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PubMed1994

Familial risk of breast cancer and abortion.

We found that the risk of breast cancer associated with a family history of breast cancer increased with the number of abortions (induced as well as spontaneous) in a study of 495 breast cancer cases and 785 controls aged 20 to 56 years. For the women who had undergone at least two abortions, the risk associated with a family history did not seem to depend on the type of abortion. This finding suggests that the effect of a family history on the risk of breast cancer is modified by event(s) resulting from abortions. Further epidemiological studies should be conducted to verify the existence of this interaction.

Abortion, Induced↗
PubMed1995

[Relationship between nutrition and dental caries in a scientific perspective].

The consumption of sugars is supposed to be one of the main etiological factors of dental caries. However, in epidemiological studies only a faint relationship is found between nutrition and caries. One reason is the preventive effect of fluoride in modern industrialized countries. In this article attention is paid to factors which can modify the harmful effect of sugars in foods and allied products: the composition and consistency of the product, the way the product is consumed, environmental factors in the mouth such as composition of saliva and plaque, and local availability of fluoride. Results are presented of an epidemiological study into the relationship between consumption of sweet snacks and caries experience of primary school children.

Cariostatic Agents↗
PubMed1999

Distance, lighting, and parental beliefs: understanding near work in epidemiologic studies of myopia.

PURPOSE: To develop measures and indices of factors (distance of eye from object, posture, and lighting) that may modify a possible effect of near work activity on myopia. METHODS: The duration of near work, the distance of an object from eye, lighting conditions, and other sociodemographic characteristics were asked in an interview. Both distance and lighting information from the questionnaire were compared with more precise measurements. RESULTS: Diopter hours were quantified as the duration of near work multiplied by the reciprocal of the distance which the activity was performed. The intraclass correlation coefficient of the reliability of distance information for each type of near work activity ranged from 0.43 to 0.91. Home light meter readings were significantly higher for children who were reading under both room and reading light, and the distances from the questionnaire were comparable to the measured distances. CONCLUSIONS: Measures of posture, distance, and lighting factors have been developed to study the possible effect modifiers of the effects of near work on myopia.

Accommodation, Ocular↗
PubMedDate not supplied

Dietary differences with green tea intake among middle-aged Japanese men and women.

BACKGROUND: Although several epidemiologic investigations have suggested a protective role of green tea against cardiovascular diseases and cancer, few studies examined how consumption of green tea was associated with intake of other dietary factors. METHODS: In the winters of 1989-1991, 880 men ages 40-49 years were randomly sampled from the general populations of five Public Health Center districts of Japan. Response rate was 72% (n = 634). A convenience sample of 373 spouses also consented to participate. They were interviewed on the frequency of consumption of green tea and 37 food items. A 3-day weighed food record was collected from a subgroup of the subjects (207 men and 164 women) to calculate daily intake of 22 nutrient variables. Consumption of the foods and nutrients was compared with three levels of green tea intake (< 1, 1-4, and > 4 cups/days) after adjustment for potential confounders. RESULTS: Among men, green tea was associated significantly with consumption of 10 foods (P < 0.05) and at borderline significance with 4 nutrients (P < 0.1). These foods and nutrients included fruits (apple, orange juice), vegetables (green, yellow, and pickled), total lipid, cholesterol, and carotene. Among women, green tea was associated with 6 foods and total energy. CONCLUSION: The results indicate that consumption of green tea is associated with diets that could modify the risks of cardiovascular diseases and cancer, especially among men. When the health effects of green tea are examined by observational epidemiologic studies, potential confounding and effect modification by other dietary factors should be controlled thoroughly.

Adult↗
PubMed1991

Dietary calcium and blood pressure: modifying factors in specific populations.

