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Biomedical subjects

B MacMahon

Publications and source records attributed to B MacMahon.

At least 91 records · Page 5Linked to original sources
PubMed1978

Oral contraceptive use: association with frequency of hospitalization and chronic disease risk indicators.

A questionnaire was mailed to 97,364 married women, aged 26--50, resident in Greater Boston in 1970, requesting information on lifetime oral contraceptive (OC) use, reproductive history, education, and hospitalization experience in 1969; 65,843 women responded. In 1973 a second questionnaire was mailed to 37,292 of these women, including all OC users and an equal number of non-users matched on age, parity, education, and town of residence. This questionnaire related to use of OCs, other female hormones, and the menopause. OC use was most strongly related to age, with a sixfold increase in use from the oldest women (of whom 10 per cent had used OCs at some time) to the youngest. Use was directly related to education and mobility and inversely related to parity. Reasons for beginning and ceasing use differed for women of different ages and educational attainment. Thus, use of OCs varies with social and reproductive characteristics that are risk indicators for many diseases. OC use was associated with increased risk of hospitalization for thromboembolic disease (risk ratio = 1.5, 95 per cent confidence limits 1.2, 3.2) and for mental illness, hyperthyroidism, hypertension, and cancer of the cervix. OC users were hospitalized for many non-life threatening conditions 20 to 40 per cent more frequently than were non-users.

Adult↗
PubMed1978

Estrogen profiles of premenopausal women with breast cancer.

Population surveys have demonstrated an inverse relationship between breast cancer incidence rates and the urine "estriol ratio," the concentration of estriol relative to the sum of the concentrations of estrone and estradiol. In this study, the urine estriol ratio was evaluated in premenopausal breast cancer patients and control women from Boston and San Francisco. Although at least 2 years had passed since last use of oral contraceptives, women with a history or oral contraceptive use for 19 months or longer excreted estrogen in low concentrations compared to nonusers and so were excluded. Among the remaining 73 cases and 55 controls, the cases had lower estriol ratios and higher estrone and estradiol levels than did controls. However, these differences, which averaged about 10%, were not statistically significant. Thus the hypothesis that a low estriol ratio is a cause of breast cancer is given only minimal support. Among women in their 40's, the excretion of estrogens is subject to many influences and is difficult to study. The many determinants of estrogen excretion, including age and oral contraceptive use, should be accommodated in the design of future studies of the estriol ratio.

Adult↗
PubMed1977

Reduction in mortality from coronary heart disease in men residing at high altitude.

In New Mexico, where inhabited areas vary from 914 to over 2135 m above sea level, we compared age-adjusted mortality rates for arteriosclerotic heart disease for white men and women for the years 1957-1970 in five sets of counties, grouped by altitude in 305-m (1000-foot) increments. The results show a serial decline in mortality from the lowest to the highest altitude for males but not for females. Mortality rates for males residing in the county groups higher than 1220 m in order of ascending altitude were 98, 90, 86 and 72 per cent of that for the county group below 1220-m altitude (P less than 0.0001). The results do not appear to be explained by artifacts in ascertainment, variations in ethnicity or urbanization. A possible explanation of the trend is that adjustment to residence at high altitude is incomplete and daily activities therefore represent greater exercise than when undertaken at lower altitudes.

Acclimatization↗
PubMed1976

Oestrogen profiles of parous and nulliparous women.

Women who bear their first child at an early age have lower breast-cancer incidence-rates than do women who are older at first birth or who remain nulliparous. The urine "oestriol ratio", the concentration of oestriol relative to the sum of the concentrations of oestrone and oestradiol, is inversely related to a population's breast-cancer rate. To evaluate the relationship between these two breast-cancer risk indicators the urine oestriol ratio was determined for recently delivered uniparous women aged 19-23, 25-27, and 29-34 years and nulliparous women of comparable ages. In the follicular phase, the youngest parous women had an oestriol ratio 40% higher than, and significantly different from, the ratios of all other groups which were otherwise quite similar. In the luteal phase, the oestriol ratio of the youngest parous women was again distinctively raised and generally the oestriol ratios of parous women were higher than those of nulliparae. The results are not explained by differing frequencies of ovulation among the groups or by confounding from several breast-cancer risk indicators. These findings support the hypothesis that oestrogen metabolism, as reflected by the urine oestriol ratio, is a determinant of breast-cancer risk.

Adult↗
PubMed1976

Some international differences in treatment and survival in breast cancer.

In a recent study, 5-year survival rates for breast cancer patients in Boston (Massachusetts), Glamorgan (Wales), Slovenia (Yugoslavia) and Tokyo (Japan) were 57.3%, 49.5%, 41.9% and 74.9%, respectively. In this report, data are presented on the types of treatment used in the four areas and on the relationship of differences in treatment practices to the differences in survival rates. Generally, surgically treated patients who also had radiotherapy had lower survival rates than patients in the same area who had similar operations without radiotherapy. In each area, the survival rate was higher for patients who had radical mastectomy than for those who had simple mastectomy. The Japanese patients had the highest survival rate within nearly every treatment and extent-treatment category. Thus, the high survival rate of these patients was not explained by the variables considered. Survival differences between Boston, Glamorgan and Slovenia were largely explained by differences in extent of disease and type of treatment. As the nature of the treatment--survival trends was consistent with the interpretation that treatment tended to be selected according to apparent prognosis, the degree to which treatment customs were determinants of the differences in survival rate among the three areas is uncertain.

Boston↗
PubMed1976

Menopausal estrogens and breast cancer.

1891 women given conjugated estrogens for the menopause were followed for 12 years (mean) for incidence of breast cancer. Overall, 49 cases were observed; 39.1 were expected on the basis of rates in the general population (relative risk = 1.3, P = 0.06). The relative risk increased with follow-up duration, progressing to 2.0 after 15 years (13/6.6, P = 0.01). The excess risk after 10 years was not due simply to prolonged estrogen use, since there was no clear dose-response relation to accumulated years of use. However, higher risk accrued to women using higher-dose tablets and those taking the medication on an other than daily basis. In addition, after 10 years of follow-up observation, two factors related to low risk of breast cancer, multiparity and oophorectomy, were no longer so related. Finally, estrogen use was related to an especially high risk of breast cancer among women in whom benign disease developed after they had started the drug.

Aged↗
PubMed1976

Chronic mastitis and carcinoma of the breast.

733 women in whom chronic mastitis had been diagnosed were followed for an average of 30-3 years. 49 died from breast cancer compared with an expected number of 18-8. The excess risk of dying from breast cancer persisted for at least 30 years after chronic mastitis was diagnosed.

Adult↗
PubMed1976

Oral contraceptives and reduced risk of benign breast diseases.

In 1970 a questionnaire on oral-contraceptive use was mailed to 97,254 married women 25 to 49 years of age in Greater Boston. Sixty-nine per cent responded. During the subsequent 30 months, 1072 of the women were hospitalized for breast diseases. Hospitalization rates for fibrocystic disease were similar for non-users of oral contraceptives and users of one to 12 months' duration. However, users for 13 months to 24 months and 25 or more months had rates only 70 and 35 per cent, respectively, of those of non-users. Detailed analysis of these results, and their similarity to findings in previous studies, suggest that the association is causal--use of oral contraceptives appears to lower risk of fibrocystic breast disease. A similar association was seen for fibroadenoma. Rates of breast cancer were lower for users than for non-users, but this finding was neither related to duration of use nor statistically significant.

Adenofibroma↗