Cancer in the Elderly: A Prospective Study Among Hawaiian Japanese Men

In the United States, little has been done to compare the cancer risk of elderly subjects, aged 65 and older, with that of younger subjects. Although the elderly constitute only 12% of the population, they are diagnosed with more than 50% of the cancers. The study consisted of 7, 783 Japanese-American men, born from 1900-1919 and examined from 1965-1968. During 154, 000 person-years of follow-up, 1, 478 incident cases of cancer were identified. The incidence rate of cancer was high among the elderly (142.7 per 10, 000 person-years) compared with younger subjects (48.2 per 10, 000 person-years), yielding a significant (p < 0.05) rate ratio of 3.0. Of the site-specific cancers, prostate cancer showed the highest rate raio of 7.0, followed by oral, stomach, lung, and colon cancer. In addition, the five-year age-specific rates for stomach and colon cancer rose directly with age. A similar pattern was also observed for lung and prostate cancer in men before age 80, but the rates declined thereafter. The findings from this study suggest that the reduction in risk for cancers of the prostate, oral cavity, stomach, lung, and colon must be viewed as a major goal for improving the public health in the elderly population.

Feasibility of collecting buccal cell DNA by mail in a cohort study

This study assessed the feasibility of obtaining buccal cell DNA by mail from participants in a large, community-based cohort study in Hawaii. Mouthwash collection kits were sent to a total of 355 randomly selected Japanese, Caucasian, and Hawaiian cohort members. Subjects were requested to swish 10 ml of mouthwash in their mouth for 60 s and expel it into a collection cup, which they mailed back to our laboratory. Half of the subjects were requested to collect a second sample. After up to two mailings and two reminder phone calls, two-thirds of the subjects returned a sample. The participation rate was lower for Hawaiians (59.0%) than for Caucasians (68.1%) and Japanese (76.3%). Participation was not affected by requesting two specimens. Participants did not differ from the total sample in terms of education and smoking status. The mean DNA yield was lower in females (41.7 microg) than males (53.4 microg) and in Japanese (37.8 microg) as compared with Hawaiians (51.9 microg) and Caucasians (54.5 microg). For subjects who returned two samples, the DNA yields were similar when both specimens were extracted in the same batch. All samples were successfully genotyped for polymorphisms in the CYP1A1, CYP2E1, GSTM1, GSTT1, and NQO1 genes by PCR-RFLP. From these and previous data, we conclude that, in situations where blood samples cannot be obtained, mail collection of mouthwash samples should be considered because it yields substantial amounts of high-quality genomic DNA for large numbers of study subjects.

Serum selenium and subsequent risk of prostate cancer

It is suspected that selenium is protective against prostate cancer. To test this hypothesis, we conducted a nested case-control study in a cohort of 9345 Japanese-American men examined between 1971 and 1977. At the time of examination, a blood specimen was obtained, and the serum was frozen. After a surveillance period of more than 20 years, 249 tissue-confirmed incident cases of prostate cancer were identified. Their stored sera and those of 249 matched controls were measured for selenium levels. Odds ratios for prostate cancer, based on quartiles of serum selenium levels, were determined using the General Estimating Equations approach. The multivariate odds ratio for the highest quartile was 0.5 (95% confidence interval, 0.3-0.9) with a two-sided P for trend of 0.02. The inverse association was more notable for cases with advanced disease and for cases diagnosed 5-15 years after phlebotomy. However, the association was mainly present in current or past cigarette smokers rather than nonsmokers, which leads to caution in the interpretation of the results.

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.

Breast cancer and oral contraceptive use in Asian-American women

Breast cancer incidence has historically been 4-7 times higher in the United States than in Asia. A previous study by the authors in Asian-American women demonstrated a substantial increase in breast cancer risk in women who migrated from Asia to the United States, with the risk almost doubling during the first decade after migration. Increased use of oral contraceptives soon after migration to the United States could possibly explain this rapid rise in risk. In a population-based case-control study of Chinese, Filipino, and Japanese-American women, aged 20-55 years, who lived in San Francisco-Oakland, California; Los Angeles, California; and Oahu, Hawaii during 1983-1987, 597 cases (70% of those eligible) and 966 controls (75%) were interviewed. Controls were matched to cases on age, ethnicity, and area of residence. Oral contraceptive (OC) use increased with time since migration; 15.0% of Asian-born women who had been in the West <8 years, 33.4% of Asian-born women who had been in the West > or =8 years, and 49.6% of Asian women born in the West had ever used OCs. However, duration of OC use (adjusted for age, ethnicity, study area, years since migration, education, family history of breast cancer and age at first full-term birth) was not associated with increased risk of breast cancer. Moreover, neither OC use before age 25 years nor before first full-term birth was associated with increased risk. Results were unchanged when restricted to women under age 45 years or under age 40 years. After adjustment for duration of OC use, women who had been in the United States > or =8 years were still at almost twice the risk of breast cancer compared with women who had been in the United States 2-7 years. This study suggests that OC use cannot explain the elevated risk observed in Asian women who migrated to the United States > or =7 years ago.

Cytochrome P450c17alpha gene (CYP17) polymorphism predicts use of hormone replacement therapy

We investigated whether a polymorphism in the cytochrome P450c17alpha gene (CYP17), which is associated with higher endogenous hormone levels, influences the use of hormone replacement therapy (HRT). The study included 749 postmenopausal women ages 44-75 years at baseline randomly selected from a larger multiethnic cohort. African-American, Japanese, Latina, and white women were included in the study. Women who carry the CYP17 A2/A2 genotype were about half as likely as women with the A1/A1 genotype to be current HRT users (odds ratio = 0.52; 95% confidence interval, 0.31-0.86). This association was present in all four racial/ethnic groups and for women above and below the median weight of 150 pounds. These findings suggest that the actual risk of breast cancer associated with HRT use may be higher than previously reported.

Auto-inactivation by cleavage within the dimer interface of Kaposi's sarcoma-associated herpesvirus protease

An autolysis site of functional and structural significance has been mapped within the dimer interface of Kaposi's sarcoma-associated herpesvirus protease. Cleavage 27 residues from the C terminus of the 230 amino acid residue, 25 kDa protein was observed to cause a loss of dimerization and proteolytic activity, even though no active site moieties were lost. Gel-filtration chromatography and analytical ultracentrifugation were used to analyze the changes in oligomerization upon autolysis. The selective auto-disruption of this essential protein-protein interface by proteolytic cleavage resulted in a 60 % loss in mean residue ellipticity by circular dichroism as well as a 20 % weaker, 10 nm red-shifted intrinsic protein fluorescence emission spectrum. These apparent conformational changes induced a strict inhibition of enzymatic activity. An engineered substitution at the P1' position of this cleavage site attenuated autolysis by the enzyme and restored wild-type dimerization. In addition to retaining full proteolytic activity in a continuous fluorescence-based enzyme assay, this protease variant allowed the determination of the enzyme's dimerization dissociation constant of 1.7 (+/-0.9) microM. The structural perturbations observed in this enzyme may play a role in viral maturation, and offer general insight into the allosteric relationship between the dimer interface and active site of herpesviral proteases. The functional coupling between oligomerization and activity presented here may allow for a better understanding of such phenomena, and the design of an enzyme variant stabilized to autolysis should further the structural and mechanistic characterization of this viral protease.