Epidemiologic findings continue to add to the body of evidence supporting a relationship between calcium intake and blood pressure. These findings also indicate that there is a threshold of the potential protective effect of adequate calcium intake, below which the risk of hypertension increases at a greater rate. The set point of this threshold, estimated at 700-800 mg/d, may be modified by a variety of factors including dietary patterns and components, lifestyle, and genetics. This may explain, at least in part, the heterogeneous response observed in dietary-intervention studies. In animal models of hypertension it was shown that greater amounts of calcium must be given to cause a blood pressure change comparable with that in normal animals, suggesting that in high-risk human populations in which calcium metabolism may be disordered, calcium intake may have to be increased to amounts greater than 700-800 mg/d to demonstrate the blood-pressure-lowering effect. Calcium intake at or above the currently recommended daily allowance of 800 mg could be of potential benefit to certain racial groups, individuals ingesting excessive alcohol, and pregnant women, all of whom generally consume low amounts of calcium and who are at higher risk of developing hypertension.

Animals↗
PubMed1980

Blindness prevention through control of ocular hypertension: an epidemiological assessment.

From a case-control study we have quantified the effect (relative risk) of presenting intraocular pressure on visual field loss in primary open angle glaucoma. We found this effect to be modified by both age and sex. Using these effect values we have estimated the potential for prevention of glaucomatous blindness in clinical and community settings. The clinical, public health, and research implications of these findings and estimates are discussed.

Age Factors↗
PubMed1976

The effect of toothbrushing frequency on oral hygiene and gingival health in school children: reassessment after two and one-half years.

An epidemiological survey of brushing frequency, oral hygiene (OHI-S), and gingival condition (GI modified) was conducted on 290, 12- to 15-year-old schoolschildren. The purpose of the survey was to compare the clinical findings with the children's states frequency of toothbrushing. Since the same children had participated in a similar study approximately 2 1/2 years earlier, it was also of interest to determine what effect, if any, a change in reported brushing habits might exert over the oral status of the children. As in a previous study, the stated level of brushing activity was high. Approximately 46 percent of the children claimed to brush twice a day, and 40 percent once a day. The poorest oral hygiene and highest level of gingivitis were associated with the group of children that claimed to brush less than once a day. In general, the children that claimed to brush their teeth more frequently had lower mean OHI-S and GI scores indicating less oral debris and gingivitis. For males-females combined the optimal effect on oral hygiene and gingival condition, on a statistical basis, was detected at the level of twice-daily brushing. Increased brushing frequency beyond this level did not produce significant improvement in OHI-S or GI scores.

Adolescent↗
PubMed2006

Effects of instrument precision and spatial variability on the assessment of the temporal variation of ambient air pollution in Atlanta, Georgia.

Data from the U.S. Environmental Protection Agency Air Quality System, the Southeastern Aerosol Research and Characterization database, and the Assessment of Spatial Aerosol Composition in Atlanta database for 1999 through 2002 have been used to characterize error associated with instrument precision and spatial variability on the assessment of the temporal variation of ambient air pollution in Atlanta, GA. These data are being used in time series epidemiologic studies in which associations of acute respiratory and cardiovascular health outcomes and daily ambient air pollutant levels are assessed. Modified semivariograms are used to quantify the effects of instrument precision and spatial variability on the assessment of daily metrics of ambient gaseous pollutants (SO2, CO, NOx, and O3) and fine particulate matter ([PM2.5] PM2.5 mass, sulfate, nitrate, ammonium, elemental carbon [EC], and organic carbon [OC]). Variation because of instrument imprecision represented 7-40% of the temporal variation in the daily pollutant measures and was largest for the PM2.5 EC and OC. Spatial variability was greatest for primary pollutants (SO2, CO, NOx, and EC). Population-weighted variation in daily ambient air pollutant levels because of both instrument imprecision and spatial variability ranged from 20% of the temporal variation for O3 to 70% of the temporal variation for SO2 and EC. Wind

Air Pollutants↗
PubMed1998

Pronounced impact of Th1/E47cs mutation compared with -491 AT mutation on neural APOE gene expression and risk of developing Alzheimer's disease.

