Development of a culturally sensitive food frequency questionnaire for use in the Southern Community Cohort Study

A food frequency questionnaire (FFQ) was developed to assess long-term habitual dietary intake in a cohort of approximately 100,000 40 to 79 year-old men and women living in the Southeastern US. Using the NHANES-III database for the southem region for specific race and sex subgroups, a list of 262 food categories was developed, coded and reduced to 102 food items that could discriminate between racial groups and account for large portions of cancer-relevant nutrients. The developed FFQ was tested in a pilot study in three southeastern states involving 239 African Americans and Whites, aged 56.9 +/- 12.2 years. The frequencies of consumption and portion sizes of the 102 foods were determined and intakes of various nutrients were estimated and compared with the NHANES-III data. African Americans reported higher total energy intakes and higher consumption of macronutrients and several micronutrients, compared to Whites. Estimated nutrient indices were higher among pilot study than among NHANES-III participants, although adjustment for total energy essentially eliminated the differences. Analysis of the frequency distribution of individual foods shows that the questionnaire includes commonly eaten foods that can discriminate between African Americans and Whites. The FFQ is currently being calibrated within the cohort study population.

Singapore Chinese Health Study: development, validation, and calibration of the quantitative food frequency questionnaire

This report describes the development and validation/calibration of a structured food frequency questionnaire for use in a large-scale cohort study of diet and health in Chinese men and women aged 45-74 years in Singapore, the development of a food composition database for analysis of the dietary data, and the results of the dietary validation/calibration study. The present calibration study comparing estimated intakes from 24-hour recalls with those from the food frequency questionnaires revealed correlations of 0.24-0.79 for energy and nutrients among the Singapore Chinese, which are comparable to the correlation coefficients reported in calibration studies of other populations. We also report on the nutritional profiles of Singapore Chinese on the basis of results of 1,880 24-hour dietary recalls conducted on 1,022 (425 men and 597 women) cohort subjects. Comparisons with age-adjusted corresponding values for US whites and blacks show distinct differences in dietary intakes between the Singapore and US populations. The Singapore cohort will be followed prospectively to identify dietary associations with cancer risk and other health outcomes.

Combined effects of well-done red meat, smoking, and rapid N-acetyltransferase 2 and CYP1A2 phenotypes in increasing colorectal cancer risk

Heterocyclic amines (HAAs) are suspected carcinogens that are formed in meat when it is cooked at high temperature for long durations. These compounds require metabolic activation by CYP1A2 and N-acetyltransferase (NAT) 2 or NAT1 before they can bind to DNA. It has been hypothesized that well-done meat increases the risk of colorectal cancer (CRC), especially in individuals with the rapid phenotype for CYP1A2 and NAT2. This association may be particularly strong in smokers because smoking is known to induce CYP1A2. We conducted a population-based case-control study on Oahu, Hawaii to specifically test this hypothesis. An in-person interview assessed the diet and preference for well-done red meat of 349 patients with CRC and 467 population controls. A urine collection after caffeine challenge and a blood collection were used to assess phenotype for CYP1A2 and NAT2 and genotype for NAT2 and NAT1, respectively. No statistically significant main effect association with CRC was found for red meat intake, preference for well-done red meat, the NAT2 rapid genotype, the CYP1A2 rapid phenotype or the NAT1*10 allele. However, in ever-smokers, preference for well-done red meat was associated with an 8.8-fold increased risk of CRC (95% confidence interval, 1.7-44.9) among subjects with the NAT2 and CYP1A2 rapid phenotypes, compared with smokers with low NAT2 and CYP1A2 activities who preferred their red meat rare or medium. No similar association was found in never-smokers, and there was no increased risk for well-done meat among smokers with a rapid phenotype for only one of these enzymes or for smokers with both rapid phenotypes who did not prefer their red meat well-done. These data provide additional support to the hypothesis that exposure to carcinogens (presumably HAAs) through consumption of well-done meat increases the risk of CRC, particularly in individuals who are genetically susceptible (as determined by a rapid phenotype for both NAT2 and CYP1A2) and suggest that smoking, by inducing CYP1A2, facilitates this effect.

Vegetables, fruits, legumes and prostate cancer: a multiethnic case-control study

The evidence for a protective effect of vegetables, fruits, and legumes against prostate cancer is weak and inconsistent. We examined the relationship of these food groups and their constituent foods to prostate cancer risk in a multicenter case-control study of African-American, white, Japanese, and Chinese men. Cases (n = 1619) with histologically confirmed prostate cancer were identified through the population-based tumor registries of Hawaii, San Francisco, and Los Angeles in the United States and British Columbia and Ontario in Canada. Controls (n = 1618) were frequency-matched to cases on ethnicity, age, and region of residence of the case, in a ratio of approximately 1:1. Dietary and other information was collected by in-person home interview; a blood sample was obtained from control subjects for prostate-specific antigen determination. Odds ratios (OR) were estimated using logistic regression, adjusting for age, geographic location, education, calories, and when indicated, ethnicity. Intake of legumes (whether total legumes, soyfoods specifically, or other legumes) was inversely related to prostate cancer (OR for highest relative to lowest quintile for total legumes = 0.62; P for trend = 0.0002); results were similar when restricted to prostate-specific antigen-normal controls or to advanced cases. Intakes of yellow-orange and cruciferous vegetables were also inversely related to prostate cancer, especially for advanced cases, among whom the highest quintile OR for yellow-orange vegetables = 0.67 (P for trend = 0.01) and the highest quintile OR for cruciferous vegetables = 0.61 (P for trend = 0.006). Intake of tomatoes and of fruits was not related to risk. Findings were generally consistent across ethnic groups. These results suggest that legumes (not limited to soy products) and certain categories of vegetables may protect against prostate cancer.

Calibration of the dietary questionnaire for a multiethnic cohort in Hawaii and Los Angeles

The performance of the dietary questionnaire used in a multiethnic cohort study in Hawaii and Los Angeles was assessed in a calibration substudy that compared diet reported from the questionnaire with three 24-hour dietary recalls. For the calibration substudy, subjects from each of eight subgroups defined by sex and ethnic group (African-American, Japanese-American, Latino, and White) were chosen randomly from among the cohort members, and each participant's previous day's diet was assessed by telephone recall on three occasions over approximately 2 months. After completing the three 24-hour recalls, each calibration subject was sent a second questionnaire; 1,606 persons completed three recalls and a second questionnaire (127 to 267 per ethnic-sex group). This report describes correlation coefficients and calibration slopes for the relation between the 24-hour recalls and second questionnaire values for a selected set of macro- and micronutrients, as absolute intakes, nutrient densities, and calorie-adjusted nutrients. In all subgroups, estimates of the correlation between the questionnaire and 24-hour recalls were greater after energy adjustment (average correlations ranged from 0.57-0.74 for nutrient densities and from 0.55-0.74 for calorie-adjusted nutrients) than when absolute nutrient values were used (average range 0.26-0.57). For absolute nutrient intakes, the correlations were greatest for Whites, somewhat lower for Japanese-Americans and Latinos, and lowest for African-Americans. After energy adjustment, the difference between subgroups were diminished, and the correlations were generally highly satisfactory.

A multiethnic cohort in Hawaii and Los Angeles: baseline characteristics

The authors describe the design and implementation of a large multiethnic cohort established to study diet and cancer in the United States. They detail the source of the subjects, sample size, questionnaire development, pilot work, and approaches to future analyses. The cohort consists of 215,251 adult men and women (age 45-75 years at baseline) living in Hawaii and in California (primarily Los Angeles County) with the following ethnic distribution: African-American (16.3%), Latino (22.0%), Japanese-American (26.4%), Native Hawaiian (6.5%), White (22.9%), and other ancestry (5.8%). From 1993 to 1996, participants entered the cohort by completing a 26-page, self-administered mail questionnaire that elicited a quantitative food frequency history, along with demographic and other information. Response rates ranged from 20% in Latinos to 49% in Japanese-Americans. As expected, both within and among ethnic groups, the questionnaire data show substantial variations in dietary intakes (nutrients as well as foods) and in the distributions of non-dietary risk factors (including smoking, alcohol consumption, obesity, and physical activity). When compared with corresponding ethnic-specific cancer incidence rates, the findings provide tentative support for several current dietary hypotheses. As sufficient numbers of cancer cases are identified through surveillance of the cohort, dietary and other hypotheses will be tested in prospective analyses.

