Victoria Persky

Soy intake and cancer risk: A review of the in vitro and in vivo data

International variations in cancer rates have been attributed, at least in part, to differences in dietary intake. Recently, it has been suggested that consumption of soyfoods may contribute to the relatively low rates of breast, colon, and prostate cancers in countries such as China and Japan. Soybeans contain a number of anticarcinogens, and a recent National Cancer Institute workshop recommended that the role of soyfoods in cancer prevention be investigated. In this review, the hypothesis that soy intake reduces cancer risk is considered by examining relevant in vitro, animal, and epidemiological data. Soybeans are a unique dietary source of the isoflavone genistein, which possesses weak estrogenic activity and has been shown to act in animal models as an antiestrogen. Genistein is also a specific inhibitor of protein tyrosine kinases; it also inhibits DNA topoisomerases and other critical enzymes involved in signal transduction. In vitro, genistein suppresses the growth of a wide range of cancer cells, with IC50 values ranging from 5 to 40 microM (1-10 micrograms/ml). Of the 26 animal studies of experimental carcinogenesis in which diets containing soy or soybean isoflavones were employed, 17 (65%) reported protective effects. No studies reported soy intake increased tumor development. The epidemiological data are also inconsistent, although consumption of nonfermented soy products, such as soymilk and tofu, tended to be either protective or not associated with cancer risk; however, no consistent pattern was evident with the fermented soy products, such as miso. Protective effects were observed for both hormone- and nonhormone-related cancers. While a definitive statement that soy reduces cancer risk cannot be made at this time, there is sufficient evidence of a protective effect to warrant continued investigation.

Effect of environmental molds on risk of death from asthma during the pollen season.

OBJECTIVE Many studies have noted an association of ambient aeroallergen levels with exacerbation of asthma. This study was undertaken to examine the relationship of aeroallergen levels with asthma-related mortality in Chicago. METHODS The association of environmental aeroallergen levels with death caused by asthma among 5- to 34-year-olds in Chicago was examined for the period of 1985 through 1989. Logistic regression analysis was used to compare the probability of a death caused by asthma occurring on the basis of environmental tree, grass, or ragweed pollen and mold spore levels. RESULTS Mean mold spore levels but not tree, grass, or ragweed pollen levels were significantly higher for days on which asthma-related death occurred than for days on which no deaths occurred (z = 2.80, p < 0.005). The odds of a death caused by asthma occurring on days with mold spore counts of 1000 spores per cubic meter or greater was 2.16 times higher (95% confidence interval = 1.31, 3.56, p = 0.003) than on days on which mold spore counts were less than 1000 spores per cubic meter. The association with mold spore levels remained significant on multivariate logistic regression with mold spore counts measured as a continuous variable and controlling for pollens, with the odds of an asthma-related death occurring being 1.2 times higher (95% confidence interval = 1.07-1.34) for every increase of 1000 spores per cubic meter in daily mold spore levels. CONCLUSION Although death caused by asthma also involves personal, social, and medical access factors, these data suggest that exposure to environmental molds may play a role in asthma-related mortality and should be considered in prevention strategies.

Hormone disruption by PBDEs in adult male sport fish consumers.

Background Persistent pollutants, such as polychlorinated biphenyls (PCBs), affect endocrine function. Human exposure to polybrominated diphenyl ethers (PBDEs), which are similar in structure to PCBs, has increased recently, but health effects have not been well studied. Objectives Our goal in this study was to determine whether PBDE body burdens are related to thyroid and steroid hormone levels, thyroid antibodies, and thyroid disease in a cohort of frequent and infrequent adult male sport fish consumers. Methods We tested serum from 405 adult males for PBDE congeners, PCB congeners, testosterone, sex-hormone–binding globulin (SHBG), SHBG-bound testosterone, thyroglobulin antibodies, and the thyroid hormones thyroxine (T4), triiodothyronine (T3), thyroid-stimulating hormone (TSH), and T4-binding globulin (TBG). We collected data on demographics, fish consumption, medical diseases, and medication use. Results The median sum of PBDEs was 38 ng/g lipid. In 308 men without thyroid disease or diabetes, PBDEs were positively related to measures of T4 and reverse T3 and inversely related to total T3 and TSH. PBDEs were positively related to the percentage of T4 bound to albumin, and inversely related to the percentage of T4 bound to TBG. Associations of BDE congeners with hormones varied. BDE-47 was positively associated with testosterone levels. Participants with PBDEs over the 95th percentile were more likely to have thyroglobulin antibodies, although high PBDE exposure was not associated with thyroid disease. PBDE effects were independent of PCB exposure and sport fish consumption. Conclusions PBDE exposure, at levels comparable with those of the general U.S. population, was associated with increased thyroglobulin antibodies and increased T4 in adult males.

