Evaluation of a diet history questionnaire for epidemiologic studies

Screening tool for identifying adults with excessive salt intake among community-dwelling adults: a population-based cohort study

BACKGROUND

Excessive salt intake is widely known to be a cause of hypertension, cardiovascular events, and so on. However, simple tools for screening excessive salt intake are lacking.

OBJECTIVE

We aimed to develop a simple screening tool to identify community-dwelling adults with excessive salt intake.

METHODS

The present study involved participants who received health check-ups in Fukushima, Japan, in 2016 and 2017. We defined data from the 2016 check-up as the derivation set, and data from those who received check-ups in 2017 but not 2016 as the validation set. The outcome measure was excessive salt intake, defined as the estimated daily salt intake of 1 SD or more. Candidate predictors associated with the outcome were extracted using the Delphi method by an expert panel and narrowed down with clinical expertise and stepwise backward selection. The screening tool was developed using a coefficient-based multivariable scoring method and externally validated.

RESULTS

A total of 1101 participants were included in the derivation set and 249 in the validation set. At the conclusion of the deviation process, 8 predictors were selected and scored. The areas under the receiver operating characteristic curve for derivation and external validation were 0.70 (95% CI: 0.67, 0.74) and 0.71 (95% CI: 0.62, 0.80), respectively. The calibration slope and intercept for external validation were 1.16 and -0.03, respectively.

CONCLUSION

We developed a screening tool to identify adults with excessive salt intake. By extracting groups with excessive salt intake, target populations needing intervention for salt reduction can be highlighted efficiently.

Metformin-associated prevention of weight gain in insulin-treated type 2 diabetic patients cannot be explained by decreased energy intake: A post hoc analysis of a randomized placebo-controlled 4.3-year trial

Metformin prevents weight gain in patients with type 2 diabetes (T2D). However, the mechanisms involved are still unknown. In this post hoc analysis of the HOME trial, we aimed to determine whether metformin affects energy intake. Patients with T2D were treated with 850 mg metformin or received placebo added to insulin (1-3 times daily) for 4.3 years. Dietary intake was assessed at baseline, after 1 year and after 4.3 years, according to the dietary history method. Among the 310 included participants, 179 (93 placebo, 86 metformin) completed all 3 dietary assessments. We found no significant difference in energy intake after 4.3 years between the groups (metformin vs placebo: -31.0 kcal/d; 95% CI, -107.4 to 45.4; F-value, 1.3; df = 415; P = .27). Body weight in placebo users increased significantly more than in metformin-users during 4.3 years (4.9 ± 4.9 vs 1.1 ± 5.2 kg; t test: P ≤ .001). Linear mixed models did not show a significant effect of energy intake as explanation for the difference in weight gain between the groups (F-value, 0.1; df = 1; P = .82). In conclusion, the prevention of weight gain by metformin cannot be explained by reduced energy intake.

Comparison of two dietary assessment methods by food consumption: results of the German National Nutrition Survey II

PURPOSE

To further characterise the performance of the diet history method and the 24-h recalls method, both in an updated version, a comparison was conducted.

METHODS

The National Nutrition Survey II, representative for Germany, assessed food consumption with both methods. The comparison was conducted in a sample of 9,968 participants aged 14-80. Besides calculating mean differences, statistical agreement measurements encompass Spearman and intraclass correlation coefficients, ranking participants in quartiles and the Bland-Altman method.

RESULTS

Mean consumption of 12 out of 18 food groups was higher assessed with the diet history method. Three of these 12 food groups had a medium to large effect size (e.g., raw vegetables) and seven showed at least a small strength while there was basically no difference for coffee/tea or ice cream. Intraclass correlations were strong only for beverages (>0.50) and revealed the least correlation for vegetables (<0.20). Quartile classification of participants exhibited more than two-thirds being ranked in the same or adjacent quartile assessed by both methods. For every food group, Bland-Altman plots showed that the agreement of both methods weakened with increasing consumption.

CONCLUSIONS

The cognitive effort essential for the diet history method to remember consumption of the past 4 weeks may be a source of inaccurateness, especially for inhomogeneous food groups. Additionally, social desirability gains significance. There is no assessment method without errors and attention to specific food groups is a critical issue with every method. Altogether, the 24-h recalls method applied in the presented study, offers advantages approximating food consumption as compared to the diet history method.

Prospective study of ready-to-eat breakfast cereal consumption and cognitive decline among elderly men and women

OBJECTIVE

To examine associations between frequency of ready-to-eat-cereal (RTEC) consumption and cognitive function among elderly men and women of the Cache County Study on Memory Health and Aging in Utah.

DESIGN

A population-based prospective cohort study established in Cache County, Utah in 1995.

SETTING AND PARTICIPANTS

3831 men and women > 65 years of age who were living in Cache County, Utah in 1995.

MEASUREMENT

Diet was assessed using a 142-item food frequency questionnaire at baseline. Cognitive function was assessed using an adapted version of the Modified Mini-Mental State examination (3MS) at baseline and three subsequent interviews over 11 years. RTEC consumption was defined as daily, weekly, or infrequent use.

RESULTS

In multivariable models, more frequent RTEC consumption was not associated with a cognitive benefit. Those consuming RTEC weekly but less than daily scored higher on their baseline 3MS than did those consuming RTEC more or less frequently (91.7, 90.6, 90.6, respectively; p-value < 0.001). This association was maintained across 11 years of observation such that those consuming RTEC weekly but less than daily declined on average 3.96 points compared to an average 5.13 and 4.57 point decline for those consuming cereal more or less frequently (p-value = 0.0009).

CONCLUSION

Those consuming RTEC at least daily had poorer cognitive performance at baseline and over 11 years of follow-up compared to those who consumed cereal more or less frequently. RTEC is a nutrient dense food, but should not replace the consumption of other healthy foods in the diets' of elderly people. Associations between RTEC consumption, dietary patterns, and cognitive function deserve further study.

Consumption of food groups and the risk of pancreatic cancer: a case-control study

PURPOSE

The purpose of this study is to investigate whether the consumption of specific food groups predicts the risk of pancreatic cancer, a case-control study of nutrition and pancreatic cancer among French-Canadians was carried out in Montreal, Quebec, Canada.

METHODS

A total of 179 pancreatic cancer cases (97 males and 82 females) and 239 population-based control subjects were interviewed. Dietary intake was evaluated via a validated food frequency questionnaire that gathers information on over 200 different food items and beverages. Odd ratios (ORs) and 95% confidence intervals (CIs) were computed by unconditional logistic regression.

