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H A Kahn

Publications and source records attributed to H A Kahn.

At least 19 recordsLinked to original sources
PubMed1995

Validity of 24-hour dietary recall interviews conducted among volunteers in an adult working community.

There is considerable uncertainty regarding the validity of dietary data collected from free-living populations. Nevertheless, few attempts have been made to validate dietary assessment instruments. To address this issue, we compared average daily protein intake estimated from 24-hour dietary recall interviews to protein intake estimated from urinary nitrogen excretion in 24-hour samples. Among 244 community-dwelling adults who volunteered for a hypertension study, men (n = 139) overreported dietary protein intake by 12 to 19%. In contrast, women (n = 105) reported a dietary protein intake almost exactly in agreement with estimates based on urinary nitrogen levels. Thin men reported about one-third more protein intake than was reflected in their urinary nitrogen measurements. Our results suggest that the accuracy of dietary recall estimates may vary across subgroups of the population. Additional information from sufficiently large validation studies would be helpful in determining the role of dietary assessment instruments which are already in wide use in epidemiologic research. Until such information is obtained, doubts will remain regarding the validity of inferences drawn from nutritional epidemiologic studies.

Adult↗
PubMed1994

Hypothermia and bleeding during abdominal aortic aneurysm repair.

Patients undergoing abdominal aortic aneurysm repair routinely have a depressed core body temperature during surgery, and hypothermia is known to cause abnormalities in coagulation. This study was designed to determine whether platelet function is altered as a result of hypothermia or heparin during abdominal aortic aneurysm repair. Ten patients scheduled for abdominal aortic aneurysm surgery were prospectively studied. Bleeding times and temperature were measured every hour beginning preoperatively. Each patient was heparinized intraoperatively, and the effects reversed with protamine sulfate prior to closure. Despite efforts to keep the patients warm, all of them developed hypothermia (mean lowest core temperature 34.8 +/- 0.7 degrees C). A significant linear relationship between the change in core temperature and the change in bleeding time was demonstrated. In 7 of 10 cases the greatest change in bleeding time occurred when patients experienced the lowest mean core temperature and not when they were heparinized. These data suggest that hypothermia has a marked effect on platelet function during abdominal aortic aneurysm repair. Although heparin can cause abnormalities in platelet function, hypothermia may be a more important role in inhibiting normal platelet function. By preventing severe hypothermia (< 35 degree C), excessive bleeding associated with abdominal aortic aneurysm repair may be minimized without the concomitant risk of blood product transfusion.

Aortic Aneurysm, Abdominal↗
PubMed1987

A step towards using urinary nitrogen as a tool for validating 24-hour dietary recall interviews.

In an active population, can urinary nitrogen output provide a satisfactory basis for estimating protein intake without preliminary screening to rule out metabolic disease? A successful demonstration would justify comparing average protein intake for active groups derived from 24-hour recall interviews with that obtained from 24-hour urine specimens. This could then be a practical test of the hypothesis that 24-hour recall data provide valid estimates for groups. Volunteers (45) from a university population limited their diet for four days to a commercially prepared liquid diet and provided a 24-hour urine specimen beginning on the morning of the fourth day. For men, average daily intake of protein was 112.8 grams and the estimated intake based on urinary nitrogen was 114.5. Corresponding data for women were 84.6 and 83.9. Screening for metabolic disease seems unnecessary but persons restricting their intake to less than their caloric needs will have their protein intake overestimated on the basis of urinary nitrogen measurement.

Adult↗
PubMed1985

Multiple logistic function versus Mantel-Haenszel procedure in the analysis of risk factors for prevalence of hepatitis A antibodies.

Multiple logistic function and Mantel-Haenszel procedure are compared in their ability to control confounding in a large set of data. In this specific application substantial equivalence is found between the two techniques. When both techniques are applicable and data are not sparse, the authors prefer stratification, which is simpler and free of assumptions.

Hepatitis A↗
PubMed1984

Prevalence of hepatitis A antibodies in Italy.

