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H Brenner

Publications and source records attributed to H Brenner.

At least 91 records · Page 5Linked to original sources
PubMed2000

Inverse relationship between gastric colonization of Helicobacter pylori and diarrheal illnesses in children: results of a population-based cross-sectional study.

It has been suggested that carriage of Helicobacter pylori may protect against infections by exogenous intestinal pathogens. An analysis was done of all children who were screened for school fitness during 1996-1998 in Ulm, Germany, to compare rates of diarrheal illnesses in H. pylori-positive and H. pylori-negative children. Of 2477 5-8-year-old children studied, 304 (12.3%) were H. pylori-positive by carbon 13-labeled urea breath test. For H. pylori-positive children, diarrhea within the prior 3 months was less often reported than for H. pylori-negative children (54.3% vs. 76.1%; P<.001, adjusted for nationality). Compared with H. pylori-negative children, the odds ratio (OR) for the occurrence of diarrhea within the prior 3 months was 0.37 (95% confidence interval [CI], 0.28-0.49) for H. pylori-positive children; after adjustment for covariates, the OR was 0.56 (95% CI, 0.42-0.76). These data support the hypothesis that H. pylori colonization may protect against diarrheagenic gastrointestinal infections.

Child↗
PubMed2000

Obesity, overweight and patterns of osteoarthritis: the Ulm Osteoarthritis Study.

The objective of this study was to assess the association between obesity and osteoarthritis (OA) of the knee, hip, and hand. OA patterns were studied in 809 patients with knee or hip joint replacement due to OA. Patients with OA were categorized as having bilateral or generalized OA according to the presence of radiographic OA in the contralateral joint or different finger joints, and as normal weight, overweight, or obese according to their body mass index (BMI). Odds ratios (OR) and 95% confidence intervals (CI) for relative weight and OA patterns were estimated with multivariable logistic regression. Eighty-five percent of participants had bilateral OA, 26% had generalized OA, and 31% were obese. Obesity (BMI >/= 30 kg/m(2); OR = 8.1; 95% CI: 2.4-28) and overweight (BMI >/= 25 kg/m(2); OR = 5.9; 95% CI: 2.0-18) were strongly associated with bilateral knee OA. No association between obesity and bilateral hip OA (OR = 0.7; 95% CI: 0.3-1.7) nor generalized OA (OR = 1.1; 95% CI: 0.6-2.1) was observed. Obesity seems to be a mechanical rather than a systemic risk factor for OA with the knee joint being especially susceptible.

Aged↗
PubMed2000

Individual and joint contribution of family history and Helicobacter pylori infection to the risk of gastric carcinoma.

BACKGROUND: Helicobacter pylori infection and a positive family history of gastric carcinoma have been identified as risk factors for the disease. It is unclear, however, to what degree their impact on the risk of gastric carcinoma is independent, because H. pylori also clusters within families. METHODS: The authors carried out a population-based, statewide case-control study in Saarland, Germany, to assess the individual and joint contributions of family history and H. pylori infection to the risk of gastric carcinoma. Cases included 68 patients with histologically verified gastric carcinoma. Controls included 239 patients with colorectal carcinoma who were matched to the cases by age and gender. Information on family history (defined as gastric carcinoma in at least one first-degree relative) and potential confounders was collected by standardized interviews. Immunoglobulin G antibodies against H. pylori were measured by enzyme-linked immunosorbent assay. In addition, antibodies against the CagA antigen were determined by Western blot analysis. RESULTS: H. pylori infection and family history were positively related, and both risk factors were more common among cases than among controls. Although the association between family history and gastric carcinoma was somewhat reduced by control for H. pylori infection, both risk factors still showed strong independent relations with gastric carcinoma after control for each other. Compared with uninfected subjects who had no family history, subjects with both a positive family history and infection with a CagA positive H. pylori strain had a more than 8-fold total risk of gastric carcinoma (adjusted odds ratio [OR], 8.2; 95% confidence interval [CI], 2.2-30.4) and a 16-fold risk of noncardia gastric carcinoma (OR, 16.0; 95% CI, 3.9-66.4). CONCLUSIONS: Infection with CagA positive H. pylori strains and a positive family history appear to be strong independent risk factors for gastric carcinoma. They may be useful markers for identifying subjects at high risk for the disease and for targeting efforts of prevention and early detection.

Adult↗
PubMed2000

Potential gain in efficiency and power to detect gene-environment interactions by matching in case-control studies.