RESULTS

After adjustment for age, smoking, diabetes status, proxy interview, gender and total energy intake, a reduced risk of pancreatic cancer was related to vegetables and vegetable products [OR = 0.47; 95%CI: (0.21-1.06) p-trend = 0.024], while an increased risk was associated with the consumption of lamb, veal and game [OR = 2.24; 95%CI: (1.11-4.52) p-trend = 0.026], when the upper and lower quartiles of intake were compared. Changes in dietary intake over the last decade revealed an elevated risk with augmented consumption of soups, sauces and gravies [OR = 2.32; 95%CI: (1.20-4.49) p-trend=0.03], beef products [OR = 2.07; 95%CI: (0.95-4.51) p-trend=0.05] as well as fish and shellfish [OR = 1.48; 95%CI: (0.78-2.80) p-trend=0.05].

CONCLUSIONS

These findings suggest that a diet rich in vegetables and vegetable products may decrease the risk of pancreatic cancer.

Diet and prostate cancer risk with specific focus on dairy products and dietary calcium: a case-control study

BACKGROUND

Despite the prevalence of prostate cancer worldwide, only a few risk factors have been well-established. The role of diet, especially of dairy products, in the etiology of prostate cancer is still controversial.

METHODS

This study assessed the association of dietary components, particularly dairy products and dietary calcium, on prostate cancer risk in a case-control study of 197 cases and an equal number of individually matched controls recruited in Montreal, Canada. A semi-quantitative food frequency questionnaire was administered in which the usual consumption frequency and amounts consumed of more than 200 food items were recorded.

RESULTS

We found a twofold increased risk of prostate cancer associated with an increased intake of dairy products {Odds Ratio (OR) = 2.19; 95% Confidence Intervals (CI) 1.22-3.94}. A significant trend of decreasing prostate cancer risk with higher intake was found for legumes, nuts, finfish/shellfish and for alpha-tocopherol after adjustment for calcium intake. Milk was the only dairy product significantly associated with prostate cancer risk, with OR = 2.27; 95% CI (1.25-4.09) for the highest versus lowest quartiles of consumption. Calcium, the main micronutrient contained in dairy products, showed only a borderline association with prostate cancer risk (P = 0.09), with slightly higher risk for higher calcium intake. In conclusion, this study supports the hypothesis that dairy products, especially milk, are involved in the etiology of prostate cancer. However, the mechanisms by which the various nutrients in dairy products and total diet may interact to influence this risk remain unknown.

Assessing diet in longitudinal birth cohort studies

Diet is an important component of a person's environment. It is important for adults and particularly for mothers during pregnancy and while breast feeding, and for children in utero and during later growth and development. Measurement of the type and amount of foods consumed is complex. Here we describe the different methods that can be used, when and when not to use each one, and the importance of validation studies.

Comparative validation of standard, picture-sort and meal-based food-frequency questionnaires adapted for an elderly population of low socio-economic status

OBJECTIVE

To compare the validity of a modified Block food-frequency questionnaire (FFQ), a picture-sort administration of the FFQ (PSFFQ) and a meal pattern-based questionnaire (MPQ) in a multi-ethnic population of low socio-economic status (SES).

DESIGN

Participants completed six 24-hour dietary recalls (24HR) over six months; the FFQ, PSFFQ and MPQ were completed in random order in the subsequent month. Instruments were interviewer-administered. The PSFFQ and MPQ were developed in formative research concerning difficulties for older adults in responding to standard food-frequency instruments.

SETTING

Rural North Carolina, USA. Subjects One hundred and twenty-two African American, Native American and white adults aged > or = 65 years, with approximately one-third in each ethnic group. Inclusion criteria included education < or = 12 years and income < or = 150% of national poverty level or Medicaid recipient.

RESULTS

Comparing median intakes from the average of the 24HR with the three diet assessment instruments, the MPQ tended to overestimate intakes compared with the FFQ and PSFFQ. Correlations among nutrients obtained by the 24HR and the other three instruments were generally statistically significant and positive. Across nutrients, the PSFFQ was most highly correlated with the 24HR for women, while the FFQ was most highly correlated with the 24HR for men.

CONCLUSIONS

Dietary assessments using 24HR and FFQ were similar to results reported elsewhere, although correlations between 24HR and FFQ were somewhat lower. Interviewer-administered dietary assessments should be used with caution to evaluate dietary intake among older adults with low SES. Gender differences and the lower correlations should be investigated more thoroughly to assist in choosing dietary assessment instruments for this population.

Associations of Mammographic Density with Dietary Factors in Japanese Women

BACKGROUND

A high percentage of mammographic dense area has been strongly associated with a risk of beast cancer. The present cross-sectional study evaluated the relations of percent density with dietary factors, such as fats, protein, dietary fiber, and soy isoflavones.

METHODS

Study subjects were 601 (348 premenopausal and 253 postmenopausal) Japanese women who were recruited from a mammographic screening center. The size of the total breast area and the dense area were measured quantitatively using an automated mammographic mass detection method. Intakes of nutrients were estimated with a validated semiquantitative food-frequency questionnaire.

RESULTS

The crude means of the percent density were 39.2% and 18.9% in premenopausal and postmenopausal women, respectively. There were no significant associations of any dietary factors with the percent density in premenopausal women. In postmenopausal women, percent density was significantly positively associated with intakes of protein, total fat, and saturated fat after controlling for covariates; the increase in the means of percent density were 7.2%, 5.6%, and 9.2% in the highest versus lowest quartile of intakes for protein, total fat, and saturated fat, respectively (P for linear trend were 0.006, 0.04, and 0.01, respectively). Carbohydrate intake was inversely associated with percent density; the mean of percent density was 6.0% lower in the highest versus the lowest quartile of intake (P(trend) = 0.03). The associations of dietary factors with dense area were very similar to those with percent density.

CONCLUSION

These dietary factors may have implications for the risk of breast cancer in postmenopausal women.

Dietary carotenoid intake and colorectal cancer risk

Several studies have found inverse associations between fruit and vegetable consumption and colorectal cancer risk, suggesting the potential etiological importance of carotenoids (and other phytochemicals) contained in these foods. However, only one study (a case-control study) has examined the association between dietary carotenoids other than beta-carotene and colorectal cancer risk. In the study reported here, we examined the relationships between dietary intakes of beta-carotene, alpha-carotene, lycopene, lutein, and beta-cryptoxanthin and colorectal cancer risk in a large cohort study of Canadian women. A case-cohort analysis was undertaken within the cohort of 56,837 women who were enrolled in the Canadian National Breast Screening Study and who completed a self-administered dietary questionnaire. During follow-up to the end of 1993, a total of 388 women were diagnosed with colorectal cancer. For comparative purposes, a subcohort of 5,681 women was randomly selected. After exclusions for various reasons, the analyses were based on 295 cases and 5,334 noncases. We did not find any clear association between intake of any of the studied carotenoids and colorectal cancer risk in the study population as a whole or in subgroups defined by smoking status, relative body weight (body mass index), intakes of total fat, energy, alcohol, and folic acid, or menopausal status. Our data do not support any association between dietary intakes of the studied carotenoids and colorectal cancer risk. However, given that this is the first prospective cohort study of carotenoids in relation to colorectal cancer, further studies are warranted.

