Health symptoms in Persian Gulf veterans: where do we go from here?
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Adult↗
Biomedical subjects
M C Hatch
Publications and source records attributed to M C Hatch.
Epidemiology of pregnancy-induced hypertension.
Mounting evidence clearly indicates an immunologic basis for PIH, parity being the most convincing factor. Genetic susceptibility, physiologic change, and environmental influence may also modulate an individual's risk of developing PIH. Pathologic and follow-up studies further suggests further suggest that currently diagnosed PIH may actually be a heterogeneous entity comprising several disorders of different etiologies (150), such as chronic renal disease, borderline chronic hypertension, genetic susceptibility to hypertension, and genuine PIH. For many diseases, etiologic research and clinical management often go hand in hand. Unfortunately, in the case of PIH, etiologic research may have followed clinical steps too closely and have been misled. For clinical management, genuine preeclampsia and preeclampsia superimposed on chronic hypertension are treated as virtually the same: The ultimate goal is to prevent eclampsia. Because a sizable portion of PIH is probably due to chronic renal disease or latent chronic hypertension (33), and late-onset gestational hypertension is of less concern than preeclampsia, one could argue that it may not be clinically important to separate the subtypes of PIH. In etiologic research, however, by focusing on a heterogeneous outcome we have confused ourselves and hampered our progress. On the other hand, one should also realize that currently available techniques are unlikely to substantially improve our proficiency in differential diagnosis. Besides renal biopsy, which is impractical, especially in epidemiologic research, there are virtually no measures available that can distinguish genuine PIH from hypertension due to latent renal disorder, chronic hypertension, or genetic susceptibility. Until noninvasive measures with acceptable-sensitivity and specificity are available for differential diagnosis, frustration in etiologic research on PIH is likely to continue. One clue that may potentially advance our knowledge of the pathogenesis and future prevention of PIH is the finding that smoking reduces risk of PIH. Epidemiologists should transfer this knowledge to laboratory scientists.
Female↗
Stress, work, and pregnancy complications.
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Bias↗
Anthropometric and reproductive factors and the risk of pancreatic cancer: a case-control study in Shanghai, China.
To examine the possible role of body size and reproductive factors in pancreatic cancer, data were analyzed from a population-based case-control study conducted in Shanghai, China. 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. Deceased cases (19%) were excluded from the study. Controls (n = 1,552) were randomly selected from permanent Shanghai residents and frequency-matched to cases by gender and age. Information on body size and reproductive and other possible risk factors was collected through personal interviews. After adjustment for age, income, smoking and other confounders, a positive dose-response relation between body mass index and risk of pancreatic cancer was observed in both sexes. Among women, the risk of pancreatic cancer was significantly associated with number of pregnancies and live births. Compared with 0-2 pregnancies or live births, the odds ratio (OR) for 8 or more pregnancies was 1.90, while that for 5 or more births was 1.88. A modest elevation in risk, independent of parity, was associated with early age at first birth. Risk increased over 40% among women with a first birth at or before age 19 years relative to those at age 26 years or older. Ever use of oral contraceptives was associated with excess risk, though based on small numbers of users. Our findings suggest that, in Shanghai, obesity, gravidity, parity and perhaps use of oral contraceptives are associated with moderate increases in risk of pancreatic cancer, indicating that hormonal determinants deserve further investigation.
Aged↗
Continuous labor support from labor attendant for primiparous women: a meta-analysis.
OBJECTIVE: To evaluate the available literature on the effects of continuous labor support among primiparous women. DATA SOURCES: We did a Medline search using the keywords "labor support," "doula," and "monitrice." Papers published in English from 1965 to May 1995 were eligible for this review. We also cross-checked all the references in the selected reports. METHODS OF STUDY SELECTION: We identified seven randomized clinical trials published during that period; four of these were eligible for our meta-analysis. DATA EXTRACTION AND SYNTHESIS: Meta-analysis of four studies conducted among young, low-income, primiparous women who gave birth on a busy labor floor in the absence of a companion suggested that continuous labor support by a labor attendant shortens the duration of labor by 2.8 hours (95% confidence interval [CI] 2.2-3.4), doubles spontaneous vaginal birth (relative risk [RR] 2.01, 95% CI 1.5-2.7) and halves the frequency of oxytocin use (RR 0.44, 95% CI 0.4-0.7), forceps use (RR 0.46, 95% CI 0.3-0.7), and cesarean delivery rate (RR 0.54, 95% CI 0.4-0.7). Women with labor support also reported higher satisfaction and a better postpartum course. CONCLUSION: Labor support may have important positive effects on obstetric outcomes among young, disadvantaged women. Further studies on benefit relative to cost are needed before a broad-scale program is advocated.
