Reproducibility and validity of food intake measurements from a semiquantitative food frequency questionnaire

Validation of the American Cancer Society Cancer Prevention Study II Nutrition Survey Cohort Food Frequency Questionnaire

We assessed the validity and reproducibility of a self-administered 68-item food frequency questionnaire completed in 1992-1993 by approximately 185,000 adults. Four hundred forty-one participants completed four 24-hour dietary recall interviews over a 1-year period and a repeat administration of the food frequency questionnaire. For 20 nutrients and 10 food groups, measured nutrient intakes, but not food group intakes, were consistently lower by food frequency questionnaire than by recall. Energy-adjusted, attenuation-corrected Pearson validity correlations ranged from 0.12 to 0.80, with a median of 0.58. Reproducibility measures were generally high, with a median of 0.69. The food frequency questionnaire performed similarly to food frequency questionnaires used in other cohort studies, indicating similar ability to examine diet-disease relations.

Trends in fruit and vegetable consumption among adults in 16 US states: Behavioral Risk Factor Surveillance System, 1990-1996

OBJECTIVES

This study examined trends in fruit and vegetable consumption among adults in 16 US states.

METHODS

Data from telephone surveys were used to stratify respondents by sociodemographic and health-related characteristics.

RESULTS

The proportion of adults who consumed fruits and vegetables at least 5 times daily was 19%, 22%, and 23% in 1990, 1994, and 1996, respectively. While the proportion increased among those with active leisure-time physical activities and normal weight, it remained almost the same among inactive people and dropped among the obese.

CONCLUSIONS

Progress in fruit and vegetable intake from 1990 to 1994 was encouraging, but it changed little between 1994 and 1996.

An interactive CD-ROM for nutrition screening and counseling

OBJECTIVES

The goal of this project was to develop an interactive CD-ROM for nutrition screening and counseling, designed to produce dietary behavior change in fat and fruit and vegetable intake.

METHODS

The design was based on principles of relevance to the learner, readiness for change, feedback, individualization, facilitation of skills, and goal setting. It was tested in community settings such as libraries, senior centers, and Women, Infants, and Children clinics.

RESULTS

Nearly 80% of the respondents (n = 284), including numerous low-income persons, reported learning something new about nutrition and health or their own dietary habits. More than 50% of those recontacted 2 to 4 weeks later had put some of their dietary goals into practice.

CONCLUSIONS

This program is useful for dietary screening, feedback, skill building, and motivation in settings in which in-person counseling by nutrition professionals is not feasible.

Relative validity of a food frequency questionnaire among tin miners in China: 1992/93 and 1995/96 diet validation studies

OBJECTIVE

Diet validation research was conducted to compare the respondents' reporting of dietary intake in a food frequency questionnaire (FFQ) with intake reported in food recalls. Because the population received annual salary increments that could modify food intake, diet validation studies (DVSs) were conducted during two time intervals.

DESIGN

A 99-item FFQ was administered by an interviewer twice in a 1-year interval, and responses to each FFQ item were compared with 28 days of interviewer-administered food recalls that were collected in four 1-week intervals during each season of 1992/93. The second validation study in 1995/96 had a similar design to the earlier one.

SETTING

A prospective cohort study of lung cancer among tin miners in China was initiated in 1992, with dietary and other risk factors updated annually.

SUBJECTS

Among a cohort of high risk tin miners for lung cancer, two different samples (n = 141 in 1992/93, and n = 113 in 1995/96) for each diet validation study were randomly selected from four mine units, that were representative of all worker units.

RESULTS

Miners reported a significantly higher average frequency of intake of foods in the food recalls than the FFQ, with few exceptions. Deattenuated Pearson correlation coefficients of the frequency of food intake between the FFQ and food recalls were in the range of -0.40 to 0.72 in both studies, with higher positive correlations for beverages and cereal staples than for animal protein sources, vegetables, fruits and legumes. The percentage of individuals with exact agreement in the extreme quartiles of intake in the food recalls and FFQ ranged from 0 to 100% in both studies.