Dietary intake of folic acid and colorectal cancer risk in a cohort of women

Folate is crucial for normal DNA methylation, synthesis and repair, and deficiency of this nutrient is hypothesized to lead to cancer through disruption of these processes. There is some evidence to suggest that relatively high dietary folate intake might be associated with reduced colorectal cancer risk, especially among individuals with low methionine intake. A case-cohort analysis was undertaken within the cohort of 56,837 women who were enrolled in the Canadian National Breast Screening Study and who completed a self-administered dietary questionnaire. During follow-up to the end of 1993, a total of 389 women were diagnosed with colorectal cancer, identified by linkage to the Canadian Cancer Database. For comparative purposes, a subcohort of 5,681 women was randomly selected from the full dietary cohort at baseline. After exclusions for various reasons, the analyses were based on 295 cases and 5,334 non-cases. Folate intake was inversely associated with colorectal cancer risk (IRR = 0.6, 95% CI = 0.4-1.1, p for trend = 0.25). The inverse association was essentially similar among individuals with low and high methionine intake, and was similar for colon and rectal cancers when those endpoints were analyzed separately. Among individuals with low methionine intake, folate intake did not appear to lower the risk of rectal cancer, a finding that may be due, in part, to the low number of cases in the subgroup analysis. Overall, our data lend some support to the hypothesis that high folate intake is associated with a reduced risk of colorectal cancer.

Assessment of habitual energy and macronutrient intake in adults: comparison of a seven day food record with a dietary history interview

OBJECTIVE

To examine the quantitative agreement between a 7 day food record and a diet history interview when these are conducted under the same conditions and to evaluate whether the two methods assess habitual diet intake differently among subgroups of age and body mass index (BMI).

DESIGN

Cross-sectional study.

SETTING

Population study, Denmark.

SUBJECTS

A total of 175 men and 173 women aged 30-60 y, selected randomly from a larger population sample of Danish adults.

INTERVENTIONS

All subjects had habitual diet intake assessed by a diet history interview and completed a 7 day food record within 3 weeks following the interview. The diet history interview and coding of records were performed by the same trained dietician.

MAIN OUTCOME MEASURE

Median between-method difference in assessment of total energy intake, absolute intake of macronutrients, and nutrient energy percentages. Difference between reported energy intake from both methods and estimated energy expenditure in different subgroups.

RESULTS

Energy and macronutrient intake was assessed slightly higher by the 7 day food record than by the diet history interview, but in absolute terms the differences were negligible. The between-method difference in assessment of total energy intake appeared to be stable over the range of age and BMI in both sexes. As compared to estimated total energy expenditure, both diet assessment methods underestimated energy intake by approximately 20%. For both methods the under-reporting increased by BMI in both sexes and by age in men.

CONCLUSIONS

Energy and macronutrient intake data collected under even conditions by either a 7 day food record or a diet history interview may be collapsed and analysed independent of the underlying diet method. Both diet methods, however, appear to underestimate energy intake dependent on age and BMI.

SPONSORSHIP

Danish Medical Research Council, the FREJA programme.

A 7-item versus 31-item food frequency questionnaire for measuring fruit, juice, and vegetable intake among a predominantly African-American population

OBJECTIVE

This study sought to determine which of 2 fruit and vegetable food frequency questionnaires (FFQs) most closely approximated intake measured by the average of four 24-hour dietary recalls.

DESIGN

Participants completed either a 31-item FFQ (n = 70) or 7-item FFQ (n = 76) on 2 occasions approximately 2 weeks apart. During the interval between FFQs1 participants provided four 24-hour dietary recalls via telephone interview.

SUBJECTS/SETTING

Participants were 146 persons with food preparation responsibilities in families of students in grades 3 through 5. Respondents were predominantly African-American women in Atlanta, Ga.

STATISTICAL ANALYSIS

Pearson correlation coefficients of log-transformed values estimated the reliability of each FFQ and compared FFQ estimates to reference values. The intraclass correlation coefficient evaluated consistency across 24-hour recalls.

RESULTS

The first FFQs overestimated intake approximately twofold. The 31-item FFQ estimates exceeded 7-item FFQ estimates by approximately 30% . Correlations with recall estimates were high for the 7-item FFQ and moderate to low for the 31-item FFQ. The second FFQ estimates were more highly correlated to reference values. From the first to the second administration, 7-item FFQ estimates dropped from 5.2 to 2.7 servings, and 31-item FFQ estimates dropped from 6.7 to 3.5 servings. Neither FFQ produced highly reliable estimates.

CONCLUSIONS

Mean total fruit and vegetable consumption was closer to reference estimates for the first 7-item FFQ and the second 31-item FFQ. The 7-item FFQ correlated more highly with reference estimates than did the 31-item FFQ. Therefore, we conclude that for African-American adults, a 1-time-administered FFQ using 7 broad food categories correlates more highly with reference values than a FFQ using 31 individual fruit and vegetable items.

The validity of self-reported energy intake as determined using the doubly labelled water technique

In the 1980s the development of the doubly labelled water (DLW) technique made it possible to determine the validity of dietary assessment methods using external, independent markers of intake in free-living populations. Since then, the accuracy of self-reported energy intake (EI) has been questioned on a number of occasions as under-reporting has been found to be prevalent in many different populations. This paper is a review of investigations using the DLW technique in conjunction with self-reported EI measures in groups including adults, children and adolescents, obese persons, athletes, military personnel and trekking explorers. In studies where a person other than the subject is responsible for recording dietary intake, such as parents of young children, EI generally corresponds to DLW determined energy expenditure. However, in instances where the subjects themselves report their intake, EI is generally under-reported when compared with energy expenditure. It was originally believed that this phenomenon of under-reporting was linked to increased adiposity and body size, however, it is now apparent that other factors, such as dietary restraint and socio-economic status, are also involved. This paper therefore aims to present a more comprehensive picture of under-reporting by tying in the findings of many DLW studies with other studies focusing particularly on the characteristics and mechanisms for under-reporting. Awareness of these characteristics and mechanisms will enable researchers to obtain more accurate self-reports of EI using all dietary recording techniques.

