Diet, serum markers and breast cancer mortality in China

This county-based correlation study examined associations of breast cancer mortality with dietary habits and certain serum biochemical markers, utilizing data collected from an ecological survey in 65 Chinese rural counties. Univariate correlation and multivariate regression analysis showed that consumption of animal foods, including eggs, fish and meat, was positively linked to county-wide mortality rates of breast cancer in Chinese women. No clear associations between breast cancer mortality rates and consumption of green vegetables, carrots and fruits were observed in this study. A modest inverse correlation between serum vitamin C levels and breast cancer mortality was observed, while selenium levels were positively related to the mortality rates. Positive correlations for serum ferritin and hemoglobin were found, in agreement with recent reports of an elevated cancer risk with increased body iron stores. Limitations of these ecological data preclude causal inferences, but the findings provide clues to breast cancer risk and protective factors in a low incidence area of the world.

A nested case-control study of oesophageal and stomach cancers in the Linxian nutrition intervention trial

BACKGROUND

Rates of oesophageal/gastric cardia cancer in Linxian, a rural county in north central China, are among the world's highest, but the risk factors are not well understood.

METHODS

A nested case-control study of oesophageal and stomach cancers was conducted within a cohort of 29,584 adults who participated in a randomized nutrition intervention trial. Information on participant characteristics collected during interviews before the trial began was compared between individuals who subsequently developed cancers of the oesophagus (N = 640) or stomach (N = 539), mainly cardia, and individually matched controls (control/case ratio = 5). Analyses were performed separately for oesophageal and stomach cancers using conditional logistic regression.

RESULTS

For oesophageal cancer, tobacco smoking was associated with a significantly elevated risk, with a twofold increase among long-term smokers. Alcohol consumption was uncommon and not related to risk. High consumption of eggs or fresh vegetables was associated with 20% reductions in risk, and risk significantly declined as pre-trial body mass index (BMI), an indicator of long-term nutritional status, increased. No increases in risk were associated with intake of pickled vegetables or mouldy foods, although consumption levels at the start of the trial were low. Excess risks of 40-80% were found among individuals who had reported a history of cancer, notably of the oesophagus and stomach, in parents or sibs. For stomach cancer, only low BMI was significantly associated with elevated risk.

CONCLUSIONS

This study indicates that several risk factors for oesophageal and stomach cancers in Linxian, including smoking, nutritional deficiency, and familial cancer occurrence, resemble those in other areas of the world and contribute partly to the remarkably elevated rates in this area of China.

Occupation, physical activity, and risk of prostate cancer in Shanghai, People's Republic of China

Based on occupational data for all (n = 264) prostate cancer cases diagnosed during 1980-84 in urban Shanghai and on employment information from the 1982 census, standardized incidence ratios (SIR) were calculated for occupational groups classified by job type and physical activity level. White-collar workers (professionals, government officials, clerical workers, salespersons) had an elevated incidence of prostate cancer, although the excesses were not significant. In addition, when jobs were classified by time spent sitting or energy expenditure, men employed in occupations with low physical activity levels tended to have moderately elevated risks of prostate cancer. Findings from this study in an area with one of the world's lowest incidence rates of prostate cancer add to the accumulating evidence that jobs with a low level of physical activity are associated with an increased prostate-cancer risk.

Current status of lung cancer diagnosis and treatment in Shanghai

The status of diagnosis and treatment of lung cancers discovered during 1 year in the Shanghai population are presented. A total of 940 lung cancers was detected from inhabitants of 35-64 years of age, with a male/female ratio of 1.8:1. Pathology showed 35.7% adenocarcinoma and 35.1% squamous cell carcinoma. There was a predominance of adenocarcinoma (47.6%) in females and of squamous cell carcinoma (44.6%) in males. Most (68.6%) of the lesions detected were already advanced in contrast to 14.7% of Stage I disease. The need for vigilance on the part of doctors was demonstrated by the fact that 23.3% of patients were seen by the doctor within 1 month after presenting with symptoms and 44.5% of them had their diagnosis suspected within 1 month after their first hospital visit. The treatment consisted of surgery for 33.3%, chemotherapy for 35%, traditional Chinese medicine for 20% and symptomatic management for 9.6% of patients. As only 55.8% Stage I patients were treated by surgery, the treatment protocol seemed to be improperly biased. The adequate training of health workers was shown by the fact that 79.7% of these patients were confirmed by pathology and/or cytology and most of the Stage I lesions were diagnosed outside the hospital.