CONCLUSIONS

Among Chinese miners, the range in correlations between the food recalls and the FFQ were due to: (i) market availability of foods during the food recall weeks compared to their annual reported intake in the FFQ; (ii) cultural perception of time; and (iii) differences in how the intake of mixed dishes and their multi-ingredient foods were reported in the recalls vs. the FFQ. The range in the percentage of agreement in the same quartiles and the changes in food intake over time may have implications for the analysis of the diet-disease relationship in this cohort.

Fluid intake and the risk of bladder cancer in men

BACKGROUND

Studies in animals have shown that the frequency of urination is inversely associated with the level of potential carcinogens in the urothelium. In humans, an increase in total fluid intake may reduce contact time between carcinogens and urothelium by diluting urinary metabolites and increasing the frequency of voiding. The data on fluid intake in relation to the risk of bladder cancer are inconclusive.

METHODS

We examined the relation between total fluid intake and the risk of bladder cancer over a period of 10 years among 47,909 participants in the prospective Health Professionals Follow-up Study. There were 252 newly diagnosed cases of bladder cancer during the follow-up period. Information on total fluid intake was derived from the reported frequency of consumption of the 22 types of beverages on the food-frequency questionnaire, which was completed by each of the 47,909 participants who were free of cancer in 1986. Logistic-regression analyses were performed to adjust for known and suspected risk factors for bladder cancer.

RESULTS

Total daily fluid intake was inversely associated with the risk of bladder cancer; the multivariate relative risk was 0.51 (95 percent confidence interval, 0.32 to 0.80) for the highest quintile of total daily fluid intake (>2531 ml per day) as compared with the lowest quintile (<1290 ml per day). The consumption of water contributed to a lower risk (relative risk, 0.49 [95 percent confidence interval, 0.28 to 0.86] for > or =1440 ml [6 cups] per day vs. <240 ml [1 cup] per day), as did the consumption of other fluids (relative risk, 0.63 [95 percent confidence interval, 0.39 to 0.99] for >1831 ml per day vs. <735 ml per day).

CONCLUSIONS

A high fluid intake is associated with a decreased risk of bladder cancer in men.

Fruit and vegetable intake and incidence of bladder cancer in a male prospective cohort

BACKGROUND

Previous epidemiologic studies of fruit and vegetable intake and bladder cancer risk have yielded inconsistent results, especially with regard to the types of fruits and vegetables consumed. We examined total fruit and vegetable intake, as well as intakes of subtypes of fruits and vegetables, in relation to bladder cancer risk in a large male prospective cohort study.

METHODS

Two hundred fifty-two cases of incident bladder cancer were diagnosed from 1986 through January 31, 1996, among 47,909 men enrolled in the Health Professionals Follow-up Study. Each participant in this cohort completed a 131-item food-frequency questionnaire in 1986 and subsequently in 1990 and 1994. We used logistic regression analyses to examine fruit and vegetable intake in relation to bladder cancer risk, after adjusting for age, history of cigarette smoking, current smoking status, geographic region, total fluid intake, and caloric intake.

RESULTS

We observed a weak, inverse association that was not statistically significant between total fruit and vegetable intake and bladder cancer risk. Intake of cruciferous vegetables was inversely associated with risk (relative risk = 0.49; 95% confidence interval = 0.32-0.75, for the highest category of cruciferous vegetable intake compared with the lowest), but intakes of yellow or green leafy vegetables or carotenoid-rich vegetables were not associated with risk. Individual cruciferous vegetables, except for coleslaw, were all inversely related to bladder cancer risk, but only the associations for broccoli and cabbage were statistically significant.

CONCLUSIONS

Data from this study indicate that high cruciferous vegetable consumption may reduce bladder cancer risk, but other vegetables and fruits may not confer appreciable benefits against this cancer.

Potassium, magnesium, and fruit and vegetable intakes are associated with greater bone mineral density in elderly men and women

BACKGROUND

Osteoporosis and related fractures will be growing public health problems as the population ages. It is therefore of great importance to identify modifiable risk factors.