Possession of the apolipoprotein E (APOE) epsilon4 allele is the most frequently associated genetic susceptibility factor for Alzheimer's disease (AD). Recently, new polymorphisms in the regulatory region of the APOE gene have been described. We analysed the effects of three of these mutations (-491 AT, -427 CT and Th1/E47cs) on disease risk in a large case-control study, and tested their impacts on APOE allelic expression in brain tissues. The Th1/E47cs T allele was associated with an increased risk of occurrence of AD, while the -491 T allele was associated with a decreased risk, independently of the APOE epsilon2/epsilon3/epsilon4 polymorphism effect. However, the impact of the Th1/E47cs mutation was the strongest. The -427 CT polymorphism was not associated with the disease. In AD subjects heterozygous for the epsilon4 allele, analysis of allelic expression showed that the relative expression levels of the epsilon4 allele were higher than those of the corresponding controls. Consistent with epidemiological data, the relative level of expression of the epsilon4 allele was modified accordingly to the presence or absence of the two main promoter polymorphisms, indicating, in vivo, the deleterious effect of the Th1/E47cs T allele and the protective effect of the -491 T allele in population. These data indicate that in addition to the qualitative effect of the APOE epsilon2/epsilon3/epsilon4 polymorphisms on the AD occurrence, the quantitative variation of expression of these alleles due to functional APOE promoter mutations, is a key determinant of AD development.

Aged↗
PubMed1996

Rationale for effective treatment of hypercholesterolemia.

The primary objective of treating hypercholesterolemia is to reduce the patient's risk of developing coronary artery disease (CAD). Reducing low-density lipoprotein (LDL) cholesterol levels to achieve National Cholesterol Education Program (NCEP) goal lipid levels greatly reduces this risk. Treatment of additional risk factors for CAD (high blood pressure, diabetes, smoking) should be addressed and modified as part of appropriate patient management, but a high LDL cholesterol level is a major risk factor. Therefore, to effectively modify morbidity and mortality, reaching and maintaining NCEP target lipid levels should be the goal of lipid-lowering therapy. Epidemiologic data indicate that most adults in the United States need <30% reduction in LDL cholesterol level to achieve their NCEP goal. Regardless of the intervention or therapeutic agent used, the results of numerous studies have demonstrated that reducing LDL cholesterol levels to NCEP goals will result in significant reduction of CAD risk.

Adult↗
PubMed2006

High serum selenium and reduced risk of advanced colorectal adenoma in a colorectal cancer early detection program.

BACKGROUND: Epidemiologic and animal studies suggest that selenium may reduce risk of colorectal cancer. However, the epidemiologic data is mainly from relatively small investigations, limiting their interpretation. Although substantial evidence suggests that smoking is a strong effect modifier for other antioxidative nutrients, little is known about smoking-selenium interactions in colorectal tumors. METHODS: We studied the association of serum selenium and advanced colorectal adenoma, a cancer precursor, in 758 cases and 767 sex- and race-matched controls, randomly selected from the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial. Cases had at least one verified advanced adenoma (> or = 1 cm or villous elements, or high-grade dysplasia) of the distal colon, and controls had a negative sigmoidoscopy. RESULTS: The multivariable odds ratio (OR) comparing participants in the highest quintile of serum selenium with those in the lowest quintile was 0.76 [95% confidence interval (95% CI), 0.53-1.10; P(trend) = 0.01]. The inverse association between serum selenium and advanced colorectal adenoma was significant among recent smokers (OR, 0.53; 95% CI, 0.27-1.01 for highest versus lowest tertile; P(trend) = 0.008). Serum selenium was unrelated to adenoma risk in nonsmokers and former smokers who quit smoking > or = 10 years ago. CONCLUSION: Selenium may reduce the risk of developing advanced colorectal adenoma, particularly among the high-risk group of recent smokers.

Adenoma↗
PubMed1992

Disease modification in rheumatoid arthritis with special reference to cyclosporin A.