BACKGROUND: There is growing interest in interactions between genetic and environmental risk factors of disease, but adequate power to detect such interactions in epidemiologic studies is of concern. The aim of this paper is to quantify the effect of matching on the efficiency of estimation and power to detect gene-environment interactions in case-control studies. METHODS: Starting from an empirical example in cancer epidemiology, we simulated frequency matched and unmatched case-control studies for a wide range of assumptions regarding the prevalence and the effects of an environmental and a genetic factor on disease risk as well as the quality and quantity of the interaction between these factors. Simulated studies were analyzed with multivariable logistic regression. RESULTS: Matching increased the efficiency and power in most scenarios. The gain was most pronounced in scenarios assuming a low prevalence of the environmental exposure. In such scenarios, equivalent power was only obtained with more than twice as many unmatched than matched controls. CONCLUSIONS: Frequency matching for known environmental risk factors with a low prevalence in the population may increase the efficiency of estimation and power of case-control studies to detect gene-environment interactions considerably. Investigators should weigh the gain in efficiency and power against known potential disadvantages of matching.

Case-Control Studies↗
PubMed2000

Helicobacter pylori infection among offspring of patients with stomach cancer.

BACKGROUND & AIMS: A positive family history is associated with an increased risk of stomach cancer. We compared the prevalence of Helicobacter pylori infection, a known risk factor for stomach cancer, between subjects with and without parental history of stomach cancer to evaluate a potential role of H. pylori infection in familial aggregation of stomach cancer. METHODS: A total of 1351 men and women aged 30-74 years who participated in the German Health and Nutrition Survey conducted in the western part of Germany in 1987-1988 were included in the study. Detailed information on sociodemographic factors, nutritional factors, and parental history of cancer was obtained by standardized interviews. Serum samples were analyzed for immunoglobulin G antibodies against H. pylori by enzyme-linked immunosorbent assay. RESULTS: The prevalence of H. pylori infection was much higher (69%) among subjects with a parental history of stomach cancer than among other subjects (44%). This association persisted after control for potential confounders by multiple logistic regression (adjusted odds ratio, 2.7; 95% confidence interval, 1.3-5.9), and was particularly strong among subjects below age 55 (adjusted odds ratio, 5.1; 95% confidence interval, 1.6-16.1). CONCLUSIONS: These results suggest that familial aggregation of stomach cancer may be explained at least partly by familial clustering of H. pylori infection.

Adult↗
PubMed2000

Seropositivity to chlamydial lipopolysaccharide and Chlamydia pneumoniae, systemic inflammation and stable coronary artery disease: negative results of a case-control study.

OBJECTIVES: We investigated the association between seropositivity to chlamydial lipopolysaccharide (cLPS) or Chlamydia pneumoniae (CP) and angiographically documented coronary artery disease (CAD), and we examined the relationship between serostatus and markers of systemic inflammation. BACKGROUND: The potential contribution of CP to atherogenesis is still a matter of debate, and inflammation has been suggested to represent the link between infection and atherosclerotic disease. METHODS: Subjects age 40 to 68 years were recruited for this case-control study between October 1996 and November 1997: 312 patients with at least one coronary stenosis >50% and 479 age- and sex-matched blood donors without manifest CAD or history of angina. Antibodies against cLPS and CP, C-reactive protein (CRP), fibrinogen, plasma viscosity, leukocytes and neutrophils were determined. The study had a power of >80% to detect an odds ratio (OR) of 1.55 or above for the prevalence of immunoglobulin (IgG) antibodies against cLPS at a significance level of alpha = 0.05. RESULTS: Prevalence of IgG antibodies against cLPS was not different between cases and controls (61% vs. 62%; p = 0.7). The adjusted OR for the presence of CAD given positive IgG serostatus against cLPS was 0.9 (95% CI; 0.6 to 1.3). Similarly, no difference in the prevalence of IgG antibodies against CP was seen (88% vs. 87%; p = 0.6); the adjusted OR was 1.0 (95% CI; 0.6 to 1.6). Markers of inflammation did not show any statistically significant difference between cLPS seropositives and seronegatives. CONCLUSIONS: Our results indicate no strong association between CP and CAD, and increased systemic inflammation in patients with CAD does not seem to be due to seropositivity to cLPS or CP.

Adult↗
PubMed2000

Analytic strategies for recurrent events in epidemiologic studies: background and application to hospitalization risk in the elderly.

