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1.
Ethics Med Public Health ; 28: 100891, 2023 Jun.
Article in English | MEDLINE | ID: mdl-37095763

ABSTRACT

Background: As Covid-19 spread rapidly, many countries implemented a strict shelter-in-place to "flatten the curve" and build capacity to treat in the absence of effective preventative therapies or treatments. Policymakers and public health officials must balance the positive health effects of lockdowns with economic, social, and psychological costs. This study examined the economic impacts of state and county level restrictions during the 2020 Covid-19 pandemic for two regions of Georgia. Methods: Taking unemployment data from the Opportunity Insights Economic Tracker with mandate information from various sites, we examined trends before and after a mandate's implementation and relaxation using joinpoint regression. Results: We found mandates with the largest impact on unemployment claims rates were the shelters-in-place (SIPs) and closures of non-essential businesses. Specific to our study, mandates had an effect where first implemented, i.e., if the state implemented an SIP after the county, the state-wide SIP had no additional measurable effect on claims rates. School closures had a consistent impact on increasing unemployment claims rates, but to a lesser degree than SIPs or business closures. While closing businesses did have a deleterious effect, implementing social distancing for businesses and restricting gatherings did not. Notably, the Coastal region was less affected than the Metro Area. Additionally, our findings indicate that race ethnicity may be a larger predictor of adverse economic effects than education, poverty level, or geographic area. Conclusions: Our findings coincided with other studies in some areas but showed differences in what indicators may best predict adverse effects and that coastal communities may not always be as impacted as other regions in a state. Ultimately, the most restrictive measures consistently had the largest negative economic impacts. Social distancing and mask mandates can be effective for containment while mitigating the economic impacts of strict SIPs and business closures.

2.
Infect Dis Model ; 5: 256-263, 2020.
Article in English | MEDLINE | ID: mdl-32110742

ABSTRACT

The initial cluster of severe pneumonia cases that triggered the COVID-19 epidemic was identified in Wuhan, China in December 2019. While early cases of the disease were linked to a wet market, human-to-human transmission has driven the rapid spread of the virus throughout China. The Chinese government has implemented containment strategies of city-wide lockdowns, screening at airports and train stations, and isolation of suspected patients; however, the cumulative case count keeps growing every day. The ongoing outbreak presents a challenge for modelers, as limited data are available on the early growth trajectory, and the epidemiological characteristics of the novel coronavirus are yet to be fully elucidated. We use phenomenological models that have been validated during previous outbreaks to generate and assess short-term forecasts of the cumulative number of confirmed reported cases in Hubei province, the epicenter of the epidemic, and for the overall trajectory in China, excluding the province of Hubei. We collect daily reported cumulative confirmed cases for the 2019-nCoV outbreak for each Chinese province from the National Health Commission of China. Here, we provide 5, 10, and 15 day forecasts for five consecutive days, February 5th through February 9th, with quantified uncertainty based on a generalized logistic growth model, the Richards growth model, and a sub-epidemic wave model. Our most recent forecasts reported here, based on data up until February 9, 2020, largely agree across the three models presented and suggest an average range of 7409-7496 additional confirmed cases in Hubei and 1128-1929 additional cases in other provinces within the next five days. Models also predict an average total cumulative case count between 37,415 and 38,028 in Hubei and 11,588-13,499 in other provinces by February 24, 2020. Mean estimates and uncertainty bounds for both Hubei and other provinces have remained relatively stable in the last three reporting dates (February 7th - 9th). We also observe that each of the models predicts that the epidemic has reached saturation in both Hubei and other provinces. Our findings suggest that the containment strategies implemented in China are successfully reducing transmission and that the epidemic growth has slowed in recent days.

