Exercise responses in children and adults with a Fontan circulation at simulated altitude.

Background: Traveling to high altitude has become more popular. High-altitude exposure causes hypobaric hypoxia. Exposure to acute high altitude, during air travel or mountain stays, seems to be safe for most patients with congenital heart disorders (CHD).

Risk factors for breast cancer at various ages.

A brief overview is presented of breast cancer risk factors with particular reference to the time in a woman's life when they seem to operate. High incidence of the disease in Western societies is associated with early ovarian maturation and late onset of reproduction. In biologic terms this means proliferation without differentiation of breast cells over a long period of time.

A comparative study of risk factors for hyperplasia and cancer of the endometrium.

A cohort study has been carried out to investigate risk factors for cancer as well as hyperplasia of the endometrium. Over the 13 years for which we followed 25,000 women aged 40-65 (who took part in a population-based screening programme for breast cancer), 111 cases of endometrial cancer and 109 cases of endometrial hyperplasia were diagnosed. A comparison of the outcome between the two disease entities revealed that large body weight among postmenopausal women and the use of oestrogenic drugs at all ages were risk factors for both cancer and hyperplasia of the endometrium.

Endometrial cancer in a cohort screened for breast cancer.

In a cohort of 25,000 women aged 40-65 years at intake in a periodic screening programme for breast cancer the occurrence of endometrial cancer was studied during a follow-up period of up to 18 years. The authors examined whether they could confirm the existence of a number of relationships between this cancer and some reproductive and anthropometric factors which had been found in several case-control studies and in a few cohort studies. A comparison was made between 147 cases of endometrial cancer occurring during the period of follow-up and a random sample of 900 women taken from the cohort (334 being premenopausal and 566 postmenopausal on the day of intake).

Regularity and length of menstrual cycles in women aged 41-46 in relation to breast cancer risk: results from the DOM-project.

The effect of regularity and length of the menstrual cycle on breast cancer risk was studied prospectively in 78 cases and 383 age-matched controls who participated in a breast cancer screening programme, the DOM-project, in Utrecht, the Netherlands. Before entering the screening programme when they were aged 41-46, the women kept a menstrual calendar during at least three consecutive cycles. Cycles were considered to be irregular if any of three cycles was shorter than 21 days or longer than 35 days and/or if variation between cycle lengths was more than five days.

Urinary nicotine metabolite excretion and lung cancer risk in a female cohort.

A nested lung cancer case-control study was carried out using 397 12 h urine samples originally collected from a cohort of over 26,000 women aged 40-64 at entry who were then followed for up to 15 years. The urine samples from active smokers were first identified using a simple qualitative method and their total nicotine metabolites/creatinine ratios then determined by automated colorimetric methods. The results obtained demonstrated the capacity of nicotine metabolite estimations in a single 12 h sample of urine to predict the subsequent risk of lung cancer.

Urinary cotinine and lung cancer risk in a female cohort.

In a cohort of women aged 40-64 at entry, 12 h urine samples were obtained at the beginning of a follow-up period of up to 15 years in which incident cases of lung cancer were registered as well as deaths from lung cancer. In this cohort a nested case-control study (n = 397) was carried out by measuring urinary cotinine. The method for quantitation of cotinine was sensitive enough to study lung cancer risk not only in active smokers but also in passive smokers.

Obesity and subcutaneous fat patterning in relation to survival of postmenopausal breast cancer patients participating in the DOM-project.

The effect of obesity and fat distribution on survival of breast cancer patients was studied prospectively in 241 women with a natural menopause who participated in a breast cancer screening project, the DOM-project in Utrecht, The Netherlands. Mean follow-up time was 9.1 years and endpoint of interest was death from breast cancer.

Validity of urinary biomarkers of exposure to tobacco smoke following prolonged storage.

Background: The utility of using biomarkers of smoking in epidemiological studies depends not only on the validity and precision of the laboratory procedure but often on the long-term stability of the analytes of interest in stored biological samples.

Methods: We retrieved urine samples collected in 1976-1977 from women included in a cohort study in Utrecht and for whom information on smoking status was available. Creatinine and thiocyanate were measured in 1976-1977 on fresh samples.

Age at menarche and breast cancer risk in nulliparous women.

Early age at menarche is a known risk factor for breast cancer, some inconsistency in the literature not withstanding. Relative risks for an early menarcheal onset as compared to a late onset vary from 1.0 to 1.

A prospective study on obesity and subcutaneous fat patterning in relation to breast cancer in post-menopausal women participating in the DOM project.

The associations of body fat and body fat distribution with breast cancer risk were examined in a prospective study in 9,746 post-menopausal women with a natural menopause, aged 49-66 at intake, participating in a breast cancer screening project (the DOM project in Utrecht). During a follow-up period of 15 years (mean follow-up time 12.5 years) 260 women developed breast cancer.

A feasibility study on weight reduction in obese postmenopausal breast cancer patients.

An attempt was made to undertake a randomized clinical trial of weight reduction in obese postmenopausal breast cancer patients as an adjuvant to primary surgical and radiotherapeutic treatment. The rationale was to improve prognosis which has been shown to be worse in the obese (probably because of its effect on extra-ovarian oestrogen production). Difficulties in recruiting a sufficient number of patients and the introduction of tamoxifen as anti-oestrogenic adjuvant therapy led to the decision to modify the aim of the study by limiting it to a feasibility study in 102 patients.

Preventive intervention in breast cancer, but when?

After an introductory note on primary preventive intervention of breast cancer during adulthood, the author defends and extends a hypothesis that relates most of the known risk factors for this disease to the development of preneoplastic lesions in the breast. If changes in lifestyle concerning nutritional and/or reproductive risk factors during puberty and adolescence would turn out to be unacceptable socially, an alternative approach might be found in chemoprevention based on cell differentiation.

Further evidence of benefits of a (non-randomised) breast cancer screening programme: the DOM project.

Study Objective: The aim was to demonstrate the benefits of breast cancer screening on mortality.

Design: The study was an evaluation of a breast cancer screening programme by means of different approaches: (1) a case-control study, breast cancer deaths being the cases; (2) comparing the numbers of breast cancer deaths in screened and unscreened women; (3) comparing breast cancer mortality before and after start of the programme; (4) comparing breast cancer mortality in different large cities; (5) comparing screening activity with mortality reduction.

Setting: The setting was a breast cancer screening programme in the city of Utrecht, the DOM project, for women aged 50-64 years old at intake, birth cohort 1911-1925.