Dietary fat and prostate cancer: current status

Efforts to elucidate the causes of prostate cancer have met with little success to date. All that is known with certainty is that the incidence increases exponentially with age, varies by geography and by race or ethnicity, and is higher among men whose father or brother had the disease. Because the incidence changes in migrants and their offspring, exogenous factors certainly contribute to the risk of prostate cancer. Early epidemiologic studies implicated dietary fat as a likely causal factor for this cancer. However, scientific support for such an association has diminished in recent years as more epidemiologic evidence has accrued. Accordingly, we reviewed the relevant English language literature on this topic, including epidemiologic and animal studies, as well as current concepts regarding the involvement of fat in carcinogenesis to re-examine the fat-prostate cancer hypothesis. We conclude that dietary fat may indeed be related to prostate cancer risk, although the specific fat components that are responsible are not yet clear. Given the diverse effects of fatty acids on cellular biology and chemistry, it seems likely that the relationship is complex, involving the interplay of fat with other dietary factors, such as antioxidant vitamins and minerals, or with genetic factors that influence susceptibility. Some suggestions for further research are offered.

Soy intake and risk of breast cancer in Asians and Asian Americans

Evidence from case-control studies suggests, although not entirely consistently, that soy intake may protect against breast cancer. The designs and findings of studies conducted in Asian women living in Japan, Singapore, China, and the United States are reviewed. Because of the considerably higher intake of soy by native Asians than by Asian Americans living in California and Hawaii, these studies investigated different segments of the dose-response relation between soy intake and breast cancer risk. Data are not sufficient to determine the amount or frequency of soy intake effective in protecting against breast cancer. Of concern is that soy intake may be homogeneously high in Asia, making it difficult to identify differences in breast cancer risk between high and moderate daily consumers. In studies conducted in Asian Americans, it is difficult to be certain that soy intake is not a marker of other factors related to Western lifestyle that are causally associated with risk of breast cancer. Additional studies assessing the role of soy and breast cancer are needed. These studies should assess intake of all food sources of soy, considering portion size as well as other dietary and nondietary factors that may confound the soy-breast cancer association. A better understanding of the mechanisms whereby soy intake may influence the risk of breast cancer is also needed. Dietary intervention studies with soy will provide information on the acute effects of soy on endogenous hormone concentrations. Cross-sectional and longitudinal studies are necessary to investigate the longer-term relations between hormone concentrations and soy intake in women.

In situ detection of hepatitis B, C, and G virus nucleic acids in human hepatocellular carcinoma tissues from different geographic regions

We performed a retrospective study to determine the prevalence of hepatitis B virus (HBV), hepatitis C virus (HCV), and hepatitis G virus (HGV) genomes in formalin-fixed, paraffin-embedded liver tissues from hepatocellular carcinoma (HCC) patients in various geographic areas. The prevalence of each hepatitis virus in the liver tissues that have both carcinoma and noncarcinoma regions was different among the countries. HCV was the most prevalent in Japan (75 of 122 [61.5%]), Spain (9 of 15 [60%]), and the United States (27 of 65 [41.5%]); HBV was the most prevalent in Korea (45 of 55 [82%]) and among Japanese Americans in Hawaii (4 of 8 [50%]). Genotype II/1b was the most common genotype of HCV encountered in HCCs in these countries. In contrast, HGV RNA was undetectable in all tested HCCs. "Cryptogenic HCC," defined as HCC of unknown etiology, was seen 4 (3%) and 4 (6.2%) of Japanese and American patients, respectively, but this was not found in other countries. Interestingly, patients with HCC related to primary biliary cirrhosis (4.6%), who were excluded from analysis as hepatitis virus infections, were present only in the United States, but not in other countries. This study suggests that HCV, particularly genotype II/1b, and HBV may play an important role in hepatocarcinogenesis in these countries. There was no evidence of any relation between HGV infection and development of HCC.

Serum vitamin D metabolite levels and the subsequent development of prostate cancer (Hawaii, United States)

OBJECTIVES

Because several serum studies of vitamin D metabolites have produced equivocal results on their relation to prostate cancer risk, the purpose of this study is to evaluate this association further.

METHODS

A nested case-control study in a cohort of 3,737 Japanese-American men examined from 1967 to 1970 was conducted in Hawaii (United States). At the time of examination, a single blood specimen was obtained, and the serum was frozen. After a surveillance period of over 23 years, 136 tissue-confirmed incident cases of prostate cancer were identified. Their stored sera and those of 136 matched controls were measured for the following: 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D, calcium, phosphorus, and parathyroid hormone.

RESULTS

There were no notable differences between cases and controls in their median serum levels of the five laboratory measurements. Odds ratios (OR) for prostate cancer, based on the quartiles of serum levels in controls, were also determined. The ORs for the highest quartiles relative to the lowest were 0.8 (95 percent confidence interval [CI] = 0.4-1.8) for 25-hydroxyvitamin D and 1.0 (CI = 0.5-2.1) for 1,25-dihydroxyvitamin D.

CONCLUSION

It is possible that the lack of sufficient numbers of study subjects with low vitamin D levels affected the results. Nonetheless, the findings suggest that there is a lack of a strong association between vitamin D and prostate cancer.

Serum micronutrients and prostate cancer in Japanese Americans in Hawaii

Numerous dietary studies and several serum micronutrient studies have produced equivocal results on the relation of vitamins A and E to prostate cancer risk. To evaluate this association further, we conducted a nested case-control study in a cohort of 6860 Japanese-American men examined from 1971 to 1975. At the time of examination, a single blood specimen was obtained, and the serum was frozen. After a surveillance period of more than 20 years, 142 tissue-confirmed incident cases of prostate cancer were identified. Their stored sera and those of 142 matched controls were measured by high-performance liquid chromatography for the following: total carotenoids, lutein, zeaxanthin, beta-cryptoxanthin, lycopene, alpha-carotene, beta-carotene, total retinoids, retinol, total tocopherols, alpha-tocopherol, delta-tocopherol, and gamma-tocopherol. Odds ratios for prostate cancer, based on quartiles of serum micronutrient levels, were determined using conditional logistic regression analysis. The odds ratio for the highest quartiles were 1.8 (95% confidence interval, 0.9-3.9) for beta-cryptoxanthin, 1.6 (0.8-3.5) for beta-carotene, 0.8 (0.4-1.5) for retinol, and 0.7 (0.3-1.5) for gamma-tocopherol, but none of the differences was statistically significant. For the other micronutrients, the results were also unremarkable. The findings of this study indicate that none of the micronutrients is strongly associated with prostate cancer risk.

