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P A van Noord

Publications and source records attributed to P A van Noord.

At least 19 recordsLinked to original sources
PubMed2001

Determinants of circulating insulin-like growth factor (IGF)-I and IGF binding proteins 1-3 in premenopausal women: physical activity and anthropometry (Netherlands).

OBJECTIVE: Epidemiologic studies suggest that subjects with elevated plasma concentrations of insulin-like growth factor (IGF)-I are at increased risk of developing cancer. The objective of our study was to assess whether cancer risk factors such as lack of physical activity, obesity, and central body fat distribution are associated with plasma levels of IGF-I and related proteins (i.e. IGF binding proteins 1-3 and C-peptide). METHODS: A cross-sectional study was conducted in a population of 225 premenopausal women, aged 49-57, participating in the Prospect-EPIC study in the Netherlands. Plasma concentrations of IGF-I, IGFBP-1, IGFBP-2, IGFBP-3, and C-peptide were determined. On the day of blood collection height, weight, and waist and hip circumference were measured. Habitual physical activity was assessed using a validated self-administered questionnaire. RESULTS: Mean concentrations of plasma IGF-I, IGFBP-1, IGFBP-2, IGFBP-3, and C-peptide were 156.1, 14.3, 434.4, 3062, and 2.86 ng/ml, respectively. Women in the highest tertile for physical activity had lower plasma concentrations of IGF-I, IGFBP-3, and C-peptide, and higher concentrations of IGFBP-1 and IGFBP-2, as compared to women in the lowest tertile. However, these differences were not statistically significant. BMI and related measures were significantly inversely associated with IGFBP-1 and IGFBP-2, and positively with IGFBP-3 and C-peptide. Linear regression analyses showed that the non-significant association of physical activity with components of the plasma IGF system was further attenuated by adjusting for obesity and central body fat distribution. CONCLUSIONS: Our data suggest that an active lifestyle is not independently associated with the plasma IGF system. We did confirm that a lean body shape is associated with higher concentrations of IGFBP-1 and IGFBP-2, and possibly also with lower concentrations of IGF-I and IGFBP-3.

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PubMed2001

Prospect-EPIC Utrecht: study design and characteristics of the cohort population. European Prospective Investigation into Cancer and Nutrition.

The European Prospective Investigation into Cancer and Nutrition (EPIC), which has been established in order to investigate the relations between nutrition and cancer, was initiated in 1990 and involves 10 European countries with heterogeneous dietary patterns and differing cancer incidence rates. This manuscript presents the design, recruitment and baseline characteristics of the Prospect-EPIC cohort co-ordinated in Utrecht, The Netherlands. The cohort is based on volunteers recruited among women participating in a regional breast cancer screening program. It comprises of 17,357 subjects aged 50-69 years at enrolment from Utrecht and vicinity, who have consented to participate in the study and its follow-up. Each participant filled out a general questionnaire and a food frequency questionnaire. Participants were also physically examined and have donated a blood sample. Participation rate was 34.5%. Blood samples were donated by most participants (97.5%) and detailed informed consents were obtained from 87.4% of participants. Mean age at enrolment was 57 years. Anthropometric, lifestyle and morbidity characteristics of the cohort population did not differ largely from those of similar study populations in The Netherlands. Based on the Prospect-EPIC population, we intend to conduct prospective total cohort, nested case-control or case-cohort studies, in order to investigate relations between consumption of certain food groups or nutrients and chronic diseases, including hormone dependant cancers such as breast, colon, endometrial and ovary cancers.

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PubMed2001

Oral contraceptive use in relation to age at menopause in the DOM cohort.

BACKGROUND: We investigated the hypothesis that long-term use of oral contraceptives (OCs), in particular high-dose OCs, could postpone age at menopause. METHODS: Data was used from 8701 women who participated in a breast cancer screening programme in Utrecht (DOM-3 cohort), and who did not use hormone replacement therapy (HRT) or OCs in the 4 years prior to their last menses. Data on OC-use, menopausal status, age at menopause, year of birth, parity, smoking behaviour, socio-economic status, body mass index and age at menarche was available. Use of high-dose OCs has been defined in this study as OC-use before 1972. The data was analysed by means of linear regression and Cox's proportional hazards analysis. Women still menstruating, women with surgical menopause and women lost to follow-up were censored at their last known date of menstruation. Endpoint was the natural menopause (n = 4589). RESULTS: The use of high-dose OCs advanced the onset of menopause by approximately 1.2 months for every year of OC-use compared with no OC-use. High-dose OC-use for > or = 3 years, adjusted for confounding variables, increased the risk of earlier menopause compared with no OC-use (adjusted hazard ratio 1.12; 95% CI 1.03--1.21). The use of lower dose OCs did not increase the risk of earlier menopause (adjusted hazard ratio 1.00; 95% CI 0.91--1.09). CONCLUSIONS: These results are inconsistent with the hypothesis that long-term use of OCs could postpone the onset of menopause by inhibiting follicle depletion. Possible explanations are discussed.