Intake of flavonoids and lung cancer

BACKGROUND

To investigate the possible relationship between intake of flavonoids-powerful dietary antioxidants that may also inhibit P450 enzymes-and lung cancer risk, we conducted a population-based, case-control study in Hawaii.

METHODS

An in-person interview assessed smoking history and usual intake of 242 food items for 582 patients with incident lung cancer and 582 age-, sex-, and ethnicity-matched control subjects. Subjects who donated a blood sample were genotyped for the P450 enzyme variant allele CYP1A1*2 by use of a polymerase chain reaction-based method. Logistic regression analysis was used to compute odds ratios (ORs) and 95% confidence intervals (CIs). All P values are two-sided.

RESULTS

After adjusting for smoking and intakes of saturated fat and beta-carotene, we found statistically significant inverse associations between lung cancer risk and the main food sources of the flavonoids quercetin (onions and apples) and naringin (white grapefruit). The lung cancer OR for the highest compared with the lowest quartile of intake was 0.5 (95% CI = 0.3-0.9) for onions (P for trend =.001) and 0.6 (95% CI = 0.4-1.0) for apples (P for trend =.03). The OR for the highest compared with the lowest tertile of intake for white grapefruit was 0.5 (95% CI = 0.2-0.9) (P for trend =.02). No association was found for important food sources of other flavonoids. Using published food-composition data for flavonoids, we found an inverse association between intake of quercetin and risk of lung cancer (P for trend =.07) that appears consistent with associations for its food sources. The effect of onions was particularly strong against squamous cell carcinoma (a cell type specifically associated with CYP1A1*2 in our study) and was modified by the CYP1A1 genotype, suggesting that CYP1A1 may play a role in this association.

CONCLUSION

If replicated, particularly in prospective studies, these findings would suggest that foods rich in certain flavonoids may protect against certain forms of lung cancer and that decreased bioactivation of carcinogens by inhibition of CYP1A1 should be explored as underlying mechanisms.

Isoflavone levels in soy foods consumed by multiethnic populations in Singapore and Hawaii

Concentrations and glucosidic conjugation patterns of isoflavones were determined in soy foods consumed by multiethnic populations in Singapore and Hawaii. Six raw and 11 cooked food groups traditionally consumed in Singapore and 8 food groups consumed in Hawaii were analyzed by reversed-phase high-pressure liquid chromatography with diode array detection. Mean total isoflavone levels varied between 35 and 7500 ppm, with the lowest values found in soy milk and burgers and the highest levels observed in soybean and its seeds and in supplements. Total isoflavone levels and conjugation patterns varied as a function of soybean variety, storage conditions, and food processing. A large contribution to the differences in total isoflavone content between food groups was due to the water content in foods and to leaching of polar analytes into the water phase during boiling. Soy protein drinks and traditional soy foods were found to possess very similar isoflavone amounts considering usual serving sizes.

Independent and joint effects of family history and lifestyle on colorectal cancer risk: implications for prevention

It has been suggested that, for a substantial proportion of "sporadic" colorectal cancers (CRCs), inheritance determines individual susceptibility and that lifestyle determines which susceptible individuals express cancer. Because the genetic basis of this inherited susceptibility remains undefined, we used family history of the disease as a proxy for a genetic predisposition to examine its interactions with a variety of lifestyle factors in a large population-based case-control study of CRC. The subjects were 698 male and 494 female Japanese, Caucasian, Filipino, Hawaiian, and Chinese patients diagnosed with CRC in Hawaii during 1987-1991 and 1192 population controls matched to cases on age, sex, and ethnicity. Fourteen percent of the cases and 6% of the controls reported a family history of CRC among parents or siblings. After adjusting for other covariates, significant interactions with family history were found for beef and ethanol intakes in males (P = 0.03). Relative to men without a family history and whose intake fell in the lower third, odds ratios (ORs) for CRC for men with a family history and in the upper tertile of intake were 10.8 [95% confidence interval (CI), 4.2-27.6] and 7.5 (CI, 3.1-18.2) for beef and ethanol, respectively. The corresponding ORs for men without a family history and in the upper tertile were 1.5 (CI, 1.0-2.3) and 1.4 (CI, 1.0-1.9), respectively. No interactions were detected in women. Using a summary measure of lifestyle, we found that family history was not associated with CRC among men who were at the lower-risk tertile for all of the lifestyle risk factors. In contrast, the OR for men with a family history and at the higher-risk tertile for all of the lifestyle variables was 11.7 (CI, 5.8-23.9). In the absence of a family history, this OR was 4.8 (CI, 3.2-7.2). These data suggest that family history increases the risk of sporadic CRC in men mainly through its interaction with lifestyle exposures, primarily a high beef and ethanol intake, and are consistent with recent reports of effect modifications of dietary associations by metabolic genes. Computation of population attributable risks also suggested that a comprehensive reduction in exposure to lifestyle risk factors--and more specifically to ethanol and beef for individuals with a familial predisposition for the disease--may have a large beneficial effect on CRC incidence.

Urinary total isothiocyanate (ITC) in a population-based sample of middle-aged and older Chinese in Singapore: relationship with dietary total ITC and glutathione S-transferase M1/T1/P1 genotypes

Isothiocyanates (ITCs), degradation products of glucosinolates (which occur naturally in a variety of cruciferous vegetables), have been shown to exhibit chemopreventive activity. These compounds are metabolized in vivo to form the corresponding dithiocarbamates, which are the major urinary metabolites of ITCs, by a pathway involving the glutathione S-transferase (GST) class of enzymes. Using a newly developed assay that measures total ITC (primarily ITC conjugates) in urine, we examined the relationships between cruciferous vegetable intake (obtained from a food frequency/portion size questionnaire administered in person); dietary total ITC level; GSTM1, GSTT1, and GSTP1 genotypes; and levels of total ITC in spot urine samples collected from 246 Singapore Chinese (111 men and 135 women), ages 45-74 years, who are participants of the Singapore Cohort Study on diet and cancer. Consumption level of cruciferous vegetables was high in study subjects (mean consumption = 345 times per year, mean daily intake = 40.6 g), which was >3 times the comparable level of intake in the United States. Mean daily intake of total ITC among study subjects was 9.1 micromol, and there was a 2.5-fold difference between the 25th and 75th percentile values. Seventy-three % of study subjects tested positive for ITC in urine, and there was a 4-fold difference between the 25th and 75th percentile values among the positive subjects. There was a highly significant positive association between dietary intake and urinary excretion levels of total ITC (two-sided P = 0.0003) that was stronger than the association between overall cruciferous vegetable intake and urinary ITC level, which also was statistically significant (P = 0.0004). There was no difference in urinary ITC levels between GSTM1-null and GSTM1-positive study subjects (P = 0.61) or between subjects with differing GSTP1 genotypes (P = 0.77), but urinary excretion of ITC was significantly higher among GSTT1-positive subjects, relative to GSTT1-null subjects (P = 0.006). The strength of the association between GSTT1 genotype and urinary total ITC level was highly dependent on the level of cruciferous vegetable consumption (or dietary ITC level) in study subjects. Among subjects in the lowest tertile of cruciferous vegetable intake, there was little evidence of an association between GSTT1 genotype and urinary total ITC level (P = 0.67). In contrast, there was a strong and statistically significant association between GSTT1 genotype and urinary total ITC among subjects in the highest tertile of cruciferous vegetable intake (P = 0.02), whereas those in the middle tertile of cruciferous vegetable consumption exhibited an association of intermediate strength (P = 0.04). These results suggest the presence of GSTT1 inducers in cruciferous vegetables.

Cruciferous vegetables in relation to renal cell carcinoma

Little is known about the possible role of diet in the development of renal cell carcinoma (RCC). A population-based case-control study was conducted in non-Asians of Los Angeles; it included 1,204 RCC patients and an equal number of neighborhood controls matched to the index cases by sex, date of birth (within 5 years) and ethnicity. Information on intake frequencies of food groups rich in vitamins A and C, various carotenoids and nitrosamines or their precursors was collected through in-person, structured interviews. After adjustment for non-dietary risk factors including level of education, obesity, history of hypertension, cigarette smoking and regular use of analgesics and amphetamines, there were strong inverse associations between cruciferous and dark green vegetable intakes and RCC risk (both p values for linear trend < 0.001). In terms of nutrients, there were significant inverse associations of RCC risk with consumption of a variety of carotenoids including alpha-carotene (p < 0.001), beta-carotene (p = 0.004), beta-cryptoxanthin (p = 0.01) and lutein (p = 0.005). However, after adjustment for these nutrients, we still observed a significant residual effect of cruciferous vegetables, suggesting that other substances present in these vegetables may be responsible, at least partially, for the observed reduction in risk of RCC. Dietary nitrosamines and their precursors were not related to RCC risk.