OBJECTIVE

We investigated associations between dietary components contributing to an alkaline environment (dietary potassium, magnesium, and fruit and vegetables) and bone mineral density (BMD) in elderly subjects.

DESIGN

Dietary intake measures were associated with both cross-sectional (baseline) and 4-y longitudinal change in BMD among surviving members of the original cohort of the Framingham Heart Study. Dietary and supplement intakes were assessed by food-frequency questionnaire, and BMD was measured at 3 hip sites and 1 forearm site.

RESULTS

Greater potassium intake was significantly associated with greater BMD at all 4 sites for men and at 3 sites for women (P < 0.05). Magnesium intake was associated with greater BMD at one hip site for both men and women and in the forearm for men. Fruit and vegetable intake was associated with BMD at 3 sites for men and 2 for women. Greater intakes of potassium and magnesium were also each associated with less decline in BMD at 2 hip sites, and greater fruit and vegetable intake was associated with less decline at 1 hip site, in men. There were no significant associations between baseline diet and subsequent bone loss in women.

CONCLUSION

These results support the hypothesis that alkaline-producing dietary components, specifically, potassium, magnesium, and fruit and vegetables, contribute to maintenance of BMD.

Is whole grain intake associated with reduced total and cause-specific death rates in older women? The Iowa Women's Health Study

OBJECTIVES

This study sought to determine whether nutrient-rich whole grains reduce mortality risk.

METHODS

The study included 38,740 Iowa women, aged 55 to 69 years. A food frequency questionnaire was used to obtain data on grain intake.

RESULTS

Median whole grain intake quintiles ranged from a median of 0.2 to more than 3 servings per day. Women with higher intakes had healthier lifestyles and less baseline disease. The total death rate decreased in increasing quintiles, and the pattern repeated for cancer, cardiovascular disease, and other causes combined. Adjusted for lifestyle and baseline disease, the relative hazard rate ratio for total death was about 0.85 in daily consumers of whole grain. Findings persisted in strata of baseline healthy and diseased and were not explained by dietary fiber. Rates of total mortality, but not cardiovascular disease mortality, were higher among frequent consumers of refined grain.

CONCLUSIONS

Total mortality risk was inversely associated with whole grain intake and positively associated with refined grain intake. Refined grains contributed more than 20% of energy intake, and whole grains contributed 1%. Substitution of whole for refined grain may reduce chronic disease risk in the United States.

Reproducibility and validity of dietary patterns assessed with a food-frequency questionnaire

BACKGROUND

Recently, the analysis of dietary patterns has emerged as a possible approach to examining diet-disease relations.

OBJECTIVE

We examined the reproducibility and validity of dietary patterns defined by factor analysis using dietary data collected with a food-frequency questionnaire (FFQ).

DESIGN

We enrolled a subsample of men (n = 127) from the Health Professionals Follow-up Study in a diet-validation study in 1986. A 131-item FFQ was administered twice, 1 y apart, and two 1-wk diet records and blood samples were collected during this 1-y interval.

RESULTS

Using factor analysis, we identified 2 major eating patterns, which were qualitatively similar across the 2 FFQs and the diet records. The first factor, the prudent dietary pattern, was characterized by a high intake of vegetables, fruit, legumes, whole grains, and fish and other seafood, whereas the second factor, the Western pattern, was characterized by a high intake of processed meat, red meat, butter, high-fat dairy products, eggs, and refined grains. The reliability correlations for the factor scores between the 2 FFQs were 0.70 for the prudent pattern and 0.67 for the Western pattern. The correlations (corrected for week-to-week variation in diet records) between the 2 FFQs and diet records ranged from 0.45 to 0.74 for the 2 patterns. In addition, the correlations between the factor scores and nutrient intakes and plasma concentrations of biomarkers were in the expected direction.

CONCLUSIONS

These data indicate reasonable reproducibility and validity of the major dietary patterns defined by factor analysis with data from an FFQ.