Due to the intraindividual dependence, specific analytic strategies are needed to assess risk factors for recurrent events. Although well established in the biostatistics literature, applications of these techniques are almost nonexistent in the field of epidemiology. The authors applied four different regression approaches for recurrent events (logistic, Poisson, and two different Cox proportional hazards regressions) to derive rate ratios of hospitalizations for various prognostic factors in a cohort of 2424 frail elderly. Over a median follow-up of 670 days, 3299 hospitalizations were observed in 1564 persons. Estimated rate ratios were similar in all four approaches and virtually identical in three. With all methods, confidence intervals of the rate ratios were considerably wider than with naive Poisson regression neglecting intraindividual dependence of events. Appropriate analysis of recurrent events is feasible with minor modifications of multivariable models familiar to epidemiologists and should no longer be neglected in epidemiologic research. In our setting, Poisson regression was the most convenient approach.

Aged↗
PubMed2000

Serum uric acid and patterns of radiographic osteoarthritis--the Ulm Osteoarthritis Study.

OBJECTIVE: To assess the association between uric acid and patterns of osteoarthritis (OA). METHODS: OA patterns were studied in 809 patients with arthroplasty due to hip or knee OA. Patients with OA were categorized as having bilateral or generalized OA according to the presence of radiographic OA in the contralateral or different finger joints. Odds ratios (OR) and 95% confidence intervals (CI) for thirds of serum uric acid and OA patterns were estimated with multivariable logistic regression. RESULTS: Eighty-five percent of the participants had bilateral OA and 26% generalized OA. A positive association between serum uric acid and generalized OA was observed in patients with hip OA (highest versus lowest tertile OR=3.5; 95% CI: 1.3-9.1), but not among patients with knee OA (corresponding OR = 1.1). Serum uric acid was not associated with bilateral OA. CONCLUSION: Our results suggest a possible role of elevated serum uric acid in the multifactorial etiology of generalized OA.

Aged↗
PubMed2000

Does maternal smoking hinder mother-child transmission of Helicobacter pylori infection?

Evidence for early childhood as the critical period of Helicobacter pylori infection and for clustering of the infection within families suggests a major role of intrafamilial transmission. In a previous study, we found a strong inverse relation between maternal smoking and H. pylori infection among preschool children, suggesting the possibility that mother-child transmission of the infection may be less efficient if the mother smokes. To evaluate this hypothesis further, we carried out a subsequent population-based study in which H. pylori infection was measured by 13C-urea breath test in 947 preschool children and their mothers. We obtained detailed information on potential risk factors for infection, including maternal smoking, by standardized questionnaires. Overall, 9.8% (93 of 947) of the children and 34.7% (329 of 947) of the mothers were infected. Prevalence of infection was much lower among children of uninfected mothers (1.9%) than among children of infected mothers (24.7%). There was a strong inverse relation of children's infection with maternal smoking (adjusted odds ratio = 0.24; 95% confidence interval = 0.12-0.49) among children of infected mothers, but not among children of uninfected mothers. These results support the hypothesis of a predominant role for mother-child transmission of H. pylori infection, which may be less efficient if the mother smokes.

Breath Tests↗
PubMed2000

Molecular wall effects: are conditions at a boundary "boundary conditions"?

This paper addresses and answers "no" to the question of whether the literal molecular-dynamically-derived species velocities prevailing at a solid surface bounding a two-component fluid continuum undergoing molecular diffusion constitute the appropriate species-velocity boundary conditions to be imposed upon the fluid continuum. In a broader context, generic boundary condition issues arising from the presence of different length scales in continuum-mechanical descriptions of physical phenomena are clarified. This is achieved by analyzing a model problem involving the steady-state diffusion of a dilute system of Brownian spheres (the latter envisioned as tractable models of solute "molecules") through a quiescent viscous solvent continuum bounded laterally by solid plane walls. Both physicochemical (potential energy) and hydrodynamic (steric) wall interaction effects experienced by the Brownian spheres are explicitly accounted for in our refined, microscale continuum model of the diffusion process. Inclusion of these "solid-wall-fluid" (s-f ) boundary-generated forces [above and beyond the usual "fluid-fluid" (f-f ) intermolecular forces implicit in the conventional Fick's law macroscale continuum description] serves to simulate the comparable s-f molecular boundary forces modeled in molecular dynamics simulations of the diffusional process. A singular perturbation framework is used to clarify the physical interpretation to be ascribed to "continuum-mechanical boundary conditions." In this same spirit we also clearly identify the origin of the physical concept of a "surface field" as well as of the concomitant surface transport conservation equation for strongly adsorbed species at solid walls. Our analysis of such surface phenomena serves to emphasize the fact that these are asymptotic, surface-excess, macroscale concepts assigned to a surface, rather than representing literal molecular material entities physically confined to the surface. Overall, this paper serves to illustrate the manner in which molecular simulations need to account for these different length scales and corresponding scale-dependent concepts if such analyses are to avoid drawing incorrect inferences regarding the molecular origins of continuum-mechanical boundary conditions.

