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PubMed1991

Epidemiologic analysis of warfare. A historical review.

Although warfare is thought to be responsible for high and increasing levels of morbidity and mortality in the modern era, little comparative epidemiologic research is available on the subject. Most research on past wars has been carried out for purposes of military planning. The present report provides an overview of the direct health impacts of various wars on military and civilian populations during the last 200 years. Risk factors for injury and death are analyzed. Changes in weaponry, military strategy, and medical services are found to modify the health effects of warfare.

History, 17th Century↗

PubMed1995

[Toxicology of reproduction and development. Changes in the male reproductive function caused by drugs and pollutants: potential effects on offspring].

Published clinical observations underline the difficulty of defining with epidemiological studies the effects that chemicals such as drugs, illicit substances environmental and workplace pollutants might have on the offspring through the male parent. The Authors highlight how defining this issue might help both guide preclinical research and evaluate correctly clinical observations which are often difficult to interpret based only on observations in the female parent. Clinical research already available shows that some chemicals are able to modify fertility by acting either at the neuroendocrine level or on the testis. However, it is more difficult to identify and quantify the potential damage to the offsprings during the different phases of pregnancy and postnatal life. Finally, the Authors discuss the parameters that should be considered to obtain an algorithm for evaluating the reproductive risk in males, along the lines of the risk for the embryo and fetus due to the use of drugs during pregnancy. Moreover, it is suggested that among the unwanted effects of drugs and pollutants, those related to the different components and phases of the male reproductive function be reported also in relation to the patient's age.

Environmental Pollutants↗

PubMed2006

Dietary phytoestrogen intake is associated with reduced colorectal cancer risk.

Evidence suggests dietary phytoestrogens may reduce the risk of certain hormonal cancers (e.g. breast and prostate). There is a paucity of data regarding phytoestrogens and colorectal cancer risk. Phytoestrogens are plant compounds with estrogen-like activities. Main classes include isoflavones (found in legumes such as soy) and lignans (found in grains, seeds, nuts, fruits, and vegetables). Although isoflavones have dominated phytoestrogen cancer research, lignans may be more relevant to North American diets. Food questionnaires and analytic databases have recently been modified to incorporate some lignan information. We conducted a case-control study to evaluate the association between phytoestrogen intake and colorectal cancer risk. Colorectal cancer cases were diagnosed in 1997-2000, aged 20-74 y, identified through the population-based Ontario Cancer Registry, and recruited by the Ontario Familial Colorectal Cancer Registry. Controls were a sex and age-group matched random sample of the population of Ontario. Epidemiologic and food frequency questionnaires were completed by 1095 cases and 1890 control subjects. Multivariate logistic regression analysis was used to obtain adjusted odds ratio (OR) estimates. Dietary lignan intake was associated with a significant reduction in colorectal cancer risk [OR (T3 vs. T1) = 0.73; 95% CI: 0.56, 0.94], as was isoflavone intake [OR (T3 vs. T1) = 0.71; 95% CI: 0.58, 0.86]. We evaluated interactions between polymorphic genes that encode enzymes possibly involved in metabolism of phytoestrogens (CYPs, catechol O-methyl transferase, GSTs, and UGTs) and found no significant effect modification with respect to phytoestrogen intake. This finding that phytoestrogen intake may reduce colorectal cancer risk is important, because dietary intake is potentially modifiable.

Colorectal Neoplasms↗

PubMed1998

Use of two-segmented logistic regression to estimate change-points in epidemiologic studies.

In many epidemiologic data, the dose-response relation between a continuous exposure and the risk of disease abruptly changes when the exposure variable reaches an unknown threshold level, the so-called change-point. Although several methods are available for dose-response assessment with dichotomous outcomes, none of them provide inferential procedures to estimate change-points. In this paper, we describe a two-segmented logistic regression model, in which the linear term associated with a continuous exposure in standard logistic regression is replaced by a two-segmented polynomial function with unknown change-point, which is also estimated. A modified, iteratively reweighted least squares algorithm is presented to obtain parameter estimates and confidence intervals, and the performance of this model is explored through simulation. Finally, a two-segmented logistic regression model is applied to a case-control study of the association of alcohol intake with the risk of myocardial infarction and compared with alternative analyses. The ability of two-segmented logistic regression to estimate and provide inferences for the location of change-points and for the magnitude of other parameters of effect will make this model a useful complement to other methods of dose-response analysis in epidemiologic studies.