Nutritional assessment in intravenous drug users with HIV/AIDS

Studying metabolic, endocrine, and gastrointestinal (MEG) disorders in drug abuse and HIV infection is important. Equally important, however, are the tools we use to assess these disorders. Assessment of nutritional status may include any combination of biochemical and body composition measurements, dietary intake assessment, and metabolic studies. Each method has its strengths and weaknesses and there is no perfect tool. When assessing nutritional status in injection drug users (IDU) and in HIV-infected people, the decision on which method or methods to use becomes even more complex. A review of studies reported during the XII World Conference on AIDS reveals that of 64 abstracts on the topic of nutrition in HIV-infected adults, only 11 assessed diet, 41 assessed anthropometry, and 24 assessed some form of biochemical measure. The most commonly reported methods for dietary intake included 24-hour recalls, food records, and food frequencies. The commonest methods used for measuring body composition included height, weight, bioimpedance, and dual-energy x-ray absorptiometry (DEXA). Biochemical measurements included various blood nutrients, lipids, and albumin. Methods varied greatly between studies, and caution should be taken when trying to compare results across studies, especially among those using different methods. Currently, few studies deal with the development of methods that can be used for research in HIV-infected and IDU populations. We need to work toward better tools in dietary intake assessment, body composition, and biochemical measurements, especially methods that will allow us to track changes in nutritional status over time.

Validity of nutrient estimates by food frequency questionnaires based either on exact frequencies or categories

PURPOSE

The study was designed to assess if category-based Food Frequency Questionnaires (FFQ) could be substituted for exact-frequency based questionnaires.

METHODS

Nutrient estimates on 203 subjects from Toronto, Canada, derived from recoding an exact frequency based 132 item food frequency questionnaire (E-FFQ) into categories were evaluated for validity against a 7-day food record (FR).

RESULTS

Among men, the median Pearson's correlation coefficient (for energy adjusted nutrients) between FR and E-FFQ was 0.53, ranging from 0.26 for thiamin to 0.72 for calcium. The median correlation dropped to a value of 0.40 (range: 0.18 for thiamin to 0. 56 for carbohydrate) when a category-based FFQ (C-FFQ) and FR were compared. Data on women showed a similar pattern; a median correlation of 0.50 from E-FFQ and 0.42 from C-FFQ.

CONCLUSIONS

While the results varied with individual nutrients, overall it is concluded that when validated against food records, the use of exact frequencies in FFQs yielded higher correlation coefficients for most nutrients, and slightly better agreement within quartiles of categories than recoded frequency categories.

Validity and reproducibility of a quantitative food frequency questionnaire for a cohort study in Japan

BACKGROUND

A self-administered quantitative food frequency questionnaire (Qx) was developed for a population-based cohort study on cancer in Takayama, Japan.

METHODS

The Qx was tested among 58 male and 59 female volunteers. Average daily nutrient intakes for the previous year calculated from the Qx were compared with those from 3-day food records and four 24-h recalls. The Qx was also validated among 37 volunteers by comparing the nutrient intakes calculated from the Qx with 12 1-day food records during a year. We also calculated the intra-class correlation coefficients for various nutrients between the Qx and the second Qx administered by the same volunteers 1 year after the first survey.

RESULTS

Pearson correlation coefficients between total energy from the Qx and 3-day records were 0.38 for men and 0.25 for women and those between the Qx and 24-h recalls were 0.19 and -0.02 for men and women, respectively. Correlations between the several nutrients from the Qx and 3-day records ranged from 0.2 to 0.5 for both men and women. These correlations after energy adjustment ranged from 0.2 to 0.6 for men and from 0.1 to 0.7 for women. In general, the correlations for various nutrients between the Qx and 12 1-day records were higher than those described above. The intra-class correlation coefficients ranged from 0.46 to 0.78 in men and from 0.36 to 0.67, except for vitamin C in women. When the information on portion size was excluded, almost all of the above indices showed somewhat lower figures.

CONCLUSION

These results suggest that our food frequency questionnaire with portion size information can be used to estimate nutrient intakes of each individual.

Energy and nutrient intakes and health practices of Latinas and white non-Latinas in the 3 months before pregnancy

OBJECTIVE

To describe the health practices and energy and nutrient intakes from diet and supplements of foreign- and US-born Latinas and white non-Latinas in the 3 months before pregnancy.

DESIGN

A descriptive study in which data were obtained retrospectively from 2 questionnaires: an interviewer-administered questionnaire on the subject's medical, reproductive, family, occupational, and lifestyle history and a subject-administered (and interviewer-assisted) 100-item food frequency questionnaire.

SUBJECTS/SETTING

A population-based sample of California women (n = 462) who gave birth between 1989 and 1991 to single, live-born infants. One third of women were Latinas, of whom 58.1% were foreign born.

STATISTICAL ANALYSES

Means, standard deviations, and percentiles were computed for energy and nutrient intakes of the total population and for white non-Latinas; US-born Latinas; and foreign-born Latinas. One-way analysis of variance was used to compare group means.

RESULTS

Mean and median energy intake in all ethnic groups exceeded 2,000 kcal/day, although less than half of the population consumed 5 servings of fruit and vegetables per day. For iron, half of the women were below the Recommended Dietary Allowance. In contrast to the dietary intake of white non-Latinas and US-born Latinas, foreign-born Latinas had the lowest contribution of fat to total energy intake and the highest dietary intake of carbohydrate, cholesterol, fiber, grain products, protein foods, folate, vitamin C, iron, and zinc.

CONCLUSIONS

A woman's ethnicity, as well as whether her place of birth was within or outside of the United States, may be predictors of her dietary and health practices before pregnancy. Vitamin, mineral, and food supplementation and consumption of cold breakfast cereal may be avenues for improving perinatal micronutrient intake.

Validation and comparison of two computerized methods of obtaining a diet history

The aim of this study was to validate two computerized methods of obtaining a diet history (DH and EBIS). The food consumption of 12 men and eight women was calculated by weighing each food item over a period of 8 days. Thereafter the diet history was taken over this period by using both programs alternatively. The intake of energy, protein, fat and carbohydrates, and 10 further nutrients was evaluated and the percentage difference calculated. In general, the intake of nutrients calculated from the diet history tended to be underestimated by most of the people interviewed. The mean daily intake of the nutrients calculated from the DH program deviates from -34% to +20% (mean SD = 48.1) and -35% to +15% for EBIS (mean SD = 28.1). In conclusion, both computerized methods proved useful for epidemiological studies, but not for the determination of deficiencies in individuals.