Vitamin K intake and hip fractures in women: a prospective study

BACKGROUND

Vitamin K mediates the gamma-carboxylation of glutamyl residues on several bone proteins, notably osteocalcin. High serum concentrations of undercarboxylated osteocalcin and low serum concentrations of vitamin K are associated with lower bone mineral density and increased risk of hip fracture. However, data are limited on the effects of dietary vitamin K.

OBJECTIVE

We investigated the hypothesis that high intakes of vitamin K are associated with a lower risk of hip fracture in women.

DESIGN

We conducted a prospective analysis within the Nurses' Health Study cohort. Diet was assessed in 72327 women aged 38-63 y with a food-frequency questionnaire in 1984 (baseline). During the subsequent 10 y of follow-up, 270 hip fractures resulting from low or moderate trauma were reported.

RESULTS

Women in quintiles 2-5 of vitamin K intake had a significantly lower age-adjusted relative risk (RR: 0.70; 95% CI: 0.53, 0.93) of hip fracture than women in the lowest quintile (< 109 microg/d). Risk did not decrease between quintiles 2 and 5 and risk estimates were not altered when other risk factors for osteoporosis, including calcium and vitamin D intakes, were added to the models. Risk of hip fracture was also inversely associated with lettuce consumption (RR: 0.55; 95% CI: 0.40, 0.78) for one or more servings per day compared with one or fewer servings per week), the food that contributed the most to dietary vitamin K intakes.

CONCLUSIONS

Low intakes of vitamin K may increase the risk of hip fracture in women. The data support the suggestion for a reassessment of the vitamin K requirements that are based on bone health and blood coagulation.

Study of prediagnostic selenium level in toenails and the risk of advanced prostate cancer

BACKGROUND

In a recent randomized intervention trial, the risk of prostate cancer for men receiving a daily supplement of 200 microg selenium was one third of that for men receiving placebo. By use of a nested case-control design within a prospective study, i.e., the Health Professionals Follow-Up Study, we investigated the association between risk of prostate cancer and prediagnostic level of selenium in toenails, a measure of long-term selenium intake.

METHODS

In 1986, 51,529 male health professionals aged 40-75 years responded to a mailed questionnaire to form the prospective study. In 1987, 33,737 cohort members provided toenail clippings. In 1988, 1990, 1992, and 1994, follow-up questionnaires were mailed. From 1989 through 1994, 181 new cases of advanced prostate cancer were reported. Case and control subjects were matched by age, smoking status, and month of toenail return. Selenium levels were determined by neutron activation. All P values are two-sided.

RESULTS

The selenium level in toenails varied substantially among men, with quintile medians ranging from 0.66 to 1.14 microg/g for control subjects. When matched case-control data were analyzed, higher selenium levels were associated with a reduced risk of advanced prostate cancer (odds ratio [OR] for comparison of highest to lowest quintile = 0.49; 95% confidence interval [CI] = 0.25-0.96; P for trend = .11). After additionally controlling for family history of prostate cancer, body mass index, calcium intake, lycopene intake, saturated fat intake, vasectomy, and geographical region, the OR was 0.35 (95% CI = 0.16-0.78; P for trend = .03).

CONCLUSIONS

Our results support earlier findings that higher selenium intakes may reduce the risk of prostate cancer. Further prospective studies and randomized trials of this relationship should be conducted.

Possible explanations for the tooth loss and cardiovascular disease relationship

Several studies have shown relationships between periodontal disease and cardiovascular disease (CVD). A few studies have also shown that tooth loss may be associated with increased risk of coronary heart disease and stroke. We have reviewed the relevant literature to assess possible explanations for the reported associations between tooth loss and CVD. In particular, we considered whether the reported association between tooth loss and CVD could be explained by antecedent periodontal disease, antecedent caries, the extraction process, dietary changes following tooth loss, or confounding or bias from other sources. Since access to care and attitudes to health care may influence the decision to extract teeth, as well as cardiovascular disease risk, one needs to be cautious about confounding from behaviorally related factors. Available evidence suggests that further studies are needed to rule out that confounding is a possible explanation for the tooth loss and CVD relationship, that prior periodontal disease may not completely explain the tooth loss-CVD relationship, and that the role of diet needs to be further explored

