The Tromsø physical activity questionnaire has acceptable validity and provides valid estimates of high-intensity leisure activity. However, these results underscore the need for collecting objectively PA measurements in large epidemiological studies.

Metabolic components [body mass index (BMI), blood pressure, serum lipids] and physical activity may affect biological mechanisms of importance for breast cancer prognosis. A population-based survival study among 1,364 breast cancer cases within the Norwegian Counties Study during 1974-2005 was conducted. Pre-diagnostic measurements of BMI, blood pressure, serum lipids, and self-reported physical activity were assessed. Multivariable Cox proportional hazard models were used in analyses (SAS version 9.11). Among these breast cancer cases (age at diagnosis 27-79 years), 429 women died (8.2 mean follow-up years). Those with a BMI >or= 30 kg/m(2) had a 1.47 higher risk of dying during follow-up than women with a BMI of 18.5-25 kg/m(2) [hazard ratio (HR) = 1.47, 95% CI 1.08-1.99]. Women with BMI < 25 kg/m(2) and age of diagnosis >or=55 years had a 66% reduction in overall mortality if they regularly exercised before diagnosis compared with sedentary women (HR = 0.34, 95% CI 0.16-0.71). Women in the highest tertile of total cholesterol had a 29% increase in mortality compared to women in the lowest tertile (HR = 1.29, 95% CI 1.01-1.64). Additionally, women in the highest tertile of blood pressure had a 41% increase in mortality compared to women in the lowest tertile of blood pressure (HR = 1.41, 95% CI 1.09-1.83). Our study supports a relationship between mortality not only in relation to BMI, but also blood pressure, lipids, and physical activity among breast cancer patients. These factors may all be important targets for invention among breast cancer patients.

Our findings support the hypothesis that early age at menarche, together with adult overweight and obesity, result in high levels of 17-beta-estradiol throughout the menstrual cycle.

LPA and HR were associated with metabolic risk score, and this score was associated with daily level of E2, pointing to important biologic mechanisms operating between a sedentary lifestyle and an increased breast cancer risk.

Since lung cancer is among the cancers with the highest incidence and has the highest mortality rate of cancer worldwide, the means of reducing its impact are urgently needed. Emerging evidence shows that physical activity plays an etiological role in lung cancer risk reduction. The majority of studies support the fact that total and recreational physical activity reduces lung cancer risk by 20-30% for women and 20-50% for men, and there is evidence of a dose-response effect. The biological mechanisms operating between physical activity and lung cancer are likely complex and influenced by many factors including inherited or acquired susceptibility genes, gender, smoking, and other environmental factors. Several plausible biological factors and mechanisms have been hypothesized linking physical activity to reduced lung cancer risk including: improved pulmonary function, reduced concentrations of carcinogenic agents in the lungs, enhanced immune function, reduced inflammation, enhanced DNA repair capacity, changes in growth factor levels and possible gene-physical activity interactions. Future research should target the possible subgroup effects and the biologic mechanisms that may be involved.

Objective There is conflicting evidence as to whether duration of lactation may decrease the risk of subsequent development of an unfavorable maternal metabolic profile including overweight and obesity. We hypothesized that duration of lactation is associated with a more favorable metabolic profile and healthier anthropometrical measurements. Methods 98 parous women from the Norwegian EBBA I-study (Energy Balance and Breast cancer Aspects-study), a cross-sectional study of healthy premenopausal women aged 25-35 years, historical lactation data were collected, anthropometrical measurements were taken, fasting blood samples (serum glucose, triglycerides, total cholesterol and HDL-cholesterol) were drawn and women were asked to fill in a pre-coded food diary. Results Mean time since last birth was 4.7 years, mean number of children was 1.9, mean total duration of lactation was 19 months and average length of lactation per child was 10.3 months. Women who on average lactated for less than 10 months per child had higher mean levels of fasting

BACKGROUNDOvarian hormones, parity and length of ‘menarche-to-first birth’ time interval are known risk factors for breast cancer, yet the associations between 17β-estradiol, progesterone and these reproductive factors remain unclear.METHODSA total of 204 women (25–35 years) who participated in the Norwegian EBBA-I study collected daily saliva samples for one complete menstrual cycle, and filled in a reproductive history questionnaire. Anthropometry was measured and saliva samples were analyzed for ovarian hormones. Associations between parity, the interval and ovarian hormones, and effects of hormone-related lifestyle factors were studied in linear regression models.RESULTSMean age was 30.7 years, and age of menarche 13.1 years. Parous women had on average 1.9 births, and age at first birth was 24.5 years. No association was observed between parity and ovarian steroids. In nulliparous women, higher waist circumference (≥77.75 cm) and longer oral contraceptive (OC) use (≥3 years) were associated with higher levels of 17β-estradiol. Short (<10 years) versus long (>13.5 years) ‘menarche-to-first birth’ interval was associated with higher overall mean (Ptrend = 0.029), 47% higher maximum peak and 30% higher mid-cycle levels of 17β-estradiol. We observed a 2.6% decrease in overall mean salivary 17β-estradiol with each 1-year increase in the interval.CONCLUSIONSNulliparous women may be more susceptible to lifestyle factors, abdominal overweight and past OC use, influencing metabolic and hormonal profiles and thus breast cancer risk. Short time between ‘menarche-to-first birth’ is linked to higher ovarian hormone levels among regularly cycling women, suggesting that timing of first birth is related to fecundity.

Background: Adult height and insulin are thought to modify the development of breast cancer. However, little is known about the association between height and 17B-estradiol, a key factor in breast carcinogenesis, and whether insulin modifies such an association. Methods: Among 204 healthy women, ages 25 to 35 years, who participated in the Energy Balance and Breast Cancer Aspect I study, adult height (in centimeters) and fasting serum concentrations of insulin (pmol/L) were measured. 17B-Estradiol concentrations were measured in daily saliva samples throughout an entire menstrual cycle through RIA. Age and multivariate linear regression models were used to study the association between adult height and 17B-estradiol levels throughout an entire menstrual cycle and whether serum levels of fasting insulin may modify such an association.