Disease modifying antirheumatic drugs improve clinical markers of synovial inflammation as well as acute phase reactants and functional status in patients with rheumatoid arthritis. Some of the disease modifying antirheumatic drugs probably also retard radiographic progression. Data from prospective observational studies and epidemiological studies indicate a modest and temporary effect. New treatment modalities are needed, including both new strategies and new drugs. Cyclosporin A improves clinical markers of synovial inflammation and is useful for individual patients with rheumatoid arthritis. However, further studies are required to investigate the long term efficacy and tolerance of cyclosporin in rheumatoid arthritis.

Arthritis, Rheumatoid↗
PubMed1996

[BCG vaccination].

The author expounds the fairly obscure history of BCG vaccination. Summarises the efficiency of accomplished vaccinations of different geographical areas. He accounts the diversity of results by the distinction of technical and methodical conditions and disparity in virulence of BCG strains. Overviews the Inland and European routine and the risk of possible complications. The favourable position of domestic childhood tuberculosis is due to the effective preventive arrangements. Considering the international and national epidemiology of tuberculosis in adults the administration of BCG vaccine, by chance in modified form, is recommended further on.

Age Factors↗
PubMed2002

The relation of body mass index to asthma, chronic bronchitis, and emphysema.

BACKGROUND: Recent studies have suggested a relationship between asthma and obesity. Despite these reports, the effect of being underweight or overweight as a risk factor for airway obstructive diseases (AODs) is not clear. OBJECTIVES: To determine whether a relation of body mass index (BMI) to asthma, chronic bronchitis (CB), or emphysema exists (analysis 1), and, if so, whether the association between obesity and asthma is modified by gender (analysis 2). DESIGN: Nested case-control study from the longitudinal cohort of the Tucson Epidemiologic Study of Airways Obstructive Diseases. PATIENTS: Analysis 1: physician-confirmed incident cases of asthma (n = 102), CB (n = 299), or emphysema (n = 72) who denied any prior AODs. Analysis 2: all 169 incident cases of asthma, regardless of any previous AODs, stratified by gender and by other potential effect modifiers. In both analyses, we selected only subjects at least 20 years old who had weight and height measured during the study. MEASUREMENTS: BMI and other risk factors were assessed prior to the onset of the AOD (cases) or prior to the last completed survey (control subjects). RESULTS: A diagnosis of emphysema was significantly associated with a BMI < 18.5 (odds ratio [OR], 2.97; 95% confidence interval [CI], 1.33 to 6.68, when compared to healthy control subjects). A BMI >/= 28 increased the risk of receiving a diagnosis of asthma (OR, 2.10; 95% CI, 1.31 to 3.36) and CB (OR, 1.80; 95% CI, 1.32 to 2.46). About 30% of the patients with asthma and 25% of the patients with CB (vs 16% of the control subjects, p < 0.001) were preobese or obese, regardless whether BMI was assessed before the diagnosis or before the onset of respiratory symptoms. The relation of elevated BMI to asthma was significant only among women. CONCLUSIONS: Patients with emphysema are more likely to be underweight, and patients with CB are more likely to be obese. However, the temporal relationship between abnormal BMI and the onset of COPD is uncertain. Preobese and obese women are at increased risk of acquiring asthma. This relation, particularly if it is causal, has potentially relevant public health implications.

Adult↗
PubMed2002

Smoking (active and passive) and breast cancer: epidemiologic evidence up to June 2001.

The first generation of studies evaluating the association between exposure to tobacco smoke and breast cancer merely compared active to nonactive smokers, with varying degrees of detail in the definition of active smoking. With rare exceptions, studies of this kind failed to show an effect of smoking on breast cancer risk. However, such analysis is probably insufficient. The most recent reports on the smoking-breast cancer connection have two characteristics. Some have separated women exposed to passive smoking from those nonexposed to either active or passive smoke. Other reports have focused on factors that modify the effect of smoking on breast cancer incidence, such as genetic markers or hormone receptors. A minority of reports combines these two characteristics. This review addresses the epidemiologic evidence for a link between smoking and breast cancer and discusses the implications of this evidence for future studies.

Adult↗
PubMed1995

Studies of cancer and radiation dose among atomic bomb survivors. The example of breast cancer.