Risk factors for cancers of the nasal cavity and paranasal sinuses among white men in the United States

A case-control analysis of cancer of the nasal cavity and sinuses was performed using data from the 1986 National Mortality Followback Survey. Data on cigarette smoking, alcohol consumption, usual diet, and other factors from 147 white men who died from nasal cancer and from 449 controls who died from other causes were compared. Cigarette smoking was related to an increased risk of nasal cancer, with a doubling of risk among heavy or long-term smokers and a reduction in risk among long-term quitters. Among nonsmokers, having a spouse who smoked was associated with a significantly elevated risk of nasal cancer. After adjustment for smoking, a significant dose-response relation was also noted between alcohol drinking and risk of nasal cancer. High consumption of salted/smoked foods was associated with elevated risk, and risk tended to decrease with increasing intake of vegetables. Associations were more pronounced for cigarette smoking and certain dietary items when the analysis was restricted to maxillary sinus cancer. The study confirms that cigarette smoking is a risk factor for nasal cancer, and provides further evidence that dietary factors may play a role in the etiology of this malignancy.

Declining incidence is greater for esophageal than gastric cancer in Shanghai, People's Republic of China

Temporal trends in the incidence of esophageal and gastric cancers during 1972 to 1989 were addressed in urban Shanghai, the location of China's longest standing cancer registry. Over the 18 year study period, esophageal cancer rates decreased more than 50% from 28.8/100,000 person-years in 1972-74 to 13.3/100,000 in 1987-89 among men and from 11.3/100,000 to 5.4/100,000 among women. Reductions were apparent in each age group, but most pronounced among younger generations, with more than a 75% decline in incidence among those under age 55 years. The incidence rate for stomach cancer among men decreased 20% from 62.0/100,000 in 1972-74 to 50.1/100,000 in 1987-89. The reduction among women, however, was minor, from 23.9/100,000 to 23.2/100,000. The patterns varied by age, with declines among persons 45-64 years and increases among those in older and younger age groups. The determinants of these trends are not clear, but appear related in part to dietary changes.

Toxicokinetics of sulfasalazine (salicylazosulfapyridine) and its metabolites in B6C3F1 mice

The toxicokinetics of salicylazosulfapyridine (SASP) and its metabolites were investigated in male and female B6C3F1 mice either following single intravenous (5 mg/kg) or oral (67.5, 675, 1350, and 2700 mg/kg) doses, or following three consecutive daily oral doses (675, 1350, and 2700 mg/kg). Plasma concentrations of SASP and its metabolites were quantified by HPLC. Upon intravenous administration, SASP rapidly disappeared from blood with a mean residence time of 0.45-0.78 hr. The only metabolite of SASP found in plasma after an intravenous dose was sulfapyridine (SP). In both sexes, the absolute oral bioavailability of SASP ranged between 16.6-18.2% at a dose of 67.5 mg/kg, and between 2.6-8.7% at doses of 675-2700 mg/kg. Following oral administration of SASP, both SP and AcSP were identified in plasma. The area under the plasma concentration-time curves (AUC) of SP at all four oral doses were approximately 21- to 32-fold or 5- to 25-fold greater than those of SASP in male or female mice, respectively. The acetylated form of SP and AcSP, produced AUC values higher than SASP but much less than SP. Multiple oral doses with SASP did not alter the temporal patterns of SASP absorption and elimination in comparison to a single dose. However, SP accumulated in both sexes following multiple oral doses. A gender-dependent difference in toxicokinetic profiles for SASP and SP was also observed. Female mice displayed a higher Cmax of SASP and SP than did male mice. Although the volume of distribution of SASP was similar in both sexes, the systemic clearance of SASP in males was about twice that observed in females.(ABSTRACT TRUNCATED AT 250 WORDS)

Continuous versus intermittent nitroglycerin administration in experimental heart failure: vascular relaxation and radioligand binding to adrenoceptors and ion channels