Alcohol Drinking↗

PubMed2005

Recovery from DSM-IV alcohol dependence: United States, 2001-2002.

AIMS: To investigate the prevalence and correlates of recovery from Diagnostic and Statistical Manual version IV (DSM-IV) alcohol dependence by examining the past-year status of individuals who met the criteria for prior-to-past-year (PPY) dependence. DESIGN: Cross-sectional, retrospective survey of a nationally representative sample of US adults 18 years of age and over (first wave of a planned longitudinal survey). METHODS: This analysis is based on data from the 2001-02 National Epidemiologic Survey on Alcohol and Related Conditions (NESARC), in which data were collected in personal interviews conducted with one randomly selected adult in each sample household. A subset of the NESARC sample (total n = 43 093), consisting of 4422 US adults 18 years of age and over classified with PPY DSM-IV alcohol dependence, were evaluated with respect to their past-year recovery status: past-year dependence, partial remission, full remission, asymptomatic risk drinking, abstinent recovery (AR) and non-abstinent recovery (NR). Correlates of past-year status were examined in bivariate analyses and using multivariate logistic regression models. FINDINGS: Of people classified with PPY alcohol dependence, 25.0% were still classified as dependent in the past year; 27.3% were classified as being in partial remission; 11.8% were asymptomatic risk drinkers who demonstrated a pattern of drinking that put them at risk of relapse; 17.7% were low-risk drinkers; and 18.2% were abstainers. Only 25.5% of people with PPY dependence ever received treatment. Being married was associated positively with the odds of both AR and NR, and ethanol intake was negatively associated with both. Severity of dependence increased the odds of AR but decreased the odds of NR. The odds of AR (but not NR) increased with age and female gender but were decreased by the presence of a personality disorder. Treatment history modified the effects of college attendance/graduation, age at onset and interval since onset on the odds of recovery. CONCLUSIONS: There is a substantial level of recovery from alcohol dependence. Information on factors associated with recovery may be useful in targeting appropriate treatment modalities.

Adolescent↗

PubMed2002

Effects of air pollution on daily clinic visits for lower respiratory tract illness.

The authors used data obtained from clinic records and environmental monitoring stations in Taiwan during 1998 to estimate the association between air pollution and daily numbers of clinic visits for lower respiratory tract illness. A small-area design and hierarchical modeling were used for the analysis. Rates of daily clinic visits were associated with current-day concentrations of nitrogen dioxide, carbon monoxide, sulfur dioxide, and particulate matter less than or equal to 10 microm in aerometric diameter. People over age 65 years were the most susceptible, and estimated pollution effects decreased as the exposure time lag increased. The analysis also suggested that several community-specific variables, such as a community's population density and yearly air pollution levels, modified the effects of air pollution. In this paper, the authors demonstrate the use of a small-area design to assess acute health effects of air pollution.

Adolescent↗

PubMed1982

Analytic, experimental, and theoretical neuroepidemiology: applications to occupational neurology.

Analytic neuroepidemiologic studies can be particularly valuable in identifying factors associated with either a high or low risk of disease in the industrial environment. Intervention strategies can then be formulated and the effectiveness of such programs can be tested using the techniques of experimental neuroepidemiology. By constructing mathematical models (theoretical neuroepidemiology) of actual situations, it is possible to attempt to predict how the frequency of disease will change if certain aspects of the environment are modified.

Cross-Sectional Studies↗

PubMed2004

Impaired glucose tolerance and cardiovascular disease: the possible role of post-prandial hyperglycemia.

