoxanthin
Folate
Vitamin D
EPA
DHA
• 166-items commonly
consumed nation-wide
and locally available
• Nine possible responses,
"never" to "six or more"
times/day
• Dietary supplement use:
vitamins
• Each participant was
asked about the average
intake of each food item
over the past year
• Open ended

10. N=101: 12DDR, FFQ 1, FFQ 2, & biomarkers
kcal/day intake for men 800 - >4200,
for women 600 - >3600 kcal/day.
Data collection of the validation study, 2014 – 2015
N=131, 12DDR
on different days of the week
DR DR DR DR DR DR DR DR DR DR DR DR DR
FFQ 1
Blood
samples
FFQ 2

11. Computation of nutrient intakes
from the diet records and the FFQs
• Computer software with Food Composition Table 2010 &
Fatty Acids Composition Table 2005
• Without vitamin supplements

12. Measurement of
biomarkers
β-carotene, β-cryptoxanthin: High-
Performance
Liquid Chromatography (HPLC)
Folate: Chemiluminescent Immunoassay
(CLIA)
Fatty acids: Gas Chromatography (GC)
25-Hydroxy Vitamin D: Enzyme
Immunoassay (EIA)

13. Statistical analyses
• Validity coefficient (VC) was calculated by use of the method of triads
• De-attenuated correlation coefficients between the energy-adjusted nutrients
from FFQs and DRs were calculated to account for the within-person variation in
replicate DRs
rc = ro 1 + [(𝜎𝑤
2/𝜎𝑏
2)/𝑛]
Regression coefficient was calculated from regressing the average of energy-
adjusted nutrient intake from DRs on energy-adjusted nutrient intake calculated
from FFQs
• Intraclass correlation coefficient (ICC) was uses to assess the reproducibility of
the repeated measures for the first- and the second 6DDRs and FFQ 1 and FFQ 2
• The energy adjustment was conducted by use of the residuals model. All data
were log-transformed

14. The method
of triads The method of triads to estimate the correlation
b/w intake and true intake from three pairwise
correlations between FFQ, reference method, and
biomarker

15. The method of triads Triangular comparisonbetweenquestionnaire(Q),
referencemethod(R), and biochemicalmarker(M) - the method of
triads.
The model assumes that measurements Q, R, and M are linearly
related to the true intake T and that their random errors are
uncorrelated. The

16. Energy adjusted nutrient intakes
by the residual method
y = 4E-05x + 5973
R² = 3E-11
0
2000
4000
6000
8000
10000
12000
14000
0 500 1000 1500 2000 2500 3000 3500 4000
β-Carotene
intake
(μg/day) Total energy intake (kcal/day)
Energy-adjusted
y = 2.8904x - 317.33
R² = 0.1827
0
2000
4000
6000
8000
10000
12000
14000
16000
β-Carotene
intake
(μg/day)
Total energy intake (kcal/day)
Energy-unadjusted

17. Results

18. Characteristics
of the study
participants
101, 2014-2015
Characteristics of
the study
population
Mean (SD)
Female in the
population % 73
Age year old 57 (13)
Weight kg 60 (12)
Height cm 158 (9)
Body mass index
(kg/m2)
24 (3)
Current smoker % 4

19. Comparison of
nutrient intakes
by 12DDRs,
FFQ1, and FFQ2

20. Spearman de-attenuated correlations (r) between adjusted-
nutrient intakes from FFQ and the average of adjusted-nutrient
intakes from DRs
Nutrients
FFQ2
Energy-adjusted
Observed De-attenuated
r r a
Protein g 0.46 (0.35, 0.56) 0.52 (0.34, 0.66)
Total fat g 0.58 (0.50, 0.64) 0.65 (0.48, 0.78)
SFA g 0.64 (0.60, 0.68) 0.72 (0.56, 0.83)
MUSFA g 0.51 (0.40, 0.59) 0.58 (0.39, 0.72)
PUFA g 0.40 (0.26, 0.51) 0.56 (0.26, 0.75)
n-3PUFA g 0.35 (0.20, 0.48) 0.50 (0.20, 0.72)
n-6PUFA g 0.42 (0.29, 0.53) 0.59 (0.29, 0.79)
Cholesterol mg 0.50 (0.39, 0.59) 0.68 (0.38, 0.85)
Carbohydrate g 0.45 (0.33, 0.55) 0.51 (0.32, 0.66)
Vitamin A μgRE 0.45 (0.34, 0.55 0.53 (0.33, 0.68)
Vitamin D μg 0.48 (0.37, 0.57) 0.69 (0.34, 0.87)
Folate μg 0.51 (0.41, 0.59) 0.55 (0.37, 0.68)
β-Carotene μg 0.38 (0.24, 0.50) 0.43 (0.23, 0.60)
β-Cryptoxanthin μg 0.54 (0.46, 0.62) 0.68 (0.45, 0.82)
EPA (20:5 n-3) g 0.48(0.37, 0.57) 0.62 (0.37, 0.79)
DHA (22:6 n-3) g 0.47(0.36, 0.57) 0.62 (0.37, 0.79)
a De-attenuated correlation coefficient was calculated using rc = ro 1 + [(𝜎𝑤
2/𝜎𝑏
2)/𝑛], where ro is the
observed correlation between the energy-adjusted nutrients from the FFQ2 and DRs, 𝜎𝑤
2
is the within-
person variation, and 𝜎𝑏
2
is the between-person variation, and