Methodology of a two-step quantified nutritional questionnaire and its effect on results

The effects of methodology on the results of epidemiologic studies that involve collection of nutritional data, especially those involving long-term-onset illnesses such as cancer, have not yet been carefully evaluated. We present methodological features of a quantitative dietary history and physical activity questionnaire and discuss their contribution to the final results. The results of our analysis are as follows: 1) Forty-seven percent of the population consumed > 100 food items yearly. 2) The mean number of calories contributed by items eaten less than once a week exceeded 200 kcal/day in 50% of interviewees. 3) Seventy-six percent of the patients had undergone dietary changes during the course of adult life. Of the 379 individuals who reported no changes when asked general questions, 61.8% reported changes when asked specifically about each food item in the questionnaire. 4) Physical activity was significantly correlated with mean daily energy intake (r = 0.208, p < 0.001). We conclude that certain methodological features of questionnaires, such as extensive listing of food items, precise documentation of food quantity, inquiries about former eating habits, and inclusion of questions about physical activity, increase accuracy in evaluations of dietary habits. Our analysis provides practical information for future planning of nutritional questionnaires.

Dietary energy and nutrients in relation to preclinical prostate cancer

Previous studies of diet and prostate cancer have focused on advanced disease and have suggested a positive association with saturated fat intake. We report a study assessing the relationship between diet and preclinical prostate cancer. A total of 215 men with preclinical prostate cancer and 593 controls with no evidence of cancer participated in a case-control study conducted in Quebec City between October 1990 and May 1993. The study population comprised two groups: men treated surgically for benign prostatic hypertrophy and participants in a prostate cancer screening program. Trained nutritionists interviewed the participants on their usual diet using a diet history questionnaire. Odds ratios for prostate cancer associated with quartiles of dietary intake and P values for trend were estimated by logistic regression while controlling for age, education, group, and family history of prostate cancer. A positive association was observed between total energy intake and preclinical prostate cancer (p = 0.004). The odds ratios for prostate cancer increased with each quartile of energy intake: 1.00, 1.77, 1.90, and 2.67. After adjustment for energy, nutrients were not associated with prostate cancer. This study provides some evidence that total energy intake is related to preclinical prostate cancer and suggests that diet could be involved earlier than thought in the occurrence of prostate cancer.

Cardiovascular risk factors and behavior lifestyles of young women: implications from findings of the Bogalusa Heart Study

The primary purposes of this article are to highlight important issues related to cardiovascular risk factors and behavior life-styles in young women and to examine racial (black-white) differences in risk factors that relate to cardiovascular disease. In childhood, some girls show cardiovascular risk factors of higher blood pressure levels, dyslipidemia, and obesity, all of which continue into young adulthood. Factors that contribute to abnormal risk factors are a high-saturated fat diet, excess energy intake related to inactivity, and cigarette smoking. Trends of obesity are documented; and young white girls are continuing to use tobacco, more so than boys and black girls. Although the onset of clinical cardiovascular disease is delayed in women, the stage is set in childhood for the development of early cardiovascular risk.

Performance of a shortened telephone-administered version of a quantitative food frequency questionnaire

PURPOSE

We evaluated the performance of a telephone-administered food frequency questionnaire in a study of 190 men and women, 30-79 years of age, who participated as controls in a study of colon cancer.

METHODS

The telephone version of the questionnaire was modified from a longer food frequency questionnaire originally administered in person to each of the participants. One month later, the telephone questionnaire was administered to a subgroup of 190 participants and readministered to 169 members of the subgroup two weeks later to assess the reproducibility and comparative validity of the instrument.

RESULTS

The unadjusted correlation for energy between the original in-person full food frequency questionnaire and the abbreviated telephone version was 0.69. The median energy intake from the telephone version was 17% lower in men and 23% lower in women. The energy and sex-adjusted correlation coefficients for other nutrients ranged from 0.45 for vitamin E to 0.78 for fiber. The intraclass correlation coefficients to measure reproducibility ranged from 0.62 for animal protein to 0.83 for folate.

CONCLUSIONS

These data indicate that this brief, telephone-administered questionnaire is reproducible and provides a ranking of nutrient intake comparable to that provided by a full in-person interview.

Nutritional factors and colon carcinoma: a case-control study involving French Canadians in Montréal, Quebec, Canada

BACKGROUND

In a population-based case-control study of colon carcinoma and nutrition involving the francophone community in Greater Montreal, a total of 402 cases (200 males and 202 females) and 668 controls (239 males and 429 females) were interviewed.

METHODS

Cases from 1989-1993 were identified through the admission offices of 5 major francophone teaching hospitals in Montreal and were ages 35-79 years. Controls matched by age, place of residence, and language were selected by a modified random digit dialing method. Information on dietary intake was collected with a quantitative food frequency questionnaire.

RESULTS

No associations were evident between colon carcinoma and total energy, protein, or carbohydrate consumption, whereas a suggestive inverse association was found with total fat intake, with an odds ratio (OR) of 0.78 (P = 0.0637), and with saturated fat intake as well (OR = 0.71, P = 0.0893). A strongly significant inverse association was found with dietary fiber (OR = 0.50, P = 0.0018). The strongest inverse association concerning fiber was found with fiber from vegetable sources (OR = 0.57, P = 0.0096), and a suggestive (although nonsignificant) inverse association (OR = 0.74, P = 0.0687) was found with fiber from fruits. Calcium was inversely associated with risk (OR = 0.69, P = 0.0411), as was dietary intake of vitamin A (OR = 0.67, P = 0.0162), retinol, (OR = 0.069, P = 0.0409), vitamin E (OR = 0.53, P = 0.0028), and alphatocopherol (OR = 0.63, P = 0.0256). Although there was no association demonstrated between dietary beta-carotene intake and risk, a suggestive (although nonsignificant) inverse association with intake of other types of carotene was observed (OR = 0.76, P = 0.0740). No association was found between intake of other nutrients investigated in this study and risk of colon carcinoma.

CONCLUSIONS

There is strong evidence from epidemiologic studies that high intake of fat and meat are risk factors for colorectal carcinoma in humans, whereas high intake of vegetable and fruit are inversely associated with risk of colon carcinoma. The findings from this study are in agreement with this observation.

Risk factors for the development of colorectal carcinoma and their modification

In this article the authors review factors determining risk for the development of colorectal cancer (CC) and their modification. Emphasis is placed on understanding the difference between average risk and high risk individuals. Risk factors including genetics, diet, environment, and coexistent diseases are discussed. The data regarding modification of risk via dietary, pharmaceutical, and prophylactic endoscopic and surgical interventions are reviewed.