Prevalence of hepatitis A antibodies among 5005 naval recruits aged 18-26 from all parts of Italy was almost double in the south and islands (83.3%) as compared to the north and central regions (45.2%). Social-demographic variables such as education and number of siblings are associated with prevalence of anti-HAV. Hepatitis A infection is still an early acquired infection in Italy, particularly in the south where among the 18-26-year-old recruits with education limited to lower middle school or less and eight siblings or more, prevalence of anti-HAV was 95%. Good correlation exists in Italy between prevalence of anti-HAV and incidence of reported cases of hepatitis.

Adolescent↗
PubMed1984

Association between reported diet and all-cause mortality. Twenty-one-year follow-up on 27,530 adult Seventh-Day Adventists.

This report examines the association between mortality from all causes during a 21-year period and frequency of consumption of 28 specific foods among 27,530 adult California members of the Seventh-Day Adventist Church. Food consumption was measured at the beginning of the study (1960) by a self-administered questionnaire. Deaths were identified by computer-assisted matching of study subjects to the file of death certificates for all deaths that occurred in California during 1960-1980. All-cause mortality showed a significant negative association with green salad consumption and a significant positive association with consumption of eggs and meat. For green salad and eggs, the association was stronger for women; for meat, the association was stronger for men. All the observed associations were adjusted for age, sex, smoking history, history of major chronic disease, and age at initial exposure to the Adventist Church.

Adult↗
PubMed1983

Hepatitis B in two Italian General Hospitals.

A study to evaluate the extent of Hepatitis B among Hospital Staff in two hospitals in central Italy, blood tested 1212 individuals (80.2% of the staff). 33.7% of staff tested was positive to at least 1 marker of prior B hepatitis infection. The study confirms that B hepatitis is an occupational hazard for those exposed to blood. Specific risks in terms of odds ratios are estimated to be about 2.0 for professional nurse compared to other nursing categories, about 1.7 for staff in high risk departments compared to low risk departments and about 5.0 for professional nurses in high risk departments compared to clerks or nurses aides in low risk departments. The computation of attributable risk indicates that working in a hospital contributes only a minor fraction of the total national burden of this disease. However, immunization of hospital workers in Italy can prevent every year as many as 6,500 new Hepatitis B infections in this high risk group.

Adult↗
PubMed1983

Prevalence of hepatitis B markers in Italy.

Among 5005 Navy recruits aged 18-26 years from all sections of Italy, whose blood was tested in 1981, regional prevalence of serologic markers for hepatitis B was higher in southern Italy and in the Italian islands as compared with northern Italy and central Italy (4.3% vs. 2.3% for hepatitis B surface antigen (HBsAg) and 23.5% vs. 10.5% for any B marker). Social-demographic variables such as region, family size, and education were associated with hepatitis B as were the more traditionally associated variables related to blood or medical care such as history of intravenous injection, history of blood transfusion, or exposure to hospital. Number of siblings was positively related and educational attainment inversely related to prevalence of hepatitis B markers. The prevalence of HBsAg among Italian males aged 18-26 years with residence in southern Italy or in the Italian islands, whose education was limited to lower middle school, and who were from a family of eight siblings or more, is 14.6%. These are among the highest prevalence rates for hepatitis B antigen ever reported for a general population group in Europe. Good correlation exists between incidence of reported cases of hepatitis and prevalence of markers in the different regions of Italy.

Adolescent↗
PubMed1982

Prevalence of hepatitis markers in Roman children.

A random sample of sera from children admitted over a 23-month period to a large paediatric hospital in Rome for diagnoses believed unrelated to viral hepatitis, was tested for HBsAG, anti-HBs, anti-HBc and anti-HAV. No sex or area of residence differences were found. The prevalence for markers of prior hepatitis B infection in children aged 1-12 years was 6.5%, in agreement with other observations in Italy and European countries. Prevalence of anti-HAV among children age 1-12 admitted for diagnoses believed unrelated to viral hepatitis was 10%. Prevalence of hepatitis markers in Roman women of reproductive age is estimated as 23.5 for B and 68.2 for A.