3.
BMC Med ; 16(1): 192, 2018 10 18.
Article in English | MEDLINE | ID: mdl-30333024

ABSTRACT

Infectious diseases continue to pose a significant public health burden despite the great progress achieved in their prevention and control over the last few decades. Our ability to disentangle the factors and mechanisms driving their propagation in space and time has dramatically advanced in recent years. The current era is rich in mathematical and computational tools and detailed geospatial information, including sociodemographic, geographic, and environmental data, which are essential to elucidate key drivers of infectious disease transmission from epidemiological and genetic data. Indeed, this paradigm shift was driven by dramatic advances in complex systems approaches along with substantial improvements in data availability and computational power. The burgeoning output of infectious disease spatial modeling suggests that we are close to a fully integrated approach for early epidemic detection and intervention. This special collection in BMC Medicine aims to bring together a broad range of quantitative investigations that improve our understanding of the spatiotemporal transmission dynamics of infectious diseases in order to mitigate their impact on the human population.


Subject(s)
Communicable Diseases/epidemiology , Public Health/methods , Humans
4.
J Theor Biol ; 442: 79-86, 2018 04 07.
Article in English | MEDLINE | ID: mdl-29330056

ABSTRACT

The early dynamics of an infectious disease outbreak can be affected by various factors including the transmission mode of the disease and host-specific factors. While recent works have highlighted the presence of sub-exponential growth patterns during the early phase of epidemics, empirical studies examining the contribution of different factors to early epidemic growth dynamics are lacking. Here we aim to characterize and explain the early incidence growth patterns of local HIV/AIDS epidemics in Brazil as a function of socio-demographic factors. For this purpose, we accessed annual AIDS incidence series and state-level socio-demographic variables from publicly available databases. To characterize the early growth dynamics of the HIV/AIDS epidemic, we employed the generalized-growth model to estimate with quantified uncertainty the scaling of growth parameter (p) which captures growth patterns ranging from constant incidence (p=0) to sub-exponential (0 < p < 1) and exponential growth dynamics (p=1) at three spatial scales: national, regional, and state levels. We evaluated the relationship between socio-demographic variables and epidemic growth patterns across 27 Brazilian states using mixed-effect regression analyses. We found wide variation in the early dynamics of the AIDS epidemic in Brazil, displaying sub-exponential growth patterns with the p parameter estimated substantially below 1.0. The mean p was estimated to be 0.81 at the national level, with a range of 0.72-0.85 at the regional level, and a range of 0.28-0.96 at the state level. Our findings support the notion that socio-demographic factors contribute to shaping the early growth dynamics of the epidemic at the local level. Gini index and socio-demographic index were negatively associated with the parameter p, whereas urbanicity was positively associated with p. The results could have theoretical significance in understanding differences in growth scaling across different sexually transmitted disease systems, and have public health implications to guide control.


Subject(s)
Acquired Immunodeficiency Syndrome/epidemiology , Epidemics , HIV Infections/epidemiology , Socioeconomic Factors , Acquired Immunodeficiency Syndrome/transmission , Acquired Immunodeficiency Syndrome/virology , Algorithms , Brazil/epidemiology , Databases, Factual , Geography , HIV/physiology , HIV Infections/transmission , HIV Infections/virology , Humans , Incidence , Models, Theoretical
5.
Epidemiol Infect ; 144(4): 810-9, 2016 Mar.
Article in English | MEDLINE | ID: mdl-26289100

ABSTRACT

Salmonella enterica causes an estimated 1 million domestically acquired foodborne illnesses annually. Salmonella enterica serovar Enteritidis (SE) is among the top three serovars of reported cases of Salmonella. We examined trends in SE foodborne outbreaks from 1973 to 2009 using Joinpoint and Poisson regression. The annual number of SE outbreaks increased sharply in the 1970s and 1980s but declined significantly after 1990. Over the study period, SE outbreaks were most frequently attributed to foods containing eggs. The average rate of SE outbreaks attributed to egg-containing foods reported by states began to decline significantly after 1990, and the proportion of SE outbreaks attributed to egg-containing foods began declining after 1997. Our results suggest that interventions initiated in the 1990s to decrease SE contamination of shell eggs may have been integral to preventing SE outbreaks.


