Biomedical subjects

M C Hatch

Publications and source records attributed to M C Hatch.

At least 37 records · Page 2Linked to original sources

PubMed1995

Dietary factors and the risk of pancreatic cancer: a case-control study in Shanghai China.

In Shanghai, China, age-adjusted incidence rates for pancreatic cancer have increased steadily, beginning in the early 1970s. To examine the effects of diet on this cancer, a population-based case-control study was conduct. Cases (n = 451) were permanent residents of Shanghai, 30-74 years of age, newly diagnosed with pancreatic cancer between October 1, 1990 and June 30, 1993. Decreased cases (19%) were excluded from the study. Controls (n = 1552) were selected among Shanghai residents, frequency matched to cases by gender and age. Information on usual adult dietary intake was obtained by trained interviewers in person, using a food frequency questionnaire. Dietary associations were measured by odds ratios and 95% confidence intervals. Risks of pancreatic cancer were inversely associated with consumption of vegetables (P for trend among men = 0.03; among women = 0.15) and fruits (P among men = 0.02; among women = 0.08). Reductions in risk were related also to intake of dietary fiber and micronutrients abundant in plant sources, such as vitamins C and E and carotene. There was also an inverse association with egg consumption (P for trend among men = 0.08; among women = 0.001). No consistent positive associations were observed with intake of other food groups, including preserved animal foods, fresh red meat, organ meat, poultry, and staple foods. On the other hand, risks increased with frequency of consumption of preserved vegetables and foods that were deep fried, grilled, cured, or smoked, providing clues to the possible role of nitrosamines, polycyclic aromatic hydrocarbons, and heterocyclic aromatic amines. The inverse associations observed with intake of dietary fat and protein in our study were unexpected, although these findings were based on consumptions well below the average intake in Western countries, where most previous studies on pancreatic cancer were conducted. Our results suggest that dietary variations have contributed little to the rising trends of pancreatic cancer in Shanghai. However, given the improving food availability and changing dietary patterns in China, further study of dietary and nutritional risk factors for pancreatic cancer appears warranted.

Adult↗

PubMed1993

Urinary aflatoxin levels, hepatitis-B virus infection and hepatocellular carcinoma in Taiwan.

Using a urinary immunoassay to measure aflatoxin metabolites, we examined the associations between exposure to aflatoxin, chronic infection with the hepatitis-B virus (HBV) and background rates of hepatocellular carcinoma (HCC) mortality in a cross-sectional survey of 250 residents from 8 areas of Taiwan with a 4-fold variation in age-adjusted HCC mortality. Specimens of fasting blood and overnight urines were used to determine HBV carrier status and excretion of aflatoxin in the subjects surveyed. While the prevalence of hepatitis-B virus carriers showed moderate variability, there was a 500-fold range in urinary aflatoxin levels. Mean log-transformed levels of aflatoxin metabolites were similar in males and females and in HBV carriers and non-carriers. In the 8 townships, HCC mortality correlated positively with both area HBV carrier prevalence and mean aflatoxin levels. The primary analyses, however, were conducted at the individual level. Each subject's aflatoxin level was treated as the response variable in a multiple regression model, and the corresponding sex-specific area HCC rate was included as a predictor along with the individual's carrier status, age and sex; alcohol consumption and cigarette smoking were also considered. In these analyses, a significant association was again observed between the marker of aflatoxin exposure and the background rate of HCC mortality. In females, the slope of the regression line was somewhat steeper in HBV carriers, but this pattern was not seen in males and formal testing yielded no statistically significant evidence of an interaction. Our findings are consistent with the hypothesis that aflatoxin plays an independent role in hepatocellular carcinoma in Taiwan.

Adult↗

PubMed1993

Maternal exercise during pregnancy, physical fitness, and fetal growth.

The value of exercise during pregnancy is controversial; both benefits and risks have been hypothesized. As empiric evidence is scant, the issue was investigated in a prospective study that assessed the impact on fetal growth of maternal exercise in each trimester of pregnancy. A cohort of over 800 prenatal patients was recruited from obstetric practices in Pennsylvania and New York between January 1987 and June 1989. Subjects were interviewed at entry into care and recontacted at 28 and 36 weeks of gestation. In women with prior adverse outcomes or a lack of conditioning, the associations between maternal exercise and fetal growth were equivocal. In fit, low-risk, prenatal patients, exercise was positively associated with fetal growth. With low-moderate exercise levels, the adjusted mean birth weights were about 100 g higher than in nonexercisers (117 g; 95% confidence interval 17 to 217 g). With heavier exercise, larger birth weight increments were seen, close to 300 g in those who exercised throughout pregnancy at levels of about 2,000 kcal/week in energy expenditure (276 g; 95% confidence interval 54 to 497 g). These results suggest that the guidelines issued by the American College of Obstetricians and Gynecologists may be too stringent for well-conditioned, low-risk, prenatal patients. Additional research to define safe limits more precisely seems warranted.