There is increasing evidence that the post-prandial state is an important contributing factor in the development of atherosclerosis. In subjects with impaired glucose tolerance, whereas fasting glycemia is in reference range, the post-prandial phase is characterized by a rapid and large increase in blood glucose levels. The possibility that this post-prandial "hyperglycemic spike" may be relevant to the development of cardiovascular disease in these subjects has received recently much attention. The oral glucose tolerance test, although highly non-physiological, has been used largely as model of the post-prandial state, and epidemiological studies have shown that impaired oral glucose tolerance is associated with an increased risk of cardiovascular disease, because the glycemia level after 2 hours of the glucose challenge is a direct and independent risk factor. Most of the cardiovascular risk factors are modified in the post-prandial phase and are directly affected by an acute increase of glycemia. The mechanisms through which acute hyperglycemia exerts its effects may be identified in the production of free radicals, which favours the development of an endothelial dysfunction, a prothrombotic and proinflammatory condition. Future studies may evaluate whether correcting the post-prandial hyperglycemia in the impaired glucose tolerance state can form part of the strategy for the prevention and management of cardiovascular diseases in these subjects.

Blood Glucose↗

PubMed2004

Body mass index and risk of colorectal cancer in women (United States).

OBJECTIVE: Epidemiologic data relating obesity to risk of colorectal cancer in women have been inconclusive. Two recent studies have suggested that the association may be modified by estrogen status; BMI was positively associated with colorectal cancer risk among women with high estrogen exposures [premenopausal women, and postmenopausal women who currently received postmenopausal hormone therapy (PMH)]. We prospectively investigated the role of BMI in colorectal cancer risk along with the modifying effects of estrogen in a large cohort from the Women's Health Study. METHODS: Among 39,876 apparently healthy women aged > or = 45 years at baseline (54% of them were postmenopausal), 37,671 were eligible for the present study. During an average of 8.7 years of follow-up, 202 women had a confirmed diagnosis of colorectal cancer. Baseline BMI was calculated by dividing self-reported weight in kilograms by height in meters squared. RESULTS: The multivariate relative risks (RRs) and 95% confidence interval (CI) of colorectal cancer were 1.72 (1.12-2.66) for 27-29.9 kg/m2, and 1.67 (1.08-2.59) for > or = 30 kg/m2, as compared with BMI < 23 kg/m2 ( p for trend = 0.02). This positive association was seen primarily in the proximal colon ( p for trend = 0.004). When the association was further examined according to PMH use among postmenopausal women, we found that both current and never users with higher BMI were at a greater risk of colorectal cancer ( p for interaction between BMI and PMH use = 0.33). As compared with BMI < 23 kg/m2, the multivariate RRs and 95% CI for 27-29.9 and > or = 30 kg/m2 were 1.98 (0.98-3.99) and 1.41 (0.65-3.06) among current users, and 1.05 (0.42-2.65) and 2.91 (1.40-6.06) among never users. CONCLUSIONS: These data suggest that higher BMI was associated with an elevated risk of colorectal cancer, and the positive relationship was not altered by estrogen exposure among postmenopausal women.

Aged↗

PubMed1999

Development of a database for assessing dietary phytoestrogen intake.

For the past two decades, epidemiologists have observed lower risks of lung, breast, prostate, colon, and other cancers in populations that frequently consume fruits and vegetables. Numerous phytoestrogens have been shown to be anticarcinogenic under experimental conditions and may account for at least part of the cancer-prevention effects of fruit and vegetable consumption. These plant constituents include isoflavonoids, coumestans, lignans, phytosterols, and flavonoids. DietSys, the nutrient analysis program associated with the National Cancer Institute Health Habits and History Questionnaire (HHHQ), and other nationally available nutrient analysis databases do not fully assess these constituents. Therefore, we modified DietSys to include these components in foods on the basis of published values. In addition, as part of an epidemiological study of prostate cancer, we modified the food-frequency component of the HHHQ to include the main foods contributing to phytoestrogen intake. Although there are limitations to the consistency and quality of many of the values because they were gathered from a variety of sources, our approach should provide a useful first tool for assessing the epidemiological association between phytoestrogen consumption and cancer risk. Furthermore, this work has already facilitated the identification of the major dietary contributors with phytoestrogen activity and prioritized future laboratory analyses of specific foods toward the development of a more complete and accurate database.

Anticarcinogenic Agents↗

PubMed2001

Dietary whey protein protects against azoxymethane-induced colon tumors in male rats.