A comprehensive program of medical follow-up of survivors of the atomic bombings of Hiroshima and Nagasaki, Japan, by the Radiation Effects Research Foundation (RERF) has produced quantitative estimates of cancer risk from exposure to ionizing radiation. For breast cancer in women, in particular, the strength of the radiation dose response and the generally low level of population risk in the absence of radiation exposure have led to a clear description of excess risk and its variation by age at exposure and over time following exposure. Comparisons of RERF data with data from medically irradiated populations have yielded additional information on the influence of population and underlying breast cancer rates on radiation-related risk. Epidemiological investigations of breast cancer cases and matched controls among atomic bomb survivors have clarified the role of reproductive history as a modifier of the carcinogenic effects of radiation exposure. Finally, a pattern of radiation-related risk by attained age among the survivors exposed during childhood or adolescence suggests the possible existence of a radiation-susceptible subgroup. The hypothetical existence of such a group is lent plausibility by the results of recent family studies suggesting that heritable mutations in certain genes are associated with familial aggregations of breast cancer. The recent isolation and cloning of one such gene, BRCA1, makes it likely that the hypothesis can be tested using molecular assays of archival and other tissue obtained from atomic bomb survivor cases and controls.

Adolescent↗
PubMed2001

Global survey of genetic variation in CCR5, RANTES, and MIP-1alpha: impact on the epidemiology of the HIV-1 pandemic.

Expression of CC chemokine receptor 5 (CCR5), the major coreceptor for HIV-1 cell entry, and its ligands (e.g., RANTES and MIP-1alpha) is widely regarded as central to the pathogenesis of HIV-1 infection. By surveying nearly 3,000 HIV+ and HIV- individuals from worldwide populations for polymorphisms in the genes encoding RANTES, MIP-1alpha, and CCR5, we show that the evolutionary histories of human populations have had a significant impact on the distribution of variation in these genes, and that this may be responsible, in part, for the heterogeneous nature of the epidemiology of the HIV-1 pandemic. The varied distribution of RANTES haplotypes (AC, GC, and AG) associated with population-specific HIV-1 transmission- and disease-modifying effects is a striking example. Homozygosity for the AC haplotype was associated with an increased risk of acquiring HIV-1 as well as accelerated disease progression in European Americans, but not in African Americans. Yet, the prevalence of the ancestral AC haplotype is high in individuals of African origin, but substantially lower in non-Africans. In a Japanese cohort, AG-containing RANTES haplotype pairs were associated with a delay in disease progression; however, we now show that their contribution to HIV-1 pathogenesis and epidemiology in other parts of the world is negligible because the AG haplotype is infrequent in non-Far East Asians. Thus, the varied distribution of RANTES, MIP-1alpha, and CCR5 haplotype pairs and their population-specific phenotypic effects on HIV-1 susceptibility and disease progression results in a complex pattern of biological determinants of HIV-1 epidemiology. These findings have important implications for the design, assessment, and implementation of effective HIV-1 intervention and prevention strategies.

Africa↗
PubMed1997

Transitional studies.

Transitional studies are studies using biological markers that bridge the gap between laboratory experiments and population-based epidemiology. The goal of these studies is to characterize and validate biomarkers and to assess the following: intra- and inter-subject variability; the feasibility of marker use in field conditions; confounding and effect-modifying factors for the marker; and mechanisms reflected by the biomarker. Another goal is to optimize the conditions for the use of biomarkers. Transitional studies involving biomarkers of exposure or effect are distinguished from etiological studies because the biomarker is generally the outcome or dependent variable. Despite this difference, transitional studies can be epidemiological studies, but they may also include laboratory studies to assess reliability (and accuracy) and to identify parameters for collecting, processing and storing biological specimens prior to assay. Generally, transitional studies involve healthy people, patients or workers with specific exposures. At some point in the validation of a biomarker the line between transitional and etiological studies becomes blurred. None the less, it is useful to identify transitional studies as a distinct set of efforts to validate and characterize biomarkers. Transitional studies can be divided into three functional categories: developmental, characterization and applied studies.

Animals↗