Delivery, Obstetric↗
Do stressful life events affect duration of gestation and risk of preterm delivery?
The present study was designed to test the relation between stressful life events experienced during pregnancy and the risk of preterm delivery and shortened duration of pregnancy. We collected data prospectively in a general population sample, including repeated questionnaire measures of exposure to stressful life events during pregnancy. Between August 1989 and September 1991, 8,719 Danish-speaking women with singleton pregnancies attended antenatal care. Of these women, 5,873 (67%) completed all questionnaires. When indicating an event, the woman was asked to rate the amount of stress induced by this event. Measurement of gestational duration was primarily based on early ultrasound scan. When we evaluated life events independently of the individual's appraisal, we found no association with duration of gestation or risk of preterm delivery. In contrast, life events assessed by the subject as highly stressful were associated with shorter mean duration of gestation and increased risk of preterm delivery. This association was observed primarily with events experienced between the 16th and 30th week of gestation. Women who had one or more highly stressful life events had a risk of preterm delivery 1.76 times greater than those without stressful events (95% confidence interval = 1.15-2.71). We found no evidence for a buffering effect of social support.
Adult↗
Psychosocial work stress and pregnancy-induced hypertension.
We examined the association between work during pregnancy and pregnancy-induced hypertension in a prospective cohort study of 717 women. We classified cases, whom we identified by uniform review of blood pressures and proteinuria in prenatal records, into two categories: gestational hypertension (N = 16, 2.5%) and preeclampsia (N = 11, 1.7%). All cases of pregnancy-induced hypertension occurred among the 575 subjects who worked during the first trimester of pregnancy. The association with employment was not explained by primiparity or other known risk factors, or by physical work demands, long work hours, or total hours of paid work, housework, and child care. Stressful job characteristics, however, did show associations with pregnancy-induced hypertension. In particular, gestational hypertension was associated with low decision latitude and low job complexity among women in lower-status jobs [standardized odds ratio (SOR) = 2.4 for low latitude, 95% confidence interval (CI) = 1.1-5.2; SOR = 2.1 for low complexity, 95% CI = 1.0-4.6]. Among women in higher-status jobs, gestational hypertension was associated with job pressures/low control (SOR = 3.6, 95% CI = 0.9-15.1). Psychosocial job stressors, not studied previously, might explain earlier reports of a raised risk of pregnancy-induced hypertension among pregnant workers.
Adult↗
Stress, social support and pregnancy outcome: a reassessment based on recent research.
We present an assessment of studies published in the last decade that consider the relationship of stress and social support to preterm delivery or fetal growth retardation. Included in the review are all reports on the direct effects of stressors or psychological distress; the indirect effects of stressors or distress through health behaviours such as smoking; and the direct and buffering effects of social support. Although an important stimulus for recent stress research has been the attempt to explain racial and social class differences in birth outcome, the recent data show that stressful life events during pregnancy, though more common in disadvantaged groups, do not increase the risk of preterm birth. In contrast, intimate social support from a partner or family member appears to improve fetal growth, even for women with little life stress. Questions unanswered by the research to date are whether elevated levels of depressive symptoms affect pregnancy outcome, either directly or by encouraging negative health behaviours, and whether chronic (vs. acute) stressors are harmful. Additional research is also needed to determine whether psychosocial factors interact with specific clinical conditions to promote adverse pregnancy outcomes. Focusing on intimate support and how it benefits pregnancy outcome could lead to the design of more effective interventions.
Black or African American↗
Reproductive and developmental effects of disinfection by-products in drinking water.
Recent epidemiologic studies have reported associations between the consumption of chlorinated drinking water and reproductive and developmental effects. Here we review the available epidemiologic data, assess the hazard potential posed by exposure to disinfection by-products, identify critical data gaps, and offer recommendations for further research. The epidemiologic evidence supporting associations between exposure to water disinfection by-products (DBPs) and adverse pregnancy outcomes is sparse, and positive findings should be interpreted cautiously. The methods used during the early stages of research in this area have been diverse. Variability in exposure assessment and endpoints makes it difficult to synthesize or combine the available data. Exposure misclassification and unmeasured confounding may have lead to bias in risk estimation. Future studies of reproductive outcome and exposure to chlorinated water should use improved methods for exposure assessment to 1) assure selection of appropriate exposure markers, 2) assess seasonal and annual fluctuations in DBPs, 3) assess variability within the distribution system, and 4) assess exposure through multiple routes such as bathing and showering, as well as consumption. Population-based studies should be conducted to evaluate male and female fertility, conception delay, growth retardation, and specific birth defects. The reproductive and developmental effects of exposure to DBPs could be efficiently explored in ongoing investigations by incorporating valid exposure markers and relevant questionnaire information. Future studies should make use of naturally occurring variability in the concentrations of DBPs and may incorporate biomarkers of exposure and effect in their design. Epidemiologic investigations should be conducted in parallel with laboratory-based and animal studies in a coordinated, multidisciplinary approach.
