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Biomedical subjects

P E Sartwell

Publications and source records attributed to P E Sartwell.

At least 19 recordsLinked to original sources
PubMed1995

The distribution of incubation periods of infectious disease. 1949.

1. Characteristics of the distribution of incubation periods of a number of infectious diseases, as reported in the literature, have been reviewed. 2. The usual frequency curve of incubation time takes the form of a logarithmic normal curve. This appears to be equally true of diseases with very short and very long incubation periods. 3. The measure of variation in incubation periods used in this study, termed the dispersion factor, is the antilogarithm of the logarithmic standard deviation. Dispersion factors for most of the diseases studied range from 1.2 to 1.5 and are independent of mean length of incubation. 4. Some epidemiological uses for a knowledge of the distribution of incubation time are discussed.

Communicable Diseases↗
PubMed1989

Oral contraceptives and vascular disease.

This update on the cardiovascular risks of oral contraceptives unfortunately adds little to our original 1982 review for the following reasons: 1) There are many different formulations on the market, and they keep changing; 2) Women often use different formulations, stopping and starting as well as switching; 3) The statistical power of the studies often does not permit analyses by specific formulations; 4) The required information (brand name) is sometimes not collected or not collected reliably; 5) Apparently few case-control studies are being conducted to address these issues. Data that are available, interpreted cautiously, suggest either a continuance of the previously observed risk or a small to modest diminution with the use of the newer oral contraceptive formulations. The earlier advice to physicians still seems prudent and is briefly stated: 1) Try to avoid prescribing oral contraceptives for women over 35 years of age; 2) Women who smoke cigarettes should avoid using oral contraceptives, and users should not smoke; 3) Prescribe the formulation with the lowest dose and/or potency of estrogen that is effective and that does not cause unacceptable "breakthrough" bleeding; 4) Women with hypertension should be carefully monitored, and women who develop hypertension while on oral contraceptives should be switched to another form of contraception, if possible. Although oral contraceptives are the most effective form of contraception currently widely available, all risks of a contraceptive method must be compared with corresponding measures of effectiveness and with the risks of unwanted pregnancy. In particular, oral contraceptive users can reduce their risk of myocardial infarction by a reduction or elimination of cigarette smoking.

Adult↗
PubMed1979

Increased risk of thrombosis due to oral contraceptives: a further report.

In a previously reported case-control study of the relationship between oral contraceptives and thromboembolism, there were 461 cases and 1302 controls, individually matched on age, race, marital status, hospital, and date of admission. Initially, the control patients had not been matched with the cases for the presence or absence of six factors thought to predispose to or precipitate thromboembolic disease. The present paper reports the effects of taking into consideration these factors in the controls. Two methods of analysis (matched set, and logistic regression) gave closely similar results. Where the case series consisted of idiopathic cases, the revised estimate of the relative risk was reduced from 7.2 to 4.7 by these procedures; for predisposed cases, it was increased from 1.2 to 2.2. The explanation suggested in the previous report for the failure to find an increased risk for cases with predisposition receives support from these findings. Variation in the relative risk was examined for four separate diagnostic categories: venous thrombosis alone, pulmonary embolism alone, venous thrombosis and pulmonary embolism together, and myocardial infarction. The relative risk estimates were greater than unity for each thrombosis category for both predisposed and non-predisposed cases. The relative risk was not found to vary significantly according to age or smoking status.

Adolescent↗
PubMed1978

Benign and malignant breast tumours: epidemiological similarities.

Reproductive risk factors were estimated for 783 cases of cystic disease of the breast, 155 fibroadenoma, 94 miscellaneous breast conditions, and 284 breast cancers. Controls were matched for age, race, ever-married status, time of hospitalization and pay status. The most consistent attributes are a tendency to be still premenopausal, to have had her first pregnancy beyond the age of twenty-five years (or to have had none), and to have had fewer total pregnancies than the control. All are associated with a longer menstrual life prior to onset of the disease than the controls. Findings for cystic disease are compared with other studies. Patients with benign breast disease share some of the demonstrated risk factors for breast cancer.

Adenofibroma↗
PubMed1978

Agreement rates between oral contraceptive users and prescribers in relation to drug use histories.

A comparison between prescriber records and patient-reported oral contraceptive histories obtained during a case-control study of thromboembolism and oral contraceptive use served as the basis for evaluating the extent of agreement between these two sources of information. Agreement between oral contraceptive user and prescriber was highest on the name of the most recently-used product (89% agreement), and dropped to 62.5% on the name of the product taken before the more recent one. For total duration of oral contraceptive use (to within one month of hospital admission), agreement (defined as differences not exceeding one month) was 36%, while 39% showed the users reporting longer duration of use, and 25% showed users reporting shorter duration. Cases showed a higher rate of agreement with prescriber records than the controls on both the name of the product and the total duration of use. Disagreement from prescriber records in the direction of reporting longer duration of use was 45% for the controls compared to 27% for the cases. These results indicate that while user information in connection with the most recently used oral contraceptive can be acceptable in studies employing the case-control research strategy, user reports about previous oral contraceptive use may be less useful.

Adolescent↗
PubMed1977

Exogenous hormones, reproductive history, and breast cancer.

We studied 284 patients (20-74 years of age) with carcinoma of the breast and 367 controls; all were admitted to one hospital between 1969 and 1972. The disease was associated with nulliparity, first pregnancy over 20 years of age, premenopausal status, and a lower frequency of artificial menopause. After adjustment for these factors, no significant difference was found between the breast cancer patients and controls in their prior use of either estrogens or oral contraceptives, but the confidence limits on the relative risk, especially for oral contraceptives, were large.

Adult↗
PubMed1975

The current mortality rates of radiologists and other physician specialists: deaths from all causes and from cancer.

The cohort mortality experience of radiologists and other specialists over a 50-year period was examined on the assumption that these groups would differ relative to a presumed decrease in radiation exposure. Radiologists had an excess in all-cause mortality rates compared to the other specialists for all cohorts who entered the Radiological Society of North America before 1940; the excess remained even when the cancer deaths were removed from the rates. These data are consistent with the concept of accelerated aging due to radiation. The cancer mortality rates for radiologists were higher than those of other specialists for an additional decade through 1949. The 1950-1959 cohort had not aged sufficiently to demonstrate the expected peak cancer mortality in the 60-64 year age group. Several hypotheses are presented to suggest reasons for differences in the trends of age-specific cancer mortality by cohorts of entry.

Adult↗