Epidemiological studies have suggested a relationship between diet and colon cancer incidence. Results from animal studies suggest that whey protein, but not casein protein, may provide protective effects against experimentally induced breast cancer in animals. In the current study, we investigated the effects of casein and whey diets on chemically induced colon cancer in male rats. Pregnant female Sprague Dawley rats (days 3-4 of gestation) were maintained on modified AIN-93G diets formulated with a single protein source of either casein or whey. Life-time exposure to these diets was studied in the F1 generation (experiment A) or the F2 generation (experiment B). Male offspring were weaned to the same diets as the dams and were maintained on these diets throughout the study. At age 90 days, all rats received azoxymethane once a week for 2 weeks (s.c., 15 mg/kg). Forty weeks after the last azoxymethane injection, all rats were euthanized, the colon was examined visually for tumors, and each tumor was histologically evaluated. The weights and distribution of all of the tumors were recorded. In experiment A, rats fed the casein diet had a 56% incidence of colon tumors compared with 30% of the rats on whey-based diets (P < 0.05). In experiment B, rats fed the casein diet had 50% incidence of colon tumors compared with 29% in the whey group (P < 0.05). There were no significant effects of diet on tumor multiplicity or mass. These results suggest that consumption of whey protein-containing diets may reduce the risk of developing colon tumors.

Animals↗

PubMedDate not supplied

Epidemiology of breast cancer. Preventive aspects.

Descriptive data demonstrate a marked variation in the incidence of breast cancer in distinct populations, which is closely linked to socioeconomic status and correlated with a differential age-specific incidence pattern and time trends. These suggest a westernization effect, and the possible existence of two distinct disease entities--pre- and postmenopausal. Known risk factors may be defined in a number of ways. From a preventive standpoint, a practical classification is suggested whereby risk factors are grouped as preventable, modifiable, unapproachable or spurious. The only risk factors which seem definite at present are estrogen exposure, family history and radiation, with the possible contribution of benign breast disease, replacement hormones, and diet. The only preventable factors are radiation and possibly long-term hormonal replacement, but their contribution to the disease indicence in the population is minimal. Two theoretically modifiable factors are diet and age at first birth, but the latter cannot be easily influenced, and the effect of dietary modification is still unsubstantiated.

Adolescent↗

PubMed2004

Surgery for left ventricular aneurysm: early and late survival after simple linear repair and endoventricular patch plasty.

OBJECTIVE: Simple linear resection and endoventricular patch plasty are alternative techniques to repair postinfarction left ventricular aneurysm. The aim of the study was to compare these 2 methods with regard to early mortality and long-term survival. METHODS: We retrospectively reviewed 159 patients undergoing operations between 1989 and 2003. The epidemiologic design was of an exposed (simple linear repair, n = 74) versus nonexposed (endoventricular patch plasty, n = 85) cohort with 2 endpoints: early mortality and long-term survival. The crude effect of aneurysm repair technique versus endpoint was estimated by odds ratio, rate ratio, or relative risk and their 95% confidence intervals. Stratification analysis by using the Mantel-Haenszel method was done to quantify confounders and pinpoint effect modifiers. Adjustment for multiconfounders was performed by using logistic regression and Cox regression analysis. Survival curves were analyzed with the Breslow test and the log-rank test. RESULTS: Early mortality was 8.2% for all patients, 13.5% after linear repair and 3.5% after endoventricular patch plasty. When adjusted for multiconfounders, the risk of early mortality was significantly higher after simple linear repair than after endoventricular patch plasty (odds ratio, 4.4; 95% confidence interval, 1.1-17.8). Mean follow-up was 5.8 +/- 3.8 years (range, 0-14.0 years). Overall 5-year cumulative survival was 78%, 70.1% after linear repair and 91.4% after endoventricular patch plasty. The risk of total mortality was significantly higher after linear repair than after endoventricular patch plasty when controlled for multiconfounders (relative risk, 4.5; 95% confidence interval, 2.0-9.7). Linear repair dominated early in the series and patch plasty dominated later, giving a possible learning-curve bias in favor of patch plasty that could not be adjusted for in the regression analysis. CONCLUSIONS: Postinfarction left ventricular aneurysm can be repaired with satisfactory early and late results. Surgical risk was lower and long-term survival was higher after endoventricular patch plasty than simple linear repair. Differences in outcome should be interpreted with care because of the retrospective study design and the chronology of the 2 repair methods.