Age Factors↗
PubMed2001

The role of genetic factors in age at natural menopause.

BACKGROUND: Environmental factors explain only a small part of the age variance at which menopause commences. The variation in natural menopause is a trait predominantly determined by interaction of multiple genes, whose identity and causative genetic variation remains to be determined. Menopause is a retrospective marker for the reproductive capacity of preceding years, since subfertility and infertility precede menopause at distinct time-intervals. In the present study we have investigated the contribution of genetic factors to menopausal age. METHODS: Data were collected from a random population sample of singleton and twin sisters participating in a prospective breast cancer screening project, who had subsequently experienced natural menopause. Heritability of menopausal age was estimated with analysis of variance, Mx modelling and Gibbs sampling. RESULTS: All produced almost identical heritability estimates of 0.85-0.87 for singleton sisters, suggesting a strong genetic contribution to menopausal age. Twin data were used to distinguish additive genetic from common environmental effects; a heritability of 0.71-0.72 was determined, which does not deviate significantly from the estimate for singleton sisters. CONCLUSIONS: According to our findings, a woman with a family history of early menopause risks early menopause and consequently early reproductive failure herself.

Aging↗
PubMed2000

Sequential analysis of matched dichotomous data from prospective case-control studies.

Sequential analysis of randomized controlled clinical trials and epidemiological prospective (matched) case-control studies can have ethical or economical advantages above a fixed sample size approach. It offers the possibility to stop early when enough evidence for an apparent effect of the risk factor or lack of the expected effect is achieved. In clinical trials it is well accepted to stop the trial early in favour of the alternative hypothesis. In epidemiological studies, in general, the need is not felt to stop early in case of a clear exposure effect. Little attention has been paid, however, to early stopping and accepting the null hypothesis. In metabolic epidemiological studies, where analysis destroys the biological material, the question of efficient use of samples, for example, those stored in a biobank, becomes crucial. Also a slow accrual of cases or the costs of follow-up of a cohort nested study can make it desirable to stop a study early once it becomes clear that no relevant exposure effect will be found. Matching can further reduce the amount of information necessary to reach a conclusion. We derived test statistics Z (efficient score) and V (Fisher's information) for the sequential analysis of studies with dichotomous data where each case can be matched to one or more controls. A variable matching ratio is allowed. These test statistics can be entered into the software PEST to monitor the course of the study. The double sequential probability ratio test and the double triangular test were evaluated with simulated data for odds ratios equal to 1.5, 2.0 and 2.5 and various type I and type II error probabilities both under H(0) and under H(1). Our simulations resulted in average and median values for the amount of information (V) that are far less than those for a fixed sample size study. Efficiency gain ranges from 32 per cent to 60 per cent. The proposed sequential analysis was applied in an investigation on the possible relationship between the polymorphism of the MTHFR-gene and rectal cancer in a cohort of women with cases matched by age to one and to three controls. A sequential analysis of matched data can lead to early stopping in favour of H(0) or H(1), thus conserving valuable resources for future testing. A sequentially designed study can be more economical and less arbitrary than a study that makes use of conditional power or conditional coverage probability calculations to decide early stopping.

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PubMed2000

Age at menopause, body mass index, and the risk of colorectal cancer mortality in the Dutch Diagnostisch Onderzoek Mammacarcinoom (DOM) cohort.

We investigated whether age at menopause is associated with subsequent mortality from colorectal cancer along with the possible modification of this association by body mass index. Our data are from the Diagnostisch Onderzoek Mammacarcinoom cohort of 10,671 postmenopausal women in the Netherlands, enrolled between 1974 and 1977, with a median follow-up of 18 years. During this follow-up, 95 women died of colorectal cancer. Women 49 years of age or older at menopause showed a lower risk of colorectal cancer mortality compared with women younger than 49 at menopause. This protective effect, however, was found only among nonoverweight women (< or =24 kg/m2), for whom the hazard ratio was 0.46 (95% confidence interval = 0.21-1.03). In larger women, the hazard ratio was 1.17 (95% confidence interval = 0.68-2.00).

