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Biomedical subjects

J D Kark

Publications and source records attributed to J D Kark.

119 records · Page 7Linked to original sources
PubMed1981

Serum vitamin A (retinol) and cancer incidence in Evans County, Georgia.

A total community sample of 3,102 individuals from Evans County, Georgia, was followed for 12-14 years. During this period, 129 documented new cases of cancer were ascertained from medical records and death certificates. Cases were considered for inclusion only if documented at least 12 months after subjects were inducted into the cohort study. Cases were classified as definite, probable, and possible by strict criteria. Blood samples were drawn at the beginning of the study in 1960-62 and sera were frozen. Serum vitamin A (retinol) levels were measured in 1976 on the stored sera of 85 cancer patients and for 174 age-, race-, and sex-matched controls. Retinol estimations were performed by a fluorometric method after alumina column separation. Experiments conducted to simulate the exposure to light, thawing, and refreezing that sera may have undergone during the 14-16 years of storage showed retinol to be quite stable in response to these possible insults. As compared to controls, persons that eventually developed cancer had significantly lower mean serum retinol levels at least 12 months before the cancer diagnosis. The association was in the same direction for all 4 race-sex groups, although stronger overall for males than females, and was consistent for the various cancer sites and cell types. Both matched and regression residual analyses were used to control for the confounding variables considered: age, race, sex, obesity, social class, and smoking.

Age Factors↗
PubMed1977

Analysis of prospective epidemiologic studies by minimum distance case-control matching.

This paper presents the use of a matching method for analysis of prospective epidemiologic studies which generate a relatively small number of cases of a given disease. In such studies, matching in the manner presented may be of a given disease. In such studies, matching in the manner presented may be superior to other methods of analysis in removing bias due to confounding. A multivariate minimum-distance matching algorithm is used for computer selection of controls for the cases and the method is illustrated by application to a prospective cardiovascular disease study. The main advantages are that the results are easy to understand and interpret, and that there is no possibiligy of bias due to confounding variables when close matches are obtained. In contrast, the results of multivariate analysis may be difficult to understand and interpret, and the removal of bias due to confounding is dependent on the assumptions of the mode. It is recommended that the matching method should be used in addition to and at times stead of other methods of analysis whenever a study involves a relatively small number of cases and a large source of controls of controls on whom relevant study variables have already been documented.

Epidemiologic Methods↗
PubMedDate not supplied

The three-year incidence of non-B viral hepatitis morbidity in a controlled trial of pre-exposure immune serum globulin prophylaxis.

A trial of pre-exposure immune serum globulin (ISG) vs. the prevailing policy of post-exposure ISG for the prevention of viral hepatitis was undertaken among 23,447 male and female military recruits in Israel, an endemic area for hepatitis A virus infection. We are reporting on the three-year follow-up of the incidence of non-B hepatitis among 12,835 male recruits, half of whom had been allocated to receive ISG on their first day of service, while the other half served as a non-vaccinated ("regular care") control group. Over the three-year period the overall cumulative incidence in the intervention group was half that of the control group (3.6 per 1000 vs. 7.2 per 1000; p = 0.0037). Protection was virtually absolute for up to nine months' follow-up. ISG may have provided prolonged partial protection well in excess of six to nine months. Between 10 to 18 months, half as many cases occurred in the intervention group as in the controls. By 18 months the difference in incidence between the study groups had reached a plateau and was highly significant (p = 0.002). Between 19 and 36 months the case increment in the two groups was similar. The benefit of receiving pre-exposure ISG remained evident three years after inception of the trial in this indigenous military population living in an endemic area.

Clinical Trials as Topic↗
PubMedDate not supplied

Effect of moderate exercise on serum lipids in young men with low high density lipoprotein cholesterol.