A prospective study of dietary fiber types and symptomatic diverticular disease in men

To examine prospectively dietary fiber calculated from food composition values based on analytic techniques and specific dietary fiber types in relation to risk of diverticular disease, we analyzed data from a prospective cohort of 43,881 U.S. male health professionals 40-75 y of age at base line; subjects were free of diagnosed diverticular disease, colon or rectal polyps, ulcerative colitis and cancer. The insoluble component of fiber was inversely associated with risk of diverticular disease relative risk (RR) = 0. 63, 95% confidence interval (CI), 0.44-0.91, P for trend = 0.02, and this association was particularly strong for cellulose (RR = 0.52, 95% CI, 0.36-0.75, P for trend = 0.002). The association between diverticular disease and total dietary fiber intake calculated from the AOACstandards method was not appreciably different from results using the Southgate or Englyst method [for AOAC method, RR = 0.60, 95% CI, 0.41-0.87; for Southgate method, RR = 0.61, 95% CI, 0.42-0. 88; for Englyst method, RR = 0.60, 95% CI, 0.42-0.87, for the highest quintiles]. Our findings provide evidence for the hypothesis that a diet high in dietary fiber decreases the risk of diverticular disease, and this result was not sensitive to the use of different analytic techniques to define dietary fiber. Our findings suggest that the insoluble component of fiber was significantly associated with a decreased risk of diverticular disease, and this inverse association was particularly strong for cellulose.

Bone mineral density and dietary intake in patients with Crohn's disease

Individuals diagnosed with Crohn's disease are at an increased risk for developing low bone density. The exact cause of low bone mineral density in Crohn's disease patients has not been determined. The purpose of this study was to assess the incidence of low bone mineral density in premenopausal women with Crohn's disease and to determine the role diet plays in bone mineral density for this population. Bone mineral density of the lumbar spine (L2-L4), proximal femur, and forearm was measured in 51 female controls and 50 females with Crohn's disease using dual energy X-ray absorptiometry (Lunar DPXPlus, Madison, WI). Dietary intake for all Crohn's disease participants was analyzed using both 3-d dietary records and a food frequency questionnaire. When compared to healthy controls, bone mineral density values of Crohn's disease participants were decreased for all sites, particularly the spine (1.169 +/- 0.114, p = 0.054), Ward's area (0.831 +/- 0.128, p = 0.052), and the femoral neck (0.927 +/- 0.100, p = 0.01). Factors associated with lower bone density in Crohn's participants were weight, corticosteroid usage, length and age of diagnosis, history and length of resection, and dietary intakes of magnesium, copper, magnesium, vitamin K, and zinc. The results of this study indicate for the first time that diet plays a role in the development of low bone density in premenopausal women with Crohn's disease.

Association of apo E polymorphism with plasma lipid levels in a multiethnic elderly population

