Obtaining informed consent in an illiterate population.

BACKGROUND: Esophageal cancer is highly prevalent among the Turkman people in Northeastern Iran. In order to evaluate its etiology, there is an on-going prospective cohort study in this area involving approximately 50000 subjects over the age of 40 years. The majority of these subjects are illiterate, thus obtaining informed consent is very important and difficult. METHODS: Initially, we explained the aim and study method to religious leaders and health-sanitary officials. One week prior to obtaining informed consent, potential participants were given adequate information about the research process by trained health personnel at their own home. Thus, participants had sufficient time to consider the research and consult with local health personnel, religious authorities, family, neighbors, friends and those who previously participated in the study. Potential participants could observe the research process directly and then be included in the study if they agreed. RESULTS: A total of 50045 individuals agreed to participate in the study, of which 70% were illiterate. There were no refusals due to the medical ethical aspects of this study. CONCLUSION: The method of awareness in this study can be a useful pattern for research on elderly and illiterate individuals who are participants in research studies in Iran and other countries.

Vitamin deficiency in Golestan Province, northern Iran: a high-risk area for esophageal cancer.

OBJECTIVE: 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.