Adult↗

PubMed1997

Parity-associated weight gain and its modification by sociodemographic and behavioral factors: a prospective analysis in US women.

OBJECTIVE: To examine how the relationship between parity increase and weight gain is modified by sociodemographic and behavioral factors. DESIGN: Prospective longitudinal data from the first National Health and Nutrition Examination Survey (NHANES I, 1971-75) and its follow-up of those aged 25 y and older, the NHANES I Epidemiologic Follow-up Survey (NHEFS, 1982-84). SUBJECTS: The analytical sample was nationally representative of the United States and included 2952 white or African-American non-pregnant women aged 25-45 y at baseline, who were re-measured approximately 10 y later. MEASUREMENTS: Statistical interactions in multiple linear and logistic regression models were examined to identify how eight sociodemographic and three behavioral factors modified the effect of parity increase on body weight change and risk of substantial weight gain. RESULTS: Factors that increased parity-associated weight gain included being African-American, living in a rural area, not working outside the home, having fewer children, lower income and lower education, and being unmarried. Among white women, being younger and having higher body weight at baseline increased parity-associated weight gain, while among African-American women, being older and having lower body weight increased parity-associated weight gain. African-American smokers gained less weight with an increase in parity, while the interactions between smoking and physical activity with parity-associated weight gain in whites were complex. CONCLUSION: The effects of sociodemographic and behavioral factors on parity-associated weight gain varied by race and parity change, with the most consistent findings being that unmarried and unemployed white women had greater parity-associated weight gain, while both white and African-American women who smoked, had higher education, or higher parity had lower parity-associated weight gain. This information may contribute to better targeting and more effective interventions to prevent postpartum weight retention.

Adult↗

PubMed1999

Association of Helicobacter pylori infection with gastric carcinoma: a meta-analysis.

OBJECTIVE: As conflicting studies have recently been published, we aimed to determine if Helicobacter pylori (H. pylori) infection is associated with gastric adenocarcinoma. METHODS: This was a meta-analysis of observational epidemiological studies. RESULTS: A total of 42 studies met the selection criteria and were categorized by the type of study design: eight cohort and 34 case-control studies. The pooled odds ratio for H. pylori in relation to gastric carcinoma was 2.04 (95% CI: 1.69-2.45). Both patient age (OR 0.77, 95% CI: 0.68-0.89) and intestinal type cancers (OR 1.14, 95% CI: 1.05-1.25) were independent effect modifiers. Analysis of other effect modifiers showed no relationship with female gender (OR 0.76, 95% CI: 0.64-0.89), stage of cancer (advanced %) (OR 1.12, 95% CI: 0.88-1.43), anatomical location (cardia %) (OR 1.54, 95% CI: 0.32-7.39) or cohort (nested case-control) studies (OR 1.72, 95% CI: 0.32-9.17). There was significant heterogeneity among the studies (tau2 = 149; p < 0.001). The quality of the studies varied considerably, with the majority of excellent studies producing positive results and the very poor to moderate studies producing mixed results. CONCLUSIONS: H. pylori infection is associated with a 2-fold increased risk of developing gastric adenocarcinoma.

Adenocarcinoma↗

PubMed2001

Longchain n-3 polyunsaturated fatty acids and blood vessel function.