Journal Article↗
PubMed2000

Extent and determinants of hospitalization in a cohort of older disabled people.

OBJECTIVES: The purpose of this prospective cohort study was to determine the extent and determinants of hospitalization in a population sample of older disabled people. DESIGN: A longitudinal cohort study. SETTING: Noninstitutionalized disabled people in the region of Augsburg, South Germany. PARTICIPANTS: The study population included 2427 persons, aged 60 years and older, who, between 1991 and 1993, applied for benefits from the statutory health insurance system provided to the most severely handicapped noninstitutionalized persons. MEASUREMENTS: Baseline variables were derived from a standardized medical examination. Information about hospitalization and mortality until June 30, 1996, was extracted from records of the pertinent health insurance plan. Rate ratios (RRs) of hospitalization were derived from a multivariable Poisson regression model corrected for the correlation of multiple hospitalizations for each person. RESULTS: The overall absolute hospitalization rate was 6.7 hospitalizations per 10 person-years at risk, with a mean length of stay per hospitalization of 19.2 days. Multivariable analysis showed an inverse association of age and hospitalization. Persons cared for primarily by their children had a lower rate of hospitalization (RR = 0.83) than persons relying mainly on professional home care. Medical causes of disability and dependency with respect to activities of daily living were unrelated to the hospitalization rate. A total of 1415 persons (58.3%) died during follow-up. The rate of hospitalization was twice as high among these subjects compared with others. The hospitalization rate increased rapidly during the last year of life, with a peak increase in the last 3 months. CONCLUSIONS: This study expands the current inadequate database on hospitalization in Europe. Further expansion is necessary for the efficient allocation of medical resources to older people, a group steadily increasing in numbers.

Activities of Daily Living↗
PubMed2000

Hormone replacement therapy and patterns of osteoarthritis: baseline data from the Ulm Osteoarthritis Study.

OBJECTIVES: It has been suggested that hormone replacement therapy (HRT) may protect against osteoarthritis (OA). The aim of this paper was to assess the association between HRT and radiographically defined patterns of OA. METHODS: 475 consecutive women aged 50 years or older (mean age 66.1) who underwent hip or knee joint replacement because of advanced OA in four hospitals in south west Germany were enrolled in a cross sectional study. Participants underwent a standardised interview including detailed history of medication use and a physical examination. Furthermore, radiographs of the joint being replaced and of the contralateral joint as well as of both hands were obtained. Patients were categorised as having bilateral or unilateral OA according to the presence or absence of radiographic OA in the contralateral joint. If radiographic OA of different hand and finger joint groups was present, participants were categorised as having generalised OA (GOA). Logistic regression was used to estimate odds ratios and their 95% confidence intervals for the association between HRT and bilateral or GOA while adjusting for potential confounders. RESULTS: Fifty five women (11.6%) were using HRT. The median duration of use was 5.4 years. The prevalence of bilateral and GOA was similar among users of ORT (86.3% and 27.5%, respectively) and among non-users of HRT (88.7% and 35.7%, respectively). After adjustment for potential confounding factors, the odds ratios (95% confidence intervals) of bilateral OA and GOA among HRT users compared with non-users was 1.21 (0.48, 3.03) and 1. 21 (0.53, 2.74), respectively. CONCLUSION: Despite limited generalisability because of the selective study sample, these data do not support the hypothesis that HRT acts as a systemic protective factor against OA.

Aged↗
PubMed2000

Sickness absence and early retirement on health grounds in the construction industry in Ireland.