The association of plasma micronutrients with the risk of cervical dysplasia in Hawaii

Limited data from hematological studies suggest that certain nutrients, including carotenoids, tocopherols, and vitamin C, may protect against malignant change in cervical tissue. Recognizing that human papillomavirus (HPV) infection induces most neoplastic transformation of cervical tissue, the authors conducted a case-control study to examine the association of plasma micronutrient concentrations with the risk of cervical dysplasia after careful adjustment for HPV infection, using a sensitive and reliable HPV detection method. The sample included 147 multiethnic women, between 18 and 65 years of age, with biopsy-confirmed squamous intraepithelial lesions (SILs) of the cervix and 191 clinic controls identified between 1992 and 1996. Cases were identified through cytology and pathology logs in three clinics on Oahu, Hawaii. Controls were selected randomly from admission logs of the participating clinics. In-person interviews were conducted in the subjects' homes, and a fasting blood sample was drawn to measure plasma levels of lutein, lycopene, cryptoxanthin, total carotene, retinol, tocopherol, ascorbic acid, and cholesterol. The presence and type of HPV was determined in exfoliated cell samples using PCR dot blot hybridization. Mean plasma lycopene, total cryptoxanthin, and alpha-cryptoxanthin levels were lower among cases than controls. We found an inverse dose-response of alpha-cryptoxanthin, total tocopherol, and alpha-tocopherol to the odds ratios for cervical SIL after adjustment for HPV and other confounders. The odds ratio among women in the highest compared with the lowest quartile was 0.3 (95% confidence interval, 0.1-0.7) for alpha-cryptoxanthin and 0.3 (95% confidence interval, 0.1-0.8) for alpha-tocopherol. Negative trends in the odds ratios were suggested for other carotenoids and vitamin C, but these were weak, and confidence intervals were wide. Our results support existing evidence that high plasma levels of antioxidants may reduce the risk of cervical SILs independent of HPV infection. These findings are significant because diet is potentially modifiable, and nutrition education and dietary intervention might be targeted at specific high-risk groups.

Isoflavonoid levels in spot urine are associated with frequency of dietary soy intake in a population-based sample of middle-aged and older Chinese in Singapore

Soy products contain high amounts of isoflavonoids, which have been shown to exhibit possible cancer-protective properties. Chinese populations in Asia, in particular, have a high level of soy intake and a relatively low risk of hormone-dependent cancers. In this study, we assessed the distributions of dietary soy isoflavonoids (daidzein, genistein, and glycitein) and urinary soy isoflavonoids and their metabolites (daidzein, genistein, glycitein, equol, and O-desmethylangolensin) among 147 Singapore Chinese (76 men and 71 women) ages 45-74 years, who are participants of the Singapore Cohort Study on diet and cancer. Urinary values were measured from spot samples collected 10-20 months following recruitment, when usual dietary habits were assessed by a structured food frequency/portion size questionnaire administered in person. Dietary levels of daidzein and genistein were comparable within individuals and about seven times higher than the level of dietary glycitein. All three dietary isoflavonoids showed an approximately 3.5-fold difference between the 25th and 75th percentile values. Similarly, daidzein was the most abundant and glycitein the least abundant of the five isoflavonoid compounds in urine. There was a 4.9-fold difference between the 25th and 75th percentile values for the sum of the five urinary isoflavonoids. Among study subjects, there were statistically significant, dose-dependent associations between frequency of overall soy intake and levels of urinary daidzein (two-sided P = 0.03) and sum of urinary daidzein, genistein, and glycitein (two-sided P = 0.04). In contrast, there were no associations between frequency of overall soy intake and levels of the two daidzein metabolites (equol and O-desmethylangolensin) in urine (two-sided P = 0.85 and 0.34, respectively). We suggest that within the range of exposures experienced by Singapore Chinese, urinary level of daidzein or the sum of daidzein, genistein, and glycitein obtained from a spot sample can serve as a biomarker of current soy consumption in epidemiological studies of diet-disease associations.

Telephone vs face-to-face interviews for quantitative food frequency assessment

OBJECTIVE

To develop and test a quantitative food frequency method for administration by telephone.

DESIGN

A comparison study of telephone and face-to-face interviews was conducted among a representative sample of the five major ethnic groups in Oahu, Hawaii. Two interviews were administered 4 to 6 months apart by trained interviewers using identical questionnaires and color photographs of food items showing three different portion sizes. The order of the interviewing methods was randomly assigned. The questionnaire included 115 food items selected to estimate 80% or more of usual dietary intakes. Frequencies and quantities of each item consumed during the past year were obtained.

SUBJECTS/SETTING

Subjects were recruited from the Health Surveillance Program of the Hawaii State Department of Health and consisted of 167 men and 158 women, aged 45 to 74 years, who provided a telephone number. Eighty percent of the face-to-face interviews were conducted in the subjects' homes and 20% were conducted at the workplace or the University of Hawaii Cancer Research Center, if requested.

STATISTICAL ANALYSES

The paired t test was used to compare the mean daily intakes obtained by the telephone and face-to-face methods. Agreement was measured by the intraclass correlation coefficient (ICC), Pearson correlation coefficient and weighted kappa statistic.

RESULTS

The means of energy and each nutrient were slightly higher in the first interview than the second, regardless of the interviewing method. Because of close correspondence among all 3 statistical measures of agreement, only the ICCs are reported. The ICCs ranged from .61 for protein and vitamin A to .69 for dietary cholesterol among men, and from .61 for vitamin C to .74 for saturated fat among women. Agreement was not significantly affected by age, gender, ethnicity, order of interview, or educational level.

APPLICATIONS

Telephone interviews to obtain quantitative food frequencies are cost-efficient methods for estimating usual dietary intakes among persons in widely scattered geographic areas. Photographs of the foods in 3 portion sizes mailed in advance help the respondents estimate amounts eaten.

Diet, body size, physical activity, and the risk of endometrial cancer

Endometrial cancer is associated with increased weight and body size, diabetes, and other conditions that may result from an excess in calories or lack of physical activity. Although a few studies have explored the effect of dietary constituents on the risk of endometrial cancer, the nature of the joint association of these constituents and obesity, energy intake, or energy expenditure with risk is unknown. A population-based case-control study was conducted in Hawaii to examine the association of diet, body size, and physical activity with the risk of endometrial cancer. Subjects included 332 histologically confirmed, primary endometrial cancer cases and 511 controls identified between 1985 and 1993. Cases and controls were residents of Oahu, Hawaii who were between 18 and 84 years of age and were from one of the following ethnic groups: Japanese, Caucasian, Native Hawaiian, Filipino, and Chinese. Cases were identified through the Hawaii Tumor Registry and matched to the controls on age (+/-2.5 years) and ethnicity. In-person interviews, conducted in the subjects' homes, included dietary, reproductive, menstrual, and medical histories and use of exogenous hormones, physical activity, and other lifestyle variables. Weight, girth, and skinfold measurements were taken at the time of the interview. We found a strong dose-response relation of increased body size to the development of endometrial cancer after adjustment for energy intake. The odds ratio (OR) for endometrial cancer among women in the highest quartile of body mass index (BMI; kg/m2) was more than four times that among women in the lowest quartile. Waist, hip, midarm, and wrist girths were positively associated with the estimated risk of endometrial cancer after adjustment for total calories and other nondietary risk factors, although the trends in the ORs were attenuated after adjustment for BMI. Physically active women had a modest reduction in their risk of disease compared with inactive women. Cases consumed a greater percentage of their calories from fat and a lower percentage of their calories from carbohydrates than did controls. Adjustment for BMI reduced the ORs for the highest compared with the lowest quartile of fat calorie intake from 2.0 (95% confidence interval, 1.3-3.2) to 1.6 (95% confidence interval, 1.0-2.6), suggesting that part of the association is explained by obesity. There was a differential effect of fat on endometrial cancer according to BMI. For all components of fat, the associations with endometrial cancer were either minimal or absent among leaner women (i.e., those with BMI below the median), whereas, among more obese women, two-fold differences in risk were observed between women above and below the median of fat intake. Foods that are high in fat and cholesterol, such as red meat, margarine, and eggs, were positively associated with endometrial cancer, whereas cereals, legumes, vegetables, and fruits, particularly those high in lutein, were inversely associated. These findings suggest that women who avoid being overweight and who consume a diet low in plant and animal fats and high in complex carbohydrates are at a reduced risk of endometrial cancer.