The cardiovascular health benefits of longchain n-3 polyunsaturated fatty acids (PUFAs) have been reported to exert at several different cellular control mechanisms. These include, effects on lipoprotein metabolism, haemostatic function, platelet/vessel wall interactions, anti-arrhythmic actions and also inhibition of proliferation of smooth muscle cells and therefore growth of the atherosclerotic plaque. Fish oil feeding has also been found to result in moderate reductions in blood pressure and to modify vascular neuroeffector mechanisms. The majority of such cardiovascular benefits of n-3 PUFAs are likely to be mediated in the vascular wall and at the vascular endothelium level, since this monolayer of cells plays a central role in the regulation and maintenance of cardiovascular homeostasis and function. While these processes include endothelium-derived vasorelaxant and vasoconstrictor compounds, the vascular endothelium also plays host to many receptors, binding proteins, transporters and signalling mechanisms. Accordingly, endothelial dysfunction, which underlies many cardiovascular disease conditions, can trigger acute vascular events including vasospasm, thrombosis or restenosis leading to ischaemia. The longchain n-3 PUFAs have been reported to possess several properties that may positively influence vascular function. These include favourable mediator profiles (nitric oxide, eicosanoids) that influence vascular reactivity, change in vascular tone via actions on selective ion channels, and maintenance of vascular integrity. In addition to direct effects on contractility, n-3 PUFAs may affect vascular function, and the process of atherogenesis, via inhibition of vascular smooth muscle cell proliferation at the gene expression level, and by modifying expression of inflammatory cytokinesis and adhesion molecules. Collectively, these properties are consistent with pleiotropic actions of longchain n-3 PUFAs, and may explain the beneficial cardiovascular protection of this family of fatty acids that have been clearly evident through epidemiological data as well from more recent large-scale clinical trials.

Anti-Arrhythmia Agents↗

PubMed2006

Refining the attention deficit hyperactivity disorder phenotype for molecular genetic studies.

It is well established that attention deficit hyperactivity disorder (ADHD) is a familial and highly heritable disorder. Consequently, much effort is being directed towards searching for specific susceptibility genes. There is a growing trend, across the field of complex disease genetics, towards undertaking secondary analyses based on refined phenotypic definitions and in testing whether specific susceptibility genes modify the phenotypic presentation of the disorder in question. It is crucial that good, empirically derived arguments are made before undertaking multiple analyses on different phenotype refinements. In this review article, we consider the evidence from genetic epidemiological studies as well as key clinical studies that provide guidance on examining the ADHD phenotype for the purpose of molecular genetic studies. Specifically, findings on categorical versus dimensional conceptualisations of ADHD, reporter effects, comorbidity, ADHD subtypes and persistence are reviewed. Current evidence suggests that for the purpose of identifying susceptibility genes for ADHD, parent and teachers should be used as informants and that focusing on the clinical diagnosis of ADHD is useful. There is also good empirical support in favour of examining antisocial behaviour in ADHD. Genetic studies of dimensional ADHD are useful for other complementary purposes.

Attention Deficit Disorder with Hyperactivity↗

PubMed1997

Body iron stores and the risk of carotid atherosclerosis: prospective results from the Bruneck study.

BACKGROUND: Fe2+ released from tissue iron stores may accelerate lipid peroxidation by virtue of its pro-oxidant properties and thus promote early atherogenesis. METHODS AND RESULTS: The present prospective survey addresses the potential association between serum ferritin concentrations and the 5-year progression of carotid atherosclerosis as assessed by ultrasonographic follow-up evaluations. The study population comprises a random sample of 826 men and women 40 to 79 years old. Serum ferritin was one of the strongest risk predictors of overall progression of atherosclerosis. The main part of this association appeared to act through modification of the atherogenic potential of LDL cholesterol (OR [95% CI] for a 1-SD unit increase in ferritin at LDL levels of 2.5, 3.6, and 4.9 mmol/L: 1.55 [1.30 to 1.85], 1.77 [1.40 to 2.24], and 2.05 [1.50 to 2.80]; P=.0012 for effect modification). Changes in iron stores during the follow-up period modified atherosclerosis risk, in that a lowering was beneficial and further iron accumulation exerted unfavorable effects. All these findings applied equally to incident atherosclerosis and the extension of preexisting atherosclerotic lesions. The significance of prominent iron stores in the development of carotid stenosis was clearly less pronounced. Finally, ferritin and LDL cholesterol showed a synergistic association with incident cardiovascular disease and death (n=59). CONCLUSIONS: The present study provided strong epidemiological evidence for a role of iron stores in early atherogenesis and suggests promotion of lipid peroxidation as the main underlying pathomechanism. This hypothesis could in part explain the sex difference in atherosclerotic vascular disease.

Adult↗