Serum micronutrients and upper aerodigestive tract cancer

Numerous dietary studies have found that vegetables and fruits protect against upper aerodigestive tract cancer. To evaluate the role of beta-carotene and other specific carotenoids, a nested case-control study using prediagnostic serum was conducted among 6832 American men of Japanese ancestry examined from 1971 to 1975. During a surveillance period of 20 years, the study identified 28 esophageal, 23 laryngeal, and 16 oral-pharyngeal cancer cases in this cohort. The 69 cases were matched to 138 controls. A liquid chromatography technique, designed to optimize recovery and separation of the individual carotenoids, was used to measure serum levels of lutein, zeaxanthin, beta-cryptoxanthin, lycopene, alpha-carotene, beta-carotene, retinol, retinyl palmitate, and alpha-, delta-, and gamma-tocopherol. With adjustment for cigarette smoking and alcohol intake, we found that alpha-carotene, beta-carotene, beta-cryptoxanthin, total carotenoids and gamma-tocopherol levels were significantly lower in the 69 upper aerodigestive tract cancer patients than in their controls. Trends in risk by tertile of serum level were significant for these five micronutrients. These significant trends persisted in cases diagnosed 10 or more years after phlebotomy for the three individual carotenoids and total carotenoid measurements. The odds ratios for the highest tertile were 0.19 (95% confidence interval, 0.05-0.75) for alpha-carotene, 0.10 (0.02-0.46) for beta-carotene, 0.25 (0.06-1.04) for beta-cryptoxanthin, and 0.22 (0.05-0.88) for total carotenoids. When the cases were separated into esophageal, laryngeal, and oral-pharyngeal cancer, both alpha-carotene and beta-carotene were consistently and strongly associated with reduced risk at each site. The findings suggest that alpha-carotene and other carotenoids, as well as beta-carotene, may be involved in the etiology of upper aerodigestive tract cancer.

Obesity, alcohol consumption, smoking, and mortality

PURPOSE

The goals of this study were to assess prospectively the impact of obesity, alcohol use, and smoking on total mortality and to test the etiologic hypothesis that subjects with two or more of these risk factors may experience an elevated risk of overall mortality.

METHODS

Information on body mass index (BMI), alcohol intake, cigarette smoking, and other life-style factors was obtained from a cohort of 8006 Japanese-American men living in Hawaii. They were between 45 and 68 years of age at the initial examination (1965-1968). After 22 years of follow-up that included nearly 159,000 person-years of observation, 2667 deaths from all causes were identified.

RESULTS

There was a significant quadratic (J-shaped) relation between BMI and overall mortality. A weaker J-shaped pattern in risk was also present for the intake of alcohol. A strong positive association was observed with pack-years of cigarette smoking. A synergistic interaction between BMI and alcohol was statistically significant (P = 0.0017). Specifically, men who had the lowest body mass (BMI < 21.21 kg/m2) and drank moderately to heavily (> or = 25 oz/mo) experienced a 63% excess risk (relative risk, 1.63; 95% confidence interval; 1.33 - 1.99) compared to a reference group composed of men who had intermediate body mass (BMI, 21.21 - 26.30 kg/m2) and drank occasionally to lightly (0.01 - 24.99 oz/mo). The increase in risk due to the interactive effect of low BMI and high alcohol intake was stronger (and statistically significant) than when each of these risk factors was considered separately (excess risk, 28% and 2%, respectively). There was no significant interaction for BMI and cigarette smoking, for alcohol and cigarette smoking, or for the three factors combined.

CONCLUSIONS

The most important finding of this study was that, in addition to confirming that cigarette smoking could shorten life, extreme (high or low) BMI values and high alcohol consumption are each potentially harmful to health, but even more so if moderate or heavy drinking is concomitant with low body mass, a possible indicator for low intake of nutrients.

Tofu and risk of breast cancer in Asian-Americans

Breast cancer rates among Asian-Americans are lower than those of US whites but considerably higher than rates prevailing in Asia. It is suspected that migration to the US brings about a change in endocrine function among Asian women, although reasons for this change remain obscure. The high intake of soy in Asia and its reduced intake among Asian-Americans has been suggested to partly explain the increase of breast cancer rates in Asian-Americans. We conducted a population-based case-control study of breast cancer among Chinese-, Japanese-, and Filipino-American women in Los Angeles County MSA, San Francisco Oakland MSA, and Oahu, Hawaii. Using a common questionnaire which assessed frequency of intake of some 90 food items, 597 Asian-American women (70% of those eligible) diagnosed with incident, primary breast cancer during 1983-1987 and 966 population-based controls (75% of those eligible) were interviewed. Controls were matched to cases on age, ethnicity, and area of residence. This analysis compares usual adult intake of soy (estimated primarily from tofu intake) among breast cancer cases and control women. After adjustment for age, ethnicity and study area, intake of tofu was more than twice as high among Asian-American women born in Asia (62 times per year) compared to those born in the US (30 times per year). Among migrants, intake of tofu decreased with years of residence in the US. Risk of breast cancer decreased with increasing frequency of intake of tofu after adjustment for age, study area, ethnicity, and migration history; the adjusted OR associated with each additional serving per week was 0.85 (95% CI = 0.74-0.99). The protective effect of high tofu intake was observed in pre- and postmenopausal women. This association remained after adjustment for selected dietary factors and menstrual and reproductive factors. However, this study was not designed specifically to investigate the role of soy intake and our assessment of soy intake may be incomplete. We cannot discount the possibility that soy intake is a marker of other protective aspects of Asian diet and/or Asian lifestyle.

Serum androgens and prostate cancer

It is suspected that male hormones are associated with the risk of prostate cancer. To test this hypothesis, we conducted a nested case-control study in a cohort of 6860 Japanese-American men examined from 1971 to 1975. At the time of examination, a single blood specimen was obtained, and the serum was frozen. After a surveillance period of more than 20 years, 141 tissue-confirmed incident cases of prostate cancer were identified, and their stored sera and those of 141 matched controls were assayed for total testosterone, free testosterone, dihydrotestosterone, 3-alpha-androstanediol glucuronide, androsterone glucuronide, and androstenedione. Odds ratios for prostate cancer, based on quartiles of serum hormone levels, were determined using conditional logistic regression methods. The odds ratios for the highest quartiles were 1.37 (95% confidence interval, 0.73-2.55) for 3-alpha-androstanediol glucuronide and 1.24 (95% confidence interval, 0.62-2.47) for androstenedione, but none of the differences was statistically significant. The results were unremarkable for the other four hormonal measurements. In addition, the patients and controls were compared by hormonal ratios (i.e., total testosterone:dihydrotestosterone), but the results were also unremarkable. The findings of this study indicate that none of these androgens is strongly associated with prostate cancer risk.

A prospective study of colon and rectal cancer among Hawaii Japanese men

The goals of this study were to assess the association of diet, alcohol, smoking, and other life-style factors with the risk of colon and rectal cancer and to examine the differences in the risk factors associated with each cancer site. Information on diet, alcohol, smoking, and other life-style factors was obtained from 7945 Japanese-American men who were living in Hawaii and examined from 1965 through 1968. After 174,514 person-years of observation, 330 incident cases of colon cancer and 123 incident cases of rectal cancer were diagnosed by histology. The risk of both colon and rectal cancer increased with age, alcohol intake, and pack-years of cigarette smoking. For colon cancer, there was also a direct association with body mass index and heart rate, while an inverse association was observed with serum cholesterol, intake of monounsaturated fatty acid, and percentage of calories from fat. For rectal cancer, the risk decreased with an increase in the intake of carbohydrates as percentage of calories. These findings suggest that some of the risk factors for colon cancer are different from those for rectal cancer.