Apolipoprotein E polymorphisms are important determinants of blood lipid levels and have been associated with longevity and atherosclerosis. However, information is limited on the effects of apo E variation on the lipids of nonwhite and elderly individuals. We tested the hypothesis that apo E polymorphisms are associated with plasma lipid levels in an elderly, multiethnic population. Cross-sectional data from 1068 noninstitutionalized individuals from northern Manhattan over the age of 64 who were not on a lipid-lowering diet or drug were analyzed. The ethnic distribution was 34% African-Americans, 47% Hispanics, and 19% non-Hispanic Caucasians. In the entire group, the most prevalent apo E allele was epsilon 3 (76%), followed by epsilon 4 (16%) and epsilon 2 (8%); epsilon 4 was more prevalent in African-Americans (21%) than in non-Hispanic Caucasians (12%) or Hispanics (14%). The apo epsilon 2 allele was the most important correlate of plasma lipids, but association varied across ethnoracial groups. After being adjusted for age, sex, obesity, diabetes mellitus, and alcohol intake, LDL cholesterol levels declined with each apo epsilon 2 allele by 8.8 mg/dL in Hispanics and by 25.6 and 18.1 mg/dL in non-Hispanic Caucasians and African-Americans, respectively (P < .001). No significant independent effect was noted for any apo E genotype on HDL cholesterol. Overall, there was a reduction in the total/HDL cholesterol ratio, per apo epsilon 2 allele, of 0.82 in non-Hispanic Caucasians and 0.43 and 0.48 in African-American and Hispanic individuals, respectively (P < .05). In a multivariate model, apo epsilon 4 did not significantly affect plasma lipid levels. Plasma triglyceride levels were inversely correlated with the number of apo epsilon 4 alleles (175, 159, and 143 mg/dL with 0, 1, and 2 alleles, respectively; P =.002), and this effect increased with age. Thus, in an elderly, multiethnic population, apolipoprotein E polymorphisms were important determinants of blood lipids, with differing effects depending on ethnicity. The presence of apo epsilon 2 was associated with lower LDL cholesterol levels and total/HDL cholesterol ratio, although apo epsilon genotype did not influence HDL cholesterol levels. Prospective studies are needed to test whether apo epsilon 2 protects against incident cardiovascular disease in the elderly.

Food habits of young and middle-aged women living outside the capital cities of Australia

Young (18-22 years) and middle-aged (45-49 years) women living in urban and rural areas of New South Wales completed a brief food frequency questionnaire as part of a wider health survey. Urban women in both age groups consumed meat less frequently than women in rural areas, and women in the less populated rural areas were more likely to eat green and yellow vegetables and least likely to eat dried beans. There were few other geographic differences in food habits. Middle-aged women consumed reduced-fat milk, fruit, vegetables, fish, biscuits and cakes significantly more frequently, and rice, pasta, full-cream milk, fried food and take-away food less frequently than younger women. Smokers in both age groups consumed fresh fruit, vegetables and breakfast cereals significantly less frequently than non-smokers, and women with low levels of habitual physical activity consumed fresh fruit and cereals less frequently than more active women. The findings suggest that strategies aimed at changing eating behaviours should be age-group-specific and targeted specifically to smokers and less active women.

Mouthwash use and dentures in relation to oral epithelial dysplasia

This case-control study investigated the potential association between oral epithelial dysplasia (OED) and both mouthwash and denture use. Incident OED cases aged 20-79 years were identified through two oral pathology laboratories. Controls were pair-matched (1:1) to cases on age (+/- 5 years), gender, appointment date and surgeon. A telephone interview was used to obtain exposure information. Odds ratios (ORs) and 95% confidence intervals (95% CIs) were generated using conditional logistic regression. Based upon 127 case-control pairs and after adjusting for smoking, drinking, education and either denture or mouthwash use, the OR for OED and regular mouthwash use (1+ uses/week for 6+ months) was 0.8 (95% CI, 0.4-1.5) while the OR for OED and wearing a denture was 0.7 (95% CI, 0.4-1.3). There were no clear trends of increased OED risk with increased mouthwash use or years of denture wearing. Our findings suggest that neither mouthwash nor denture use are associated positively with OED risk.