Dietary fiber and colorectal cancer risk

We conducted a population-based case-control study among different ethnic groups in Hawaii to evaluate the role of various types and components of fiber, as well as micronutrients and foods of plant origin, on the risk of colorectal cancer. We administered personal interviews to 698 male and 494 female Japanese, Caucasian, Filipino, Hawaiian, and Chinese cases diagnosed during 1987-1991 with adenocarcinoma of the colon or rectum and to 1,192 population controls matched to cases by age, sex, and ethnicity. We used conditional logistic regression to estimate odds ratios, adjusted for caloric intake and other covariates. We found a strong, dose-dependent, inverse association in both sexes with fiber intake measured as crude fiber, dietary fiber, or nonstarch polysaccharides. We found inverse associations of similar magnitude for the soluble and insoluble fiber fractions and for cellulose and noncellulosic polysaccharides. This protective effect of fiber was limited to fiber from vegetable sources, with an odds ratio of 0.6 (95% confidence interval = 0.4-0.9) and 0.5 (95% confidence interval = 0.3-0.7) for the highest compared with the lowest quartile of intake for men and women, respectively. We found associations of the same magnitude for soluble and insoluble vegetable fiber, but no clear association with fiber from fruits or cereals. This pattern was consistent between sexes, across segments of the large bowel (right colon, left colon, and rectum), and among most ethnic groups. The effect of vegetable fiber may be independent of the effects of other phytochemicals, since the effect estimates remained unchanged after further adjustment for other nutrients. Intakes of carotenoids, light green vegetables, yellow-orange vegetables, broccoli, corn, carrots, bananas, garlic, and legumes (including soy products) were inversely associated with risk, even after adjustment for vegetable fiber. The data support a protective role of fiber from vegetables against colorectal cancer, which appears independent of its water solubility property and of the effects of other phytochemicals. The data also indicate that certain vegetables and fruits may be protective against this disease through mechanisms other than their fiber content.

Associations of sedentary lifestyle, obesity, smoking, alcohol use, and diabetes with the risk of colorectal cancer

Variation in colorectal cancer rates between countries and within ethnic groups upon migration and/or Westernization suggests a role for some aspects of Western lifestyle in the etiology of this disease. We conducted a population-based case-control study in the multiethnic population of Hawaii to evaluate associations between colorectal cancer and a number of characteristics of the Western lifestyle (high caloric intake, physical inactivity, obesity, smoking, and drinking) and some of their associated diseases. We interviewed in person 698 male and 494 female United States-born or immigrant Japanese, Caucasian, Filipino, Hawaiian, and Chinese patients diagnosed in 1987-1991 with colorectal cancer and 1192 population controls matched on age, sex, and ethnicity. Conditional logistic regression was used to estimate odds ratios adjusting for dietary and nondietary risk factors. Place of birth and duration of residence in the United States were unrelated to colorectal cancer risk. Energy intake (independent of the calorie source) and body mass index were directly associated with risk, and lifetime recreational physical activity was inversely associated with risk. The associations with these factors were independent of each other, additive (on the logistic scale) and stronger in men. When individuals were cross-categorized in relation to the medians of these variables, those with the higher energy intake and body mass index and lower physical activity were at the highest risk (for males, OR, 3.0; 95% confidence interval, 1.8-5.0, and for females, OR, 1.7; 95% confidence interval, 1.0-3.2). Smoking in the distant, as well as recent, past and alcohol use were directly associated with colorectal cancer in both sexes. Individuals with a history of diabetes or frequent constipation were at increased risk for this cancer, whereas past diagnosis of hypercholesterolemia was inversely associated with risk. The findings were consistent between sexes, among ethnic groups, and across stages at diagnosis, making bias an unlikely explanation. These results confirm the data from immigrant studies that suggest that the increase in colorectal cancer risk experienced by Asian immigrants to the United States occurred in the first generation because we found no difference in risk between the immigrants themselves and subsequent generations. They also agree with recent findings that suggest that high energy intake, large body mass, and physical inactivity independently increase risk of this disease and that a nutritional imbalance, similar to the one involved in diabetes, may lead to colorectal cancer.

Association of soy and fiber consumption with the risk of endometrial cancer

The authors conducted a case-control study among the multi-ethnic population of Hawaii to examine the role of dietary soy, fiber, and related foods and nutrients on the risk of endometrial cancer. Endometrial cancer cases (n = 332) diagnosed between 1985 and 1993 were identified from the five main ethnic groups in the state (Japanese, Caucasian, Native Hawaiian, Filipino, and Chinese) through the rapid-reporting system of the Hawaii Tumor Registry. Population controls (n = 511) were selected randomly from lists of female Oahu residents and matched to cases on age (+/-2.5 years) and ethnicity. All subjects were interviewed using a diet history questionnaire that included over 250 food items. Non-dietary risk factors for endometrial cancer included nulliparity, never using oral contraceptives, fertility drug use, use of unopposed estrogens, a history of diabetes mellitus or hypertension, and a high Quetelet's index (kg/cm2). Energy intake from fat, but not from other sources, was positively associated with the risk of endometrial cancer. The authors also found a positive, monotonic relation of fat intake with the odds ratios for endometrial cancer after adjustment for energy intake. The consumption of fiber, but not starch, was inversely related to risk after adjustment for energy intake and other confounders. Similar inverse gradients in the odds ratios were obtained for crude fiber, non-starch polysaccharide, and dietary fiber. Sources of fiber, including cereal and vegetable and fruit fiber, were associated with a 29-46% reduction in risk for women in the highest quartiles of consumption. Vitamin A and possibly vitamin C, but not vitamin E, were also inversely associated with endometrial cancer, although trends were not strong. High consumption of soy products and other legumes was associated with a decreased risk of endometrial cancer (p for trend = 0.01; odds ratio = 0.46, 95% confidence interval 0.26-0.83) for the highest compared with the lowest quartile of soy intake. Similar reductions in risk were found for increased consumption of other sources of phytoestrogens such as whole grains, vegetables, fruits, and seaweeds. Ethnic-specific analyses were generally consistent with these results. The observed dietary associations appeared to be largely independent of other risk factors, although the effects of soy and legumes on risk were limited to women who were never pregnant or who had never used unopposed estrogens. These data suggest that plant-based diets low in calories from fat, high in fiber, and rich in legumes (especially soybeans), whole grain foods, vegetables, and fruits reduce the risk of endometrial cancer. These dietary associations may explain in part the reduced rates of uterine cancer in Asian countries compared with those in the United States.

A case-control study of diet and colorectal cancer in a multiethnic population in Hawaii (United States): lipids and foods of animal origin

Temporal trend and migrant studies have indicated that the etiology of colorectal cancer is predominantly environmental and, hence, modifiable. Animal fat intake has been frequently, but inconsistently, associated with the risk of this disease. We conducted a population-based case-control study in Hawaii (United States) among ethnic groups at different risks of the disease to evaluate the role of dietary lipids and foods of animal origin on the risk of colorectal cancer. We interviewed 698 male and 494 female Japanese, Caucasian (White), Filipino, Hawaiian, and Chinese patients diagnosed during 1987-91 with pathologically confirmed adenocarcinoma of the colon or rectum, and 1,192 population controls matched to cases on age, gender and ethnicity. Odds ratios (OR), adjusted for caloric intake and other dietary and non-dietary risk factors, were estimated using conditional logistic regression. Intakes of total fat, saturated fat (S) and polyunsaturated fat (P) were not related to the risk of colorectal cancer. However, an inverse association was found for the P/S ratio, with ORs of 0.6 in both genders (95 percent confidence interval [CI] = 0.4-1.0 for males; CI = 0.3-0.9 for females) for the highest compared with the lowest quartile (P < 0.05 for trend). Intakes of red meat and processed meat were associated with the risk of cancer in the right colon and rectum, respectively, in men only. Fat-trimmed red meat and fish intakes were not related to risk. Chicken eaten without skin was associated inversely with risk in both genders. The strongest association was found for eggs, with an OR of 2.7 (CI = 1.7-4.0) and 2.3 (CI = 1.4-3.7) for the highest compared with the lowest quartile of intake in men and women, respectively (P < 0.001 for trend). This association was dose-dependent, not explained by known confounders or other dietary variables, and was very consistent between genders, among ethnic groups, and across all segments of the large bowel. These data suggest that the ratio of polyunsaturated to saturated fat may be a better indicator of colorectal cancer risk than the absolute amount of specific fats in the diet. They also suggest that eggs and, possibly, untrimmed red meat and processed meat increase, and chicken eaten without skin decreases, colorectal cancer risk.