Subject(s)
Disease Outbreaks/statistics & numerical data , Eggs/microbiology , Food Microbiology/trends , Foodborne Diseases/epidemiology , Salmonella Infections/epidemiology , Salmonella enteritidis/physiology , Foodborne Diseases/microbiology , Humans , Incidence , Salmonella Infections/microbiology , United States/epidemiology
6.
Health Educ Res ; 24(1): 119-27, 2009 Feb.
Article in English | MEDLINE | ID: mdl-18281710

ABSTRACT

The association between condom norms and unprotected sexual intercourse was examined within social and sexual networks of young African American men who have sex with men (MSM) in an HIV epicenter of the southern United States. We used a chain-link design to recruit 158 young African American men: 95 initial participants, 56 contacts of participants (alters) and 7 contacts of alters. Men in the high-risk group, compared with those in the no-risk group, perceived significantly lower approval concerning condom use in their social and sexual networks. Also, 100 participants could be connected to each other in 86 dyads of social and sexual networks. Within these dyads, men perceived that their friends and acquaintances approved for them to use condoms but that their friends and acquaintances did not use condoms themselves. Low HIV risk behavior appears associated with perceived social norms that support one's use of condoms, even when perceived norms do not support condom use by network members themselves.


Subject(s)
Black or African American/psychology , Condoms/statistics & numerical data , HIV Infections/psychology , Homosexuality, Male/psychology , Risk-Taking , Adult , Health Knowledge, Attitudes, Practice , Humans , Male , Perception , Social Support , Unsafe Sex/psychology
7.
Sex Transm Infect ; 83(1): 10-5, 2007 Feb.
Article in English | MEDLINE | ID: mdl-17283360

ABSTRACT

In industrialised countries, a rapid epidemic phase of HIV transmission has largely given way to more moderated endemic transmission. The dynamics of endemic transmission may differ substantially from those generating epidemic spread. We hypothesise that three elements play an important role in maintaining endemicity in high prevalence urban environments. First, persons are likely to be subject to multiple risks from multiple sources rather than engaging in a single, hierarchically classified, risk behaviour. Second, the network structure in these environments may include a substrate of "fixed" factors (a large connected component, a characteristic degree distribution and small world phenomenon) upon which is superimposed a number of variable factors (transitivity, assortativity) that determine the level of prevalence. Third, the geographic range of persons in these milieux is constricted, making it likely that new partners will already be connected. The confluence of these three factors assures the ongoing risk bombardment needed for maintenance of endemicity. Further empirical and theoretical analysis will be required in order to validate this hypothesis.


Subject(s)
HIV Infections/transmission , Bacterial Proteins , Endemic Diseases/statistics & numerical data , Female , HIV Infections/epidemiology , Humans , Male , Membrane Proteins , Prevalence , Sexual Behavior , Sexual Partners , Social Environment , Substance-Related Disorders , Urban Health
8.
9.
J Clin Densitom ; 7(1): 101-10, 2004.
Article in English | MEDLINE | ID: mdl-14742894

ABSTRACT

The interpretation of results measured by quantitative ultrasound (QUS) of the heel depends on the population studied. We measured estimated bone mineral density (BMD) of the heel using the Hologic Sahara sonometer. People were studied at county fairs, health fairs, and churches. Subjects were not on treatments that would affect bone density, other than calcium supplementation. This included 823 Caucasian women, 131 African American women, and 301 Caucasian men. In contrast to women, for Caucasian men the squared term for age was not significant, and a straight line of decline was the best fit for estimated BMD. African American women had a standard deviation larger than that reported by Hologic for Caucasian women. We compared a history of self-reported fractures with a subject's estimated BMD. An estimated BMD of 0.57 gm/cm2 included 75% of all fractures. This cutoff point was associated with increased fracture prevalence in subjects over age 50, relative risk of 1.4. This result corresponds to the Hologic data T-score of -0.2. When used as a screening tool for osteoporosis fracture risk, an estimated BMD of 0.57 gm/cm2 seems reasonable in those subjects over age 50.