Urinary tract infection during pregnancy: its association with maternal morbidity and perinatal outcome.

OBJECTIVES. The effects of antepartum urinary tract infection on adverse maternal and perinatal outcomes were examined. Antepartum urinary tract infection has been previously implicated as a risk factor for numerous outcomes. METHODS. Crude and multivariable analyses were performed with a perinatal registry cohort of 25,746 mother/infant pairs. RESULTS. Elevated risks were observed for exposure to urinary tract infection and low birthweight, prematurity, preterm low birthweight, premature labor, hypertension/preeclampsia, maternal anemia, and amnionitis. Urinary tract infection was associated with perinatal death only among subjects 20 to 29 years of age. CONCLUSIONS. These findings underscore the importance of antepartum urine screening to identify patients at risk for adverse outcomes.

Relationships of Race and Socioeconomic Status with Prevalence, Severity, and Symptoms of Asthma in Chicago School Children

BACKGROUND Asthma mortality rates in Chicago are among the highest in the United States, with substantially greater rates in poor and minority populations. How much of the differential can be attributed to differences in prevalence versus severity or access to care has not been determined. OBJECTIVE To examine rates of asthma prevalence, severity, and symptoms and to explore the relationships of these rates to race and socioeconomic status in a random sample of Chicago school children. METHODS Self-administered survey. RESULTS Overall, rates of asthma were higher than previously reported, with 16% of students in the stratified cluster random sample of 3,670 children in the 7th and 8th grades having had asthma. Prevalence rates were significantly higher in schools with >98% African Americans than in other schools, with the highest prevalence rates seen in African American schools in low income neighborhoods. Rates were associated with the percent of African American children in the school and with median income of the schools census tract. Relationships were most consistent with indices of more severe disease. CONCLUSIONS Asthma prevalence is higher than previously noted, with rates greatest in minority and low income populations. Differences are more striking for measures of severity than for symptoms of wheezing, but are far less than previously reported differences in mortality, suggesting that additional factors, such as differential access to continuous health care, may be affecting high death rates from asthma in Chicago.

Organochlorine Exposure and Incidence of Diabetes in a Cohort of Great Lakes Sport Fish Consumers

Background Studies have demonstrated ubiquitous human exposure to persistent organic pollutants (POPs) such as p,p′-diphenyldichloroethene (DDE) and polychlorinated biphenyls (PCBs). Although there is considerable evidence that POP exposures are associated with prevalent diabetes, these studies do not establish causality because the cross-sectional study design does not allow for assessment of temporality of the exposure–disease association. Prospective studies, however, have been lacking. Objectives This study was designed to determine whether POP body burdens are related to incidence of diabetes in a cohort of Great Lakes sport fish consumers. Methods The cohort was established in the early 1990s and followed through 2005. We tested serum for DDE and PCB congeners and assessed diabetes diagnosis, demographics, and fish consumption. Associations of diabetes with exposures were examined prospectively in participants without diabetes in 1994–1995, followed through 2005. Annual percent changes in DDE and PCB-132/153 from 1994 to 2005 were examined by diabetes status. Results DDE exposure was associated with incident diabetes. Incident diabetes was not associated with mono-ortho PCB-118, total PCBs, or years of sport fish consumption. Annual percent change in DDE and PCB-132/153 did not differ significantly by diabetes status. Conclusions This study demonstrates an association between DDE exposure and incident diabetes. The findings of an association of DDE with incident diabetes and the lack of effect of diabetes on annual percent change in POPs do not support the hypothesis that associations of POPs with diabetes are attributable to reverse causality. Additional studies should address the biological pathways by which DDE could affect glucose homeostasis.