Relative weight, weight change, height, and breast cancer risk in Asian-American women

BACKGROUND

Breast cancer incidence rates have historically been four to seven times higher in the United States than in China or Japan, although the reasons remain elusive. When Chinese, Japanese, or Filipino women migrate to the United States, their breast cancer risk rises over several generations and reaches that for white women in the United States, indicating that modifiable exposures are involved. In a previous report on this case-control study of breast cancer in Asian-American women, designed to take advantage of their diversity in risk and lifestyle, we demonstrated a sixfold gradient in risk by migration history, comparable to the international differences in breast cancer incidence rates.

PURPOSE

In this analysis, we have examined the roles of adult height, adiposity, and weight change in breast cancer etiology.

METHODS

A population-based, case-control study of breast cancer was conducted among women of Chinese, Japanese, and Filipino ethnicities, aged 20-55 years, living in San Francisco-Oakland (CA), Los Angeles (CA), and Oahu (HI) during the period from April 1, 1983, through June 30, 1987. We successfully interviewed 597 (70%) of 852 eligible case subjects and 966 (75%) of 1287 eligible control subjects from August 1985 through February 1989. Subjects were asked about current height, usual adult weight, and usual weight in each decade of life, excluding the most recent 3 years and any periods of pregnancy.

RESULTS

Height, recent adiposity (weight in the current decade of life/height 1.5), and recent weight change (between the current and preceding decades of life) were strong predictors of breast cancer risk after adjustment was made for accepted breast cancer risk factors. Risk doubled (relative risk [RR] = 2.01; 95% confidence interval [CI] = 1.16-3.49) over the 7-inch (17.8-cm) range in height (two-sided P for trend = .003), with comparable effects in both premenopausal and postmenopausal women. Except for reduced risk in the heavy, younger women (weight/height 1.5 > 29 kg/m 1.5 and < 40 years old), risk was positively associated with usual adult adiposity. Trends in risk became more striking as adiposity in each succeeding decade of adult life was considered. Women in their 50s and in the top quintile for their age group had twice the breast cancer risk (RR = 2.13; 95% CI = 1.17-3.87) of women in the bottom quintile (two-sided P for trend = .004). Women in their 50s, above the median adiposity for their age group, and with a recent gain of more than 10 pounds had three times the risk (RR = 3.01; 95% CI = 1.45-6.25) of women below the median adiposity and with no recent weight change. Recent weight loss was consistently associated with reduced risk (RRs of approximately 0.7) relative to no recent weight change.

CONCLUSIONS

Adult adiposity, weight change, and height are critical determinants of breast cancer risk. Increased adiposity and weight gain in the decade preceding diagnosis are especially influential, suggesting that excess weight may function as a late stage promoter.

IMPLICATIONS

Weight maintenance and/or reduction as an adult, possibly accompanied by specific changes in diet and physical activity, may have a significant and rapid impact on breast cancer risk.

Menstrual and reproductive factors and risk of breast cancer in Asian-Americans

We conducted a population-based case-control study of breast cancer among Chinese-, Japanese- and Filipino-American women in Los Angeles County Metropolitan Statistical Area (MSA), San Francisco-Oakland MSA and Oahu, Hawaii. One objective of the study was to quantify breast cancer risks in relation to menstrual and reproductive histories in migrant and US-born Asian-Americans and to establish whether the gradient of risk in Asian-Americans can be explained by these factors. Using a common study design and questionnaire in the three study areas, we successfully conducted in-person interviews with 597 Asian-American women diagnosed with incident, primary breast cancer during the period 1983-87 (70% of those eligible) and 966 population-based controls (75% of those eligible). Controls were matched to cases on age, ethnicity and area of residence. In the present analysis, which included 492 cases and 768 controls, we observed a statistically non-significant 4% reduction in risk of breast cancer with each year delay in onset of menstruation. Independent of age at menarche risk of breast cancer was lower (odds ratio; OR=0.77) among women with menstrual cycles greater than 29 days. Parous Asian-American women showed a significantly lower risk of breast cancer then nulliparous women (OR=0.54). An increasing number of livebirths and a decreasing age at first livebirth were both associated with a lower risk of breast cancer, although the effect of number of livebirths was no longer significant after adjustment for age at first livebirth. Women with a pregnancy (spontaneous or induced abortions) but no livebirth had a statistically non-significant increased risk (OR=1.84), but there was no evidence that one type of abortion was particularly harmful. A positive history of breastfeeding was associated with non-significantly lower risk of breast cancer (OR=.78). There are several notable differences in the menstrual and reproductive factors between Asian-Americans in this study and published data on US whites. US-born Asian Americans had an average age at menarche of 12.12 years-no older than has been found in comparable studies of US whites, but 1.4 years earlier than Asian women who migrated to the US. Asian-American women, particularly those born in the US and those who migrated before age 36, also had a later age at first birth and fewer livebirths than US whites. A slightly higher proportion of Asian-American women breastfed, compared with US whites. The duration of breastfeeding was similar in US-born Asians and US whites, but was longer in Asian migrants, especially those who migrated at a later age. Menstrual and reproductive factors in Asian-American women are consistent with their breast cancer rates being at least as high as in US whites, and they are. However, the effects of these menstrual and reproductive factors were small and the ORs for migration variables changed only slightly after adjustment for these menstrual and reproductive factors. These results suggest that the lower rates of breast cancer in Asians must be largely as a result of other environmental/lifestyle factors.

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.

Gastric cancer among the Japanese in Hawaii

The incidence rate of gastric cancer among men of Japanese ancestry living in Hawaii is about one-third as high as that of their counterparts living in Japan. Because of this difference, a prospective study was conducted to identify factors related to the development of gastric cancer in Hawaii. Eight thousand and six (8,006) men born from 1900-1919 were examined from 1965 to 1968 and followed for over 25 years. During this time, 250 incident cases of gastric cancer were identified. The study has found the following: 1) prior infection with Helicobacter pylori bacteria increased the risk for stomach cancer; 2) cigarette smoking was positively associated with gastric cancer with age at which smoking started being an important risk factor; 3) after taking cigarette smoking into account, alcohol intake was not related to stomach cancer risk; 4) a low pepsinogen I level identified subjects at increased risk for the intestinal histologic type of gastric cancer; 5) a low serum ferritin level was a marker for increased risk of stomach cancer; 6) there was a weak indication that the intake of vegetables and fruits was inversely related to gastric cancer; 7) there was no association of stomach cancer with levels of serum cholesterol, serum uric acid, serum micronutrients (retinol, beta-carotene or alpha-tocopherol) or blood hematocrit; 8) there was also no association of gastric cancer with body mass index or physical activity.

Diet, alcohol, smoking and cancer of the upper aerodigestive tract: a prospective study among Hawaii Japanese men

A cohort study of upper aerodigestive tract cancer was conducted among 7,995 Japanese-American men who were interviewed and examined from 1965 to 1968. Information was collected about smoking history and alcohol and dietary intake. After 24 years, 92 incident cases with histological confirmation of diagnosis were identified. Current cigarette smokers at time of examination had a 3-fold risk for upper aerodigestive tract cancer compared with never-smokers. A dose-response relationship was present with increasing amount and duration of cigarette use. Consumption of beer, wine, spirits and total alcohol was strongly associated with increased risk. Of 23 food and beverage categories, only candy/jelly/soda pop consumption had a statistically significant inverse trend. Frequent consumption of fruit was also inversely associated with this cancer. In contrast, the risk tended to be positively associated with consumption of rice, seaweed, tofu or tsukudani (a mixed dish of fish, sugar, soy sauce and seaweed), but the dose-response relationship was not statistically significant. For nutrient intake, increased calcium and fat intake decreased the risk for this cancer.

