Roberta M. Ray

BACKGROUND: Among women who practice breast self-examination (BSE), breast cancers may be detected when they are at an earlier stage and are smaller than in women who do not practice BSE. However, the efficacy of breast self-examination for decreasing breast cancer mortality is unproven. This study was conducted to determine whether an intensive program of BSE instruction will reduce the number of women dying of breast cancer. METHODS: From October 1989 through October 1991, 266,064 women associated with 519 factories in Shanghai were randomly assigned to a BSE instruction group (132,979 women) or a control group (133,085 women). Initial instruction in BSE was followed by reinforcement sessions 1 and 3 years later, by BSE practice under medical supervision at least every 6 months for 5 years, and by ongoing reminders to practice BSE monthly. The women were followed through December 2000 for mortality from breast cancer. Cumulative risk ratios of dying from breast cancer were estimated using Cox proportional hazards models. All statistical tests were two-sided. RESULTS: There were 135 (0.10%) breast cancer deaths in the instruction group and 131 (0.10%) in the control group. The cumulative breast cancer mortality rates through 10 to 11 years of follow-up were similar (cumulative risk ratio for women in the instruction group relative to that in the control group = 1.04, 95% confidence interval = 0.82 to 1.33; P =.72). However, more benign breast lesions were diagnosed in the instruction group than in the control group. CONCLUSIONS: Intensive instruction in BSE did not reduce mortality from breast cancer. Programs to encourage BSE in the absence of mammography would be unlikely to reduce mortality from breast cancer. Women who choose to practice BSE should be informed that its efficacy is unproven and that it may increase their chances of having a benign breast biopsy.

OBJECTIVE: To examine dose-response relationships between the cumulative number of months women lactated and postmenopausal risk factors for cardiovascular disease. METHODS: We examined data from 139,681 postmenopausal women (median age 63 years) who reported at least one live birth on enrolling in the Women's Health Initiative observational study or controlled trials. Multivariable models were used to control for sociodemographic (age, parity, race, education, income, age at menopause), lifestyle, and family history variables when examining the effect of duration of lactation on risk factors for cardiovascular disease, including obesity (body mass index [BMI] at or above 30), hypertension, self-reported diabetes, hyperlipidemia, and prevalent and incident cardiovascular disease. RESULTS: Dose-response relationships were seen; in fully adjusted models, women who reported a lifetime history of more than 12 months of lactation were less likely to have hypertension (odds ratio [OR] 0.88, P<.001), diabetes (OR 0.80, P<.001), hyperlipidemia (OR 0.81, P<.001), or cardiovascular disease (OR 0.91, P=.008) than women who never breast-fed, but they were not less likely to be obese. In models adjusted for all above variables and BMI, similar relationships were seen. Using multivariate adjusted prevalence ratios from generalized linear models, we estimate that among parous women who did not breast-feed compared with those who breast-fed for more than 12 months, 42.1% versus 38.6% would have hypertension, 5.3% versus 4.3% would have diabetes, 14.8% versus 12.3% would have hyperlipidemia, and 9.9% versus 9.1% would have developed cardiovascular disease when postmenopausal. Over an average of 7.9 years of postmenopausal participation in the Women's Health Initiative, women with a single live birth who breast-fed for 7-12 months were significantly less likely to develop cardiovascular disease (hazard ratio 0.72, 95% confidence interval 0.53-0.97) than women who never breast-fed. CONCLUSION: Among postmenopausal women, increased duration of lactation was associated with a lower prevalence of hypertension, diabetes, hyperlipidemia, and cardiovascular disease.

Experimental and epidemiological studies suggest that calcium and vitamin D supplements may lower blood pressure. We examined the effect of calcium plus vitamin D supplementation on blood pressure and the incidence of hypertension in postmenopausal women. The Women's Health Initiative Calcium/Vitamin D Trial randomly assigned 36 282 postmenopausal women to receive 1000 mg of elemental calcium plus 400 IU of vitamin D3 daily or placebo in a double-blind fashion. Change in blood pressure and the incidence of hypertension were ascertained. Over a median follow-up time of 7 years, there was no significant difference in the mean change over time in systolic blood pressure (0.22 mm Hg; 95% CI: -0.05 to 0.49 mm Hg) and diastolic blood pressure (0.11 mm Hg; 95% CI: -0.04 to 0.27 mm Hg) between the active and placebo treatment groups. This null result was robust in analyses accounting for nonadherence to study pills and in baseline subgroups of interest, including black subjects and women with hypertension or high levels of blood pressure, with low intakes of calcium and vitamin D or low serum levels of vitamin D. In 17 122 nonhypertensive participants at baseline, the hazard ratio for incident hypertension associated with calcium/vitamin D treatment was 1.01 (95% CI: 0.96 to 1.06.) In postmenopausal women, calcium plus vitamin D3 supplementation did not reduce either blood pressure or the risk of developing hypertension over 7 years of follow-up.