Original Article

European Journal of Clinical Nutrition (2006) 60, 971–977. doi:10.1038/sj.ejcn.1602407; published online 8 February 2006

Validity and reliability of a new food frequency questionnaire compared to 24 h recalls and biochemical measurements: pilot phase of Golestan cohort study of esophageal cancer

Guarantor: R Malekzadeh.

Contributors: The authors have contributed to the manuscript by planning the study (DDRC, IARC, NCI, NNFRI), collecting data (DDRC, NNFRI), calculating the nutritional components (DDRC, NNFRI), serum vitamin measurements (Edouard Herriot Hospital, Addenbrooke's Hospital in Cambridge,UK), analysis of data (DDRC, IARC,NCI), and preparation and revision of the manuscript (all authors). DDRC: Digestive Disease Research Center, Shariati Hospital, Tehran University of Medical Sciences, Tehran, Iran; IARC: International Agency for Research on Cancer, Lyon, France; NNFR: National Nutrition and Food Science Research Institute of Shaheed Beheshti University of Medical Science, Iran; NCI: Nutritional Epidemiology Branch, Division of Cancer Epidemiology and Genetics National Cancer Institute, Bethesda, MD, USA; Edouard Herriot Hospital and EA 3090, Lyon, France; Addenbrooke's Hospital, Unit of Clinical Biochemistry, Cambridge, UK.

A F Malekshah1,4, M Kimiagar1,4, M Saadatian-Elahi2,3, A Pourshams1, M Nouraie1, G Goglani1, A Hoshiarrad4, M Sadatsafavi1, B Golestan4, A Yoonesi1, N Rakhshani1, S Fahimi1,2, D Nasrollahzadeh1, R Salahi5, A Ghafarpour4, S Semnani5, J P Steghens3, C C Abnet6, F Kamangar6, S M Dawsey6, P Brennan2, P Boffetta2 and R Malekzadeh1

  1. 1Digestive Disease Research Center, Shariati Hospital, Tehran University of Medical Sciences, Tehran, Iran
  2. 2International Agency for Research on Cancer, Lyon, France
  3. 3Edouard Herriot Hospital and EA 3090, Lyon, France
  4. 4National Nutrition and Food Science Research Institute of Shaheed Beheshti University of Medical Science, Tehran, Iran
  5. 5Golestan University of Medical Sciences, Gorgan, Iran
  6. 6Nutritional Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, Bethesda, MD, USA

Correspondence: Professor R Malekzadeh, Digestive Disease Research Center, Tehran University Medical Sciences, Tehran, Iran. E-mail: malek@ams.ac.ir

Received 26 July 2005; Revised 28 November 2005; Accepted 21 December 2005; Published online 8 February 2006.

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Abstract

Background:

 

A pilot study was carried out to evaluate validity and reproducibility of a food frequency questionnaire (FFQ), which was designed to be used in a prospective cohort study in a population at high risk for esophageal cancer in northern Iran.

Methods:

 

The FFQ was administered four times to 131 subjects, aged 35–65 years, of both sexes. Twelve 24-h dietary recalls for two consecutive days were administered monthly during 1 year and used as a reference method. The excretion of nitrogen was measured on four 24-h urine samples, and plasma levels of beta-carotene, retinol, vitamin C and alpha-tocopherol was measured from two time points. Relative validity of FFQ and 24-h diet recall was assessed by comparing nutrient intake derived from both methods with the urinary nitrogen and plasma levels of beta-carotene, retinol, vitamin C and alpha-tocopherol.

Results:

 

Correlation coefficients comparing energy and nutrients intake based on the mean of the four FFQ and the mean of twelve 24-h diet recalls were 0.75 for total energy, 0.75 for carbohydrates, 0.76 for proteins and 0.65 for fat. Correlation coefficients between the FFQ-based intake and serum levels of beta-carotene, retinol, vitamin C and vitamin E/alpha-tocopherol were 0.37, 0.32, 0.35 and 0.06, respectively. Correlation coefficients between urinary nitrogen and FFQ-based protein intake ranged from 0.23 to 0.35. Intraclass correlation coefficients used to measure reproducibility of FFQ ranged from 0.66 to 0.89.

Conclusion:

 

We found that the FFQ provides valid and reliable measurements of habitual intake for energy and most of the nutrients studied.

Keywords:

validity, reliability, esophageal cancer, cohort study, Iran

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