The impact of the viability of Trichomonas vaginalis in urine on wet mount, culture, and PCR methods was assessed. To minimize the chance of false-negative results, urine specimens should be processed within 30 min of specimen collection and maintained at 37°C, since temperature appears to affect the viability of Trichomonas.
OBJECTIVES. Hip fractures can have devastating effects on the lives of older individuals. We determined the frequency of occurrence of hip fracture and the baseline factors predicting death and institutionalization at 6 months after hip fracture. METHODS. A representative cohort of 2812 individuals aged 65 years and older was followed prospectively for 6 years. Hip fractures were identified, and the occurrence of death and institutionalization within 6 months of the fracture was determined. Prefracture information on physical and mental function, social support, and demographic features and in-hospital data on comorbid diagnoses, fracture site, and complications were analyzed to determine predictors of death and institutionalization after hip fracture. RESULTS. Of 120 individuals suffering a hip fracture, 22 (18%) died within 6 months and 35 (29%) were institutionalized at 6 months. The predictors of death in multiple logistic regression included fracture site, a high number of comorbid conditions, a high number of complications, and poor baseline mental status. The primary predictor of institutionalization was poor baseline mental status. CONCLUSIONS. The frequency of death, institutionalization, and loss of function after hip fracture should prompt a reevaluation of the current approach to this problem.
OBJECTIVES. The purpose of this study was to determine whether diet adversely affected survival among 2572 older persons with indicators of kidney disease in a population-based cohort. Average follow-up time for survivors, of whom 1453 (57%) had died at analysis, was 14.5 years. METHODS. Kidney disease indicators were a "yes" response to "Has a doctor ever told you that you have kidney disease or renal stones?" and/or trace or greater amounts of protein in urine. Dietary protein intakes were calculated from 24-hour recalls. RESULTS. Cox proportional hazards models were used, stratified by sex, with age, body mass index, blood pressure, education, smoking status, total caloric intake, and diabetes mellitus as covariates. Relative risk of total mortality with an additional 15 g of protein per day was 1.25 (95% confidence interval [CI] = 1.09, 1.42) among White men with kidney disease indicators, vs 1.00 (95% CI = 0.95, 1.06) among those without them; relative risks of renal-related mortality were 1.32 (95% CI = 0.97, 1.79) and 0.95 (95% CI = 0.81, 1.11), respectively. No significant differences were found for White women. CONCLUSIONS. Once chronic renal disease is present, diet may be associated with earlier mortality in White males.
We evaluated the association between mortality outcomes in elderly individuals and particulate matter (PM) of varying aerodynamic diameters (in micrometers) [PM(10), PM(2.5), and PM(CF )(PM(10) minus PM(2.5))], and selected particulate and gaseous phase pollutants in Phoenix, Arizona, using 3 years of daily data (1995-1997). Although source apportionment and epidemiologic methods have been previously combined to investigate the effects of air pollution on mortality, this is the first study to use detailed PM composition data in a time-series analysis of mortality. Phoenix is in the arid Southwest and has approximately 1 million residents (9. 7% of the residents are > 65 years of age). PM data were obtained from the U.S. Environmental Protection Agency (EPA) National Exposure Research Laboratory Platform in central Phoenix. We obtained gaseous pollutant data, specifically carbon monoxide, nitrogen dioxide, ozone, and sulfur dioxide data, from the EPA Aerometric Information Retrieval System Database. We used Poisson regression analysis to evaluate the associations between air pollution and nonaccidental mortality and cardiovascular mortality. Total mortality was significantly associated with CO and NO(2) (p < 0.05) and weakly associated with SO(2)...
BACKGROUND. There is concern about but little information on how living alone affects the health and survival of older adults. METHODS. We examined the association between living arrangements (living alone, with a spouse, or with someone other than a spouse) and survival among 7651 adults, aged 45 to 74 years in the National Health and Nutrition Examination Survey (NHANES I) (1971-1975) and traced at the NHANES I Follow-up Study (1982-1984), to see whether certain sociodemographic factors (race, education, income, and employment), health behaviors (alcohol, smoking, physical activity, and obesity), or chronic medical conditions were influential in the association. RESULTS. We found a stronger association of living arrangements with survival for men than for women, and for middle-aged men than for older men. For men, those living alone and those living with someone other than a spouse were equally disadvantaged in terms of survival. Income, race, employment, and physical activity influenced the association of living arrangements and survival, but their impact varied by age, gender, and living arrangement. CONCLUSION. Living arrangements had a weak impact on survival among men, but had no effect among women.
Twenty-seven cases of enteric fever were diagnosed between January 1961 and February 1977 at a medium-sized urban hospital. Nineteen of the patients had recently travelled abroad. Fever was the only constant finding, and four patients noted fever and headache as their only symptoms. Splenomegaly was present in 30% and rose spots in just 11%. Enteric fever was initially suspected in only 63% of cases, and a mean of 4.8 days elapsed after admission before specific therapy was instituted. Salmonella was cultured from blood samples in 19 of 24 patients and from stool specimens in 21 of 27, but was never isolated from the urine. Serum O agglutinins, while eventually present in 54% of the patients tested, did not help in establishing an early diagnosis. No deaths occurred, though two patients sustained relapses. Sporadic enteric fever is unlikely to be suspected unless associated with recent foreign travel, but is easily diagnosed by usual culture methods.