Subject(s)
Calcaneus/diagnostic imaging , Osteoporosis/diagnostic imaging , Adult , Black or African American , Aged , Aged, 80 and over , Bone Density , Female , Humans , Male , Middle Aged , Osteoporosis, Postmenopausal/diagnostic imaging , Risk Factors , Ultrasonography , White People
10.
Int J Tuberc Lung Dis ; 7(12 Suppl 3): S342-8, 2003 Dec.
Article in English | MEDLINE | ID: mdl-14677820

ABSTRACT

SETTING: Literature review for the process of contact tracing for sexually transmitted diseases (STD) and for tuberculosis (TB), focusing on articles that report results of studies or commentary. OBJECTIVE: To compare and contrast contact tracing in order to highlight emerging commonalities. DESIGN: A descriptive review, based on Medline search with augmentation from other published and unpublished sources. RESULTS: Contact tracing for STD and TB have some obvious differences because of differing routes of transmission, differing sensibilities required to work with the affected populations, a different potential for anonymous contacts, and a major difference in the epidemiologic value of biomarkers. Nonetheless, the convergence of these processes on disadvantaged populations where drug use and sexual activity are important social factors has engendered an increasing similarity. CONCLUSION: A broadened approach to both, with greater attention to how ancillary contacts and associates may be of use in interrupting deeply embedded endemic disease transmission, deserves further study. Some newer approaches in the use of network-informed methods to elicit contacts and investigate the community dynamics of transmission may be of particular value in TB case investigation. These strategies will be enhanced by the availability of DNA fingerprinting, a powerful biomarker of recent Mycobacterium tuberculosis transmission and case association (a technology not available for STD contact tracing).


Subject(s)
Contact Tracing/methods , Sexually Transmitted Diseases/prevention & control , Sexually Transmitted Diseases/transmission , Tuberculosis/prevention & control , Tuberculosis/transmission , Humans
11.
Int J Tuberc Lung Dis ; 7(12 Suppl 3): S486-93, 2003 Dec.
Article in English | MEDLINE | ID: mdl-14677842

ABSTRACT

BACKGROUND: To elucidate networks of Mycobacterium tuberculosis transmission, it may be appropriate to characterize the types of relationships among tuberculosis (TB) cases and their contacts (with and without latent TB infection) in addition to relying on traditional efforts to distinguish 'close' from 'casual' contacts. SETTING: A TB outbreak in a US low incidence state. OBJECTIVE: To evaluate whether social network analysis can provide insights into transmission settings that might otherwise go unrecognized by routine practices. DESIGN: All adult outbreak-associated cases (n = 19) and a convenience sample of their contacts with and without latent TB infection (LTBI) (n = 26) were re-interviewed in 2001 using a structured questionnaire. Network analysis software was used to create diagrams illustrating important persons within the outbreak network, as well as types of activities TB cases engaged in with their contacts. RESULTS: Drug use and drug sharing were more commonly reported among cases and their infected contacts than among contacts without LTBI. TB cases central to the outbreak network used crack cocaine, uncovering the need to focus control efforts on specific sites and persons involved in illicit drug use. CONCLUSION: Outbreaks occur even in areas with low TB incidence, frequently among groups whose drug use or other illegal activities complicate control efforts. TB programs should consider the use of network analysis as a supplement to routine contact investigations to identify unrecognized patterns of M. tuberculosis transmission.


Subject(s)
Community Networks , Contact Tracing/methods , Disease Outbreaks , Tuberculosis/epidemiology , Tuberculosis/transmission , Adolescent , Adult , Aged , Aged, 80 and over , Child , Child, Preschool , Female , Humans , Infant , Kansas/epidemiology , Male , Middle Aged , Risk Factors , Sexual Behavior , Social Behavior , Substance-Related Disorders/complications , Tuberculosis/diagnosis
12.
Sex Transm Infect ; 78 Suppl 1: i159-63, 2002 Apr.
Article in English | MEDLINE | ID: mdl-12083437

ABSTRACT

This study describes the risk network structure of persons with HIV infection during its early epidemic phase in Colorado Springs, USA, using analysis of community-wide HIV/AIDS contact tracing records (sexual and injecting drug partners) from 1985 to 1999. Paired partner information from other STD/HIV programme records was used to augment network connections. Analyses were conducted with and without this supplemental information. The results suggest that a combined dendritic and cyclic structural network pattern is associated with low to moderate HIV propagation in Colorado Springs, and may account for the absence of intense propagation of the virus.