Antibodies, Viral↗
PubMed1980

Alternative definitions of open-angle glaucoma. Effect on prevalence and associations in the Framingham eye study.

Framingham Eye Study data were used to examine the effect of alternative definitions of open-angle glaucoma (OAG) on prevalence and on associations with selected variables from the Framingham Heart Study. Definitions were based on various combinations of history of glaucoma, types of visual field defects, and functions of intraocular pressure and cup-disc ratio. Visual field defect irrespective of blind spot enlargement is used as a standard for comparison. Prevalence of OAG by this definition is higher for men than for women and increases with age, more markedly than for most other definitions. Alcohol consumption is directly related to glaucoma defined either by the reference standard or by visual field defects including blind spot enlargement. Systemic blood pressure, ventricular rate, and diagnosis of diabetes are directly related to IOP.

Aged↗
PubMed1979

Quality assurance of clinical data: diagnostic standardization.

Diagnostic standardization requires substantial effort, including detailed specification of procedures in a written protocol and training of examiners in such procedures. Success is neither automatic nor assured. It is essential to monitor performance through replicate examinations and/or computation of examiner variance. When examiner variance exceeds permissible limits, consideration should be given to discarding the data.

Clinical Trials as Topic↗
PubMed1977

The Framingham Eye Study. I. Outline and major prevalence findings.

During the period 1973--1975, 2675 out of 3977 still-living members of the Framingham, Massachusetts, study population, who have been under investigation for coronary disease risk factors since 1948 and who were in 1973--1975 aged 52 to 85, were given an eye examination stressing cataract, diabetic retinopathy, macular degeneration and glaucoma. Of 2940 subjects who still lived in the local Framingham area, 2477 were examined. Local population prevalence for one or both eyes positive was: 15.5% for senile cataract, 3.1% for diabetic retinopathy, 8.8% for senile macular degeneration and 3.3% for open-angle glaucoma. The proportion of adults with poor "best" visual acuity may be much less than has been estimated by the National Health Survey and the proportion with open-angle glaucoma much more than currently suspected on the basis of foreign studies.

Age Factors↗
PubMed1977

The Framingham Eye Study. II. Association of ophthalmic pathology with single variables previously measured in the Framingham Heart Study.

Using the age-sex-specific data collected in the Framingham Heart Study 1948--1964 together with ophthalmic diagnoses made in the Framingham Eye Study in 1973--1975, the following variables were found to be associated with senile cataract: education, casual blood sugar, systemic blood pressure, height, vital capacity, serum phospholipid and hand strength; with senile macular degeneration: systemic blood pressure, height, vital capacity, left ventricular hypertrophy, hand strength and history of lung infection; with diabetic retinopathy: casual blood sugar, urine sugar and other specific elements of diabetes; with ocular hypertension: systemic blood pressure, height, casual blood sugar and pulse rate. No variables were identified as associated with open-angle glaucoma. The paper stresses the need for corroboration of these findings, which may be a mix of real and chance associations, and the need for additional analyses before any of these associations are considered evidence of factors related to risk of ophthalmic disease.

Aged↗
PubMed1976

The association of femal hormones with blindness from diabetic retinopathy.

The rates of blindness from diabetic retinopathy with or without other causes for persons in the Model Reporting Area (14 states) were determined in five-year intervals by sex. Diabetic males younger than 45 years of age had a higher rate of diabetic blindness than females under 45 years of age. However, for ages 45 and older, the risks of blindness among diabetics were approximately equal for men and women. These data were consistent with the hypothesis that the presence of female hormones improves the prognosis in diabetic retinopathy.

Adult↗
PubMed1976

Senile cataract extraction and diabetes.

A study of hospital discharge diagnoses from both national data and data from a local medical centre indicates that diabetes substantially increases the probability of cataract extraction at age 40-49, about doubles or triples the probability for age 50-69, and has little effect on risk at age 70 and over. Strengths and weaknesses of the data are discussed. Other reports, generally estimating a much stronger association between diabetes and probability of cataract extraction, at least at age 50 and above, are critically evaluated.

Adult↗