International comparison on ras gene mutations in latent prostate carcinoma

Latent carcinomas of the prostate, discovered at autopsy in men with no prior treatment for prostatic disease, were studied for ras proto-oncogene mutations. Subjects included 21 Japanese, 15 U.S. whites, 15 U.S. blacks, 20 Hawaiian Japanese and 10 Colombians. PCR and sequence-specific oligonucleotide hybridization identified mutations in 5 Japanese, in 1 Hawaiian Japanese, in 1 U.S. black, in 1 U.S. white and in 3 Colombians. The 5 Japanese tumor samples contained 3 point mutations in codon 12 of K-ras and 2 mutations in codon 12 of N-ras respectively. One tumor in a Hawaiian Japanese man also showed a K-ras point mutation at codon 12. Two Colombians and one U.S. black man had tumors with mutations at codon 61 of H-ras, while 1 Colombian showed an N-ras mutation at this codon. The overall frequency of ras gene mutations was low, but point mutations in codon 12 were most common in latent tumors of Japanese, who experienced the lowest incidence and mortality from this tumor. Latent tumors in men from ethnic groups with high mortality and incidence rates showed fewer ras mutations than the Japanese, and these were more likely to involve codon 61. This finding is consistent with prior studies of more aggressive clinical cancers in Japanese men that indicated a higher frequency of mutations at codon 61.

The rise of cancer among the elderly in Hawaii

The purpose of this study was to determine if time trends in cancer incidence among the elderly in Hawaii were similar to the trends observed in the mainland United States and to determine if the trends were comparable among the various ethnic groups living in Hawaii. Average annual incidence rates per 100,000 persons, age 65 or older, were determined by sex and ethnicity for the time periods 1973 to 1977 and 1983 to 1986 through the Hawaii Tumor Registry, a population-based central cancer registry. The incidence of all cancers combined increased 27% among men and 26% among women between the 2 time periods. Similar to the rest of the United States, melanoma and cancers of the brain, lung, colon, breast and prostate have risen substantially among elderly Hawaii residents. Comparisons across ethnic groups revealed that melanoma increased mainly among Caucasians, lung cancer increased primarily among Hawaiians and Caucasians, and colon cancer increased in all ethnic groups.

A prospective study of weight, body mass index and other anthropometric measurements in relation to site-specific cancers

The association of weight, body mass index and other anthropometric measurements with cancer was investigated in a cohort of 7,840 men, examined and interviewed from 1965-1968 in Hawaii. After 23 years of follow-up, histologically confirmed incident cases of prostate (n = 306), colon (n = 289), lung (n = 236), stomach (n = 229) and rectal (n = 108) cancer were identified. Body weight was positively associated with prostate cancer. This direct association was stronger for cases diagnosed 11 or more years after examination than for those diagnosed earlier. A similar pattern was also present for the risk of colon cancer in association with weight and body mass index. For lung cancer, increased subscapular and triceps skinfold thickness were each associated with decreased risk with adjustment for cigarette smoking, but the inverse association did not persist as the time interval from exam to cancer diagnosis lengthened. There was no significant association between anthropometric measurements and stomach or rectal cancer.

Relationship of serum uric acid to cancer occurrence in a prospective male cohort

Uric acid is a potent antioxidant and thus might protect against cancer. To test this hypothesis, we examined the relationship of serum uric acid to subsequent cancer incidence in a cohort of Japanese men in Hawaii. The study population consisted of 7889 men identified in the years 1965-1968 and followed by active hospital surveillance through November 1991. Cancer risk by serum uric acid level was analyzed using Cox proportional hazards regression with adjustment for age and, where indicated, smoking, alcohol use, and body mass index. No significant associations were seen for total cancer (1544 cases), or for cancers of the stomach (214), colon (272), rectum (105), lung (223), bladder (89), or hematopoietic system (77). For prostate cancer (293 cases), a positive association was found (relative risk for highest versus lowest quartile of serum uric acid = 1.5; 95% confidence interval 1.1-2.1; p for trend = 0.04). When the interval from examination to diagnosis was considered, this association was strongest for cases diagnosed in the first 10 years, was attenuated after 15 years, and disappeared completely after 20 years. The findings from this study do not support the hypothesis that uric acid protects against cancer occurrence.

Migration patterns and breast cancer risk in Asian-American women

BACKGROUND

Breast cancer incidence rates have historically been 4-7 times higher in the United States than in China or Japan, although the reasons remain elusive. When Chinese, Japanese, or Filipino women migrate to the United States, breast cancer risk rises over several generations and approaches that among U.S. Whites.

PURPOSE

Our objective was to quantify breast cancer risks associated with the various migration patterns of Asian-American women.

METHODS

A population-based, case-control study of breast cancer among women of Chinese, Japanese, and Filipino ethnicities, aged 20-55 years, was conducted during 1983-1987 in San Francisco-Oakland, California, Los Angeles, California, and Oahu, Hawaii. We successfully interviewed 597 case subjects (70% of those eligible) and 966 control subjects (75%).

RESULTS

A sixfold gradient in breast cancer risk by migration patterns was observed. Asian-American women born in the West had a breast cancer risk 60% higher than Asian-American women born in the East. Among those born in the West, risk was determined by whether their grandparents, especially grandmothers, were born in the East or the West. Asian-American women with three or four grandparents born in the West had a risk 50% higher than those with all grandparents born in the East. Among the Asian-American women born in the East, breast cancer risk was determined by whether their communities prior to migration were rural or urban and by the number of years subsequently lived in the West. Migrants from urban areas had a risk 30% higher than migrants from rural areas. Migrants who had lived in the West for a decade or longer had a risk 80% higher than more recent migrants. Risk was unrelated to age at migration for women migrating at ages less than 36 years. Ethnic-specific incidence rates of breast cancer in the migrating generation were clearly elevated above those in the countries of origin, while rates in Asian-Americans born in the West approximated the U.S. White rate.

CONCLUSIONS

Exposure to Western lifestyles had a substantial impact on breast cancer risk in Asian migrants to the United States during their lifetime. There was no direct evidence of an especially susceptible period, during either menarche or early reproductive life.

IMPLICATIONS

Because heterogeneity in breast cancer risk in these ethnic populations is similar to that in international comparisons and because analytic epidemiologic studies offer the opportunity to disentangle correlated exposures, this study should provide new insights into the etiology of breast cancer.