Dietary beta-carotene, vitamin C, and risk of prostate cancer: Results from the Western Electric Study

&NA; Dietary factors are likely candidates for important determinants of prostatic cancer risk. Among the most investigated nutritional factors have been antioxidants. We evaluated dietary beta‐carotene and vitamin C in relation to subsequent risk of prostate cancer in a prospective study of 1,899 middleaged men. We combined prostate cancer cases diagnosed in the first 24 years of follow‐up with incident cases identified from the Health Care Financing Administration hospitalization and outpatient files during an additional 6‐year follow‐up period. We obtained death certificates for all decedents. During the 30‐year follow‐up, prostate cancer developed in 132 men. There was no indication that consumption of beta‐carotene or vitamin C was related to increased or decreased risk of prostate cancer. Relative risks for highest vs lowest quartiles of betacarotene and vitamin C intake were 1.27 [95% confidence interval (CI) = 0.75‐2.14] and 1.03 (95% CI = 0.59‐1.60), respectively, after adjustment for age, number of cigarettes smoked per day, dietary cholesterol and saturated fat, alcohol consumption, total energy intake, and occupation. Associations between intake of these nutrients and risk of prostate cancer differed depending on whether the cancer was diagnosed during the first 19 years of follow‐up or the next 11 years of follow‐up. Overall survival over the 30 years of follow‐up was positively associated with intake of beta‐carotene and vitamin C.

Prevalence of asthma and other allergic diseases in an adolescent population: association with gender and race

OBJECTIVES To estimate the prevalence and severity of asthma in an adolescent population by sex and race. METHODS Cross-sectional, population-based survey of school children. SETTING Midwestern city experiencing damage from the 1993 Mississippi River flood. PARTICIPANTS 2,693 children attending grades 7 to 12. MEASUREMENTS Questions from the International Study of Asthma and Allergies in Childhood (ISAAC). RESULTS Two thousand six hundred ninety-three children were surveyed, for a response rate of 90%. In this population, 16.4% reported having ever been diagnosed with asthma; 25% reported wheezing in the last 12 months; 32% reported symptoms of rhinitis in the last 12 months; and 22% reported ever having hay fever. The prevalence rate for current asthma was 12.6%. Female students had significantly greater prevalence rates for current asthma (16.4% vs 9.0%, OR = 1.85); ever-diagnosed asthma (18.5% vs 14.3%, OR = 1.36); wheezing > or = 4 times in the last 12 months (12.0% vs 5.6%, OR = 1.95); current rhinitis (38.7% vs 25.4%, OR = 1.73); and hay fever (26.4% vs 18.4%, OR = 1.57). All associations with sex remained significant, except ever-diagnosed asthma, after controlling for other known risk factors in logistic regression. African-Americans had higher prevalence rates than other races with differences reaching statistical significance for ever-diagnosed asthma and current asthma; however, these relationships did not remain significant after controlling for other known risk factors in logistic regression. CONCLUSIONS Our prevalence rates were similar to those reported by other studies that used the ISAAC questionnaire. Female students reported significantly more asthma, wheezing, rhinitis, and hay fever than male students. Female students also reported more severe symptoms and a greater number of emergency room and hospital admissions.

Uric acid: a risk factor for coronary heart disease?

The association between serum uric acid the prevalence of ECG abnormalities was analyzed for 24,997 employed men women, white black, age 18–64 years, from the Chicago Heart Association (CHA) Detection Project in Industry. In addition, the relationships between uric acid 5-year mortality from all causes, from cardiovascular diseases (CVD), from coronary heart disease (CHD) were analyzed for 7804 white men women age 45-64 years from this study 967 white men age 44–63 years from the Chicago Peoples Gas Company Study. For men, the associations between uric acid the prevalence of ECG abnormalities with mortality appear to be secondary to associations between uric acid other risk factors. For women, however, the associations could not be explained by other risk factors.

DIETARY CHOLESTEROL, FAT, AND FIBRE, AND COLON-CANCER MORTALITY: An Analysis of International Data

It has been suggested that high fat, high cholesterol, and low fibre intakes play a role in the causation of colon cancer, but since they are highly intercorrelated, it is difficult to determine which (if any) variable is truly related to colon cancer. Food disappearance data for 1954--65 and mortality data for 1967--73 from 20 industrialised countries were used to assess which variables are independently related to colon cancer. Simple correlation analysis indicated that intake of total fat, saturated fat, monounsaturated fat, cholesterol, and fibres are each highly correlated with mortality-rate for colon cancer. The partial correlation of dietary cholesterol with colon cancer remains highly significant when fat or fibre is controlled. However, the partial correlations of fat or of fibre iwth colon cancer are no longer significant when cholesterol is controlled. Cross-classification showed a highly signficant main effect for cholesterol, but nor for fat or fibre. The findings support the possibility of a causal relationship between cholesterol intake and colon cancer.