Articles: disease.
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Effects of oral contraception on neoplasia of the uterine corpus are reviewed on the basis of epidemiologic studies reported to date. A duration-related protective effect against endometrial cancer occurs from use of combined oral contraceptives, those in which each active pill contains both estrogen and progestogen. The risk before age 60 years is reduced by about 38% with two years of use; use of combined OCs for 4, 8, and 12 years, respectively, confers an estimated 51%, 64%, and 70% reduction in endometrial cancer risk. ⋯ Use of combined OCs may protect against uterine leiomyomas ("fibroids"), but the evidence is not conclusive. The few findings about effects of oral contraception on the risk of adenomatous hyperplasia are of uncertain validity. Only one study, with few patients, has considered oral contraception in relation to uterine sarcomas.
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More than six-fold variation in incidence between countries, an increasing incidence among immigrants to high incidence areas, and a general increase in the incidence of breast cancer within countries, are factors which suggest a potential for prevention. Reproductive factors such as early menarche, late age at first full term birth, nulliparity, and late age at menopause increase risk of breast cancer, but manipulation of any one of these factors does not seem to be a realistic preventive tool. ⋯ Alcohol consumption by young women, and overweight among postmenopausal women may also increase the incidence of breast cancer. Consequently, reduced alcohol intake by young women, and weight reduction among overweight women after menopause may reduce the risk of breast cancer.
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Infectious diseases are the main cause of mortality and morbidity in developing countries. The Expanded Programme on Immunization, initiated by WHO in 1974, now reaches 60 mill. a year at a cost of less than 2 US $ per immunized child, and saves 2.2 mill. lives annually. The present vaccines, however, have significant shortcomings. ⋯ By only modest investments modern gene technology could give improved and new vaccines which would potentially save 20 mill. lives a year. Particularly promising is the recent development of multi-vaccine-vectors. However, poor prospects for profit in developing countries and patent "swapping" by commercial producers severely hamper development in the vaccine field.