Subject(s)
Contact Tracing , HIV Infections/transmission , Sexual Partners , Adolescent , Adult , Colorado/epidemiology , Female , Humans , Incidence , Male , Risk , Sexual Behavior , Substance Abuse, Intravenous
13.
Sex Transm Infect ; 78 Suppl 1: i152-8, 2002 Apr.
Article in English | MEDLINE | ID: mdl-12083436

ABSTRACT

Ascertaining epidemic phase for a sexually transmitted disease (STD) has depended on secular trend data which often contain significant artefacts. The usefulness of sexual network structure as an indicator of STD epidemic phase is explored in an analysis of community wide genital chlamydia reports, with network analysis of interviewed cases and linked sexual partners, in Colorado Springs, USA, 1996 to 1999. In this period, the chlamydia case rate per 100,000 increased by 46%. Three quarters of cases (n=4953) were interviewed, nominating 7365 partners; these, combined with index cases, made up the 9114 persons in the network. Epidemiologic analysis of cases suggests that secular trend increases are artefactual. Network analysis supports this view: overall network structure is fragmented and dendritic, notably lacking the cyclic (closed loops) structures associated with network cohesion and thus with efficient STD transmission. Comparison of network structure with that of an intense STD outbreak (characterised by numerous cyclic structures) suggests low level or declining endemic rather than epidemic chlamydia transmission during the study interval. These observations accord with intuitive and stochastic predictions.


Subject(s)
Chlamydia Infections/epidemiology , Disease Outbreaks , Sexual Partners , Adolescent , Adult , Chlamydia Infections/prevention & control , Colorado/epidemiology , Comorbidity , Contact Tracing , Endemic Diseases , Female , Gonorrhea/epidemiology , Gonorrhea/prevention & control , Humans , Incidence , Male , Prevalence , Recurrence , Space-Time Clustering
14.
J Clin Densitom ; 5(4): 375-81, 2002.
Article in English | MEDLINE | ID: mdl-12665638

ABSTRACT

Optimal information that should be included in ultrasound (US) heel bone mineral density (BMD) reports is not known. If additional information about further evaluation of patients with low heel BMD were included in reports, would responses for treatment improve? We screened people at health fairs using the Sahara heel US machine. For those with a T-score of

Subject(s)
Calcaneus/physiology , Osteoporosis/therapy , Practice Patterns, Physicians' , Bone Density , Calcaneus/diagnostic imaging , Calcitonin/therapeutic use , Calcium/therapeutic use , Diphosphonates/therapeutic use , Humans , Mass Screening , Osteoporosis/diagnostic imaging , Osteoporosis/prevention & control , Ultrasonography
15.
J Urban Health ; 78(3): 419-32, 2001 Sep.
Article in English | MEDLINE | ID: mdl-11564846

ABSTRACT

The purpose of this study was to investigate the hypothesis that human immunodeficiency virus (HIV) transmission may be facilitated or obstructed by network structure, incorporating a measure of risk that combines true risk and surrogates. Persons at presumed high risk for HIV were enrolled in long-term follow-up studies of urban and rural networks in Atlanta, Georgia, and Flagstaff, Arizona. We focused on respondents who were also contacts to evaluate information on both sides of the observed dyads and constructed a Risk Indicator, based on a four-digit binary number, that permitted assessment and visualization of the overall risk environment. We constructed graphs that provided visualization of the level of risk, the types of relationships, and the actual network. Although some of the findings conform to the hypotheses relating network structure to transmission, there were several anomalies. In Atlanta, HIV prevalence was most strongly related to men with a male sexual orientation, despite the widespread use of injectable drugs. In Flagstaff, an area of very low prevalence and no transmission, the risk environment appeared more intense, and the frequency of microstructures was as great or greater than representative areas in Atlanta. The network hypothesis is not yet sufficiently developed to account for empirical observations that demonstrate the presence of intense, interactive networks in the absence of transmission of HIV.