Age Factors↗
PubMed2000

Hypertension and breast cancer risk in a 19-year follow-up study (the DOM cohort). Diagnostic investigation into mammarian cancer.

BACKGROUND: To investigate whether hypertension and the use of anti-hypertensive drugs are associated with breast cancer risk. METHODS: This was a prospective study of 11, 011 women living in Utrecht, the Netherlands, aged 50-65 years at enrolment in a breast cancer screening project (DOM cohort). Women attended screening rounds between 1974 and 1985 at which blood pressure was measured and information on drug use and breast cancer risk factors was ascertained. Since 1974 (median follow-up time 19 years), information on breast cancer occurrence and death has been registered. Hypertension was defined as a systolic blood pressure > 160 mmHg or a diastolic blood pressure > 95 mmHg or current use of drugs for the indication hypertension. Cox's regression analysis was used to investigate the association between hypertension (treated or untreated) and subsequent breast cancer risk. Analyses were adjusted for age, body mass index, height, parity, familial breast cancer, smoking and oral contraceptive use. RESULTS: A total of 523 women were diagnosed with breast cancer. Hypertensive women experienced a statistically significant increased breast cancer risk of 23% (age-adjusted hazard ratio (HRa) = 1.23; 95% confidence interval (CI) 1.01 -1.49). After adjustment for all confounders, the increase was 14% (HR = 1.14; 95% CI 0.93-1.40). The decline in risk was mainly attributable to the effect of BMI. The risk was similar in treated (HR = 1.22; 95% CI 0.91-1.63) and untreated hypertensive women (HR = 1.13; 95% CI 0.91-1.40). CONCLUSION: These results do not support an association between hypertension and breast cancer, and if there is a link, it is likely to be positive and relatively small in size (+14%). This relation, if present, is not attributable to anti-hypertensive drugs, since the relation is also present in non-drug users.

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PubMed1999

True status of smear-positive pulmonary tuberculosis defaulters in Malawi.

The article reports the results of a study to determine the true outcome of 8 months of treatment received by smear-positive pulmonary tuberculosis (PTB) patients who had been registered as defaulters in the Queen Elizabeth Central Hospital (QECH) and Mlambe Mission Hospital (MMH), Blantyre, Malawi. The treatment outcomes were documented from the tuberculosis registers of all patients registered between 1 October 1994 and 30 September 1995. The true treatment outcome for patients who had been registered as defaulters was determined by making personal inquiries at the treatment units and the residences of patients or relatives and, in a few cases, by writing to the appropriate postal address. Interviews were carried out with patients who had defaulted and were still alive and with matched, fully compliant PTB patients who had successfully completed the treatment to determine the factors associated with defaulter status. Of the 1099 patients, 126 (11.5%) had been registered as defaulters, and the true treatment outcome was determined for 101 (80%) of the latter; only 22 were true defaulters, 31 had completed the treatment, 31 had died during the treatment period, and 17 had left the area. A total of 8 of the 22 true defaulters were still alive and were compared with the compliant patients. Two significant characteristics were associated with the defaulters; they were unmarried; and they did not know the correct duration of antituberculosis treatment. Many of the smear-positive tuberculosis patients who had been registered as defaulters in the Blantyre district were found to have different treatment outcomes, without defaulting. The quality of reporting in the health facilities must therefore be improved in order to exclude individuals who are not true defaulters.

Adult↗
PubMed1998

Arterial calcification found on breast cancer screening mammograms and cardiovascular mortality in women: The DOM Project. Doorlopend Onderzoek Morbiditeit en Mortaliteit.

Breast arterial calcification (BAC) has been associated with diabetes and hypertension. This prompted the authors to study the relation between BAC and cardiovascular mortality in a cohort of 12,239 women aged 50-68 years who participated in a population-based breast cancer screening project (DOM Project) in Utrecht, the Netherlands, during the period 1975-1977. Mortality data from 16-19 years of follow-up were available. The occurrence of outcome events was compared in terms of hazard ratios. Cardiovascular risk factors, including age, diabetes mellitus, hypertension, parity, Quetelet index, and smoking, were studied to identify possible confounders. Arterial calcification was seen in 9% of the women. The hazard ratio for overall mortality was 1.29 (95% confidence interval 1.06-1.58) in women with BAC detected on screening mammograms in comparison with women without BAC after correction for the above-mentioned factors. An excess of all-cause mortality was found in diabetic women with BAC (hazard ratio = 1.74, 95% confidence interval 1.19-2.56), which was also present in subgroups of coronary mortality. These results indicate that BAC is associated with an increased risk of subsequent cardiovascular death in women over age 50 years and in diabetic women in particular.

