Does risk factor epidemiology put epidemiology at risk? Peering into the future.
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The multiple cause black box paradigm of the current risk factor era in epidemiology is growing less serviceable. This single level paradigm is likely to be displaced. The signs are that the growing strength of molecular epidemiology on the one side, and of a global epidemiology based on information systems on the other, will come to dominate epidemiology and segregate it into separate disciplines. At the same time, the links with public health interests grow weaker. A multilevel ecoepidemiology has the potential to bind these strands together. (+info)
A method for calculating age-weighted death proportions for comparison purposes.
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OBJECTIVE: To introduce a method for calculating age-weighted death proportions (wDP) for comparison purposes. MATERIALS AND METHODS: A methodological study using secondary data from the municipality of Sao Paulo, Brazil (1980-1994) was carried out. First, deaths are weighted in terms of years of potential life lost before the age of 100 years. Then, in order to eliminate distortion of comparisons among proportions of years of potential life lost before the age of 100 years (pYPLL-100), the denominator is set to that of a standard age distribution of deaths for all causes. Conventional death proportions (DP), pYPLL-100, and wDP were calculated. RESULTS: Populations in which deaths from a particular cause occur at older ages exhibit lower wDP than those in which deaths occur at younger ages. The sum of all cause-specific wDP equals one only when the test population has exactly the same age distribution of deaths for all causes as that of the standard population. CONCLUSION: Age-weighted death proportions improve the information given by conventional DP, and are strongly recommended for comparison purposes. (+info)
The meaning and use of the cumulative rate of potential life lost.
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BACKGROUND: The 'years of potential life lost' (YPLL) is a public health measure in widespread use. However, the index does not apply to the comparisons between different populations or across different time periods. It also has the limit of being cross-sectional in nature, quantifying current burden but not future impact on society. METHODS: A new years-lost index is proposed-the 'cumulative rate of potential life lost' (CRPLL). It is a simple combination of the 'cumulative rate' (CR) and the YPLL. Vital statistics in Taiwan are used for demonstration and comparison of the new index with existing health-status measures. RESULTS: The CRPLL serves the purpose of between-group comparison. It can also be considered a projection of future impact, under the assumption that the age-specific mortality rates in the current year prevail. For a rare cause of death, it can be interpreted as the expected years (days) of potential life lost during a subject's lifetime. CONCLUSIONS: The CRPLL has several desirable properties, rendering it a promising alternative for quantifying health status. (+info)
Influence of sampling on estimates of clustering and recent transmission of Mycobacterium tuberculosis derived from DNA fingerprinting techniques.
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The availability of DNA fingerprinting techniques for Mycobacterium tuberculosis has led to attempts to estimate the extent of recent transmission in populations, using the assumption that groups of tuberculosis patients with identical isolates ("clusters") are likely to reflect recently acquired infections. It is never possible to include all cases of tuberculosis in a given population in a study, and the proportion of isolates found to be clustered will depend on the completeness of the sampling. Using stochastic simulation models based on real and hypothetical populations, the authors demonstrate the influence of incomplete sampling on the estimates of clustering obtained. The results show that as the sampling fraction increases, the proportion of isolates identified as clustered also increases and the variance of the estimated proportion clustered decreases. Cluster size is also important: the underestimation of clustering for any given sampling fraction is greater, and the variability in the results obtained is larger, for populations with small clusters than for those with the same number of individuals arranged in large clusters. A considerable amount of caution should be used in interpreting the results of studies on clustering of M. tuberculosis isolates, particularly when sampling fractions are small. (+info)
Reliability of information on physical activity and other chronic disease risk factors among US women aged 40 years or older.
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Data on chronic disease risk behaviors and related variables, including barriers to and attitudes toward physical activity, are lacking for women of some racial/ethnic groups. A test-retest study was conducted from July 1996 through June 1997 among US women (n = 199) aged 40 years or more who were white, black, American Indian/Alaska Native, or Hispanic. The sample was selected and interviews were conducted using a modified version of the methods of the Behavioral Risk Factor Surveillance System. For behavioral risk factors such as physical inactivity, smoking, and low fruit and vegetable consumption, group prevalences were generally similar between interviews 1 and 2. However, kappa values for selected physical activity variables ranged from 0.26 to 0.51 and tended to be lower for black women. Discordance was low for variables on cigarette smoking and exposure to environmental tobacco smoke (kappa = 0.64-0.92). Discordance was high (kappa = 0.33) for low consumption of fruits and vegetables. Additional variables for barriers to and access to exercise ranged widely across racial/ethnic groups and in terms of measures of agreement. These methods illustrate an efficient way to sample and assess the reliability of data collected from women of racial/ethnic minority groups. (+info)
Measuring food insecurity and hunger in the United States: development of a national benchmark measure and prevalence estimates.