Risk factors for lower urinary tract cancer: the role of total fluid consumption, nitrites and nitrosamines, and selected foods

Many cases of lower urinary tract cancer cannot be attributed to the known risk factors of cigarette smoking and certain occupational chemical exposures. Data from a case-control study conducted on Oahu, Hawaii, from 1979 to 1986 were used to determine the role of several additional exposures in the etiology of lower urinary tract cancer, such as total fluid intake and dietary nitrites and nitrosamines, as well as intake of selected foods. A total of 195 male and 66 female lower urinary tract cancer cases of Caucasian and Japanese ancestry were matched to two population-based controls on age, sex, and race. Total fluid intake, and tap water in particular, showed a strong inverse dose-response relationship to cancer risk among women (odds ratio (OR) for highest to lowest quartile of total fluid intake = 0.3; trend P < 0.01).. This association was stronger in smokers than nonsmokers. Although fluid intake showed no overall association among men, the findings among smokers were suggestive of an effect similar to that found in women. Intake of dietary nitrites and nitrosamines was positively associated with risk in Japanese men (for nitrites, OR for highest to lowest tertile = 2.0; trend P = 0.05; for nitrosamines, OR for highest to lowest tertile = 3.0; trend P = 0.01). Consumption of processed meats, in particular bacon, sausage, and ham, was also significantly associated with increased risk in Japanese men. No other ethnic sex group exhibited this association with processed meats, although an effect was suggested for sausage in Japanese females and for bacon in Caucasian females. Unfortunately, it was not possible to determine whether these elevated risks were due to the fat, nitrite, or sodium content of the processed meats, or to the fact that they may have been fried.

An ecological study of diet and lung cancer in the South Pacific

Incidence rates of lung cancer have been markedly lower for Fiji than for other South Pacific countries, despite similar rates of smoking. We conducted population-based surveys in several island nations of the South Pacific (Cook Islands, Fiji, Tahiti and New Caledonia) and used data from Caucasian, Japanese, Hawaiian, Filipino and Chinese controls in a case-control study of lung cancer in Hawaii to investigate the role of diet in explaining differences in lung cancer incidence among 20 ethnic-sex groups. In a stepwise linear regression of lung cancer rates on smoking, diet and other variables, smoking, as expected, explained the majority (61%) of the variability in incidence. However, several dietary components also explained significant portions of the variance. Lutein intake explained 14% and vitamin E intake, cholesterol intake and height explained 5-7% each of the remaining variance in incidence. Associations with lutein and vitamin E were inverse, whereas those with cholesterol and height were direct. Dietary beta-carotene intake was not associated with lung cancer incidence. These ecological data provide evidence for a protective effect of lutein against lung cancer. A protective effect of dietary vitamin E and a risk-enhancing effect of dietary cholesterol are also suggested.

Seasonal variations in plasma micronutrients and antioxidants

Plasma samples were collected at monthly intervals for a period of 1 year from a group of healthy nonsmoking men and women (n = 21) living in Honolulu, HI. Analysis of plasma cholesterol and triglyceride levels showed marked seasonal variations, with higher mean levels in winter months and lower values in the summer. Cholesterol and triglycerides were highly and inversely correlated with plasma levels of the provitamin A carotenoids. Mean beta- and alpha-carotene levels were highest in late summer and fall. Plasma retinol levels were significantly lower in the summer and higher in the winter. Variations (either between individuals or seasonally) in plasma retinol were unrelated to plasma provitamin A carotenoid levels. Plasma levels of alpha-tocopherol, gamma-tocopherol, beta-cryptoxanthin, and lutein were also higher in the winter and lower in the summer. Significant seasonal correlations, both positive and negative, with environmental variables, such as temperature, solar UV radiation, and rainfall, are noted for many of these plasma micronutrients. The number of samples required to accurately characterize long-term plasma levels for an individual generally ranged from 1 to 4. However, plasma retinol levels exhibited the highest ratio of intra- to interindividual variability, suggesting the need for multiple sampling (> 8 samples) for this micronutrient. Some of this variability for retinol was associated with seasonal changes. Assessment by a diet history of food and supplement intake of micronutrients and phytochemicals for 1 year showed good agreement with 1-year mean plasma levels for most carotenoids, vitamin C, and alpha-tocopherol. Retinol, gamma-tocopherol, cholesterol, and triglyceride levels in plasma were unrelated to estimates of dietary intake.(ABSTRACT TRUNCATED AT 250 WORDS)

A pilot study on the use of plasma carotenoids and ascorbic acid as markers of compliance to a high fruit and vegetable dietary intervention

The authors examined the feasibility of using plasma carotenoids and ascorbic acid as markers of compliance for dietary intervention trials aimed at increasing the quantity and variety of the fruit and vegetable intake of free-living individuals. Nineteen former cancer patients who had been successfully treated for a stage I or II squamous cell carcinoma of the mouth, pharynx, larynx, or lung were recruited. Subjects served as their own controls. However, in order to detect any seasonal trends, 4 individuals among the 19 were randomized to a nonintervention group. Subjects in the intervention group were counseled by dietitians with the goal of increasing their intake of fruits and vegetables to eight servings/day (1 serving each of dark green vegetables, yellow-orange vegetables, tomato products, and other vegetables; 3 servings of vitamin C-rich fruits; and 1 serving of other fruits). Subjects in the nonintervention group were advised to follow their usual diet. Three-day measured food records kept at base line and after 3 months of intervention, as well as unannounced 24-h dietary recalls, documented an increase in mean fruit and vegetable intake from 4.2 to 9.5 servings daily in the intervention group. A concomitant increase of 29% was observed in total plasma carotenoids (P = 0.02), with increases of 25% for plasma lycopene (P = 0.06), 31% for plasma lutein (P = 0.002), 39% for plasma beta-carotene (P = 0.01), and 57% for plasma alpha-carotene (P = 0.01). Mean plasma levels of ascorbic acid increased by 27% (P < 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Development and validation of dietary assessment methods for culturally diverse populations

Culturally diverse populations with variable dietary and disease patterns provide a unique opportunity for conducting epidemiologic studies to identify the role of diet in the etiology of chronic diseases. The dietary method for epidemiologic studies, such as cohort or case-control studies, should generally be a diet history (or quantitative food frequency) of selected food items consumed during a usual month. Knowledge of the eating patterns of each ethnic group in the study is needed to develop an appropriate questionnaire. The diet history may be validated by collecting multiple 24-h recalls or food records from representative samples of each ethnic group and comparing the mean dietary intakes with the values obtained from the diet history. Examples of studies of culturally diverse populations and the development and validation of the dietary methods are discussed.

Assessment of carotenoid intakes in humans

The availability of new food composition carotenoid values for fruits and vegetables increases our ability to test hypotheses concerning the role of antioxidant nutrients and cancer risk. To estimate the usual carotenoid intakes, a quantitative diet history covering a one-year period is recommended for epidemiologic studies on diet and cancer. The particular food items in the diet history questionnaire should be representative of the eating patterns of the study population, should contribute more than 85% of the individual carotenoid intakes, and should distinguish between the high and low consumers of particular carotenoids.

