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Biomedical subjects

T M Mack

Publications and source records attributed to T M Mack.

At least 73 records · Page 4Linked to original sources

Bladder cancer etiology. A different perspective.

The descriptive epidemiologic features of bladder cancer and lung cancer in Los Angeles County were studied for the period 1972-1976, using data from the Los Angeles County/University of Southern California Cancer Surveillance Program. The incidence pattern for bladder cancer was found to differ markedly from the pattern observed for lung cancer. As expected, the descriptive pattern for lung cancer closely paralleled the known epidemiology of cigarette smoking; in addition, it was consistent with the expected pattern of an occupationally linked disease. In contrast, the pattern observed for bladder cancer indicated that factors other than cigarette smoking and occupational exposures may be etiologically important. The available descriptive epidemiology of coffee consumption, unlike that of cigarette smoking, is consistent with the pattern of bladder cancer occurrence in Los Angeles. Available analytic studies on the association of bladder cancer and coffee consumption are consistent with a causal relationship.

Adult↗

Organic chemicals and malignant melanoma.

Chemists with cancer were interviewed to generate hypotheses that might explain an apparent excess of malignant melanoma in chemists in Los Angeles County (LAC). The chemists were identified by the LAC Cancer Surveillance Program, a population-based cancer registry. Interviews that included information on work history and exposure to specific chemicals were conducted by telephone. Chemists with melanoma were found to be better educated than chemists with other cancers and they reported more work with organic chemicals. They also cited more exposure to multiple chemicals, solvents, plastics, pesticides, benzoyl peroxide, and ionizing radiation. Although differences in educational level may account for the differences in exposure reported by cases and controls, the hypotheses that specific chemical exposures are related to melanoma occurrence are plausible and deserve further study. We also suggest that this method of generating hypotheses about cancer causes using cases identified from registries could be used more extensively.

Adult↗

Patterns of anal carcinoma by gender and marital status in Los Angeles County.

Marital status and other characteristics of 970 residents of Los Angeles County in whom cancer of the anus (including perianal skin) was diagnosed during the period 1972-1981 were compared with those of all county residents and all other persons in whom cancer was diagnosed during the same period. The incidence rate of anal cancer for single males was 6.1 times that for married males (P less than 0.001). This excess was limited to squamous and transitional cell carcinomas and was reasonably consistent by age, stage, subsite, social class and race. Single women were not at increased risk, but separated and divorced persons of both sexes were at increased risk compared to married persons. Anal cancers were more common in males under the age of 35, after which there was a substantial female predominance. This relative excess in older women occurred at all stages, subsites, and social classes of whites and also in blacks, but not in Hispanics, among whom women had lower overall incidence rates compared to both whites and blacks. The findings were consistent with the hypothesis that sexual activity involving the anus is related to anal cancer. We could not rule out the possibility that anal cancer is related to the acquired immune-deficiency syndrome (AIDS) since the incidence in young single men appears to have increased in 1980 and 1981.

Adenocarcinoma↗

Incidence of biliary tract cancer in Los Angeles.

Incidence data reported for biliary tract cancer in 4 ethnic groups of Los Angeles County are consistent with earlier reports of a similarity between the ethnic-gender distribution of gallbladder cancer and bile lithogenicity, and between that of other biliary cancer and free bilirubin. The female excess of biliary cancer proved to be highest in those ethnic groups with highest average parity, and risk was related to parity correlates such as marital status and religion (Catholic). A migration effect in Spanish-surnamed and other white females was present for both diseases.

Adult↗

Menopausal oestrogen therapy and protection from death from ischaemic heart disease.

The medical records of a Los Angeles retirement community were examined to find out the association between oestrogen replacement therapy and death from ischaemic heart disease. Women dying from ischaemic heart disease over a five-year period were compared with living and deceased control groups; both controls were matched with cases for date of birth, date of entry into the community, race, and socioeconomic status. The deceased control was also matched for date of death. Compared with living controls cases using conjugated oestrogens had a risk ratio for death from ischaemic heart disease of 0.43 (95% confidence interval 0.24-0.75). Comparison with deceased controls gave a similar relative risk. This association was not due to identifiable confounding factors. Other risk factors for ischaemic heart disease, including hypertension, diabetes, stroke, angina pectoris, and heavy cigarette smoking, were confirmed by this study.