OBJECTIVE: To establish a detailed pattern of the nature and extent of illnesses and injuries among construction workers in Ireland which cause temporary absence from work, and to identify diseases and disabilities which lead to premature retirement from the industry on health grounds. METHODS: The population base for the study consisted of construction workers who were members of the Construction Federation operatives pension and sick pay scheme. Records of sickness absence since 1981, stored on computer disks, and records of early retirement on health grounds since 1972, stored on microfiche film, were examined. Pertinent data were extracted and transferred to a database; after cleaning and the exclusion of unvalidated data, records of 28 792 absences and 3098 records of early retirement were available for analysis. Data were analysed with Access 97 and Epi Info. RESULTS: Over the period of the study the mean annual absences were 7.8/100 workers. Three quarters of absences were among younger workers; however, the rate of absence increased with age, as did the mean duration of absence. Injury was the most frequent reason for absence, followed by infectious disease, then musculoskeletal disorders. The mean annual rate of early retirement on health grounds was 5.3/1000 workers. The median age at retirement was 58 years. Cardiovascular disease and musculoskeletal disorders each accounted for nearly one third of the conditions leading to permanent disability on the grounds of which early retirement was granted. During the period of the study, over 677 000 working days were lost due to sickness absence, and over 24 000 potential years of working lives were lost due to early retirement on health grounds. CONCLUSIONS: The study has shown patterns of sickness absence and early retirement on health grounds in the Irish construction industry which will contribute to the further development of health promotion strategies for construction workers.

Adolescent↗
PubMed2000

Measurement error correction using validation data: a review of methods and their applicability in case-control studies.

Measurement error is a serious problem in the analysis of epidemiological data. In the past 20 years, a large number of methods for the correction of measurement error have been developed. While at the beginning mostly methods for cohort studies were considered, recently more attention has been paid to case-control studies. Although a variety of methods have been proposed, they are very rarely used in practice. To stimulate their use and further development, this article provides a comprehensive overview on methods developed for multivariable regression analysis of epidemiologic studies with validation data sets. The methods are systematically classified with respect to the underlying theory. An assessment of prerequisites, assumptions and performance of the available methods is given. Particular attention is paid to applicability to case-control studies and need for further research and development is pointed out.

Bias↗
PubMed2000

Association between C-reactive protein and features of the metabolic syndrome: a population-based study.

OBJECTIVE: To assess the association of circulating levels of C-reactive protein, a sensitive systemic marker of inflammation, with different components of the metabolic syndrome. RESEARCH DESIGN AND METHODS: Total cholesterol (TC), HDL cholesterol, triglycerides, uric acid, BMI , and prevalence of diabetes and hypertension were assessed in 747 men and 956 women aged 18-89 years who were participating in the population-based National Health and Nutrition Survey, which was carried out in former West Germany in 1987-1988. RESULTS: There was a statistically significant positive crude correlation between C-reactive protein and TC (R = 0.19), TG (R = 0.29), BMI (R = 0.32), glucose (R = 0.11), and uric acid (R = 0.14) (all P < 0.0001). A negative correlation was found between C-reactive protein and HDL cholesterol (R = 0.13, P < 0.0001). The age-adjusted geometric means of C-reactive protein concentrations in subjects grouped according to the presence of 0-1, 2-3, and > or =4 features of the metabolic syndrome were 1.11, 1.27, and 2.16 mg/l, respectively, with a statistically highly significant trend (P < 0.0001). CONCLUSIONS: The data suggest that a variety of features of the metabolic syndrome are associated with a systemic inflammatory response.

Adolescent↗
PubMed2000

Acquisition of Helicobacter pylori infection in a high-risk population occurs within the first 2 years of life.

OBJECTIVE: To elucidate age at acquisition of Helicobacter pylori infection, we conducted a study in a population of children known to be at high risk for H pylori infection. METHOD: Children with no symptoms who were of Turkish nationality and living in the city of Ulm, Germany, and nearby communities and on whom routine health screening examinations were performed at age 1 year (56 children), 2 years (55 children), or 4 years (69 children) were included in this cross-sectional study. Stool samples were collected by the parents and sent by mail to the University of Ulm. An H pylori antigen enzyme immunoassay for the detection of H pylori in stool was used to define current infection status. Sensitivity was 84.6% (95% CI 63. 1% to 94.7%) and specificity 97.7% (95% CI 86.2% to 99.9%) in the 4-year-old children in whom the stool test was compared with the (13)C-urea breath test. RESULTS: The prevalence of infection was 8. 9% (95% CI 3.0% to 19.6%) among the 1-year-old children, 36.4% (95% CI 23.8% to 50.4%) among the 2-year-old children, and 31.9% (95% CI 21.2% to 44.2%) among the 4-year-old children. CONCLUSION: In this high-risk group of Turkish children living in Germany, H pylori acquisition seems to occur mainly between the first and the second years of life. Therefore preventive measures such as vaccination necessitate application early in infancy. Further studies are now required to ascertain the mechanisms for transmission in this age group.

Age Factors↗