Role of nutrition in women's health: diet and breast cancer

Breast cancer, which is the most frequently diagnosed malignancy in women today, remains a major threat. As the incidence increases at 1% to 2% annually, breast cancer strikes about 182,000 US women each year and kills 46,000. Known risk factors, such as age, early menarche, late age of first pregnancy, late menopause, family history, and obesity, account for only 40% to 50% of breast cancer cases. Consequently, the etiology of 50% to 60% of cases is unknown. Perhaps no area is more controversial than the link between nutrition and cancer, in particular the association between dietary fat and the development of breast cancer. Findings from animal research and international correlation studies indicate a causal relationship between fat intake and breast cancer. A recent analysis of 12 case-control studies among postmenopausal women also showed a 50% increase in relative risk among women ingesting high intakes of saturated fat. Furthermore, analyses of postmenopausal women in Hawaii estimated that 10% to 20% of breast cancer could be prevented by notably decreasing saturated fat intake. Nevertheless, epidemiologic studies (case-control and cohort) give conflicting results regarding the causal relationship between fat intake and breast cancer. The fact that these studies have failed to consistently show a significant association between dietary fat and breast cancer risk may be attributable to the difficulty of collecting accurate dietary information and other methodologic limitations. Findings are also limited by the lack of data on the influence of a high-fat diet during childhood.(ABSTRACT TRUNCATED AT 250 WORDS)

Intake of specific carotenoids and lung cancer risk

Using newly available food composition data for carotenoids, the authors reanalyzed a population-based case-control study of diet and lung cancer conducted in Hawaii in 1983-1985 (L. Le Marchand et al., J. Natl. Cancer Inst., 81: 1158-1164, 1989). The analysis included interviews with 230 men and 102 women with lung cancer and 597 men and 268 women as controls, frequency-matched to the patients by age and sex. A previously validated quantitative diet history assessed the usual intake of foods rich in carotenoids. After adjusting for smoking and other covariates, no association was found with lung cancer risk for dietary lycopene or beta-cryptoxanthin intake, whereas dose-dependent inverse associations of comparable magnitude were found for dietary beta-carotene, alpha-carotene, and lutein. When subjects were cross-classified by their joint intakes of the latter three carotenoids, those who had a high intake (> median) for all three had the lowest risk for lung cancer. In a similar two-way interaction analysis, the previously reported inverse association of lung cancer with vegetable consumption in these data was found to be stronger than that with intake of these three carotenoids. Consistent with our previous findings, this analysis provides further evidence for a protective effect of certain carotenoids against lung cancer and for the greater protection afforded by consuming a variety of vegetables compared to only foods rich in a particular carotenoid.

A prospective study of alcohol, diet, and other lifestyle factors in relation to obstructive uropathy

The association of alcohol, diet, and other lifestyle factors with obstructive uropathy was investigated in a cohort of 6581 Japanese-American men, examined and interviewed from 1971 to 1975 in Hawaii. By studying this migrant population with its heterogeneous exposures, it increases the probabilities of identifying potential risk factors of this prostate disorder. After 17 years of follow-up, 846 incident cases of surgically treated obstructive uropathy were diagnosed with benign prostatic hyperplasia. Total alcohol intake was inversely associated with obstructive uropathy (P < 0.0001). The relative risk was 0.64 (95% confidence interval: 0.52-0.78) for men drinking at least 25 ounces of alcohol per month compared with nondrinkers. Among the 4 sources of alcohol, a significant inverse association was present for beer, wine, and sake, but not for spirits. Buddhist (vs. other) religion, rural (vs. urban) birthplace, and the presence of prostate symptoms were each associated with increased risk of obstructive uropathy, but no association was found with education, number of marriages, or cigarette smoking. Increased beef intake was weakly related to an increased risk (P = 0.047), while no association was found with the consumption of 32 other food items in the study.

Comparison of long-term dietary recall between cancer cases and noncases

A quantitative history of current dietary intake based on 83 food items was administered by interview to a representative sample of 4,809 subjects in Hawaii in 1977-1979. In 1983-1987, this history was readministered to the 131 original respondents who had subsequently developed cancer, as well as 413 randomly selected subjects who remained cancer free. A surrogate was interviewed when the original subject was unavailable. The repeat interview elicited information about diet at the time of the original interview. The authors found that recall values for macronutrients were consistently higher than original levels for both cases and noncases, which may be due in part to a modification in the administration of the repeat questionnaire. Although there were no marked differences overall between cases and noncases in the ability to recall past diet, differences between the two groups were seen in certain subsets of the sample. In the subgroup with the longest recall interval (8-10 years), cases were not able to recall their diets as well as noncases. Also, the difference between original and recall values was larger for cases with colorectal cancer and all cases diagnosed with distant stage disease, compared with noncases. This was not true for cases of breast and prostate cancer and those with localized or regional disease. The following variables were found to have no significant effect on recall for cases or noncases: sex, age, education, and type of respondent (surrogate or subject). Of the five major ethnic groups included in the study, Japanese had the best recall of their past diets, while respondents reporting a diet change between the interviews had poorer recall than did those who reported no change. These results suggest that differential misclassification in dietary case-control studies may pose a significant problem in certain instances, but that these studies can yield meaningful results with certain constraints on the study population.

High-fat foods and the risk of lung cancer

We conducted a population-based case-control study of the association of dietary cholesterol and fat with lung cancer between 1983 and 1985 on Oahu, Hawaii. The study population included 226 men and 100 women with lung cancer, and 597 male and 268 female community controls matched for age (+/- 5 years) and sex. There was a positive dose-response relation between the consumption of processed meats (luncheon meats, bacon, sausage), dairy foods (whole milk, regular ice cream), eggs, and particular desserts (fruit pies, custard/cream pies) and the risk of lung cancer in men. We also found a positive trend in the risk of lung cancer in women with increasing intake of some processed meats (bacon, Spam) and desserts (cakes, custard/cream pies). The dose-response relation tended to be stronger among men who were heavy smokers and who were diagnosed with squamous cell cancer of the lung. A positive trend in risk was found for nitrite intake in men and dimethylnitrosamine intake in men and women. These data indicate that smokers with a high intake of foods rich in fat and animal protein or who have a preference for cured meats are at increased risk of lung cancer.

The diet of Alaska Native adults: 1987-1988

Although in the past, rates of heart disease, cancer, and diabetes were lower in Alaska Natives than in US whites, these diseases are now increasing. The rate of iron-deficiency anemia for Alaska Natives continues to be higher than that in the general population. To understand the role of diet in these chronic diseases, seasonal dietary intakes of 351 Alaska Native adults from 11 communities were assessed during 1987-1988. Alaska Natives consumed more energy (19%), protein (39%), fat (21%), carbohydrate (13%), iron (25%), vitamin A (53%), and vitamin C (31%), but less calcium (19%) than did the general US adult population [National Health and Nutrition Examination Survey II (NHANES II)]; Alaska Natives consumed six times more fish but less fruits and vegetables. Results suggest that energy and protein intakes decreased in the last 30 y but the proportion of energy from fat (37%) remained unchanged. High fish consumption and large seasonal dietary variations persisted, which may protect against chronic diseases. However, excess energy and fat and low calcium, fruit, and vegetable intakes may be contributing to recent increases in chronic diseases. Dietary guidelines are proposed.

Dietary factors in lung cancer prognosis

A hypothesis-generating analysis of the role of diet on survival was conducted among a sample of 463 men and 212 women with histologically-confirmed lung cancer. Interview information was obtained from two population-based case-control studies of lung cancer conducted on the Island of Oahu, Hawaii, between 1979 and 1985. The interview consisted of a quantitative dietary history to assess the usual intake of foods 1 year prior to diagnosis, a complete tobacco history, and other demographic and lifestyle information. Records from the Hawaii Tumor Registry were reviewed for data on stage, histology, and follow-up status of these patients. A food group analysis showed a significant reduction in the risk of death with increasing consumption of all vegetables combined among women (P for trend = 0.03), but not among men. The covariate-adjusted median survival times for women from the highest to the lowest quartiles of vegetable intake were 33, 21, 15, and 18 months, respectively. The results also suggested an association of fruit intake and survival among women (P for trend = 0.02), although a similar effect was not found among men. Increased consumption of certain foods, such as tomatoes and oranges among men, and broccoli and, perhaps, tomatoes among women, appeared to improve survival. This exploratory analysis provides mixed indications that certain components of vegetables and fruits may prolong survival in lung cancer patients.

Attributable risk of breast, prostate, and lung cancer in Hawaii due to saturated fat

The dietary data from case-control studies of breast, prostate, and lung cancer in Hawaii revealed that saturated fat was a risk factor for these malignancies. The dietary intakes from the three studies were used to calculate the attributable risk (AR) due to saturated fat. For all ethnic groups combined, the ARs for the highest quartiles of intake were 14.9 percent for female breast cancer, 13.0 percent for prostate cancer, and 23.1 percent for male lung cancer. Our results suggested that a reduction of saturated fat to the lowest quartiles of intake could result in a 10 to 20 percent decrease in risk for these three cancers in Hawaii. We also examined the ethnic-specific risks associated with saturated fat consumption among the Japanese and the Caucasians in the three studies. The ARs for the highest quartiles of intake were notably higher among the Caucasians than the Japanese, primarily due to the difference in their dietary patterns. Although the calculated AR due to saturated fat was higher among the Caucasians than among the Japanese, all persons in the population would derive considerable benefit by reducing their intake of this nutrient.