Fat, caloric intake, and obesity: lifestyle risk factors for breast cancer

Dietary fat is a likely important determinant of postmenopausal breast cancer as part of an intricate and inseparable interaction of lifestyle cancer risk factors that include dietary fat, type of fat, energy intake and expenditure, and obesity. These factors possibly build upon individual susceptibilities derived from a complex array of polygenetic risk determinants. Epidemiologic studies have not provided conclusive evidence for a dietary fat-breast cancer association, partly because studies that focus on a single nutrient cannot always evaluate readily the interactive effects of other lifestyle factors. Further, persons generally underestimate their usual dietary intake, measured by either food frequency questionnaires (FFQs) or diet records. A dietary measurement model that accounts for this underreporting demonstrated that FFQs and diet records may not be able to detect a dietary fat-breast cancer association because of measurement error biases. Although meta-analysis of epidemiologic data across individual studies suggests only a week association between breast cancer and dietary fat, this result is compatible with the dietary measurement model and does not rule out a contributing role for dietary fat, either alone or with other causative factors. Research is needed that focuses on a comprehensive approach to dietary lifestyle choices and breast cancer risk and that emphasizes a fat-caloric intake-obesity linkage. The best hope for a definitive answer may rest with randomized, controlled clinical trials. Two such trials, the Women's Health Initiative and the Women's Intervention Nutrition Study, are under way.

Tumor characteristics and survival of breast cancer patients in relation to premorbid diet and body size

Nutritional factors have been suggested to play an important role in the prognosis of breast cancer through their effect on tumor characteristics. This study evaluated four tumor characteristics and prognosis in relation to premorbid diet and body size. From a cohort of 89,835 women in the National Breast Screening Study (NBSS) in Canada, data on 676 incident cases of invasive carcinoma of breast, on whom we had dietary information, were used. A high energy intake lowered the likelihood of being ER positive and PR positive but after adjusting for ER status, was still associated with a higher risk of dying of breast cancer. Total fat and various types of fats were associated with a greater likelihood that a woman would be ER and PR positive, however the likelihood of dying from breast cancer was higher with higher fat consumption. There was no significant effect of higher intakes of beta carotene or vitamin C on ER status, nodal status or tumor size, but a significantly lower risk of dying from breast cancer was observed. Higher intake of carbohydrates and calcium was associated with a lowered frequency of ER and PR positive status but also with a lower risk of dying. Of the five indicators of body size studied, higher triceps skinfold thickness was associated with a slightly lower chance of being ER positive, PR positive, and node negative, and a significantly higher likelihood of dying. It appears that while there are significant associations between some of the diet and body size variables and tumor characteristics, the effect of most nutritional factors on prognosis in breast cancer may not be mediated via their effect on tumor characteristics.

Nutritional factors and prostate cancer: a case-control study of French Canadians in Montreal, Canada

The relationship between the risk of prostate cancer and dietary intake of energy, fat, vitamin A, and other nutrients was investigated in a case-control study conducted in Montreal (Quebec), Canada. French Canadians aged 35 to 84 years with a recent, histologically confirmed diagnosis of adenocarcinoma of the prostate were identified through the admission offices of five major francophone teaching-hospitals in Montreal from 1989 to 1993. Population-based controls matched for age (+/- five years), language, and place of residence were selected by a modified random-digit dialing method. The study included 232 cases and 231 controls. Information on dietary intake was collected by means of a quantitative dietary history. No association was evident between energy intake and the risk of prostate cancer. In contrast, there was some evidence of an inverse association with intake of total fat, animal fat, monounsaturated fat, and particularly saturated fat (odds ratio = 0.69, 95 percent confidence interval = 0.40-1.18, P = 0.05), while a nonsignificant positive association was found with polyunsaturated fat. In addition, high intake of retinol and vegetable protein (highest cf lowest quartile) was associated with reduced risk, but was not statistically significant. No associations were established between intake of other nutrients and risk. These patterns persisted after adjustment for a number of potential confounding factors.

Nutrient patterns, nutritional adequacy, and comparisons with nutrition recommendations among French-Canadian adults in Montreal

OBJECTIVES

A survey was carried out in 1988-89 among French Canadians in Montreal, to provide data on food habits, dietary intakes and sociodemographic factors.

METHODS

Interviewer-administered questionnaires and 7-day food records (7D-FR) were used to gather data.

RESULTS

Some 1,450 individuals (in 845 families) were studied. Complete 7D-FR and sociodemographic data were obtained from 182 children aged 5-18 (44.8% males), and 614 adults aged 19 and over (40.1% males). Most adult respondents greatly surpassed their age-sex specific Canadian Recommended Nutrient Intakes (RNIs), except for low mean energy intakes in women aged 75 years and over (on average, 1477 kcal), and marginally lower than recommended mean calcium consumption, again in the oldest age group (particularly men). Protein furnished 16 to 17% of energy, relative fat intake varied from 34% of energy among the oldest subjects to 38% in 25 to 49 year old women (overall average, 36%). Only 15.3% of respondents consumed < or = 30% relative fat intake; most (66%) were female. Carbohydrate ranged from 45 to 49% (51%) among males and females, respectively. The oldest age group had the highest relative intake of carbohydrates. Saturated fat was 13 to 14% of energy, and the mean P:S ratio was low (.30 to .37). Some respondents had insufficient intakes relative to their RNIs, notably for energy (6.5% of the whole sample; of these, 52.5% were male) and calcium (22.5%; 69.6% females). Contingency table analysis showed this was most evident among participants of low income and education levels, smokers, and female non-smokers.

CONCLUSIONS

French Canadian Montreal adults don't meet the Nutrition Recommendations for Canadians with respect to lowering fat and saturated fat, and increasing complex carbohydrate intakes. Attention should be directed to ensuring adequate consumption of calcium-rich foods, particularly among women in susceptible stages of the lifecycle. Although average alcohol intakes appeared low, some individuals reported high levels of consumption of beer, wine or spirits which suggests the need for further investigation of population alcohol intakes and their effect on dietary choices and nutritional adequacy.

Picture-sort method for administering a food frequency questionnaire to older adults

OBJECTIVE

To assess the validity of a picture-sort approach to administering the National Cancer Institute food frequency questionnaire to older adults.

DESIGN

A picture-sort interview was conducted in each respondent's home. After the picture sort, a 24-hour recall interview was administered on the same occasion. Five additional in-home recall interviews were subsequently conducted at approximately 1-month intervals.

SUBJECTS/SETTING

Forty-seven female and 49 male volunteers aged 66 to 100 years were recruited from among Cardiovascular Health Study participants from Maryland and North Carolina.

MAIN OUTCOME MEASURES

Estimates from the picture sort and the recall for intakes of macronutrients, cholesterol, fiber, and selected vitamins and minerals exclusive of supplements.

STATISTICAL ANALYSES

Comparison of means estimated by the two methods and correlation analyses were used. Correlations were adjusted under varied assumptions about the nature of the information contained in the six 24-hour recalls relative to respondents' usual intakes.

RESULTS

After correction for attenuation, Pearson correlation coefficients for macronutrients ranged from .41 for protein to .74 for saturated fat and cholesterol. For vitamins and minerals, correlations ranged from .26 for beta carotene to .62 for calcium.