Histopathological predictors of breast cancer death among Caucasians and Japanese in Hawaii

In the United States, Caucasian women are at higher risk of death from breast cancer than age-matched Japanese-Americans. The tumors of Japanese-Americans exhibit a greater uniformity of nuclear grade (NG), greater degrees of intratumoral lymphocytic infiltration (LI), and more conspicuous sinus histiocytosis (SH) in the regional lymph nodes. To assess the impact of histopathology upon the ethnic disparity in breast cancer mortality, we compared the survival experience of Japanese and Caucasian women with breast cancer in Hawaii. The study group consisted of 443 women, aged 45-74, whose cancers were diagnosed between 1975 and 1980. Survival status at 9 or more years after diagnosis, known for 416 of these women, was used in the analyses. Age and tumor stage at diagnosis were significant predictors of breast cancer death in the logistic regression analysis. When histopathological predictor variables (NG, LI, and SH) were included in the model, age, stage, NG, and LI were independently predictive. Although NG predicted stage among all patients, and SH predicted stage among the women with invasive disease, race was an independent predictor breast cancer stage in multivariate analyses. Finally, analysis within stage subgroups revealed that race was independently predictive of cancer death among women with localized disease (confined to the breast) but not among women with regional spread (local extension or axillary nodes involves). These results indicate that histopathological differences contribute to, but only partially explain, the disparity in breast cancer mortality between Caucasians and Japanese in Hawaii.

A prospective study of diet, smoking, and lower urinary tract cancer

The association of diet and smoking with bladder cancer was investigated in a cohort study conducted in Hawaii. The study included 7995 Japanese-American men who were born between 1900 and 1919, and were examined from 1965 to 1968. After 22 years of follow-up, 96 incident cases of bladder cancer were diagnosed. Current cigarette smokers had a 2.9-fold risk of bladder cancer, compared with nonsmokers. A direct dose-response relation was observed, based on pack-years of cigarette smoking. Consumption of fruit was inversely associated with the risk of bladder cancer (P = 0.038). The relative risk was 0.6 among subjects who had the most frequent (> or = 5 times/wk) intake of fruits compared to those with the least intake (< or = 1 time/wk). A weaker inverse association with milk intake was also observed (P = 0.07). Frequent consumption of fried vegetables, pickles, or coffee increased the risk of bladder cancer, but none of these foods showed a significant dose-response relationship. There was no association of other selected foods, alcohol, total calories, protein, fat, or carbohydrates with bladder cancer risk.

Lung cancer: a prospective study of smoking, occupation, and nutrient intake

A cohort study of lung cancer was conducted among 7,961 Japanese-American men who were interviewed and examined during 1965-1968. Information was collected about their smoking history, occupation, and nutrient intake. After 22 y, 227 incident cases of lung cancer were identified. Cigarette smoking significantly increased lung cancer risk. The relative risk (RR) was 3.1 for past smokers and 11.4 for current smokers, compared with never smokers. We separated lung cancer cases according to histological type, and it was found that current smokers had a RRs of 16.0 for squamous/small-cell carcinoma and 6.8 for adenocarcinoma of the lung. Unskilled manual workers had a significantly higher risk (RR = 1.5; 95% confidence interval, 1.1-2.2) for lung cancer than workers who were engaged in nonmanual occupations. There was no association between lung cancer and the 24-h intake of total calories, protein, fat, dietary cholesterol, carbohydrates, and alcohol, but this may have resulted from the limitations of a 24-h dietary questionnaire.

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.

Adenocarcinoma of the proximal small intestine. A marker for familial and multicentric cancer?

BACKGROUND

Adenocarcinoma of the small intestine is uncommon. The Hawaii Tumor Registry (HTR) has identified 49 of these tumors since 1960, and the Japan-Hawaii Cancer Study (JHCS) has identified only four of these tumors among a cohort of 8006 Hawaiian-Japanese men followed up for a period of 22 years. Each of the four men reported by the JHCS had multicentric gastrointestinal cancers.

METHODS

Newly diagnosed cancers are recorded separately by the HTR and JHCS, and linkage is maintained between the two files. Family histories are available from the JHCS, and these are supplemented by a state population file maintained by the Department of Genetics, University of Hawaii.

RESULTS

Five men, all Japanese, were found to have carcinoma of the proximal small intestine. Each had multicentric carcinomas of the gastrointestinal tract. Carcinoma of the stomach and colon was found in the primary relatives of each of four men whose families lived in Hawaii.

CONCLUSIONS

The familial clustering of uncommon neoplasms (small bowel carcinoma and multicentric large bowel carcinoma), and the concurrence of gastric and colonic carcinoma suggests that these subjects have a genetic trait that increases susceptibility to a broad range of carcinogens.

Markers of health status in an HTLV-I-positive cohort

The health effects of chronic human T-cell lymphotropic virus type I (HTLV-I) infection were examined in a cohort of Japanese men who had emigrated from Okinawa, Japan, and had been participants in a prospective study in Hawaii since 1965. In the present follow-up study carried out in 1987-1988, various health indicators were measured in the subjects, whose mean age was 72.5 years. Participation rates were lower in the HTLV-I seropositives than in the seronegatives (46.7% vs. 76.0%) in the > or = 75-year age group. Lack of participation was significantly correlated with a high HTLV-I antibody titer. Among the participants, seropositive subjects were significantly more likely than the seronegatives to have lymphocytopenia (32.7% vs. 17.7%) and mild anemia (25.5% vs. 14.1%) after adjustment for age and socioeconomic status. The seropositives also had a higher frequency of acupuncture therapy (age-adjusted odds ratios were 2.1 and 4.2 for 1-5 treatments and > or = 6 treatments, respectively). Proportions of subjects who had been hospitalized at least twice were higher among the seropositives in the oldest age groups, 70-74 years and > or = 75 years, but not in those aged 65-69 years. Although specific disease conditions were not identified in this study, hematologic data, treatment histories, and the correlation between participation status and HTLV-I antibody titers suggest that chronic HTLV-I infection may be associated with as yet undefined adverse health effects, particularly in older age groups.

Mutations of p53 gene in hepatocellular carcinoma: roles of hepatitis B virus and aflatoxin contamination in the diet

BACKGROUND

Mutations of the p53 tumor suppressor gene have been reported in 50% of patients with hepatocellular carcinoma (HCC) from China and South Africa. These reports suggested an association of p53 mutations with high levels of aflatoxin in the diet. Most studies of p53 and HCC, however, have not fully evaluated the possible role of the hepatitis B virus (HBV). Aflatoxin is a substance produced by food mold that is known to cause HCC in experimental animals.

PURPOSE

The purpose of this study was to evaluate the relationship of p53 gene mutation to high or low levels of aflatoxin in the diet and to HBV infection.

METHODS

p53 protein and hepatitis B surface antigen (HBsAg) were evaluated by immunohistochemistry using the avidin-biotin-peroxidase system in paraffin-embedded specimens of HCC and of adjacent nontumorous liver tissue from 43 patients. Tissue specimens from three normal human livers were also evaluated. HCCs and adjacent nontumorous liver tissues were obtained from 23 patients from Qidong, China, where aflatoxin levels in the diet are high, and from 20 patients from two regions in the United States (patients from the National Institutes of Health, Bethesda, Md., and Kuakini Medical Center, Honolulu, Hawaii), where aflatoxin levels in the diet are low.

RESULTS

Mutant p53 protein was detected in the nuclei of HCCs from 14 (61%) of 23 patients from China and from three (30%) of 10 patients and six (60%) of 10 patients, respectively, from the two regions of the United States. A statistically significant association between detection of mutant p53 protein in HCC cells and the detection of HBsAg in hepatocytes of the adjacent nontumorous liver tissue was observed in patients from China and the United States considered together.