Subject(s)
HIV Infections/epidemiology , HIV Infections/transmission , HIV Seroprevalence , Risk Assessment/methods , Social Support , Adult , Black or African American , Age Distribution , Arizona/epidemiology , Contact Tracing/methods , Disease Transmission, Infectious , Female , Georgia/epidemiology , Humans , Longitudinal Studies , Male , Needle Sharing/statistics & numerical data , Population Surveillance , Risk-Taking , Sex Distribution , Sexual Behavior/statistics & numerical data , Socioeconomic Factors , Substance-Related Disorders/epidemiology , Substance-Related Disorders/virology
16.
J Am Board Fam Pract ; 14(2): 116-22, 2001.
Article in English | MEDLINE | ID: mdl-11314918

ABSTRACT

BACKGROUND: Patients with sickle cell disease cope with their disease in various ways, such as psychological counseling, hypnosis, medication, and prayer. Spirituality is a coping mechanism in a variety of diseases. This study evaluates the role of spirituality in patients coping with the pain of sickle cell disease. METHODS: Seventy-one patients from the Georgia Sickle Cell Clinic completed a questionnaire addressing their ability to cope with the pain of sickle cell disease and their degree of spirituality. A descriptive cross-sectional design was used. Correlation and multiple regression analyses were calculated for the relation between coping with the pain of sickle cell disease and spirituality. RESULTS: The questionnaire provided several scales with high internal consistency for measuring spiritual well-being and its two components, existential well-being and religious well-being, that show a correlation between high levels of spirituality and life control. The study population exhibited high levels of spirituality and religiosity, but the influence of these feelings on coping with sickle cell disease was variable. Spiritual well-being was correlated with life-control but not with perceived pain severity. CONCLUSIONS: Existential well-being was associated with general coping ability. Spiritual well-being is important for some patients who must cope with the pain of sickle cell disease.


Subject(s)
Adaptation, Psychological , Anemia, Sickle Cell/psychology , Pain/psychology , Religion , Adult , Anemia, Sickle Cell/complications , Cross-Sectional Studies , Female , Georgia , Holistic Health , Humans , Male , Middle Aged , Pain/etiology , Regression Analysis , Surveys and Questionnaires
18.
AIDS ; 14(14): 2191-200, 2000 Sep 29.
Article in English | MEDLINE | ID: mdl-11061661

ABSTRACT

OBJECTIVE: To study prospectively social networks and behavior in a group of persons at risk for HIV because of their drug-using and sexual practices, with particular emphasis on the interaction of risks and concomitant network structure. METHODS: A longitudinal study was conducted of 228 respondents in Atlanta, Georgia in six inner-city community chains of connected persons, interviewing primary respondents and a sample of their contacts every 6 months for 2 years. Ascertained were: HIV and immunologic status; demographic, medical, and behavioral factors; and the composition of the social, sexual, and drug-using networks. RESULTS: The prevalence of HIV in this group was 13.3% and the incidence density was 1.8% per year. Substantial simultaneity of risk-taking was observed, with a high level of both non-injecting (crack, 82%) and injecting (heroin, cocaine or both, 16 30%) drug use, the exchange of sex or money for drugs by men (approximately 35%) and women (57-71%), and high frequency of same-sex sexual activity by men (9.4%) and women (33%). The intensity of interaction, as measured by network features such as microstructures and concurrency, was significantly greater than that observed in a low prevalence area with little endemic transmission. CONCLUSION: The traditional hierarchical classification of risk for HIV may impede our understanding of transmission dynamics, which, in the setting of an inner-city population, is characterized by simultaneity of risk-taking, and moderately intense network interactions. The study provides further evidence for the relationship of network structure to transmission dynamics, but highlights the difficulties of using network information for prediction of individual seroconversion.


