Biomedical subjects

Jonathan Dubnov

Publications and source records attributed to Jonathan Dubnov.

6 recordsLinked to original sources

PubMed2006

On ecological fallacy, assessment errors stemming from misguided variable selection, and the effect of aggregation on the outcome of epidemiological study.

In social and environmental sciences, ecological fallacy is an incorrect assumption about an individual based on aggregate data for a group. In the present study, the validity of this assumption was tested using both individual estimates of exposure to air pollution and aggregate data for 1,492 schoolchildren living in the in vicinity of a major coal-fired power station in the Hadera region of Israel. In 1996 and 1999, the children underwent subsequent pulmonary function tests (PFT), and their parents completed a detailed questionnaire on their health status and housing conditions. The association between children's PFT results and their exposure to air pollution was investigated in two phases. During the first phase, PFT averages were compared with average levels of air pollution detected in townships, and small census areas in which the children reside. During the second phase, individual pollution estimates were compared with individual PFT results, and pattern detection techniques (Getis-Ord statistic) were used to investigate the spatial data structure. While different levels of areal data aggregation changed the results only marginally, the choice of indices measuring the children's PFT performance had a significant influence on the outcome of the analysis. As argued, differences between individual-level and group-level effects of exposure (i.e., ecological or cross-level bias) are not necessary outcomes of data aggregation, and that seemingly unexpected results may often stem from a misguided selection of variables chosen to measure health effects. The implications of the results of the analysis for epidemiological studies are discussed, and recommendations for public health policy are formulated.

Child↗

PubMed2006

A change in rabies post-exposure treatment guidelines after decision analysis in Israel.

BACKGROUND: Rabies remains a significant public health problem in Israel. Some 16 000-20 000 persons come yearly to the district health offices after being bitten by animals and 16-18% receive rabies post-exposure treatment. A quality assessment of the rabies post-exposure prophylaxis decisions was never held in Israel before. The purpose of this study was to analyse the decision-making process and to update our rabies prevention guidelines accordingly. METHODS: A retrospective evaluation study of physicians' compliance with rabies post-exposure treatment guidelines in Haifa District Health Office, Ministry of Health, during 1/11/1999 to 31/12/2002. Records of all persons seeking advice (5037) following exposure to animals during the 3 years of the study were examined. Of these 2477 were eligible for the quality audit. The remaining files were analysed for the relative contribution of the different variables considered in the decision-making process. RESULTS: Observed agreement rate and Kappa coefficient were 0.984 and 0.803, respectively. The probability of recommending vaccination was greater when the exposure was from stray dogs as opposed to cats (OR = 48.9; 95% CI 17.9-133.3), if the wound was a bite rather than a scratch (OR = 29.0; 95% CI 19.5-43.2) or in a location defined as rabies enzootic as opposed to rabies free (OR = 7.6; 95% CI 5.8-10.1). CONCLUSIONS: The study demonstrated high compliance with the written guidelines. We weighted the relative importance of the variables determining the decisions. This information was used in formulating the updated guidelines.

Adolescent↗

PubMed2006

Estimating the effect of air pollution from a coal-fired power station on the development of children's pulmonary function.

Using geographical information systems (GIS) tools, the present study analyzed the association between children's lung function development and their long-term exposure to air pollution. The study covered the cohort of 1492 schoolchildren living in the vicinity of a major coal-fired power station in the Hadera sub-district of Israel. In 1996 and 1999, the children underwent subsequent pulmonary function tests (PFT) (forced vital capacity (FVC) and forced expiratory volume during the first second (FEV(1))), and the children's parents completed a detailed questionnaire on their health status and household characteristics. A negative association was found between changes in the results of PFT and the estimated individual levels of air pollution. A sensitivity test revealed a FEV(1) decline from -4.3% for the average pollution level to -10.2% for the high air pollution level. The results of a sensitivity test for FVC were found to be similar. Association with the reported health status was found to be insignificant. As we conclude, air pollution from a coal-fired power station, although not exceeding local pollution standards, had a negative effect on children's lung function development. As argued, previous studies carried out in the region failed to show the above association because they were based on zone approaches that assign average concentration levels of air pollutants to all individuals in each zone, leading to a misclassification bias of individual exposure.

Adolescent↗

PubMed2006

Classic Kaposi sarcoma. Which KSHV-seropositive individuals are at risk?