Continuous nitroglycerin (NTG) administration causes pharmacologic tolerance in humans and animals, whereas intermittent dosing is capable of avoiding or reducing tolerance development. The mechanism of NTG-induced hemodynamic tolerance may involve specific vascular desensitization and/or neurohormonal compensation. We compared effects of long-term (10 days) NTG administration (continuous or intermittent 12 h on/12 h off transdermal dosing, 10 micrograms/min) to rats with congestive heart failure (CHF) on radioligand binding from selected tissues. Tension responses in isolated blood vessels, plasma renin activity (PRA), plasma Na+ and K+ concentrations were also determined. The maximal binding values (Bmax) for [3H]glyburide and [3H]PN 200 110 in homogenates of left ventricle, right ventricle, and brain were not significantly different after NTG administration (continuous or intermittent), as compared with control. Intermittent, but not continuous, NTG caused significant increases in beta-adrenoceptor densities in the left ventricle, as judged by [3H]dihydroalprenolol binding (Bmax values: intermittent NTG 34.5 +/- 4.8, continuous NTG 24.4 +/- 2.6, placebo control 20.9 +/- 2.9 fmol/mg protein); Kd values for all ligands were not significantly altered by NTG administration. Both intermittent and continuous NTG increased the vascular contractile response to phenylephrine in isolated rat thoracic aorta. Slight reductions (two- to four-fold shifts in EC50 values) in thoracic aorta relaxant response to NTG were observed in both treatment groups as compared with control. Intermittent and continuous NTG administration caused selective changes in beta-adrenoceptor density and vascular response. These changes may contribute partly to the phenomenon of pharmacologic tolerance after chronic nitrate administration.

A cohort study of smoking, alcohol consumption, and dietary factors for pancreatic cancer (United States)

Risk factors for pancreatic cancer were evaluated in a cohort study of 17,633 White men in the United States who responded to a mailed questionnaire in 1966 and were followed-up through 1986 for mortality. Cigarette smoking and alcohol consumption were found to be important risk factors for pancreatic cancer. Risks increased significantly with number of cigarettes smoked, reaching fourfold for smokers of 25 or more cigarettes per day relative to nonsmokers. Alcohol intake also was related significantly to risk, with consumers of 10 or more drinks per month having three times the risk of nondrinkers, but dose-response trends among drinkers were not smooth. Coffee consumption was unrelated to risk. Dietary analyses revealed a rising rate of pancreatic cancer mortality with increasing consumption of meat after adjustment for other risk factors. Men in the highest quartile of meat intake had about three times the risk of those in the lowest quartile. No consistent association, however, was observed for consumption of fruits, vegetables, or grains. This study confirms cigarette smoking as an important risk factor for pancreatic cancer, and provides evidence that elevated intake of alcohol and meat may increase the risk of this fatal malignancy.

Occupational risks for primary liver cancer in Shanghai, China

Using occupational data for over 3,400 primary liver cancer cases diagnosed between 1980 and 1984 reported to the Shanghai Cancer Registry, and employment information from the 1982 census for the Shanghai population, standardized incidence ratios were computed to generate leads to occupational risks of liver cancer. Among men, a statistically significant excess number of cases was observed for chemical processors, textile workers, wood workers, blacksmiths and machine-tool operators, and material handlers and dock workers. Increased incidence of liver cancer also was observed among female transport equipment operators. These findings indicate that a number of similar occupations are associated with increased risk of primary liver cancer in western countries and China. Although causal inferences cannot be drawn from these data, our study adds to the limited evidence of the potential role of occupational exposures in liver carcinogenesis.

Prior medical conditions and the risk of adult leukemia in Shanghai, People's Republic of China

A population-based case-control interview study of 486 adult leukemia cases and 502 healthy controls was carried out in Shanghai, People's Republic of China during 1987-89 to evaluate the etiologic role of prior medical conditions, medications, and diagnostic X-rays. Risks were examined separately for 236 cases with acute non-lymphocytic leukemia (ANLL), 79 with chronic myeloid leukemia (CML), 81 with acute lymphocytic leukemia (ALL), and 21 with chronic lymphocytic leukemia (CLL). Little difference was found between cases and controls for prior history of diabetes, hypertension, allergic conditions, most medications, and diagnostic X-rays. A few significant associations were observed for appendectomy, tuberculosis, and for several other chronic disorders with specific leukemia cell types, but the odds ratio estimates for most of these ranged from two to three and, with the exception of the two specified above, were based generally on five or fewer exposed controls. In contrast to an association with childhood leukemia in Shanghai, prior use of chloramphenicol was not linked with ANLL or other forms of adult leukemia. Further research is needed to clarify the relation of specific medical conditions and exposures with particular subtypes of leukemia, and to examine reasons for the low incidence of CLL in China and other Asian populations.

Physical activity and risk of endometrial cancer

In a population-based case-control study of endometrial cancer, we interviewed 268 cases and an equal number of matched controls regarding physical activity at work and outside of work. We also obtained self-ratings of overall physical activity levels. The results showed that nonretired women holding sedentary jobs or those reporting sedentary life-styles were at somewhat increased risk of endometrial cancer. The associations remained unchanged after adjustment for caloric intake and body mass index. Although an effect of physical inactivity on endometrial cancer risk is biologically plausible, our results show some inconsistencies, such as a lack of elevation in risk among women who were physically inactive outside of work.