Aged↗

Epidemiology of pancreas cancer in Los Angeles.

The characteristics of the 3614 Los Angeles County residents in whom cancer of the exocrine pancreas was diagnosed during the period 1972-1977 were compared with those of all county residents and patients in whom any cancer was diagnosed during the same period. Seventy-nine percent of the diagnoses had been pathologically verified. This disease still preferentially afflicts the old, the black, and men, although the differences in risk with factors other than age are modest. The disease is not evenly distributed by social class, or over time, although it is not clear that the observed differences reflect etiology. The distributions with respect to important categories of occupation and industry, religion, marital status, geography of residence, and birthplace were rather uniform. Although there is no obvious explanation for any of several unexpected minor inequities in the pattern of incidence, there is no compelling evidence to support any specific environmental cause. There is substantial evidence which is inconsistent with those environmental hypotheses that have been proposed previously.

Age Factors↗

Menopausal estrogen therapy and hip fractures.

The association between menopausal estrogen therapy and hip fracture was studied in a retirement community. Ninety-one hip fracture cases during a 5-year period in female residents under age 80 were compared to age-and race-matched community controls. Estrogen use was recorded from the medical records of the outpatient care facility and personal interviews. The estimated risk ratio for use of oral estrogens in excess of 60 months was 0.42. This protective effect was largely limited to oophorectomized women for whom the risk ratio for a comparable duration of use was 0.14; the risk significantly decreased with increased duration, but no such trend existed with increased dosage. Diabetes mellitus, low Quetelet's index, tallness, prolonged immobilization or physical inactivity, use of corticosteroids, early age at menopause, low levels of sunlight exposure, and heavy cigarette smoking were each independent risk factors for hip fracture but none confounded the observed association with estrogen use.

Adrenal Cortex Hormones↗

A case-control study of menopausal estrogen therapy and breast cancer.

The association between estrogen replacement therapy and female breast cancer was studied in two Los Angeles area retirement communities. The 138 study cases of breast cancer occurring in residents younger than 75 years were compared with age- and race-matched community control subjects. The risk ratio for a total cumulative dose in excess of 1,500 mg was estimated to be 2.5 in women with intact ovaries. This increase was present using various independent sources of drug usage information but was inconsistent at low dose and undetectable in oophorectomized women. No important sources of confounding could be identified, and no risk modifiers could be identified except for a history of surgically confirmed benign breast disease. In such women with intact ovaries, the risk ratio for a high cumulative dose rose to 5.7 relative to nonusers with normal breasts.

Age Factors↗

Descriptive epidemiology of testicular and prostatic cancer in Los Angeles.

Data from the Los Angeles County Cancer Surveillance Program (CSP) from 1972 to 1975 were used to study the descriptive epidemiology of testicular cancer and prostatic cancer. The very high black/white ratio and late age peak of cancer of the prostate contrasted sharply with the very low ratio and early age peak of testicular cancer. However, both sites had higher rates among upper occupational and social class groupings. Avalable descriptive and analytical research suggests that the etiology of prostatic cancer is most probably related to hormonal influences rather than to a horizontally transmitted agent, while the etiology of testicular cancer is most probably related to endogenous or exogenous hormonal influences in utero or in infancy, or to in utero exposure to other exogenous agents.

Adolescent↗

Postmenopausal carcinoma as a result of estrogen treatment: survey of evidence.