BACKGROUND: Classic Kaposi sarcoma (CKS) is a relatively rare vascular disease primarily affecting human immunodeficiency virus (HIV)-uninfected elderly men. The infection with Kaposi sarcoma-associated herpesvirus (KSHV) is necessary for the establishment of Kaposi sarcoma (KS), although it is not sufficient. Thus, only a small fraction of KSHV-infected individuals develops KS. The cofactors that influence risk of KS among HIV-uninfected individuals are yet to be determined. The objective of the current study was to assess potential risk factors for CKS in the KSHV-infected Jewish population in Israel. METHODS: A case-control study involved 35 CKS cases and 48 matched KSHV-infected controls. Lifestyle and medical history data from case patients and controls were compared by logistic regression analysis. RESULTS: In a multivariate analysis, the authors identified an age-related small increased risk for CKS in subjects originating from Asia and Africa. The risk for CKS increased, although not significantly statistically, in subjects who reported alcohol consumption, diabetes mellitus, herpes simplex, and asthma. No relation was found with cigarette smoking, family size, number of lifetime sexual partners, or sexually transmitted disease. CONCLUSIONS: A borderline increase in CKS risk among elderly subjects originating from Africa or Asia was identified. These results need to be further evaluated by larger studies. The authors believe that genetic and immunologic parameters may alter risk for CKS and, therefore, should also be investigated.

Adult↗

PubMed2005

Infection with Kaposi's sarcoma-associated herpesvirus among families of patients with classic Kaposi's sarcoma.

BACKGROUND: Classic Kaposi's sarcoma (CKS) primarily affects elderly Mediterranean or Eastern European men. Incidence rates of CKS in Israel are among the world's highest. In practically all cases, antibodies against Kaposi's sarcoma-associated herpesvirus (KSHV) can be detected. A relatively high seroprevalence rate of KSHV in Israel generally correlates with the incidence of CKS. A sexual mode of virus transmission is recognized among homosexual men, whereas the precise transmission routes in the heterosexual population and those with CKS are still unclear. OBJECTIVE: To better assess the transmission routes of KSHV in Israeli patients with CKS and their first-degree relatives as compared with a control group. DESIGN: Serum was collected from all study participants and tested for KSHV antibodies by means of latent and lytic immunofluorescence assays. An open reading frame 65 (ORF65) Western blot assay was applied as a confirmatory tool. SETTING: Three dermatological departments in Israel. PATIENTS: Sixty-four Jewish patients with CKS, 143 of their first-degree relatives, and 186 hospital-based control subjects. RESULTS: Seropositivity to KSHV was detected in 62 (96.9%) of the patients with CKS, in 56 (39.2%) of their first-degree relatives, and in only 21 (11.3%) of the hospital controls (P<.001). The specific relationship with the index patient (spouse, offspring, or sibling) had no significant effect on the prevalence of serpositivity in the family members. CONCLUSION: Our serologic evidence of familial clustering of KSHV infection suggests a predominantly nonsexual horizontal transmission route of the virus.

Adolescent↗

PubMed2004

Is there an association between shigellosis incidence and socioeconomic status in metropolitan Haifa?

BACKGROUND: Shigellosis incidence rates in Israel have declined continuously over the past 50 years, but they remain 20 times greater than those in the United States. Socioeconomic factors may influence shigellosis morbidity, but this may be difficult to demonstrate in the absence of data for individual patients and when using composite rates for large geographic areas. Use of census tract data for small, relatively homogeneous geographic areas may lessen the effects of the "ecological fallacy." The present study analyzes the effect of socioeconomic status (SES) on shigellosis morbidity in the Haifa metropolitan region. METHODS: The study population consisted of the 7 cities in the Haifa subdistrict that constitute the greater metropolitan region. Cases of shigellosis reported during the years 2000 and 2001 were mapped, and age-standardized rates were calculated for the census tract areas. The incidence rates were then compared with the SES category of the census tract using the Kruskal-Wallis test. RESULTS: No association was found between incidence rates of shigellosis and SES category of the census tract areas in the Haifa metropolitan area for the years 2000 and 2001 (Kruskal-Wallis chi(2)=0.440; P=.803). CONCLUSION: We found no association between shigellosis morbidity and socioeconomic status. This finding is probably real and not the result of reporting bias. Analysis of morbidity using small geographical units such as census tracts is more accurate than analysis using large geographical areas such as cities.

Censuses↗