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

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 β-carotene, retinol, vitamin C and α-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 β-carotene, retinol, vitamin C and α-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 β-carotene, retinol, vitamin C and vitamin E/α-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. © 2006 Nature Publishing Group. All rights reserved

Vitamin deficiency in golestan province, northern Iran: A high-risk area for esophageal cancer

Objectives: Dietary factors seem to play a major role in esophageal carcinogenesis in Golestan Province, a high-incidence area for esophageal cancer in northern Iran. The current study was conducted to evaluate previous reports on severe deficiency of vitamin intake in Golestan. Methods: Using a food frequency questionnaire, food intake data were collected from 30,463 healthy participants in the Golestan Cohort Study. Intake of selected nutrients was compared with recommended daily allowance and lowest threshold intake values. Results: Vitamin A intake in the majority of participants was lower than recommended values. The proportion of participants with intakes lower than lowest threshold intake was as follows: urban men, 20%; urban women, 31%; rural men, 48%; and rural women, 64%. The pattern of vitamin C deficiency was similar to that of vitamin A, however, vitamin C deficiency was less common. Daily intake of vitamin C lower than the LTI was as follows: urban men, 6%; urban women, 9%; rural men, 13%; and rural women, 19%. On the other hand, protein intake in the majority of the general population in Golestan was higher than recommended values. Conclusion: Severe deficiency in vitamin intake among women and rural dwellers may partly explain the high incidence of EC among inhabitants in rural areas and the male:female ratio that is approximately 1 in Golestan; while EC is much more common in men in many low-incidence areas

Patterns of food and nutrient consumption in northern Iran, a high-risk area for esophageal cancer

Our objectives were to investigate patterns of food and nutrient consumption in Golestan province, a high-incidence area for esophageal cancer (EC) in northern Iran. Twelve 24-h dietary recalls were administered during a 1-yr period to 131 healthy participants in a pilot cohort study. We compare here nutrient intake in Golestan with recommended daily allowances (RDAs) and lowest threshold intakes (LTIs). We also compare the intake of 27 food groups and nutrients among several population subgroups using mean values from the 12 recalls. Rural women had a very low level of vitamin intake, which was even lower than LTIs (P 0.01). Daily intake of vitamins A and C was lower than LTI in 67% and 73% of rural women, respectively. Among rural men, the vitamin intakes were not significantly different from LTIs. Among urban women, the vitamin intakes were significantly lower than RDAs but were significantly higher than LTIs. Among urban men, the intakes were not significantly different from RDAs. Compared to urban dwellers, intake of most food groups and nutrients, including vitamins, was significantly lower among rural dwellers. In terms of vitamin intake, no significant difference was observed between Turkmen and non-Turkmen ethnics. The severe deficiency in vitamin intake among women and rural dwellers and marked differences in nutrient intake between rural and urban dwellers may contribute to the observed epidemiological pattern of EC in Golestan, with high incidence rates among women and people with low socioeconomic status and the highest incidence rate among rural women