CONCLUSION

Mutations of the tumor suppressor gene p53 in hepatocellular carcinomas are not limited to patients from geographic regions where the ingestion of aflatoxin is high. In many patients, these mutations may be associated with HBV infection.

IMPLICATIONS

The possible interaction of chronic HBV infection and p53 gene mutation, suggested by these data, indicates a mechanism by which HBV infection beginning early in life could contribute to the subsequent development of HCC.

The association of diet, obesity, and breast cancer in Hawaii

A case-control study of the association of dietary fat and animal protein consumption with breast cancer was conducted between 1975 and 1980 on Oahu, Hawaii. Data from this study were used to explore the relation of selected foods and the interaction of nutrients and foods with other factors, such as body size, age at menopause, and ethnicity on the risk for breast cancer. The sample included 272 postmenopausal breast cancer cases and 296 neighborhood controls. Study participants included Japanese and Caucasian women, aged 45 to 74, who were residents of Oahu. There was a suggestion of a positive-dose response relation (P < 0.01) between sausage consumption and the odds ratio for breast cancer. Significant odds ratios for breast cancer were also found for higher intakes (above the 50th percentile) of diary items, sausage, and all meats combined. The dose-response relation for nutrients and foods tended to be stronger among women with a high Benn's index (kg/cm1.5182) compared to women with a low Benn's index. In general, subjects with high dietary intakes of fat and animal protein who were in the upper 50th percentile of body size were at the greatest risk for breast cancer. However, there was no evidence for an interaction between the dietary variables and body size, ethnic group, age at menarche, age at menopause, or age at first birth that would affect the odds ratio for breast cancer. These data suggest that women with both a high intake of foods rich in fat and animal protein and with a large body size are at increased risk for breast cancer.

Serum alpha-tocopherol concentration in relation to subsequent colorectal cancer: pooled data from five cohorts

BACKGROUND

Vitamin E is an antioxidant that inhibits mutagenesis and cell transformation. Previous findings in five prospective epidemiologic studies suggested that the level of serum alpha-tocopherol, the predominant form of vitamin E in the blood, was lower in subjects who subsequently developed colorectal cancer than in control subjects. However, the difference was neither obvious nor statistically significant in any one of these five studies.

PURPOSE

To evaluate in greater detail the association between serum alpha-tocopherol concentration and risk of colorectal cancer, we pooled and analyzed the original data from the five studies. Our analyses were designed to (a) test the hypothesis with greater statistical power, (b) examine the association after adjustment for serum cholesterol levels, and (c) evaluate the association after uniform exclusion of cases diagnosed shortly after blood specimens were drawn.

METHODS

Data for individual subjects were analyzed. To make the design of the component investigations uniformly nested case-control studies with individual matching, we matched controls to cases in two of the cohorts. Subjects were categorized according to study-specific quartile of serum alpha-tocopherol level within the study. The pooled analysis included 289 cases of colorectal cancer and 1267 matched controls.

RESULTS

For cancers of the colon and rectum combined, the matched odds ratio (OR) for the highest quartile of serum alpha-tocopherol concentration compared with the lowest was 0.6 (95% confidence interval [CI] = 0.4-1.0). Adjustment for serum cholesterol level attenuated the OR to 0.7 (95% CI = 0.4-1.1).

CONCLUSION

The results suggest that serum alpha-tocopherol concentration may be inversely related to risk of colorectal cancer. It is unclear whether an association exists, however, because the association between serum alpha-tocopherol level and decreased risk of colorectal cancer was modest, the CIs were wide, and, overall, the tests for trend in effect were not significant.

IMPLICATIONS

Larger observational studies with concurrent dietary data are needed to determine whether vitamin E has a modest but potentially important protective effect against colorectal cancer.

A prospective comparison of prostate cancer at autopsy and as a clinical event: the Hawaii Japanese experience

Prostate cancer was diagnosed in life among 274 of 8006 (3.6%) members of a cohort of Japanese men in Hawaii between 1965 and 1990. Only 55 (20%) of the 274 diagnosed cases died with prostate cancer, and they accounted for only 2% of the 2893 deaths that occurred among the men during this period. None of the 61 men whose tumor was found incidentally to a transurethral resection died as a result of this cancer, while it was the cause of death of 9 of 106 (8%) men with clinical cancer localized to the prostate. Forty-six of the 107 (43%) men with more extensive disease at the time of diagnosis died from prostate cancer. Step sectioning of the prostate identified prostate cancer in 80 of 293 (27%) autopsied Hawaii Japanese men who died after 50 years of age, reaching a frequency of 63% (10 of 16) among men over 80 years of age. The volume of 48 (60%) of these cancers was less than 150 mm3. These small tumors would probably not have been discovered in a screening program. Tumors larger than 1000 mm3 would probably be discovered using modern diagnostic procedures but were found in only 13 (4.4%) of the autopsied men. It is likely that a screening program to detect and treat such large, unsuspected tumors in this population would have had little impact upon the already low proportion of deaths due to prostate cancer among these Japanese men.

A prospective study of gastric and duodenal ulcer and its relation to smoking, alcohol, and diet

The effects of environmental exposures on the development of gastric and duodenal ulcers were investigated in a prospective study of 7,624 American men of Japanese ancestry in Hawaii. After 149,291 person-years of observation, there were 280 incident cases of gastric ulcer and 149 incident cases of duodenal ulcer. The risk of both gastric and duodenal ulcers progressively increased with increasing pack-years of cigarette smoking. In contrast, alcohol intake was not associated with either type of ulcer. The risk of gastric ulcer was positively associated with the use of table salt/soy sauce, but there was no association with the consumption of other oriental foods. The risk of duodenal ulcer was inversely associated with western style diet around 1940 and with bread intake of two or more servings per day. The authors did not find any protective or adverse effect of milk and fruit consumption on peptic ulcer risk.

Prospective study of serum cholesterol and site-specific cancers

From 1965 to 1968, 7716 Japanese-American men were examined and tested for serum cholesterol. After 22 years, 1380 incident cancer cases were identified. Of the site-specific cancers, only colon cancer cases had a significantly lower mean serum cholesterol value than that of noncases (213.0 mg/dl vs 219.0 mg/dl). When the study subjects were separated into either a low, middle or high group, based on their serum cholesterol values, there was a significant inverse trend for cases of oral/pharyngeal/esophageal cancer combined. The association was present for cases diagnosed within 10 years of examination (p = 0.012), but not for cases diagnosed after 10 years. This suggests that the inverse association is due to the metabolic effects of undiagnosed oral/pharyngeal/esophageal cancer upon serum cholesterol levels. These results are discussed in relation to other studies on serum cholesterol.