Incidence trends for cancers of the breast, ovary, and corpus uteri in urban Shanghai, 1972-89

Incidence data from the Shanghai (People's Republic of China) Cancer Registry were used to assess the temporal trends of three major female cancers during 1972-89. Rates for cancers of the breast, corpus uteri and, to a lesser extent, ovary rose over the study period. The increases in breast and ovarian cancer were most pronounced among women under age 50, whereas those for corpus uteri cancer were restricted generally to those aged 55 to 69 years. When considered by cohort year of birth, risk of breast and ovarian cancers rose among women born since 1925 and 1935, respectively, but little evidence of cohort effect was apparent for corpus uteri cancer. Potential explanations for these patterns are explored.

Occupational physical activity and the incidence of cancer of the breast, corpus uteri, and ovary in Shanghai

BACKGROUND

A sedentary life style has been consistently associated with an increased risk of colon cancer, but the evidence for its association with breast and other gynecologic cancers is limited.

METHODS

Occupational information for 3783 incident patients with cancer (breast, 2736; corpus uteri, 452; and ovary, 595) whose disease was diagnosed during the period 1980-1984 was compared with 1982 census data on employment in Shanghai urban areas. The standardized incidence ratios (SIR) of these cancers were estimated for each occupational group classified by job titles and physical activity levels.

RESULTS

A significantly increased incidence of breast cancer was found among professionals (SIR = 158), government officials (SIR = 131), and clerical workers (SIR = 143); the incidence was reduced among service workers (SIR = 87) and craftsmen (SIR = 91). Occupational physical activity, as measured by sitting time and energy expenditure, was inversely related to breast cancer incidence, with SIR of 127-131 for inactive jobs (sedentary or low-energy expenditure) and 79-93 for active jobs (long periods of standing or high energy expenditure). Similar associations, although to a lesser extent, were also seen for cancer of the corpus uteri and ovary.

CONCLUSIONS

Women with low physical activity occupations had an increased incidence of cancer of the breast, corpus uteri, and ovary; the incidence was reduced among women with high-activity jobs. These findings were consistent with observations from earlier studies and provided further evidence that physical activity may lower the risk of these female hormone-dependent cancers.

Cancer incidence trends in urban Shanghai, 1972-1989

Incidence data pertaining to more than 250,000 cancer cases diagnosed during the years 1972-1989 among residents of urban Shanghai, China, were analyzed to determine the relative importance of the various malignancies and to discover changes over time. In the most recent 3-year period, lung cancer was the most frequent cancer among men (57.0 per 100,000 person-years, age-adjusted world standard), followed by cancers of the stomach (50.1), liver (29.6), esophagus (13.3), colon (11.2) and rectum (9.4). Among women, breast cancer leads (25.1), followed by cancers of the stomach (23.2), lung (18.8), liver (10.9), colon (10.2) and rectum (7.3). The most impressive increases in incidence rates from 1972-74 to 1987-89 were observed for cancers of the gallbladder (119% and 101% among men and women, respectively), colon (85% and 78%), and brain and other nervous system (71% and 60%). In addition, increases of 20-50% occurred for cancers of the pancreas, male lung, female breast, corpus uteri, kidney, and for non-Hodgkin's lymphoma. Rates declined notably for cancers of the esophagus (-54% and -53%), cervix uteri (-86%), and to a lesser extent (10-20%) cancers of the male stomach and liver. These observed trends can be explained only partly by improvements in cancer diagnosis and completeness of the cancer registry, and most likely reflect changes in the prevalence of risk factors in this population.

Serum micronutrients and the subsequent risk of oral and pharyngeal cancer

To investigate the relationship between serum micronutrients and the subsequent risk of oral and pharyngeal cancer, a nested case-control study was conducted within a cohort of 25,802 adults in Washington County, MD, whose blood samples were collected in 1974 and stored at -70 degrees C for subsequent assays. The serum levels of nutrients in 28 individuals who developed oral and pharyngeal cancer during 1975 to 1990 were compared with levels in 112 matched controls. Serum levels of all individual carotenoids, particularly beta-carotene, were lower among subjects who developed oral and pharyngeal cancer. The risks of this malignancy decreased substantially with increasing serum level of each individual carotenoid. Persons in the highest tertile of total carotenoids had about one-third the cancer risk as those in the lowest tertile. High serum levels of alpha-tocopherol also were related to a low oral cancer risk in later years, but the risks were elevated significantly with increasing serum levels of gamma-tocopherol and selenium. The findings from this study are consistent with many previous epidemiological investigations of dietary factors for oral and pharyngeal cancer and provide further evidence for the potential role of carotenoids and alpha-tocopherol in the chemoprevention of these malignancies.