Calcium intake and the incidence of forearm and hip fractures among men

High calcium intakes are thought to be associated with strong bones and lower risk of fractures. However, findings from epidemiologic studies have not been consistent. In addition, the vast majority of such studies were conducted among women, leading to a relative lack of data concerning men. The objective of this study therefore was to investigate the relation between adult calcium intake and risk of fractures among men in the Health Professionals Follow-up Study (HPFS). During 331,234 person-years of follow-up over an 8-y period, 201 forearm and 56 hip fractures due to low or moderate trauma were reported among 43,063 men 40-75 y of age in 1986 when they first completed a questionnaire about diet and lifestyle factors. After controlling for age, smoking status, body mass index (BMI), physical activity, alcohol consumption and total energy intake, the relative risk (RR) of forearm fractures for men in the highest quintile of calcium intake (from foods plus supplements) compared with those in the lowest quintile was 0.98 [95% confidence interval (CI) = 0.59-1.61; P for trend = 0.78]; for hip fractures, the comparable RR was 1.19 (95% CI = 0.42-3.35; P for trend = 0.58). Relative risks for consuming >2.5 glasses (600 mL) of milk per day compared with one (240 mL) or fewer per week were 1.06 (95% CI = 0.69-1.62; P for trend = 0.82) for forearm fractures and 0.97 (95% CI = 0.39-2.42; P for trend = 0.56) for hip fractures. In conclusion, these results do not support a relation between calcium intake and the incidence of forearm or hip fractures in men.

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.

The impact of edentulousness on food and nutrient intake

The authors collected dietary intake data about the food and nutrient intake of 49,501 male health professionals. Edentulous participants consumed fewer vegetables, less fiber and carotene, and more cholesterol, saturated fat and calories than participants with 25 or more teeth. These factors could increase the risks of cancer and cardiovascular disease. Mean differences in intake ranged from 2 to 13 percent, independent of age, smoking, exercise and profession. Longitudinal analyses suggest that tooth loss may lead to detrimental changes in diet.

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.

Urinary oxalate excretion increases with body size and decreases with increasing dietary calcium intake among healthy adults

Increasing dietary calcium intake decreases urinary oxalate excretion by increasing intestinal precipitation of dietary oxalate as calcium oxalate. This mechanism was speculated to account for the decreased prospective incidence of kidney stones as estimated dietary calcium intake, adjusted for caloric intake, increased among men in a recent large epidemiological study. To further assess the relationship between estimated diet calcium and urinary oxalate, we studied 94 health adults, 50 women and 44 men, ages 20 to 70 years with weights ranging form 47 to 104 kg while they ate their customary diets. Each subject completed a semiquantitative food frequency questionnaire and collected three 24-hour urines preserved with HCl. The urines were collected accurately as judged by a mean intrasubject CV for creatinine excretion of 9.8% and direct relations between urinary creatinine excretion and body wt (r = 0.62; P < 0.0001), or predicted urine creatinine content for sex, age and weight using the Cockcroft and Gault formulas (r = 0.76; P < 0.0001). Estimated diet calcium intake ranged from 6.8 to 68 mmol/day (272 to 2720 mg/day) and averaged 29.5 mmol/day (1180 mg/day). Individual mean urinary oxalate excretion ranged from 0.079 go 0.332 mmol/day (7 to 29 mg/day) and averaged 0.198 mmol/day (17 mg/day). Among all subjects, daily oxalate excretion was directly related to creatinine excretion as an estimate of lean body mass (r = 0.61; P < 0.0001). Thus, oxalate excretion among men averaged 0.228 +/- 0.051 SD mmol/day, a value significantly higher than the average among women of 0.173 +/- 0.045 mmol/day (P < 0.001). Daily urine oxalate excretion/creatinine decreased curvilinearly as estimated dietary Ca intake increased (r = -0.30; P = 0.0035) and as the ratio of estimated dietary calcium to dietary oxalate increased (r = -0.39; P = 0.0001). We conclude that body size is the major determinant of urinary oxalate excretion among healthy adults, presumably reflecting variations in endogenous oxalate synthesis with lean body mass. Increasing estimated diet calcium intake, especially up to the range of 15 to 20 mmol/day (600 to 800 mg/day) has an additional effect to decrease during oxalate excretion, presumably by limiting intestinal absorption of dietary oxalate.