APPLICATIONS

Picture-sort estimates of mean nutrient intakes were comparable with estimates based on 24-hour recalls, and correlations with reference data were similar to those reported in the literature for conventionally administered food frequency questionnaires. This dietary assessment method may, therefore, offer a way to simplify or structure responses to improve ease of administration and increase respondents' liking for the interview without loss of data quality.

Reproducibility of nutrient intake in a food frequency questionnaire used in a general population

This study evaluates the reproducibility of nutrient intake in a 45-item food frequency questionnaire (FFQ). The FFQ was mailed in 1980 to persons eligible to participate in a large cohort study on diet and cancer risk; a follow-up version with 75 food items was mailed in 1988 to selected original participants. A random sample of 500 men and 500 women from the New York State general population was selected from individuals who responded to both waves of the study. The subjects' 1988 responses were compared with their original 1980 responses; Pearson's correlations ranged from 0.25 for retinol to 0.55 for vitamin C with or without supplements and vitamin E with supplements in women. Reproducibility of nutrient intake in this questionnaire indicates that brief FFQs may be a useful tool to study nutrient intake and chronic disease relationships, although they are subject to substantial measurement error and dietary change.

Reproducibility of a self-administered diet history questionnaire administered three times over three different seasons

The reproducibility of the widely used Health Habits and History Questionnaire (HHHQ) for estimating "usual past-year" nutrient intake was examined. The HHHQ was self-administered on three occasions during three different seasons; 68 women (avg age 43 yrs) provided usable data for all three questionnaires in the appropriate seasons. Intraclass correlations (ICC) among the three administrations ranged from 0.56 (carotene) to 0.82 (fat as percentage of energy), with a median of 0.72. Thus, reliability was moderate to good, and season of administration/ordinality generally had little impact on ranking of individuals. The point estimates of intake of energy and a number of nutrients were higher in the first administration (winter). Except for dietary fiber and possibly carotene, most differences disappeared when adjusted for energy using a nutrient density approach, as well as using repeated-measures regression models. The higher intake in the first administration may be due more to either learning or fatigue effect rather than an effect of seasonal food availability on perceptions of "usual" intake. These data should be used in conjunction with validity data in the future to help evaluate the gain in precision of group means (and changes in these means) and improved estimates of odds ratios and correlations between nutrients and factors such as serum values, if a questionnaire is administered more than once.

Nutrition and colorectal cancer

Epidemiologic evidence on the relation between nutrition and colorectal cancer is reviewed. Colon cancer varies approximately 20-fold internationally. Although there is clear evidence of genetic predisposition to colon cancer, much of this variation appears to be related to differences in dietary habits. At present, the data suggest that vegetables are associated with lower risk, and that fiber alone does not account for this association. Further, meat consumption is associated with increased risk but this, too, is not explained solely by its fat content. Several microconstituents of the diet may be associated with reduced risk--including folate and calcium--but phytochemicals of other sorts may be relevant. Mutagenic compounds, particularly heterocyclic amines, produced when protein is cooked, plausibly explain the meat association. The most consistent inverse association is with physical activity. Alcohol is associated, though inconsistently, with increased risk. Rectal cancer is less well studied but, at present, there are few data to suggest that the dietary risk factors are markedly different. Physical activity does not appear to be associated with a lower risk. Colorectal adenomatous polyps also appear to share the spectrum of risk factors seen with colon cancer, although, for adenomas, tobacco smoking is also a clear and consistent risk factor. There are a variety of links between the dietary epidemiology and physiology of colorectal neoplasia and the relevant pathologic and molecular changes. Other causal connections remain to be explicated.

Reproducibility and validity of a food-frequency questionnaire designed for use in girls age 7 to 12 years

This study focused on a food-frequency questionnaire (FFQ) designed to measure nutrient intake in girls aged 7 to 12 years, inclusive. The instrument's reproducibility and validity were assessed using food records (FRs) as gold standards of measurement. Log-transformed nutrient intake estimates were compared from two FFQs and between FFQs and FRs. Intraclass correlation coefficients measuring the reproducibility of the FFQ ranged from 0.11 (starch) to 0.69 (fiber). Intraclass correlation coefficients measuring agreement between FFQ and 14l-day FR data varied between 0.15 (starch) and 0.68 (vitamin B2) for the first, and between 0.06 (starch) and 0.95 (vitamin B1) for the second FFQ. FFQs were in the best agreement with FRs for the following nutrients: fiber, vitamin B1, vitamin B2, vitamin C, and beta-carotene. Joint classifications revealed that overall, 36% of subjects were similarly categorized by FFQ and FR, and 70% of those in the lowest or highest FR quartiles were were found in the lowest or highest FR quartiles were found in the lowest or highest two FFQ quartiles, respectively.

A semiquantitative food frequency questionnaire for use in epidemiologic research among the elderly: validation by comparison with dietary history

A self-administered semiquantitative food frequency questionnaire including 75 food items and providing information on the habitual intake of 31 nutritional parameters, based on the intake of protein, fat, carbohydrate, fiber and 11 vitamins and minerals, was developed for use in epidemiologic research on chronic disease among the elderly, such as diabetes and cardiovascular disease. By means of detailed frequency and quantity questions, specifications of types of food, preparation methods and seasonal variation, the questionnaire was expected to be an improvement on existing instruments. The relative validity of the questionnaire was examined in 74 men and women, aged 50-75, by comparison with a modified dietary history. Systematic differences were absent or negligible for all nutrients, except vitamin C. Bias depending on the level of intake could be ruled out for all but seven nutrients. Pearson correlation coefficients for estimates from the questionnaire and dietary history were on average 0.71 (range: 0.65-0.78) and 0.66 (range: 0.36-0.81) for macronutrients, and vitamins and minerals, respectively. Classifying individual intake estimates into tertiles of the distribution for both methods, on average 62.4 and 54.7% of the intakes were categorized into the same tertile and 3.9 and 5.9% into the opposite tertile for macronutrients, vitamins and minerals, respectively. These results demonstrate an acceptable relative validity for this newly developed questionnaire, as compared to the dietary history method.