Recent studies concerning the relationship of exogenous estrogens and endometrial cancer have been reviewed and the objections to their conclusions discussed. Even considering the most serious of these reservations, it is difficult to avoid the tentative conclusion that estrogens are causally linked to endometrial cancer and that the attributable risk is numerically sizable. Whether the medical costs will be ultimately shown to outweigh the benefits of estrogen replacement therapy will depend largely on whether or not a relationship to breast cancer is shown and on the magnitude of the effect of estrogens in preventing serious complications of ovarian failure. For the time being, treatment of menopausal symptoms with estrogens should be brief as possible, should use the lowest dose possible, and should probably be given in cyclic fashion, particularly to women with intact uteruses. Every attempt should be made to give patients a quantitative understanding of both potential risks and benefits before they decide in favor of or against estrogen therapy.

Age Factors↗

Cancer surveillance program in Los Angeles County.

A system of rapid surveillance for cancer in the population of Los Angeles County was studied, and the methodology was compared with traditional population-based registries. Comparisons with the Third National Cancer Survey were also made, and the pattern of malignant melanoma occurrence in Los Angeles residents was described.

California↗

Uterine cancer and estrogen therapy.

Recent studies concerning the relationship of exogenous estrogens and endometrial cancer have been reviewed, and the objections to their conclusions discussed. Even considering the most serious of these reservations, it is difficult to avoid the tentative conclusion that estrogens are causally linked to endometrial cancer, and that the attributable risk is numerically sizable. Whether the medical costs will be ultimately shown to outweigh the benefits of estrogen replacement therapy will depend largely on whether or not a relationship to breast cancer is shown, and on the magnitude of the effect of estrogens in preventing serious complications of ovarian failure. For the time being, estrogenic treatment of menopausal symptoms should be as brief as possible, should use the lowest dose possible, and should probably be given in cyclic fashion, particularly to women in intact uteruses. Every attempt should be made to give patients a quantitative understanding of both potential risks and benefits before they decide for or against estrogen therapy.

Adult↗

Estrogens and endometrial cancer in a retirement community.

All cases of endometrial cancer occurring among the residents of an affluent retirement community were compared with controls chosen from a roster of all women in the same community. Evidence of estrogen and other drug use and of selected medical conditions was obtained from three sources: medical records of the principal care facility, interviews, and the records of the local pharmacy. The risk ratio for any estrogen use was estimated from all available evidence to be 8.0 (95 per cent confidence interval, 3.5 to 18.1). and the for conjugated estrogen use to be 5.6 (95 per cent confidence interval, 2.8 to 11.1). Increased risk from estrogens was shown for invasive as well as noninvasive cancer, and a dose-response effect was demonstrated. For an estrogen user, the risk from endometrial cancer appeared to exceed by far the base-line risk from any other single cancer.

Age Factors↗

Urogenital tract abnormalities in sons of women treated with diethylstilbestrol.

Since in utero exposure to diethylstilbestrol (DES) is known to cause abnormalities of the female genital tract later in life, exposed male offspring were located, surveyed by mail, and compared with unexposed male offspring from the same period and medical practices. The exposed and unexposed respondents appeared comparable and did not differ in their response to most medical questions. However, a larger proportion of exposed than of unexposed boys had experienced problems in passing urine (12.9% vs. 1.8%, P = .0003) and abnormalities of the penile urethra (4.4% vs. 0%; P = .017).

Abnormalities, Drug-Induced↗

Reserpine and breast cancer in a retirement community.

In an attempt to confirm three reports suggesting a causal link between rauwolfia antihypertensive drugs and female breast carcinoma, all cases of such cancer appearing among the residents of an affluent retirement community were compared with controls chosen from a roster of all women in the same community. Most residents use a single care facility, and patterns of hypertension diagnosis, rauwolfia and other drug use, and medical-care-system patronage were abstracted from medical records. The prevalence of recorded rauwolfia use among the controls were 20 per cent, and that of other drug use was correspondingly high. The risk ratio for rauwolfia use was estimated to be 1.2 (95 per cent confidence interval, 0.7 to 2.2). Risk ratios between 1.0 and 2.0 were also found for other drug use and for measures of care-system patronage. These results do not support the hypothesis that reserpine causes breast cancer.

Aged↗