Reproducibility of a semiquantitative food frequency questionnaire to assess the intake of fats and cholesterol in The Netherlands

The reproducibility of a 104 item semiquantitative food frequency questionnaire to estimate the intake of energy, fat, fatty acids and cholesterol was assessed in a group of 93 men and women in the Netherlands. The questionnaire was administered by trained interviewers. Subjects were asked to recall the consumption of 104 items during the past month. A second interview was conducted 8 weeks later. The mean difference in nutrient intake between the two assessments was very small, with a maximum of 5% for cholesterol intake, but the variance of individual differences was considerable. Pearson correlation coefficients between two assessments 8 weeks apart ranged from 0.71 for polyunsaturated fatty acids intake (when expressed as percentage of energy intake) up to 0.91 for energy intake. The reproducibility was found to be similar in males and females. Reproducibility was assessed for separate food items as well as for 20 food groups. Items consumed were often highly reproducible and rarely had a poor reproducibility. This food frequency questionnaire is considered to be a suitable tool to estimate and monitor the intake of fat, fatty acids and cholesterol in the Netherlands.

A prospective study of alcohol, smoking, caffeine, and the risk of symptomatic diverticular disease in men

The relationship between smoking, caffeine, and alcohol intake and the risk of symptomatic diverticular disease has not been investigated directly. We examined these associations in a prospective cohort of 47,678 US men, 40 to 75 years old. During 4 years of follow-up (1988 to 1992), we documented 382 newly diagnosed cases of symptomatic diverticular disease. After adjustments for age, physical activity, and energy-adjusted intake of dietary fiber and total fat, alcohol intake (comparing those who drink > 30 g of alcohol/d to nondrinkers) was only weakly and nonsignificantly associated with risk of symptomatic diverticular disease (relative risk (RR) = 1.36; 95 percent confidence interval (CI), 0.94 to 1.97; P for trend = 0.37). We observed no association between caffeine, specific caffeinated beverages, and decaffeinated coffee and the risk of symptomatic diverticular disease. Current smoking was not appreciably associated with risk of symptomatic diverticular disease compared to nonsmokers (RR = 1.25; 95 percent CI, 0.75 to 2.09) after adjustment for age, physical activity, and energy-adjusted intake of dietary fiber and total fat. In a subset analysis restricted to men who had undergone sigmoidoscopy or colonoscopy, a modest positive association was seen between smoking and risk of symptomatic diverticular disease. These results suggest that smoking, caffeine, and alcohol intake are not associated with any substantially increased risk of symptomatic diverticular disease.

Dietary intake of marine n-3 fatty acids, fish intake, and the risk of coronary disease among men

BACKGROUND

It has been hypothesized that a diet containing n-3 fatty acids from fish reduces the risk of coronary heart disease, but few large epidemiologic studies have examined this question.

METHODS

In 1986, 44,895 male health professionals, 40 to 75 years of age, who were free of known cardiovascular disease completed detailed and validated dietary questionnaires as part of the Health Professionals Follow-up Study. During six years of follow-up, we documented 1543 coronary events in this group: 264 deaths from coronary disease, 547 nonfatal myocardial infarctions, and 732 coronary-artery bypass or angioplasty procedures.

RESULTS

After controlling for age and several coronary risk factors, we observed no significant associations between dietary intake of n-3 fatty acids or fish intake and the risk of coronary disease. For men in the top fifth of the group in terms of intake of n-3 fatty acids (median, 0.58 g per day), the multivariate relative risk of coronary heart disease was 1.12 (95 percent confidence interval, 0.96 to 1.31), as compared with the men in the bottom fifth (median, 0.07 g per day). For men who consumed six or more servings of fish per week, as compared with those who consumed one serving per month or less, the multivariate relative risk of coronary disease was 1.14 (95 percent confidence interval, 0.86 to 1.51). The risk of death due to coronary disease among men who ate any amount of fish, as compared with those who ate no fish, was 0.74 (95 percent confidence interval, 0.44 to 1.23), but the risk did not decrease as fish consumption increased.

CONCLUSIONS

Although the possibility of residual confounding by unmeasured factors cannot be entirely excluded, these data suggest that increasing fish intake from one to two servings per week to five to six servings per week does not substantially reduce the risk of coronary heart disease among men who are initially free of cardiovascular disease.