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Biomedical subjects

L G Dales

Publications and source records attributed to L G Dales.

At least 19 recordsLinked to original sources

Clinical efficacy of measles vaccine during the 1990 measles epidemic.

Because of increased measles incidence in the United States during 1989 and 1990 and the recent finding of genomic differences between vaccine virus and contemporary wild measles viruses, we conducted a study to determine whether the current measles vaccine had become less effective. Household secondary attack rates for 203 California children ages 1 to 5 years were 4.2 and 77.8% for vaccinated and unvaccinated children, respectively, and the vaccine efficacy was 95% (95% confidence interval: 89%, 97%). The protective efficacy for postexposure vaccination and use of IG were both low, 4% (95% confidence interval: less than 0, 36%) and 8% (95% confidence interval: less than 0, 59%), respectively. The measles vaccine efficacy found in this study is similar to those obtained in previous years and indicates that the measles epidemic of 1989 to 1990 occurred despite high vaccine effectiveness.

California

Transmission of measles in medical settings. 1980 through 1984.

For the five-year period 1980 through 1984, a total of 241 persons with measles in 30 states were identified as probably having acquired their infection in a medical facility. The proportion of all measles cases acquired in medical settings increased from 0.7% for 1980 through 1982 to 2.9% for 1983 and 1984. Seventy-six percent of cases were found in patients or visitors, and 24% in personnel at the medical facility where transmission occurred. The highest proportion of cases occurred in children less than 5 years of age (54.3%), followed by persons 25 to 29 years of age (14.7%). Of spread (50.0%) and patient-to-staff spread (36.7%) were most common. Medical personnel rarely transmitted disease to others. More attention needs to be given to methods of preventing spread of measles in medical facilities, such as isolation precautions, postexposure prohylaxis of potential contacts (vaccination or immune globulin), and ensuring that medical personnel are immune to measles.

Adult

Mortality in middle-aged smokers and nonsmokers.

We assessed the relation of cigarette smoking to mortality in an 11-year follow-up study of 4004 men and women, 35 to 54 years of age, who responded to urging to have multiphasic health checkups. Accounting for 48 other characteristics, both individually and in combination, failed to eliminate the association of smoking with mortality from all causes or with mortality from coronary heart disease. The smoker-to-nonsmoker mortality ratios, crude and adjusted respectively, were 2.6 and 2.1 for all causes and 4.7 and 3.6 for coronary heart disease. This analysis did not support the counterhypothesis that the association of cigarette smoking with mortality is secondary to some underlying characteristic.

Adult

A case-control study of relationships of diet and other traits to colorectal cancer in American blacks.

Ninety-nine black colorectal cancer patients and 280 matched controls from hospitals and multiphasic health checkup clinics were interviewed about past dietary habits and other traits. The colon cancer cases tended to report less frequent use of foods with at least 0.5% fiber content than did their controls. This relationship, though small, showed a consistent dose-response gradient, appeared in both case-hospital control and case-multiphasic health checkup control comparisons, and could not be accounted for by the effects of other variables. Colon and rectosigmoid junction cancer patients tended to have eaten foods with at least 5% saturated fat somewhat more often than controls. When consumption of these two groups of foods was considered in combination, significantly more colon cancer patients than controls reported a high saturated fat foods-low fibrous foods eating pattern, as opposed to a low saturated fat foods-high fibrous foods diet. Statistically significant excesses of the following traits were also reported by the colorectal cancer patients: prolonged cigar smoking in men, nulliparity in women, and history of colorectal polyps.

Adenocarcinoma

An improper use of statistical significance testing in studying covariables.

How badly a covariable confounds the association between a disease and a primary trait depends on the strength of two other associations: between covariable and disease, and between covariable and primary trait. To assess the confounding potential by testing one of these associations for statistical significance, using a 'traditional' critical level, is inadequate. Such a preliminary test places the burden of proof in the wrong direction, ignores a major aspect of confounding potential, and may be inappropriately influenced by other factors. If it must be used at all, the significance level should be 0.25 or 0.50, possibly even higher.

Statistics as Topic

Cigarette smoking habits and urine characteristics: urinalysis abnormalities are more common is smokers, but the reasons are unclear.

Voided urines of 53,000 white and 9,3000 black cigarette smokers and nonsmokers were studied. Proteinuria was found to be commoner in smokers of both races and sexes. Heavy smokers showed proteinuria more frequently than light smokers. Of eight possible explanatory variables, one, alcohol consumption history, showed some interrelationship in that the smoking status-proteinuria association disappeared among heavy drinkers. Stopping smoking was not associated with a relative decline in proteinuria prevalence. Proteinuria associated with smoking did not appear to be indicative of more serious renal disease. There was a smoker-nonsmoker difference in urine glucose response to oral glucose challenge, apparently explained by higher average 1-hour serum glucose values for smokers, of unknown mechanism but partially explained by differences in alcohol usage. Hematuria, bacteriuria, and high urine acidity tended to be more prevalent in smokers, though these relationships were not consistently significant.

Adult

Cigarette smoking and chest pain.

Analysis of questionnaire responses of 70208 persons undergoing multiphasic health checkups showed a greater proportion of cigarette smokers than nonsmokers (excesses averaging 1.6-fold in white men, 1.3-fold in white women) admitting to nine types of chest pain. This excess in smokers was greater in younger individuals, and applied about equally to anginalike and nonanginalike pain. The smoking/chest pain association was not explained by greater alcohol or coffee consumption, diminished pain tolerance, or less reliability among smokers; nor did it appear to be mediated chiefly by excess cough, shortness of breath, coronary disease, or musculoskeletal complaints in smokers. Although smokers averaged more complaints than nonsmokers, chest pain resembled clearly smoking-related symptoms, such as cough, when the number of each subject's complaints was considered. Although more smokers had chest pain no type of pain was unique to smokers, suggesting that the "tobacco angina" concept be discarded or reserved for rare patients with coronary heart disease in whom smoking clearly provokes angina pectoris.

Adolescent