Adult↗

PubMed1993

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.

Adolescent↗

PubMed1993

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.

Adolescent↗

PubMed1992

Relation of obesity and body fat distribution to endometrial cancer in Shanghai, China.

In a case-control study involving 268 cases of endometrial cancer and an equal number of population controls, we assessed the relationship of risk to body weight and fat distribution, examining weight at various ages and current anthropometric measurements. Weight gain during later adulthood and resultant high body masses were important risk predictors, indicating that obesity is an important risk factor, even in an area where the prevalence of obesity and incidence of endometrial cancer are low. Certain fat distribution patterns were related to risk of endometrial cancer independent of general obesity. In particular, fat deposits on the trunk were associated with elevated risks, with the odds ratio for the highest versus lowest quartile of subscapular skinfolds remaining significant even after adjustment for body mass index (odds ratio = 2.9; 95% confidence interval, 1.1-7.3). Central versus peripheral obesity, as measured by the subscapular:triceps ratio, also was related to increased risk, although the association failed to remain significant after adjustment for body mass (highest to lowest quartile, odds ratio = 1.7). In contrast, upper body obesity, as assessed by the waist:thigh ratio, was unrelated to risk. These results support the need for future studies assessing the relationship of hormonal and other biological parameters of fat distribution to assist in identifying causal mechanisms for this tumor.

Adolescent↗

PubMed1991

Proxy respondents in reproductive research: a comparison of self- and partner-reported data.

The quality of proxy reporting was assessed among 136 prenatal patients and their spouse/partners recruited from the obstetric services of a New Jersey hospital between 1985 and 1987. The concordance, sensitivity, and specificity of proxy reports about partners' occupation, smoking, and drinking were examined in relation to self-reports. Overall, private patients provided better proxy data than did clinic patients, and women provided better data than did men. No consistent effects on the quality of proxy reports were found in relation to age, level of education, marital status, or length of cohabitation. Partners' recent job titles appeared to be quite accurately reported, whereas partners' smoking and drinking patterns were less well-reported. For alcohol use in particular, there was evidence of considerable misclassification resulting from proxy reports even when kappa statistics and intraclass correlation coefficients suggested good agreement. Use of proxy respondents is unnecessary in reproductive studies and should be avoided when it may produce misleading results. Our data indicate that private prenatal patients and their partners can give reasonable proxy reports about job titles and smoking, but not about alcohol use. The high proportion of clinic patients who did not refer a partner (or whose partners could not be contacted) limits the generalizability of our results for this group and gives cause for concern about collecting proxy information from clinic populations.

Adolescent↗

PubMed1991

Using reproductive effect markers to observe subclinical events, reduce misclassification, and explore mechanism.

Biological markers of effect, in general less widely available than exposure markers, do exist in the field of reproduction and increasingly are being used in epidemiological studies. Several such markers, including semen quality, menstrual hormones, early pregnancy loss, and placental abnormalities, are cited as examples. We argue the value of effect markers for detecting subclinical events that are critical for reproductive performance. Such studies can extend knowledge of the true frequency and determinates of reproductive disorders. A second portion of the paper deals with the role of effect markers in reducing disease misclassification. With a hypothetical early pregnancy study as a case in point, we illustrate the degree and direction of bias associated with several different protocols and encourage epidemiologists to weigh these quantitative considerations in deciding on study design. Finally, we discuss uses of biological markers to explore mechanisms, drawing on experience in an ongoing reproductive study that is testing a hypothetical pathway from maternal psychosocial stress to reduced fetal growth using urine catecholamine levels as a physiological marker of exposure and placental vascular abnormalities as a marker of effect.

Biomarkers↗

PubMed1991

Cancer rates after the Three Mile Island nuclear accident and proximity of residence to the plant.