Prospective study of the association of alcohol with cancer of the upper aerodigestive tract and other sites

The association of alcohol consumption with cancers of the upper aerodigestive tract, hepato-biliary-pancreatic system, urogenital organs (except for prostate), and lymphohematopoietic tissue was evaluated in a prospective study of 6,701 American men of Japanese ancestry living in Hawaii. Compared with cancer-free subjects, subjects who subsequently developed cancers of the upper aerodigestive tract (oral-pharynx, esophagus, and larynx), liver, biliary tract, and lymphohematopoietic tissue consumed significantly larger amounts of total alcohol--mainly in the form of beer. Subjects who developed oral-pharyngeal and esophageal cancer also consumed larger amounts of wine and spirits. Because the upper aerodigestive tract cancers were associated positively with cigarette smoking, age-adjusted relative risks (RR) were calculated, based on joint exposure to cigarette smoking and heavy alcohol intake (greater than or equal to 30 ml/day) in this population. A markedly increased risk was observed among subjects who were both heavy alcohol drinkers and smokers (RR = 17.3, 95 percent confidence interval [CI] = 6.7-44.2), compared with subjects who who did not smoke and did not drink heavily. The risk for these cancers also was increased among heavy alcohol drinkers who were nonsmokers (RR = 8.6, CI = 2.1-36.0).

Vitamin supplement use and its correlates among elderly Japanese men residing on Oahu, HI

Use of vitamin supplements and the association with personal characteristics were investigated among 4,654 American men of Japanese ancestry in Hawaii. A total of 58 percent of the subjects who were ages 68 to 90 took vitamin supplements. Among supplement users, multivitamins were most commonly used (77 percent), followed by vitamin C (53 percent), E (43 percent), and A (10 percent). Ninety-two percent of users took at least seven pills per week when all types of pills were combined. Vitamin supplement users were more educated, more physically active, more likely to be married, and less obese than nonusers. They also slept less, smoked less, and drank less alcohol and caffeine. They took more analgesics and stomach medication and had fewer days of hospitalization in the previous 10 years compared with nonusers. Except for physical activity, use of stomach medicines, and hospitalization, the other characteristics were also positively correlated with the amount of vitamin pill intake. These findings indicate that vitamin supplement users have different health patterns compared with nonusers.

A prospective study of the attributable risk of cancer due to cigarette smoking

BACKGROUND

The goals of this study were to measure the impact of cigarette smoking on cancer incidence and to determine the attributable risk of cancer due to smoking.

METHODS

A cigarette smoking history was obtained from 8006 Japanese-American men examined from 1965 through 1968. After 22 years, 1389 incident cases of cancer were identified. There were 212 men with lung cancer; 202 with oral, esophageal, laryngeal, pancreatic, renal, ureteral, or bladder (oral-bladder) cancer; and 975 with cancer at other sites.

RESULTS

Current smokers at time of examination had a higher incidence than nonsmokers for each of the three cancer site categories. Eighty-five percent of lung cancer cases diagnosed among current and never smokers can be attributed to cigarette smoking. The attributable risks were 46%, 16%, and 29%, respectively, for oral-bladder cancers, other cancers, and all cancers combined. In turn, the corresponding attributable risks were 60%, 26%, 13%, and 21% in comparing current smokers with past smokers.

CONCLUSIONS

Current smokers can greatly reduce their risk of cancer, especially lung cancer, if they quit smoking.

Cancer incidence in Hawaiian Japanese: migrants from Okinawa compared with those from other prefectures

Japanese men in Hawaii whose ancestral roots were in Okinawa were compared to Japanese migrants from all other prefectures. The Okinawan migrants have acquired fewer cancers than men from other prefectures (P = 0.12). No one primary site accounts for this difference. Stomach cancer rates showed the largest difference between the two migrant groups. This replicates the experience of Okinawans and non-Okinawans in Japan itself. Lymphosarcoma mortality rates are much higher in Okinawa than in all Japan, but this difference is not reproduced in Hawaiian migrants. This could be explained by a post migrational decrease in HTLV-I-related acute T-cell lymphoma/leukemia. Cancer of the mouth, pharynx and esophagus has decreased in all Japanese migrants, but the decrease is much greater among Okinawan migrants, suggesting they have escaped exposure to risk factors peculiar to the Okinawan environment. Colon cancer is more common in migrant Japanese than in U.S. whites. The dramatic increase in the frequency of this tumor affects Okinawan and non-Okinawan migrants to an equal degree.

Declining seroprevalence and transmission of HTLV-I in Japanese families who immigrated to Hawaii

This study examined the seroprevalence and transmission of human T cell lymphotropic virus type I (HTLV-I) in Japanese families who originated in Okinawa, an area in which HTLV-I is endemic, and who were currently residing in Hawaii, a nonendemic area. Among a cohort of Japanese men whose sera were collected in Hawaii in 1967-1975, those of Okinawan ancestry had an HTLV-I seroprevalence of 11.4%. This study, conducted in 1987-1988, sampled 142 index subjects from this male cohort and tested them along with their wives, children, and spouses of the children for HTLV-I antibodies. Seropositivity in their wives was 11.4% and 41.2% among the seronegative and seropositive index subjects, respectively; seropositivity also increased from 29.4% to 35.3% to 58.8% with the husbands' increasing antibody levels by tertiles. Elevated antibody levels may be a marker for infectivity, which is associated with more efficient sexual transmission of HTLV-I. The age-adjusted odds ratio for the association of seropositivity between husband and wife, however, was four times lower than that reported among native Okinawans. In addition, a substantially low seroprevalence (1.3%) was found among their offspring. The decline in HTLV-I transmission in this migrant population may be due to low infectivity in the parent generation who live in a nonendemic environment, increasing numbers of offspring marrying outside of the Okinawan community, and improved living circumstances.

Prospective study of serum cholesterol levels and large-bowel cancer

Based on previous reports, it is uncertain whether serum cholesterol levels are inversely related to colon cancer risk. In this study, serum cholesterol levels were measured in 7926 Japanese-American men who were followed for over 20 years. Two hundred thirty-one incident cases of colon cancer and 97 cases of rectal cancer were identified. An increase in serum cholesterol levels was associated with a decrease in risk for colon cancer (P value for trend = .01) but not for rectal cancer. This association appeared stronger as the site of cancer moved from the sigmoid colon to the cecum. The data were further analyzed by interval from examination to diagnosis. The inverse association was present for colon cancer cases diagnosed within 10 years of examination (P value for trend less than .01), especially for cecum-ascending colon cancer cases (P less than .01). A similar inverse pattern was found for cecum-ascending colon cancer cases diagnosed after 10 years, but the association was not statistically significant. The results suggest that the preclinical effects of undiagnosed colon cancer contributed to the inverse association, but these effects do not entirely explain why the relationship with hypocholesterolemia was stronger in men who were subsequently diagnosed with right-sided colon cancer.

Cancer incidence following subtotal gastrectomy

Hawaiian Japanese men (n = 432) who had undergone subtotal gastrectomy for peptic ulcers before 1971-1975 were followed up for detection of cancer development. They showed a significant increase in colon cancer risk (P = 0.008) and lung cancer risk (P = 0.002) compared with 6161 nongastrectomized men. The association with lung cancer persisted after adjustment for cigarette use (P = 0.03). Alcohol consumption was associated with colonic cancer in this cohort, and gastrectomized men consumed more alcohol than nongastrectomized men; however, the association of gastrectomy with colon cancer persisted after adjustment for alcohol use (P = 0.02). Gastrectomized men were lighter and had lower serum lipid levels than controls, suggesting that undernutrition might favor the development of some cancers. The type of gastroenteric anastomosis did not influence the cancer risk level in the colon or lung.