Abnormalities, Drug-Induced↗
Hypertension in the elderly: correction and clarification.
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Aged↗
Cigarette smoking and alcohol consumption and the risk of pancreatic cancer: a case-control study in Shanghai, China.
Cancer of the pancreas has been rising in incidence in Shanghai, China since the early 1970s. In 1987-89, this malignancy ranked eighth in cancer incidence among men and ninth among women in Shanghai. To examine risk factors for this tumor in urban Shanghai, a population-based case-control study was conducted. Cases (n = 451) were permanent residents of Shanghai, 30 to 74 years of age, newly diagnosed with pancreatic cancer between 1 October 1990 and 30 June 1993. Deceased cases (19 percent) were excluded from the study. Controls (n = 1,552) were selected among Shanghai residents, frequency-matched to cases by gender and age. Cases and controls were interviewed about their demographic background and potential risk factors, including tobacco, alcohol and beverage consumption, diet, and medical history. Adjusted odds ratios (OR) and 95 percent confidence intervals (CI) were estimated using logistic regression models. Current cigarette smoking was associated with excess risk of pancreatic cancer in both men (OR = 1.6, CI = 1.1-2.2) and women (OR = 1.4, CI = 0.9-2.4). ORs increased significantly with number of cigarettes smoked per day, and with duration and pack-years of smoking. Risk increased three- to sixfold among those in the highest categories of cigarette consumption, while risk decreased with increasing years since smoking cessation. Former smokers who stopped smoking for 10 or more years had risks comparable to nonsmokers.
Adult↗
Early ultrasound dating of pregnancy: selection and measurement biases.
Can using early ultrasound examinations to date pregnancy introduce information bias in perinatal research? Our purpose was to identify determinants of early ultrasound examinations and to compare early ultrasound to menstrual history dating. Between January 1987 and June 1989, 1159 white, largely middle class, prenatal patients were contacted for a prospective observational study. 876 (76%) agreed to participate. Of these 764 (87%) met the eligibility criteria for this analysis, namely singleton pregnancy, delivered after 20 weeks (spontaneous or induced, vaginal or c-section), with prenatal chart abstracted. Selection factors for early ultrasound identified in multivariate analysis were: bleeding in early pregnancy, OR = 1.9 (1.0, 3.5), attendance at health maintenance organization OR = 7.2 (3.4, 15), no insurance or Medicaid only OR = 0.3 (0.1, 0.6), and increasing time from last menstrual period to first prenatal visit in weeks OR = 0.89 (0.85, 0.93). In conformity with previous results, ultrasound dating of pregnancy led to a higher estimate of preterm delivery (10 vs 7.6%), a higher estimate of term delivery (87.2 vs 82.7%) and a lower estimate of postterm delivery (2.8 vs 9.7%) than dating by menstrual history, p < 0.001. Selection factors and measurement issues, such as those described here, could introduce bias and should be carefully considered in the design, analysis and interpretation of perinatal research.
Female↗
Maternal smoking, alcohol drinking, caffeine consumption, and fetal growth: results from a prospective study.
In a prospective study of 712 pregnancies, we examined associations between maternal smoking, alcohol, and caffeine consumption and fetal growth. We interviewed patients at entry into care [12.9 +/- 4.3 (standard deviation) weeks], and at 28 and 36 weeks of gestation. We found the expected reductions in adjusted birthweight among women who smoked throughout pregnancy: 168 gm [95% confidence limits (CL) = -326, -10] for low/moderate amounts (< or = 15 cigarettes per day); 288 gm (95% CL = -491, -84) for heavy smoking (> 15 cigarettes per day). We also found a decrease in birthweight (-179 gm; 95% CL = -364, 7) among smokers who reported quiting early in pregnancy. First trimester alcohol consumption (average: four drinks per week) was associated with a 155-gm reduction in fetal growth (95% CL = -324, 15), even after adjustment for number of cigarettes smoked. The association, observed with all types of alcohol consumption, was stronger among smokers (-270 gm) but was also present in nonsmokers (-115 gm). Caffeine consumption showed no relation to fetal growth, even among heavy consumers, although they were relatively few. This study implicates heavy maternal smoking at any point in pregnancy, including solely in the early months, and possibly moderate alcohol drinking as causes of low birthweight.
Adult↗
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↗
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↗
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↗
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↗
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↗