21. Validity coefficient (VC) showing the correlations with the true intake for different
nutrients estimated from the FFQ 2, the second 6DDR and biomarkers as the reference
methods, among 101 participants in the validation study, Japan, 2014–2015
FFQ vs. Biomarker FFQ vs. True intake
Dietary
nutrients
FFQ2
vs.
Biomarkers
FFQ2
vs.
DRs
DRs
vs.
Biomarkers
FFQ2
vs.
True intake
DRs
vs.
True intake
Biomarkers
vs.
True intake
r r r VC (95% CI) CV (95% CI) VC (95% CI)
Vitamin D 0.25 0.29 0.25 0.55 (0.36, 0.87) 0.53 (0.34, 0.84) 0.46 (0.27, 0.77)
δ-Tocopherol 0.13 0.41 0.02 1.00 (0.08, 1.00) 0.08 (0.02, 1.00) 0.10 (0.00, 2.40)
α-Carotene 0.38 0.30 0.31 0.49 (0.32, 0.78) 0.27 (0.01, 1.00) 0.09 (0.45, 0.88)
β-Carotene total 0.29 0.30 0.41 0.47 (0.30, 0.73) 0.65(0.46, 0.92) 0.63 (0.45, 0.88)
β-Cryptoxanthin 0.40 0.27 0.31 0.59 (0.42, 0.81) 0.46 (0.31, 0.68) 0.69 (0.47, 1.00)
Folate 0.31 0.41 0.17 0.85 (0.51, 1.00) 0.48 (0.31, 0.77) 0.42 (0.18, 0.75)
EPA (20:5 n-3) 0.33 0.35 0.31 0.61 (0.46, 0.82) 0.57 (0.41, 0.81) 0.54 (0.36, 0.81)
DHA (22:6 n-3) 0.35 0.34 0.32 0.61 (0.44, 0.86) 0.56 (0.40, 0.79) 0.57 (0.40, 0.81)

22. Correlations and validity coefficients (95% CIs) estimated from
biomarkers, twelve 1-day diet records, and two FFQs

23. Correlations and validity coefficients (95% CIs) estimated from
biomarkers, twelve 1-day diet records, and two FFQs

24. Correlations and validity coefficients (95% CIs) estimated from
biomarkers, twelve 1-day diet records, and two FFQs

25. Regression
coefficients
(de-attenuated)
The regression coefficient
(b) is calculated by
regressing the average of
energy-adjusted nutrient
intake from the second
6DDR on the energy-
adjusted nutrient calculated
from the FFQ 2
Nutrients
FFQ2
Energy-adjusted
Regression coefficient
ba
Vitamin D 0.48****
Folate 0.44****
α-Carotene 0.20***
β-Carotene 0.32****
β-Cryptoxanthin 0.56****
EPA 0.68****
DHA 0.52****
a Test for b: * p < 0.05, ** p < 0.01*** p < 0.001, **** p < 0.0001

26. 1st 6DDRs vs. 2nd 6DDRs FFQ 1 vs. FFQ 2
Energy-unadjusted Energy-adjusted Energy-unadjusted Energy-adjusted
ICC ICC ICC ICC
Energy kcal 0.72 (0.61, 0.80) 0.53 (0.39, 0.66)
Protein 0.70 (0.59, 0.79) 0.69 (0.58, 0.78) 0.65 (0.54, 0.76) 0.38 (0.24, 0.56)
Total fat 0.68 (0.57, 0.78) 0.62 (0.49, 0.73) 0.51 (0.37, 0.65) 0.49 (0.35, 0.64)
SFA 0.70 (0.60, 0.79) 0.68 (0.56, 0.77) 0.55 (0.41, 0.68) 0.48 (0.33, 0.63)
MUSFA 0.66 (0.54, 0.76) 0.59 (0.46, 0.71) 0.50 (0.36, 0.64) 0.60 (0.47, 0.72)
PUFA 0.54 (0.41, 0.67) 0.27 (0.13, 0.48) 0.49 (0.34, 0.63) 0.46 (0.32, 0.61)
n-3PUFA 0.44 (0.29, 0.60) 0.29 (0.15, 0.50) 0.58 (0.44, 0.70) 0.45 (0.31, 0.61)
n-6PUFA 0.53 (0.39, 0.66) 0.31 (0.16, 0.51) 0.49 (0.34, 0.63) 0.53 (0.40, 0.67)
Vitamin D 0.30 (0.15, 0.50) 0.26 (0.12, 0.47) 0.68 (0.56, 0.77) 0.52 (0.38, 0.66)
Folate 0.74 (0.65, 0.82) 0.73 (0.63, 0.81) 0.51 (0.37, 0.65) 0.47 (0.33, 0.62)
β-Carotene 0.59 (0.47, 0.71) 0.60 (0.47, 0.71) 0.56 (0.42, 0.68) 0.53 (0.40, 0.67)
β-Cryptoxanthin 0.36 (0.21, 0.54) 0.29 (0.14, 0.49) 0.24 (0.10, 0.46) 0.22 (0.09, 0.46)
EPA 0.40 (0.25, 0.57) 0.34 (0.20, 0.53) 0.72 (0.62, 0.80) 0.60 (0.47, 0.72)
DHA 0.37 (0.22, 0.55) 0.32 (0.17, 0.51) 0.69 (0.57, 0.78) 0.55 (0.41, 0.68)
Intraclass correlations (ICCs)for the first- and the second 6DDR, and
for FFQ 1 and FFQ 2, completed by 101 participants

27. Acknowledgements
This research was funded by the University of
Nagasaki, the President Education and Research
Grants 2013, 2014, and 2016

28. Conclusion
The findings suggest that a carefully
designed this FFQ can reasonably
estimate important nutrients in a
Japanese population
Nutrients contributed by fruits and
vegetables tended to be over-reported
on the FFQ
Regression coefficients from this study
could be used to calibrate these intakes
to those assessed by the diet records

29. Thank you