BACKGROUND: In the light of a possible link between stress and cancer promotion or progression, and of previously reported distress in residents near the Three Mile Island (TMI) nuclear power plant, we attempted to evaluate the impact of the March 1979 accident on community cancer rates. METHODS: Proximity of residence to the plant, which related to distress in previous studies, was taken as a possible indicator of accident stress; the postaccident pattern in cancer rates was examined in 69 "study tracts" within a 10-mile radius of TMI, in relation to residential proximity. RESULTS: A modest association was found between postaccident cancer rates and proximity (OR = 1.4; 95% CI = 1.3, 1.6). After adjusting for a gradient in cancer risk prior to the accident, the odds ratio contrasting those closest to the plant with those living farther out was 1.2 (95% CI = 1.0, 1.4). A postaccident increase in cancer rates near the Three Mile Island plant was notable in 1982, persisted for another year, and then declined. Radiation emissions, as modeled mathematically, did not account for the observed increase. CONCLUSION: Interpretation in terms of accident stress is limited by the lack of an individual measure of stress and by uncertainty about whether stress has a biological effect on cancer in humans. An alternative mechanism for the cancer increase near the plant is through changes in care-seeking and diagnostic practice arising from postaccident concern.

Bias↗

PubMed1990

Polycyclic aromatic hydrocarbon-DNA adducts in spontaneously aborted fetal tissue.

Fetal tissue and placentas from 15 human spontaneous abortions were evaluated for DNA adducts of polycyclic aromatic hydrocarbons (PAHs), using a competitive enzyme-linked immunosorbent assay (ELISA) with fluorescent end-point detection. PAH-derived adducts were found in 43% of placentas, 27% of fetal liver samples and 42% of fetal lung specimens, thus confirming that the human fetus is a target for DNA damage. As there was only 60% concordance between placenta and fetal lung or liver on the presence or absence of detectable PAH adducts, the placenta was not a good surrogate for adduct formation in other fetal organs. PAH-derived adducts in fetal liver and lung presumably form as a result of transplacental exposure to environmental stimuli. Since none of the positive fetal samples were from women who reported smoking during pregnancy, cigarette smoke is, in this case, an unlikely candidate and the adducts detected must be due to some other common source(s) of hydrocarbon exposure. The high frequency of positive samples in our small series casts some doubt on whether fetal PAH-DNA adducts identify a population at increased risk for transplacental carcinogenesis.

Abortion, Spontaneous↗

PubMed1990

Cancer near the Three Mile Island nuclear plant: radiation emissions.

As a public charge, cancers among the 159,684 residents living within a 10-mile (16-km) radius of the Three Mile Island nuclear plant were studied relative to releases of radiation during the March 28, 1979, accident as well as to routine plant emissions. The principal cancers considered were leukemia and childhood malignancies. Estimates of the emissions delivered to small geographic study tracts were derived from mathematical dispersion models which accounted for modifying factors such as wind and terrain; the model of accident emissions was validated by readings from off-site dosimeters. Incident cancers among area residents for the period 1975-1985 (n = 5,493) were identified by a review of the records at all local and regional hospitals; preaccident and postaccident trends in cancer rates were examined. For accident emissions, the authors failed to find definite effects of exposure on the cancer types and population subgroups thought to be most susceptible to radiation. No associations were seen for leukemia in adults or for childhood cancers as a group. For leukemia in children, the odds ratio was raised, but cases were few (n = 4), and the estimate was highly variable. Moreover, rates of childhood leukemia in the Three Mile Island area are low compared with national and regional rates. For exposure to routine emissions, the odds ratios were raised for childhood cancers as a whole and for childhood leukemia, but confidence intervals were wide and included 1.0. For leukemia in adults, there was a negative trend. Trends for two types of cancer ran counter to expectation. Non-Hodgkin's lymphoma showed raised risks relative to both accident and routine emissions; lung cancer (adjusted only indirectly for smoking) showed raised risks relative to accident emissions, routine emissions, and background gamma radiation. Overall, the pattern of results does not provide convincing evidence that radiation releases from the Three Mile Island nuclear facility influenced cancer risk during the limited period of follow-up.

Adolescent↗

PubMed1988

Assessing female fertility.

A concern exists that infertility is on the rise among American couples. While secular trends do not support this, there is reason to believe that deferral of child bearing is associated with a delay in conception. This paper reviews the data on factors that interfere with fertility and fecundity, such as maternal age and occupational exposures. Also discussed are epidemiological tools and strategies for evaluating the various components of female fertility and for identifying adverse influences.

Female↗

PubMed1987