This paper critically discusses two previous studies concerned with predictions of HIV/AIDS in the United States and Japan during the early 1990s. Although the study in the US applied a historical theory, assuming normal distribution for the epidemic curve, the underlying infection process was not taken into account. In the Japan case, the true HIV incidence was estimated using the coverage ratio of previously diagnosed/undiagnosed HIV infections among AIDS cases, the assumptions of which were not supported by a firm theoretical understanding. At least partly because of failure to account for underlying mechanisms of the disease and its transmission, both studies failed to yield appropriate predictions of the future AIDS incidence. Further, in the Japan case, the importance of consistent surveillance data was not sufficiently emphasized or openly discussed and, because of this, revision of the AIDS reporting system has made it difficult to determine the total number of AIDS cases and apply a backcalculation method. Other widely accepted approaches can also fail to provide perfect predictions. Nevertheless, wrong policy direction could arise if we ignore important assumptions, methods and input data required to answer specific questions. The present paper highlights the need for appropriate assessment of specific modeling purposes and explicit listing of essential information as well as possible solutions to aid relevant policy formulation.
A loop-mediated isothermal amplification (LAMP) procedure for the detection of Cryptosporidium in environmental and fecal samples was developed and evaluated. This is the first demonstration of LAMP applied to detection of Cryptosporidium. Due to its specificity and simplicity, the method could become a useful diagnostic tool for epidemiologic studies of Cryptosporidium presence.
Diagnostic or screening tests are used to help determine whether or not a patient has a certain condition or disease. The ability of a diagnostic test to correctly classify subjects is expressed by the four test characteristics—sensitivity, specificity, predictive value positive, and predictive value negative. This paper describes these characteristics and discusses methods for choosing optimal tests or cutoff points to maximize expected value considering the consequences of incorrect diagnoses. Data drawn from ongoing studies of facial pain are used to illustrate some of these concepts.
We describe the third known case of hantavirus pulmonary syndrome (HPS) due to Bayou virus, from Jefferson County, Texas. By using molecular epidemiologic methods, we show that rice rats (Oryzomys palustris) are frequently infected with Bayou virus and that viral RNA sequences from HPS patients are similar to those from nearby rice rats. Bayou virus is associated with O. palustris; this rodent appears to be its predominant reservoir host.
Structural genetic variation, including copy number variation (CNV), constitutes a substantial fraction of total genetic variability and the importance of structural genetic variants in modulating human disease is increasingly being recognized. Early successes in identifying disease-associated CNVs via a candidate gene approach mandate that future disease association studies need to include structural genetic variation. Such analyses should not rely on previously developed methodologies that were designed to evaluate single nucleotide polymorphisms (SNPs). Instead, development of novel technical, statistical, and epidemiologic methods will be necessary to optimally capture this newly-appreciated form of genetic variation in a meaningful manner.
We are pleased to publish an update to "Identifiabiliity, exchangeability and epidemiological confounding" (IEEC) by Sander Greenland and James Robins, originally published in 1986 in the International Journal of Epidemiology. This is the first in a series of updates to classic epidemiologic-methods papers that EP&I has commissioned.
Because enterotoxigenic Escherichia coli (ETEC) is not identified by routine stool culture methods, ETEC outbreaks may go unrecognized, and opportunities for treatment and prevention may be missed. To improve recognition of adult ETEC outbreaks, we compared them with reported outbreaks of viral gastroenteritis. During 1975-95, we identified 14 ETEC outbreaks in the United States and 7 on cruise ships, caused by 17 different serotypes and affecting 5683 persons. Median symptom prevalences were: diarrhoea 99%, abdominal cramps 82%, nausea 49%, fever 22%, vomiting 14%. The median incubation period was 42 h, and for 8 of 10 outbreaks, the mean or median duration of illness was > 72 h (range 24-264). For 17 (81%) ETEC outbreaks, but for only 2 (8%) viral outbreaks, the prevalence of diarrhoea was > or = 2.5 times the prevalence of vomiting. ETEC outbreaks may be differentiated from viral gastroenteritis outbreaks by a diarrhoea-to-vomiting prevalence ratio of > or = 2.5 and a longer duration of illness.
Study of gene–environment interaction is important for improving accuracy and precision in the assessment of both genetic and environmental influences. This overview presents a simple definition of gene–environment interaction and suggests study designs for detecting it. Gene–environment interaction is defined as “a different effect of an environmental exposure on disease risk in persons with different genotypes,” or, alternatively, “a different effect of a genotype on disease risk in persons with different environmental exposures.” Under this strictly statistical definition, the presence or absence of interaction depends upon the scale of measurement (additive or multiplicative). The decision of which scale is appropriate will be governed by many factors, including the main objective of an investigation (discovery of etiology, public health prediction, etc.) and the hypothesized pathophysiologic model. Five biologically plausible models are described for the relations between genotypes and environmental exposures, in terms of their effects on disease risk. Each of these models leads to a different set of predictions about disease risk in individuals classified by presence or absence of a high-risk genotype and environmental exposure. Classification according to the exposure is relatively easy...