Relationship between dietary, serum, and tissue levels of carotenoids

A study was undertaken to assess the utility of the buccal scrape technique for measuring tissue levels of carotenoids in short-term intervention trials and epidemiologic studies. In 14 healthy volunteers a good correlation was found between serum beta-carotene levels and recent dietary intake of beta-carotene as estimated from measured food records. Supplementation with 30 mg/day of beta-carotene for 1 week resulted in a sixfold increase in average serum levels, while serum lycopene concentrations remained constant. Presupplementation levels of beta-carotene and lycopene in the buccal mucosa cells were not correlated with dietary intakes or with serum levels. After supplementation, levels of both carotenoids were found to increase in buccal cells, however, most of this increase was found to be an artifact due to repeated sampling. After correcting for this artifact, beta-carotene was found to increase less than twofold in tissue after supplementation.

Dietary factors in cancer of the lower urinary tract

This dietary study was based on 195 male and 66 female cases of lower urinary tract cancer, identified in Hawaii between 1977 and 1986. Each case was matched for sex, age, and ethnic group (Caucasian or Japanese) to 2 population-based controls. There was a decrease in risk with increasing levels of consumption of vitamin C in women (p = 0.03) and dark green vegetables in men (p = 0.02). When examined by quartile, the odds ratios for the highest quartile of intake compared to the lowest quartile were 0.4 for women and 0.6 for men, respectively. Although dark green vegetables are a source of carotenoids, the intake of total carotenoids, retinol and total vitamin A was weakly and inconsistently related to risk in both sexes. Among women only, there was also an inverse association with the consumption of regular ground coffee (p = 0.02) but not with other types of coffee. Finally, there were no statistically significant or consistent differences between cases and controls in the intake of artificial sweeteners and tea.

The effect of dietary fat on breast cancer survival among Caucasian and japanese women in Hawaii

182 Japanese and 161 Caucasian breast cancer patients participated in an epidemiologic case-control study from 1975-1980. They were subsequently followed until the end of 1987 to determine their survival status. Among the Japanese, patients with regional or distant disease had a relative risk (RR) of death of 13.0 (95% Confidence Interval (CI), 4.3-39.1) compared to those with in situ or localized disease, and obese patients had a RR of death of 3.5 (95% CI, 1.3-10.0) compared to non-obese subjects. Among the Caucasians, patients with advanced disease had a RR of death of 4.3 (95% CI, 1.8-10.5) compared to those with in situ or localized disease, and patients with a high fat intake had a RR of 3.2 (95% CI, 1.2-8.6) compared to subjects with a low fat intake. Menopausal status (pre- or postmenopausal) and replacement estrogen use were not related to survival from breast cancer in either ethnic group. When Japanese and Caucasian patients were compared with each other, there was no significant difference in survival between them.

Validation of a quantitative diet history method in Hawaii

The validity of a quantitative diet history method was evaluated among 262 men and women from the five major ethnic groups of Hawaii (Japanese, Caucasian, Chinese, Filipino, and Hawaiian) in 1984-1987. The reference data included four 1-week food records obtained at approximately 3-month intervals. The diet history was administered 6 months after the fourth week of food records and included 47 foods that were major sources of protein, fat, cholesterol, vitamins A and C, and beta-carotene. Photographs showing three portion sizes were utilized for quantifying intakes in the food records and the diet history. Generally, among all ethnic-sex groups, intakes from the diet history were greater than those from the record sets, particularly for the vitamins. Agreement was measured by the intraclass correlation coefficient (rl) and the weighted kappa statistic (kappa w), and consistency was measured by Spearman's rank correlation (rho). For the total group, the rl's ranged from 0.48 for vitamin A to 0.61 for cholesterol. The kappa w's were generally lower than the rl's, whereas the rho's were higher, ranging from 0.52 for vitamin C to 0.64 for cholesterol. Agreement among the ethnic-sex groups varied, with the Chinese females and the Japanese males having the higher rl's, and the Hawaiian males and females having the lowest values. The results provide evidence that the quantitative diet history gives reasonably accurate estimates of the usual dietary intakes among the major ethnic groups of Hawaii.

Vegetable and fruit consumption in relation to prostate cancer risk in Hawaii: a reevaluation of the effect of dietary beta-carotene

This is a further analysis of a case-control study of 452 prostate cancer cases and 899 population controls that was conducted in 1970-1983 among the multiethnic population of Hawaii. Because a previous analysis had shown a positive association with intake of beta-carotene, a nutrient presently being tested for chemoprevention, the authors reexamined the data for consistency among the main food sources of beta-carotene. Vegetables and fruits containing other phytochemicals suspected to be cancer inhibitors were also examined. With the exception of papaya, which was positively associated with risk among men aged 70 years and older, consumption of other yellow-orange fruits and vegetables, tomatoes, dark green vegetables, and cruciferous vegetables was not associated with prostate cancer risk. These results suggest that: 1) the positive association with beta-carotene intake among older men that the authors previously reported was essentially due to the greater papaya consumption of cases compared with controls; and 2) intake of beta-carotene, lycopene, lutein, indoles, phenols, or other phytochemicals is not associated with prostate cancer risk.

Dietary patterns of female nonsmokers with and without exposure to environmental tobacco smoke

The relationship of passive smoking to diet was examined in 82 female nonsmokers who provided a quantitative diet history in 1986. Exposure to environmental tobacco smoke (ETS) was assessed by urinary cotinine measurement. Mean values for each dietary variable, adjusted for age, ethnicity, education, and last week's ethanol intake, were compared among unexposed women and women with low or high ETS exposure. Linear relationships with amount of ETS exposure were also sought. Intakes of beta-carotene and cholesterol were found to be inversely related to ETS exposure. Since these nutrients have been associated with lung cancer risk, they are potential confounders of the passive-smoking/lung-cancer relationship. Although we estimate the confounding effect of these dietary factors to be modest, they should be measured carefully in future studies of this relationship.

A case-cohort study of diet and stomach cancer

In this case-cohort study, from 1965 to 1968, 8006 Hawaiian men of Japanese ancestry were interviewed with a 24-h dietary recall questionnaire. After a follow-up period of 18 years, 111 stomach cancer incident cases were identified. Dietary data from these patients and from 361 cancer-free men were analyzed for intake of selected foods, food groups, and nutrients. We found that the consumption of all types of vegetables was protective against stomach cancer. Specifically, subjects in the highest group of vegetable consumption (greater than or equal to 80 g/day) had a relative risk of 0.6 (95% confidence interval, 0.3-0.9) in comparison with nonconsumers. This statistically significant inverse trend persisted after adjustment for age at examination and cigarette-smoking status. Similar but weaker protective effects from consumption of green and cruciferous vegetables were also observed. In addition, an inverse association between stomach cancer risk and intake of fruits was noted (P = 0.05), but this inverse trend was weakened after the effect of cigarette smoking was taken into account. There were no other dietary factors significantly associated with the risk of gastric cancer.

An epidemiologic study of thyroid cancer in Hawaii

A population-based case-control interview study was designed to test the hypothesis that dietary iodine or the consumption of goitrogenic vegetables increases the risk of thyroid cancer. A total of 191 histologically confirmed cases (64 percent female) and 441 matched controls from five ethnic groups in Hawaii were available for analysis. Among women, intake of seafood (especially shellfish), harm ha (a fermented fish sauce), and dietary iodine were associated with an increased risk of cancer, whereas consumption of goitrogenic (primarily cruciferous) vegetables was associated with a decreased risk. Non-dietary risk factors included miscarriage (especially at first pregnancy), use of fertility drugs, family history of thyroid disease, obesity, and work as a farm laborer. The odds ratio for the combined effect of a high iodine intake and a first-pregnancy miscarriage was 4.8 (95 percent confidence interval [CI] = 1.2-19.2); and for high iodine intake and use of fertility drugs 7.3 (95 percent CI = 1.5-34.5). Among men, positive associations were found for obesity, work as a farm laborer, and a past history of benign thyroid disease. Although this study identified several dietary and non-dietary risk factors for thyroid cancer, it could not fully explain the exceptionally high incidence rates among Filipino women in Hawaii.