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Since 1992, the U.S. Department of Agriculture Food and Nutrition Service (FNS) has led a collaborative effort to develop a comprehensive benchmark measure of the severity and prevalence of food insecurity and hunger in the United States. Based on prior research and wide consultation, a survey instrument specifically relevant to U.S. conditions was designed and tested. Through its Current Population Survey (CPS), the U.S. Bureau of the Census has fielded this instrument each year since 1995. A measurement scale was derived from the data through fitting, testing and validating a Rasch scale. The unidimensional Rasch model corresponds to the form of the phenomenon being measured, i.e., the severity of food insufficiency due to inadequate resources as directly experienced and reported in U.S. households. A categorical measure reflecting designated ranges of severity on the scale was constructed for consistent comparison of prevalence estimates over time and across population groups. The technical basis and initial results of the new measure were reported in September 1997. For the 12 months ending April 1995, an estimated 11.9% of U.S. households (35 million persons) were food insecure. Among these, 4.1% of households (with 6.9 million adults and 4.3 million children) showed a recurring pattern of hunger due to inadequate resources for one or more of their adult and/or child members sometime during the period. The new measure has been incorporated into other federal surveys and is being used by researchers throughout the U.S. and Canada. (+info)
Antimicrobial susceptibilities and plasmid contents of Neisseria gonorrhoeae isolates from commercial sex workers in Dhaka, Bangladesh: emergence of high-level resistance to ciprofloxacin.
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Commercial sex workers (CSWs) serve as the most important reservoir of sexually transmitted diseases (STD), including gonorrhea. Periodic monitoring of the antimicrobial susceptibility profile of Neisseria gonorrhoeae in a high-risk population provides essential clues regarding the rapidly changing pattern of antimicrobial susceptibilities. A study concerning the prevalence of gonococcal infection among CSWs was conducted in Bangladesh. The isolates were examined with regards to their antimicrobial susceptibility to, and the MICs of, penicillin, tetracycline, ciprofloxacin, cefuroxime, ceftriaxone, and spectinomycin by disk diffusion and agar dilution methods. The total plasmid profile of the isolates was also analyzed. Of the 224 CSWs, 94 (42%) were culture positive for N. gonorrhoeae. There was a good correlation between the results of the disk diffusion and agar dilution methods. Some 66% of the isolates were resistant to penicillin, and 34% were moderately susceptible to penicillin. Among the resistant isolates, 23.4% were penicillinase-producing N. gonorrhoeae (PPNG). 60.6% of the isolates were resistant and 38.3% were moderately susceptible to tetracycline, 17.5% were tetracycline-resistant N. gonorrhoeae, 11.7% were resistant and 26.6% had reduced susceptibility to ciprofloxacin, 2.1% were resistant and 11.7% had reduced susceptibility to cefuroxime, and 1% were resistant to ceftriaxone. All PPNG isolates contained a 3.2-MDa African type of plasmid, and a 24.2-MDa conjugative plasmid was present in 34.1% of the isolates. Since quinolones such as ciprofloxacin are recommended as the first line of therapy for gonorrhea, the emergence of significant resistance to ciprofloxacin will limit the usefulness of this drug for treatment of gonorrhea in Bangladesh. (+info)
Epidemiological analysis of site relationships of synchronous and metachronous multiple primary cancers in the National Cancer Center, Japan, 1962-1996.
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BACKGROUND: Multiple primary cancer (MPC) has been recognized as a problem commonly encountered in routine medical practice. A study of MPC is necessary not only to provide insights into the etiology of cancer, but also to provide information for effective medical care by clinical oncologists. METHODS: A cohort of 49,751 cancer patients who were admitted to the National Cancer Center Hospital between 1962 and 1996 was used to study the site relationship of MPC. Logistic and Poisson regression analyses using an internal reference group within the cohort were applied for the calculation of the prevalence odds ratio (POR) for site relationships of synchronous MPC and the incidence rate ratio (IRR) for those of metachronous MPC. RESULTS: Three site combinations with elevated risks for both synchronous and metachronous MPCs, eight with elevated risk for synchronous MPC, five with elevated risk for metachronous MPC and six with decreased risk for synchronous MPC were identified with statistical significance. Among them, the increased risk of metachronous stomach cancer following lymphoma and myeoloma (POR = 1.0 and 1.1, P > 0.05; IRR = 2.5, P < 0.05) and the inverse site-correlation of synchronous MPC between [trachea, bronchus and lung] and other sites of the upper aerodigestive tract [lip, oral cavity and pharynx] (POR = 0.5 and 0.3, P < 0.05) and esophagus (POR = 0.7 and 0.3, P < 0.05) have not been reported previously. CONCLUSIONS: Our results suggest that interventions for lymphoma and myeloma might affect the development of subsequent stomach cancer and additional etiological factors other than tobacco smoking are associated with the development of cancer in the upper aerodigestive tract. (+info)