This study examines the impact of smoking, body mass index, alcohol consumption, hormone replacement therapy, and physical activity on all-cause mortality among 528 Danish women diagnosed with primary breast cancer. Participants were women enrolled in the Copenhagen City Heart Study. Prospective self-reported exposure information was collected from four points of follow-up in 1976-1978, 1981-1983, 1991-1994, and 2001-2003. Kaplan-Meier survival curves and multivariate Cox regression analyses were performed adjusting for age, disease stage, adjuvant treatment, menopausal status, parity, alcohol intake, smoking, physical activity, body mass index, and hormone replacement therapy. The study shows that smoking for total mortality [hazard ratio, 1.16; 95% confidence interval, 1.05-1.29] and obesity for both total mortality (1.61; 1.12-2.33) and breast cancer-specific mortality (1.82; 1.11-2.99) were significantly associated with decreased survival after breast cancer diagnosis. A moderate alcohol intake of 1-6 units/week (0.85; 0.64-1.12), 7-14 units/week (0.77; 0.56-1.08), and treatment with hormone replacement therapy (0.79; 0.59-1.05) were less than 1, but not statistically significantly associated with prolonged survival. A moderate physical activity of 2-4 h/week (1.07; 0.77-1.49) and a high physical activity of more than 4 h/week (1.00; 0.69-1.45) showed no association with survival after breast cancer diagnosis.

BackgroundBreast cancer is the leading malignant disease among western women with incidence increasing over time. High mammographic density is a well-established risk factor for breast cancer. We explored trends in mammographic density across birth cohorts to gain further insight into possible time trends in women’s mammographic density that might explain the historical increase in breast cancer incidence.MethodsData derived from two mammography screening programs in Denmark from 1991 to 2001, including on average 41,091 women from Copenhagen and 52,938 women from Funen aged 50–69. Mammographic density was assessed qualitatively (fatty or mixed/dense) by senior screening radiologists. The proportion of women with mixed/dense mammographic density was calculated by age at screening, screening period, and birth cohort. The Generalized Estimating Equations were used to calculate odds ratios and 95% confidence intervals. All statistical tests were two-sided.ResultsThe proportion of women with mixed/dense mammographic density increased from 45% among women born in the 1920s to 75-80% among women born in the 1940s. In Copenhagen, the age-adjusted odds ratio (95% CI) of mixed/dense mammographic density in women born in 1941–42 was 2.48 (2.22-2.76) compared with women born in 1921–22. In Funen, the age-adjusted odds ratio of mixed/dense mammographic density in women born in 1946–47 was 5.89 (5.32-6.51) compared with women born in 1924–25. Hormone use had a greater impact on mammographic density in birth cohorts of the 1920s compared with those of the 1940s.ConclusionsWe found suggestive evidence of a birth cohort pattern in mammographic density and an attenuated impact of hormone use in younger compared with older birth cohorts suggesting that postmenopausal mammographic density could be linked to changing exposures accumulated over time in women’s lives.

BackgroundBreast cancer is the leading cancer among women, and early diagnosis is essential for future prognosis. Evidence from mainly cross-sectional US studies with self-reported exposure and outcome found positive association of body mass index (BMI) with non-participation in mammographic screening, but hardly addressed the influence of potential effect-modifiers. We studied the association between objective measures of BMI and participation in mammographic screening in a Danish prospective cohort, and explored the influence of menopausal status, hormone therapy (HT), previous screening participation, and morbidities on this relationship.MethodsA total of 5,134 women from the Diet, Cancer, and Health cohort who were invited to population based mammographic screening in Copenhagen were included in analysis. Women were 50–64 years old at inclusion (1993–97) when their height and weight were measured and covariates collected via questionnaire. Odds ratios (OR) and 95% confidence intervals (CI) for the association between BMI and mammographic screening participation were estimated by logistic regression, adjusted for other breast cancer risk factors and morbidities. Effect modification was evaluated by an interaction term and tested by Wald test.ResultsUnderweight (BMI < 18.5 kg/m2, OR: 95% CI; 2.24: 1.27-3.96) and obese women of class II (BMI 35–40 kg/m2, 1.54: 0.99-2.39) and III (BMI ≥ 40 kg/m2, 1.81: 0.95-3.44) had significantly higher odds of non-participation than women with normal weight. This association was limited to postmenopausal women (Wald test p = 0.08), with enhanced non-participation in underweight (2.83: 1.52-5.27) and obese women of class II and III (1.84: 1.15-2.95; 2.47: 1.20-5.06) as compared to normal weight postmenopausal women. There was no effect modification by HT, previous screening participation, or morbidities, besides suggestive evidence of enhanced non-participation in diabetic overweight and obese women.ConclusionsUnderweight and very obese postmenopausal women were significantly less likely to participate in mammographic screening than women with normal weight, while BMI was not related to screening in premenopausal women. Effect of BMI on mammographic screening participation was not significantly modified by HT, previous screening participation, or morbidities.