Fifty-five healthy, sedentary, nonsmoking, and nonobese 24- to 26-year-old men who had low plasma concentrations of high density lipoprotein (HDL) cholesterol were selected for a study of the effect of short-term exercise on plasma lipid and lipoprotein concentrations. The participants were randomized into two groups. Of these, 28 were assigned to a 9-week program of submaximal aerobic exercise three times weekly, and 27 were assigned to a nonexercising control group. Changes in physical fitness were assessed by increments in estimated maximal oxygen consumption; this increased by 15% in the exercise group (p less than 0.001) but remained unchanged in the control group. During the study, body weights and skinfold thicknesses of both groups remained essentially unchanged after 9 weeks. There was no significant difference between the trial groups in total cholesterol, HDL cholesterol, calculated low density lipoprotein cholesterol, or in the HDL2 and HDL3 subfractions. Triglyceride levels were lower by 19 mg/dl in the exercise group as compared to the control group (p less than 0.05). We conclude that moderate aerobic exercise of 9 weeks duration in the absence of weight loss in young males with initially low HDL cholesterol did not influence their HDL cholesterol levels.

Adult↗
PubMedDate not supplied

Reduction in hepatitis A antibody prevalence among young adults in Israel.

BACKGROUND: Hepatitis A (HAV) is endemic in Israel. A number of developed countries have reported marked reductions in prevalence of antibodies. The objective of this study was to determine whether change in prior infection took place over a 7-year period and to investigate the sociodemographic characteristics of infection in Israel. METHODS: Recruitment into military service in Israel at the age of 18 is compulsory. Representative samples of male recruits were selected in 1977 and 1984. Antibodies to HAV were tested by solid phase radioimmunoassay in the 1977 sample and by an enzyme immunoassay in the 1984 sample. RESULTS: HAV antibody prevalence in 1977 was 69% (95% confidence interval (CI) 65% to 72%) versus 54% (95% CI 49% to 59%) in 1984 (p < 0.0001). The reduction was evident in all ethnic-origin groups comprising the Jewish population. In 1984 the prevalence was 28% for Jewish men of European origin, 60% for Asian origin, and 80% for the North African origin group. A statistically significant independent effect of education was evident. CONCLUSIONS: These findings point to a reduction in feco-oral transmission and hepatitis A virus infection in childhood in Israel, yet reveal considerable continuing ethnic and educational inequalities in prior exposure to infection. A potential for large outbreaks exists during transition from high to low endemicity, particularly in high-risk military populations. These populations are candidates for application of active hepatitis A vaccines now undergoing testing.

Adolescent↗
PubMedDate not supplied

Medical examination of Israeli 17-year-olds before military service as a national resource for health information.

At age 17 years Israelis undergo medical examination for the purpose of health classification for military service. The potential use of this extensive data collection system for epidemiologic studies is illustrated for selected conditions. Trends in diagnosed disorders over a 25-year period are exemplified in the changing prevalence of tuberculosis, bronchial asthma, diabetes, epilepsy and heart defects. Within birth cohorts, cross-sectional analyses of height, body mass, blood pressure and disorders--such as bronchial asthma, allergic rhinitis, diabetes, psychiatric diagnoses and such genetic conditions as familial Mediterranean fever--point to clear ethnic differences. Educational level is strongly associated with measures of health status. Potential uses of this resource include: detecting groups in need of preventive, curative and rehabilitative care, assessing changing needs and priorities of health care, evaluation of intervention programs and health services provided in childhood, a wide spectrum of etiologic studies including assessment of health effects of social change, follow-up studies including the natural history of disorders, and developing data systems such as national registries of rare or important conditions. Issues relating to data reliability and validity, changing disease classification and nonexamination of groups exempted from military service limit interpretation of findings and restrict uses of this resource. Emphasis on standardization of data collection and diagnostic criteria, quality assurance and improved data management will be necessary.

Adolescent↗
PubMedDate not supplied

The role of epidemiology in prevention of hypertension in Israel.