Subject(s)
HIV Infections/epidemiology , Sexual Behavior , Adult , Crack Cocaine , Female , Follow-Up Studies , HIV Infections/transmission , Heroin , Humans , Incidence , Interviews as Topic , Male , Prevalence , Sex Factors , Social Behavior Disorders/epidemiology , Substance Abuse, Intravenous/epidemiology , Substance-Related Disorders/epidemiology , United States/epidemiology , Urban Population
19.
Ann Epidemiol ; 10(7): 451, 2000 Oct 01.
Article in English | MEDLINE | ID: mdl-11018350

ABSTRACT

PURPOSE: To present the parallel histories of epidemiologic and electronic publishing and consider positive and negative factors that might affect their amalgam.METHODS: We performed a quantitative assessment of the arc of epidemiologic publication from 1966-1999, using major self-designated epidemiologic journals as a sample, and of scholarly electronic publication from 1991-1997, based on current literature review. We use an online, paperless journal as a case study, and review selected information-technology opinion in the area.RESULTS: By traditional standards, growth in epidemiologic publication has been considerable, with the addition of six new journals since 1966. In contrast, scholarly electronic publication for the period 1991-1997 grew from 27 to 2459 journals (not all exclusively online). Positive features of electronic publishing include flexibility, shortened time to publication, freedom from fixed publication date, diversity in presentation, and instant linkage to relevant material. A case study of a new online journal illustrates the substantive power of the medium. Negative factors include restriction (or unrestricted expansion) of the audience, the potential for hasty peer review, pitfalls in establishing credibility, an emphasis on style over content, technologic dependence, and additions to the information explosion. Relative cost and archiving are still debated. In assessing the pros and cons, it is important to distinguish electronic mechanisms that facilitate publication from electronic publishing, and to appreciate the difference between moving an existing journal to the electronic medium, and creating a new online journal.CONCLUSIONS: The movement from print to internet is probably inexorable, but a headlong rush may be ill-advised. Several models for dual publishing now exist, with the expectation that many, including the journals that serve epidemiology, will do so. The ultimate configuration is difficult to predict, but likely to be shaped in large measure by market forces, technologic advances and to a lesser extent, by habit and aesthetics.

20.
Int J Epidemiol ; 29(5): 899-904, 2000 Oct.
Article in English | MEDLINE | ID: mdl-11034975

ABSTRACT

BACKGROUND: Comparability of study participants with non-participants is customarily assessed by contrasting the distributions of sociodemographic characteristics. Such comparisons do not necessarily provide insight into whether or not participants of a given subgroup are similar to non-participants of the same subgroup. A geographical information system (GIS) may provide such insight by visually displaying the spatial distributions of participants and non-participants. In a previously reported study of heterosexuals at elevated risk for human immunodeficiency virus (HIV), traditional methods suggested distributional differences in the demographic characteristics of participants and non-participants. METHODS: Based on residential address co-ordinates for each subgroup member, we used the subgroup's centroid as the origin and constructed a 360 degrees series of overlapping box plots of the distance of subgroups members to the origin, thereby producing closed polygons for each of the box plot demarcators. RESULTS: These rotational box plots revealed similar geographical distributions for most participant and non-participant subgroups, with the exception of African-American men and women. CONCLUSIONS: Observed differences resulted in part from the study design, and provided some insight into sampling problems encountered in social network studies. Based on Tobler's supposition that 'nearby things tend to be alike', the rotational box plot is a useful additional tool for investigating sample bias.


Subject(s)
Demography , Selection Bias , Adult , Colorado/epidemiology , Female , HIV Infections/etiology , Humans , Male , Risk Factors , Sexual Behavior , Substance Abuse, Intravenous
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