Background: This study described validity of Diet History Questionnaire (DHQ) for assessing energy and nutrient intake among Iranian population. Methods: A group of experienced nutritionists translated the DHQ to Farsi language and modified it based on Iranian food habits and cooking methods. We recruited 244 healthy adults with a mean age of 42.83 ± 0.75 yrs. from healthy individuals who were friends or relatives of patients in the Cancer Institute of Iran from April 2011 to February 2012. We used the DHQ to assess dietary intakes through interviews as well as at least four 24-h recalls one in every season. Reliability was estimated by comparing data of DHQ with mean intake from 24-hour recalls using deattenuated and energy-adjusted Spearman correlation coefficients. We classified dietary intakes of two methods into three groups to probe if DHQ correctly allocates subjects into different intake groups compared to reference method. The results are reported as percent of disagreement, adjacent agreement, and complete agreement. Results: Deattenuated spearman correlation ranged from 0.18 for vitamin B12 and fat to 0.60 for sugar. It ranged from 0.13 for pantothenic acid to 0.60 for sugar in men and from 0.07 for fat to 0.58 for sugar in females. The complete agreement of methods ranged from 51% for selenium to 36% for carotene in the entire sample, from 50% for energy to 31% for niacin in males and from 49% for sugar to 27% for vitamin B12 in females. Conclusion: The DHQ is a valid tool for assessing most nutrients intake among Iranian population. In addition, it is a proper instrument in categorizing individuals based on their dietary intakes.

BackgroundPrevious studies on the link between macronutrients and breast cancer have mostly focused on individual macronutrients rather than their combination. This study investigates the association between adherence to a low carbohydrate diet and odds of breast cancer among women.MethodsThis hospital-based case-control study was carried out on 412 women with pathologically confirmed breast cancer within the past year and 456 apparently healthy controls that were matched in terms of age and residential place. Dietary data was collected using a 168-item validated FFQ. Participants were classified in terms of quintiles of percentages of energy intake from carbohydrates, proteins, and fats. Then, individuals in the highest quintile of fat and protein intake were given a score of 5 and those in the lowest quintile of these macronutrients were given a score of 1. Participants in the other quintiles of these macronutrients were given the corresponding score. In terms of carbohydrate intake, those in the highest quintile received a score of 1 and those in the lowest quintile received 5. The scores were then summed up to calculate the total low carbohydrate diet (LCD) score, which varied from 3 to 15. A higher score meant greater adherence to a low carbohydrate diet.ResultsThe mean age of study participants was 45.2 y and mean BMI was 28.4 kg/m2. Mean LCD score of participants was 8.9 ± 2.5 (8.9 ± 2.6 in cases and 9.0 ± 2.5 in controls). Although no significant association was observed between adherence to the LCD score and odds of breast cancer in the study population, a trend toward significant positive association was seen between consumption of LCD and odds of breast cancer in postmenopausal women; after controlling for several potential confounders, individuals in the third quartile of LCD score were 1.94 times more likely to have breast cancer than those in the lowest quartile (95% CI: 1.00, 3.76). This association strengthened after controlling for dietary variables (2.50; 1.18–5.32). Even after further adjustment for BMI, this association remained significant (2.64, 1.23–5.67). No significant relationship was observed in premenopausal women, either before or after controlling for confounders.ConclusionAdherence to LCD may be associated with increased odds of breast cancer in postmenopausal women. Prospective cohort studies are needed to confirm these findings.

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