High blood pressure may be the most important modifiable determinant of severe morbidity and mortality in the adult population in Israel. Because hypertension control can effect a reduction in this morbidity and mortality, programs of secondary--and subsequently primary--prevention can have a far-reaching impact on the state of health in the nation. The primary care delivery system in Israel is structurally well suited to centrally directed initiatives. Major hypertension control programs are being introduced in Israel. The General Federation of Labour Sick Fund (Kupat Holim)--the nation's chief provider of primary care--has recently undertaken a wide-scale initiative for detection and treatment of high blood pressure in its neighborhood primary care clinics. A policy decision has thus been made on a national level; resources for intervention have been made available and activities initiated. The issue in need of resolution, the authors believe, is that of the integration of rigorous epidemiologic methodology into the planning and execution of the programs, particularly in program evaluation and resultant program modification. The authors outline selected epidemiologic characteristics of hypertension in Israel, emphasizing the major role that elevated blood pressure plays as a determinant of mortality; the present status of hypertension control; current programs for control; and the role of epidemiology in preventive programs.

Adult↗
PubMedDate not supplied

Are lean smokers at increased risk of lung cancer? The Israel Civil Servant Cancer Study.

BACKGROUND: Whether leanness is related to an increased risk of lung cancer is controversial. OBJECTIVE: To examine the association of leanness with lung cancer incidence in a sample of Israeli men. METHODS: The 23-year lung cancer incidence (1963 through 1986) was determined by linkage to the Israel Cancer Registry in 9975 male civil servants aged 40 through 69 years at initial examination in 1963. In 198,298 person-years of follow-up, 153 cases of lung cancer were identified. In 1963, body mass index (BMI) and cigarette smoking status were determined; in the 1968 reexamination, lung function tests were performed and BMI was reassessed. RESULTS: Adjusted for age, smoking, and city by Cox regression, BMI was exponentially inversely related to lung cancer incidence, with a relative risk of 2.3 (95% confidence interval [CI], 1.4 to 3.8) comparing the lowest fifth of BMI (< 22.93 kg/m2) with the highest. The association was evident in light, moderate, and heavy smokers. Among smokers, the adjusted relative risk was 3.7 (95% CI, 1.9 to 7.3) for the lowest fifth of BMI. The associations were stronger for men in the lowest 10th of the BMI distribution (< 21.38 kg/m2). Controlling for lung function did not materially change the results. The adjusted population-attributable fraction associated with the lowest fifth of BMI among smokers was 20.4% (95% CI, 10.1% to 29.9%). Survival analysis showed that the association of BMI with lung cancer persisted throughout follow-up. CONCLUSIONS: The association shown between thinness and lung cancer incidence, particularly in smokers, was not attributable to the confounding factors studied, preclinical weight loss, or competing risks. Thinness in smokers may lead to, or may reflect, enhanced host susceptibility.

Adult↗
PubMedDate not supplied

Psychosocial factors among members of religious and secular kibbutzim.

Mortality in 11 secular kibbutzim between 1970 and 1985 was nearly twice that of 11 matched religious kibbutzim. A cross-sectional study was undertaken in 1991 in 10 of these settlements, 5 religious and 5 secular, to determine whether differences in risk factors could explain the unequal survival. These comprised physical, physiologic and biochemical measurements, health-relevant behaviors and psychosocial variables. This report addresses the psychosocial aspect of the study, which included assessment of sense of coherence, hostility, satisfaction with self, work-related stress, social supports and social contacts using self-administered questionnaires. The response rate among the sample of men and women, aged 35-64 years, was 76% (437 respondents, 208 men and 229 women). Analysis of variance and logistic regression (the latter comparing the upper or lower fourths of the distribution vs. the rest) were used. Religious kibbutz members reported a higher sense of coherence (odds ratio = 1.58, 95% CI 1.02 to 2.46) and a lower level of hostility (odds ratio = 0.49, 95% CI 0.33 to 0.75) than their secular counterparts. Findings for satisfaction with self and work-related stress were inconsistent; there were significant interactions between religious affiliation, sex and age. Younger women reported less satisfaction with self and higher work-related stress than the other age-sex groups in both types of kibbutz. There was no difference in social support or frequency of social contact between religious and secular kibbutzim. Voluntary work was more frequent among the religious kibbutzim. The findings are consistent with an interpretation that Jewish religious observance may enhance the formation of certain protective personality characteristics. Membership in a cohesive religious kibbutz community may increase host resistance to stressors and thereby promote overall well-being and a positive health status. This could reflect an interplay of individual and collective attributes of religion.

Adaptation, Psychological↗