Reproducibility of a diet history in older men in Hawaii

A diet history method was tested for reproducibility among 106 older men from the five major ethnic groups (Japanese, Caucasian, Hawaiian, Filipino, and Chinese) of Hawaii. The questionnaire, administered by trained interviewers, was designed to estimate the dietary intakes of total and saturated fat, cholesterol, vitamin A, beta-carotene, vitamin C, and zinc. Subjects were asked to recall their usual frequencies and amounts of consumption during a usual month of more than 100 food items, along with the intake of seasonal foods with a high vitamin A content. A second interview was conducted 1-14 months later to obtain a diet history covering the same time period as the first interview. The same questionnaire was utilized in both interviews. The effects of ethnicity, age, and recall interval (period between the diet reference date and initial interview) on the reproducibility of nutrient intakes were examined. The intraclass correlation coefficient (rI) and the weighted kappa statistic (Kw) were used to assess agreement. The overall levels of reproducibility were relatively good. Neither ethnicity, age, nor length of recall period had a major effect on reproducibility. The data suggested that this diet history method is an appropriate instrument for estimating the usual dietary intakes of a healthy heterogeneous group of older men in Hawaii.

Development of a diet history questionnaire for studies of older persons

This paper describes the criteria of a simplified diet history method and the procedures for developing a dietary questionnaire for studies of older persons. Suggestions are included on selecting food items representative of the population's dietary patterns, designing objective methods to estimate quantitative and frequency intakes of food items, and collecting information on other dietary practices. Potential problems in dietary surveys among older persons are discussed, along with their prevention or alleviation.

Vegetable consumption and lung cancer risk: a population-based case-control study in Hawaii

We conducted a population-based study of diet and lung cancer among the multiethnic population of Hawaii in 1983-1985. We completed interviews for 230 men and 102 women with lung cancer and 597 men and 268 women controls, frequency-matched to the patients by age and sex. A quantitative dietary history assessed the usual intake of foods rich in vitamins A and C and carotenoids. A clear dose-dependent negative association was demonstrated between dietary beta-carotene and lung cancer risk in both sexes. After adjusting for smoking and other covariates, the men in the lowest quartile of beta-carotene intake had an odds ratio of 1.9 (95% confidence interval, 1.1-3.2) compared to those in the highest quartile of intake. The corresponding odds ratio for women was 2.7 (95% confidence interval, 1.2-6.1). No clear association was found for retinol, vitamin C, folic acid, iron, dietary fiber, or fruits. All vegetables, dark green vegetables, cruciferous vegetables, and tomatoes showed stronger inverse associations with risk than beta-carotene. This observation suggests that other constituents of vegetables, such as lutein, lycopene, and indoles, and others, may also protect against lung cancer in humans.

Diet and colorectal cancer with special reference to fiber intake

In this nested case-control study, 8,006 American Japanese men were examined and interviewed with a dietary questionnaire from 1965 to 1968. After a follow-up period of over 16 years, 102 colon and 60 rectal cancer incident cases were identified. Dietary data from these patients and from 361 cancer-free controls were analyzed for intake of dietary fiber (DF), vitamins, minerals, macronutrients, and selected food groups. We found a significant (p = 0.042) negative association of DF and colon cancer risk among low fat intake men (less than 61 g/d). In this subgroup, the men consuming less than 7.5 g/d of DF had an adjusted relative risk (RR) for colon cancer of 2.28 (95% CI 0.93-5.60), compared to those consuming greater than or equal to 14.8 g/d of DF. We also observed (among the complete group of subjects) a significant (p = 0.011) negative association between vitamin C intake and the risk of colon cancer. Men in the lowest quintile of vitamin C intake (less than 37 mg/d) had an adjusted colon cancer RR of 1.87 (95% CI 1.03-3.37), compared to men in the highest quintile (greater than or equal to 160 mg/d). We view these dietary associations with colon cancer risk with caution. There were no other significant associations of dietary variables with colon cancer risk. Also, there were no significant associations between intake levels of DF, micronutrients, or food groups and rectal cancer risk.

Relationship of alcohol consumption to diet: a population-based study in Hawaii

The relationship of alcohol use to diet was examined in 2272 male and 2337 female adults aged 45 y and older who provided a quantitative diet history during 1977-1979. Mean values for each dietary variable, adjusted for smoking, ethnicity, income, and education, were compared in each sex between abstainers and drinkers and by tertile of ethanol intake. Linear relationships with extent of drinking were also sought. Drinkers were found to be less obese than abstainers. Consumption of carbohydrate, vitamins, calcium, fruits, fruit juices, and raw vegetables was greater among abstainers whereas consumption of fat (particularly polyunsaturated fatty acids), cholesterol, zinc, meat, pickled vegetables, and dried fish was greater among drinkers. Because validations of dietary questionnaires have shown that alcohol consumption is more accurately recalled than food intake, the possibility of a residual confounding effect for these dietary variables should be considered in epidemiologic studies of alcohol and health.

The effect of dietary cholesterol and fat on the risk of lung cancer in Hawaii

A population-based case-control study of the association between dietary lipids and lung cancer was carried out in Hawaii between March 1983 and October 1985. The sample included 226 men and 100 women with lung cancer and 597 male and 268 female controls, frequency-matched to the cases on sex and five-year age group. Personal interviews were conducted in the home by trained interviewers using a quantitative diet history method. The items in the questionnaire were chosen to provide an estimate of 85% or more of the intakes of dietary cholesterol and fat for individuals in each of the five ethnic groups included in the study. The results showed a significant positive association of dietary cholesterol and the risk of lung cancer in men, but not in women. The odds ratio for the risk of lung cancer among men in the highest compared with the lowest quartile of cholesterol intake was 2.2 (95% confidence interval 1.3-3.8). Although there was a significant trend (p less than 0.05), the effect of cholesterol suggested a threshold rather than a continuous gradient. The association of cholesterol and lung cancer was consistent for three of four ethnic groups analyzed separately. These results confirmed earlier findings by these investigators. The effect of cholesterol on the development of lung cancer was restricted to current cigarette smokers who smoked tobacco heavily and to squamous and small cell histologic types of lung cancer. Similar results were found for total, saturated, and, to some extent, unsaturated dietary fat, but because of the high correlation between fat and cholesterol (r = 0.76 for total fat and cholesterol), it was not possible to separate the effects of these nutrients.

Diet and prostatic cancer: a case-control study in Hawaii

A total of 452 cases of prostatic cancer identified through the population-based Hawaii Tumor Registry during the period 1977-1983 and 899 age-matched population controls were interviewed on the island of Oahu from 1981 to 1983. All interviews of the subjects, who comprised five different ethnic groups, were conducted in the home by use of a quantitative dietary history method. Usual weekly intake of fat, zinc, and vitamins A and C, including supplements, was determined for each subject. Among men 70 years or older, but not among younger men, and mean weekly consumption of saturated fat, carotenes, and zinc, adjusted for age and ethnicity, was greater for cases than for controls. In a multiple logistic regression analysis, the odds ratio for the highest quartile of fat intake among the older men was 1.7 (95% confidence interval (CI) 1.0-2.8). The corresponding odds ratios were 1.6 (95% CI 1.0-2.5) for carotenes, 1.4 (95% CI 0.9-2.3) for total vitamin C, and 1.7 (95% CI 1.1-2.7) for total zinc. There were significant linear trends in the odds ratios for saturated fat and zinc, but no synergistic interactions among the nutrients. The findings suggest that several different components of the diet may contribute independently to the risk of prostatic cancer in elderly men.

Vitamin A and prostate cancer in elderly men: enhancement of risk

Vitamin A intake was assessed from dietary histories on 452 men with prostate cancer and 899 population controls in Hawaii during the period 1977-1983. In the group of men less than 70 years of age, there were no significant associations of this nutrient with risk for prostate cancer. In the men greater than or equal to 70 years, however, risk increased directly with the amount of vitamin A consumed (relative risk of 2.0 for the highest relative to the lowest intake quartile, and a significant linear trend, P less than 0.01). The findings were similar for the various components of vitamin A but were somewhat stronger for total carotenes than for total retinol. These results were generally consistent across the five ethnic groups and were not affected by statistical adjustment for dietary fat. Possible mechanisms for this risk enhancement by vitamin A in elderly men are proposed.