Dietary factors and risk of prostate cancer: a case-control study in Ontario, Canada

The relationship between risk of prostate cancer and dietary intake of energy, fat, vitamin A, and other nutrients was investigated in a case-control study conducted in Ontario, Canada. Cases were men with a recent, histologically confirmed diagnosis of adenocarcinoma of the prostate notified to the Ontario Cancer Registry between April 1990 and April 1992. Controls were selected randomly from assessment lists maintained by the Ontario Ministry of Revenue, and were frequency-matched to the cases on age. The study included 207 cases (51.4 percent of those eligible) and 207 controls (39.4 percent of those eligible), and information on dietary intake was collected from them by means of a quantitative diet history. There was a positive association between energy intake and risk of prostate cancer, such that men at the uppermost quartile level of energy intake had a 75 percent increase in risk. In contrast, there was no clear association between the non-energy effects of total fat and monounsaturated fat intake and prostate cancer risk. There was some evidence for an inverse association with saturated fat intake, although the dose-response pattern was irregular. There was a weak (statistically nonsignificant) positive association between polyunsaturated fat intake and risk of prostate cancer. Relatively high levels of retinol intake were associated with reduced risk, but there was essentially no association between dietary beta-carotene intake and risk. There was no alteration in risk in association with dietary fiber, cholesterol, and vitamins C and E. Although these patterns were evident both overall and within age-strata, and persisted after adjustment for a number of potential confounding factors, they could reflect (in particular) the effect of nonrespondent bias.

Food habits of French Canadians in Montreal, Quebec

OBJECTIVES

Since the 1960's, marked sociocultural and economic changes have affected lifestyle, religious practices, and family structure among French Canadians in Quebec. Recent nutritional assessment was unavailable, despite indications of change.

METHODS

A survey was carried out in 1988 in a representative sample living in Greater Montreal, to obtain current data on food habits, nutrient intakes and sociodemographic factors, using interviewer-administered questionnaires and seven-day food records.

RESULTS

Some 845 families (1450 individuals from different age groups) were studied in two phases: summer/fall and winter/spring. Mean household size in the study population was 2.7. Among adults, extremes of educational level were observed, with 33% having elementary school only and 28% having completed university. On average, each household spent $CAN 89.90 a week for food, $26.00 for tobacco, and $13.50 for alcohol. Breakfast was eaten regularly by 90% of subjects while 96% ate lunch and 99% ate dinner. Morning snacks were consumed by 36% and afternoon snacks were taken by 50%. Milk was consumed with breakfast by 24% of respondents, with lunch by 19%, and with dinner by 24%. On weekdays, 81% of subjects ate their main meals at home, while on weekends this figure was 95%. Time spent for meals varied by meal, and was slightly longer on weekends. Specialty diets, including vegetarianism, were followed by 7% of the study subjects, while 22% adhered to health-related diets.

CONCLUSIONS

The food record analyses revealed adequate nutrient intakes overall in relation to the 1990 Canadian Recommended Nutrient Intakes, although further investigation is needed before addressing dietary quality in specific age-sex groups. Protein comprised 16% of energy, fat 38%, and carbohydrates composed 45% or 46% for males and females, respectively. Subsequent analyses will evaluate nutrient intakes in relation to health and sociodemographic indicators in this population.

Reproducibility of a comprehensive diet history in the Diabetes Control and Complications Trial. The DCCT Research Group

OBJECTIVE

To evaluate the reproducibility of a modified Burke-type diet history within the context of a long-term, randomized, 29-center clinical diabetes study.

DESIGN

Diet histories were collected by trained interviewers at the end of years 1 and 2 after subjects were randomly assigned to the intensive treatment group or the conventional treatment group. Mean daily intakes of energy, protein, carbohydrate, total fat, saturated fatty acids, monounsaturated fatty acids, polyunsaturated fatty acids, cholesterol, and dietary fiber were calculated for each treatment group at each time period.

SUBJECTS

The study population consisted of 139 subjects in the intensive treatment group and 128 subjects in the conventional treatment group. Ages ranged from 13 to 39 years; groups included men and women. Distribution by age, sex, race, proportion of smokers, weight reported as percent ideal body weight, and duration of IDDM were similar in both groups.

STATISTICAL METHODS

Differences in nutrient intake between the conventional and intensive treatment groups at each time period were tested for significance using the Wilcoxon rank-sum test. The Wilcoxon paired differences test was used to assess changes between time periods within treatment groups. Linear agreement between repeated administrations of the diet history was evaluated using Pearson's correlation coefficient, and the extent of within-subject reproducibility was assessed by intraclass correlation.

RESULTS

No statistically significant differences in energy and nutrient intakes were observed between the two groups at either year 1 or year 2. Within each treatment group, energy and nutrient intake differences between times were not statistically significant. Correlation coefficients between years 1 and 2 ranged from .51 for dietary fiber to .72 for dietary cholesterol; within-subject reproducibility was slightly higher.

APPLICATIONS

These results demonstrate long-term reproducibility for the meal-based diet history in the DCCT population.

Dietary lactose intake, lactose intolerance, and the risk of epithelial ovarian cancer in southern Ontario (Canada)

A case-control study of dietary factors and cancer of the ovary was conducted during 1989-92 in metropolitan Toronto and surrounding areas of southern Ontario, Canada. Four hundred and fifty women aged 35-79 years, with newly diagnosed, histologically verified, primary epithelial ovarian-cancer were interviewed concerning reproduction and diet. Over the same period, 564 randomly-selected population controls, frequency-matched to the cases within three 15-year age groups, also were interviewed. From information obtained by quantitative diet history, average daily macro- and micronutrient intake values were calculated through use of the United States Department of Agriculture Food Composition Databank, which was extended and modified for Canadian items and recipes. Analysis was performed with continuous, unconditional logistic-regression methods, adjusting for age at interview, number of full-term pregnancies, total duration of oral contraceptive use, and total daily caloric intake. Neither reported history of lactose intolerance, nor average daily consumption of lactose or free galactose, were found to be associated with risk of ovarian cancer. Lactose intake or intolerance did not appear to modify the protective effects of parity and oral contraceptive use. Nevertheless, other studies suggest that ovarian galactose metabolism still may have a relationship with risk of ovarian cancer, though more evidence is needed.

Assessment of the reliability of a diet history questionnaire

The purpose of this study was to estimate the reliability of a self-administered food frequency questionnaire developed at the National Cancer Institute (NCI) (Bethesda, MD). Food intake information was collected from 48 women with breast cancer and 50 women who had a familial breast cancer risk. These women were participants in a long-term investigation of diet and breast cancer at the Ohio State University (Columbus, OH). Pearson correlation coefficients were obtained for 29 nutrients. The effect of time between questionnaires, age, weight, and caloric intake was also examined. The results showed moderate reliability coefficients for most of the nutrients (r = 0.5-0.8). For the majority of nutrients, the women with breast cancer had higher coefficients than did the high-risk women. High-risk women with shorter elapsed time periods between the first and second questionnaire had higher reliability coefficients as did women who consumed fewer calories. Age and weight (standardized by height) showed no effect on reliability. Recommendations for improving the NCI questionnaire in addition to using it as a standard method of measuring food intake are discussed.