Physical activity and occupational risk of colon cancer in Shanghai, China

Using occupational data for over 2000 colon cancer cases diagnosed between 1980 and 1984 in Shanghai, and employment information from the 1982 census for the Shanghai population, standardized incidence ratios (SIR) were computed for occupational groups classified by job types and physical activity levels. Men employed in occupations with low physical activity levels had modest but significantly elevated risks of colon cancer. SIR for jobs with low activity based on sitting time was 121 (95% confidence interval, Cl: 108-135) and based on energy expenditure was 126 (95% Cl: 115-138). Corresponding SIR for women were 99 (95% Cl: 83-118) and 113 (95% Cl: 100-127). The data were also used to screen for specific occupations with elevated SIR to generate leads to occupational colon cancer. Increased incidence was observed for professional and other white collar workers, and male chemical processors and female textile workers. The findings add to the emerging evidence that workplace activity may influence the risk of this common cancer.

A population-based case-control study of dietary factors and endometrial cancer in Shanghai, People's Republic of China

The relation between diet and endometrial cancer was examined in a population-based case-control study conducted in Shanghai, People's Republic of China, between 1988 and 1990, involving interviews with 268 cases and 268 controls aged 18-74 years. The subjects' usual dietary intake of 63 major foods during the previous 10 years (disregarding any recent changes) was measured by means of a structured quantitative food questionnaire. Although women in the highest quartile of total caloric intake had a 2.1-fold increased risk of endometrial cancer, risk varied according to the source of calories. The highest quartiles of caloric intake from fat and protein were associated with odds ratios of 3.9 and 3.1, respectively, while calories from carbohydrates, the major contributor of total calories in this population, were not related to risk. The association of fat and protein with endometrial cancer risk was confined to foods of animal origin in the diet. After adjustment for age, body mass index (weight (kg)/height (m)2), and number of pregnancies, odds ratios were 3.5 (95% confidence interval (CI) 2.0-6.0) and 3.0 (95% CI 1.7-5.1) for women in the highest quartiles of intake of animal fat and animal protein, respectively. Food group analyses showed a similar pattern, with high consumption of meat, eggs, and fresh fish being associated with elevated risks. After adjustment for total calories, no significant association of risk was found with intake of vegetables or dark green/yellow vegetables, or with estimated carotene intake, although fruit and allium vegetables were associated with some reduction in risk. These results suggest that diets rich in animal fat and animal protein may play an important role in the etiology of endometrial cancer.

Correlations of colon cancer mortality with dietary factors, serum markers, and schistosomiasis in China

To determine correlates of the geographic variation in colon cancer mortality within China, dietary variables, biochemical markers, and other factors from an ecological survey in 49 Chinese rural counties were examined. High consumption of animal foods, salt-preserved vegetables, and beer was associated with increased mortality of colon cancer, whereas the rates were significantly inversely related with intake of green vegetables. Serum levels of total cholesterol, urea nitrogen, and lipid peroxide were positively correlated with colon cancer mortality, after adjustment for each other and for other blood nutrients. No appreciable associations, however, were found between colon cancer and serum levels of beta-carotene, alpha-tocopherol, vitamin C, and selenium. In addition, prevalence of schistosomiasis was significantly correlated with increased colon cancer mortality. This ecological study indicates that observations from earlier analytic investigations in Western societies may apply to a Chinese rural population and suggests that schistosomiasis and dietary factors may contribute to the remarkable geographic variation of colon cancer in China.

Molecular cloning and expression ofBacillus subtilis bglS gene inSaccharomyces cerevisiae

A 2.7-kb EcoRI DNA fragment carrying a Bacillus subtilis endo-beta-1,3-1, 4-glucanase gene (bglS) from the E. coli plasmid pFG1 was cloned into an Escherichia coli/yeast shuttle vector to construct a hybrid plasmid YCSH. The hybrid plasmid was used to transform Saccharomyces cerevisiae, and the bglS gene was expressed. Variation between levels of bglS gene expression in S. cerevisiae was about 2.3-fold, depending on the orientation of the 2.7-kb DNA fragment. Assay of substrate specificity and optimal pH of the enzyme demonstrated that the enzyme encoded by YCSH (bglS) was identical with that found in B. subtilis, but the expression level of bglS gene in S. cerevisiae (YCSH) was much lower than that in E. coli (YCSH).