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PubMed1998

Hypertension, antihypertensive drugs, and mortality from cancer among women.

OBJECTIVES: To investigate whether hypertension and the use of antihypertensive drugs are associated with mortality from cancer among women. DESIGN: A prospective study of 11075 women living in Utrecht, the Netherlands, aged 50-65 years at enrolment in a breast cancer screening project (DOM cohort). Women attended screening rounds between 1974 and 1985, during which blood pressure measurements were taken and information on drug use and smoking was ascertained. Since 1974 (median follow-up time 19 years) information on cause of death has been obtained from the patient's general practitioner. Hypertension was defined as a systolic blood pressure > 160 mmHg, a diastolic blood pressure > 95 mmHg, or current use of antihypertensive drugs. Cox regression analysis was used to investigate the association between hypertension (treated and untreated) and total and site-specific mortalities from cancer. The influences of systolic and diastolic blood pressures per 10 mmHg increase for women not using antihypertensive drugs were evaluated. Analyses were adjusted for age, smoking, and body mass index. RESULTS: In total, 704 women died of cancer and 1633 women left the study area. Hypertensive women had a greater than normal (not statistically significant) total risk of mortality from cancer [hazard ratio (HR) 1.10, 95% confidence interval (CI) 0.93-1.31]. Risks for treated and untreated hypertensive women were similar. Cancer-site-specific analyses revealed a statistically significantly lower mortality from gastrointestinal cancers among untreated hypertensive women (HR 0.64, 95% CI 0.44-0.93), whereas mortality from lung cancer was more prevalent among these women (HR 2.50, 95% CI 1.37-4.59). Mortality from lymphatic and hematopoietic cancers for drug-treated hypertensive women was greater than normal (HR 2.11, 95% CI 1.04-4.28), as was mortality from cancers of the uterus, cervix, and ovary (HR 1.80, 95% CI 1.00-3.26). CONCLUSION: These results support the hypothesis that, if there is a link between blood pressure and cancer, it is likely to be positive and relatively small (+10%); and applies also to nondrug-treated women. The relation may apply for some types of cancer, but not for others.

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PubMed1997

Age at natural menopause in a population-based screening cohort: the role of menarche, fecundity, and lifestyle factors.

OBJECTIVE: To verify whether a population-based hypothesis (age at menarche and age at natural menopause have an inverse relationship) also applies at the level of the individual and to investigate what other factors predict age at natural menopause. DESIGN: Prospective cohort study (the Doorlopend Onderzoek Morbiditeit/Mortaliteit [DOM] project). SETTING: Prevention Breast Cancer Screening Centre, Utrecht, The Netherlands. PATIENT(S): A cohort of 3,756 Dutch women, born between 1911 and 1925, participating in a population-based breast cancer screening program, who experienced a natural menopause. Three samples of women were studied: a sample who did not use oral contraceptives (OCs) (n = 3,347), a sample of OC users (n = 409), and a combined sample of OC users and nonusers (n = 3,756). MAIN OUTCOME MEASURE(S): Age at menopause and menarche, fertility patterns, OC use, height, weight, smoking, and demographic variables. RESULT(S): No relation was found between age at menarche and age at natural menopause. The total percentage of variance in age at natural menopause explained by multiple regression including all factors was minimal, ranging from 1.3% to 9.7% in OC users. Linear regression analysis indicated a slight secular trend in age at menopause. CONCLUSION(S): Frisch's hypothesis could not be corroborated at the individual level. These results suggest that age at menarche and menopause should be treated as independent risk factors for breast cancer. Modification of age at menopause by lifestyle factors (except possibly for OC use) appears minimal.

Age Factors↗
PubMed1996

Comparison of one-sample two-sided sequential t-tests for application in epidemiological studies.

In epidemiological prospective cohort studies, exposure levels of cases with disease and disease-free control subjects can be measured by laboratory analysis of previously stored biological specimens. In such studies, a sequential t-test can be used for preliminary evaluations, at the expense of the smallest possible number of specimens, of whether a new aetiological hypothesis is worth further investigation or whether specimens should rather be spared to test other, more fruitful, hypotheses. For this purpose, we recently compared two sequential probability ratio tests (SPRTs), in which the log-likelihood ratio was either based on an approximation, or computed exactly, and which were adapted to account for various control-to-case matching ratios. The tests turned out relatively conservative, particularly in terms of the significance level achieved. In the present paper, we compare an SPRT for matched or paired data based on Rushton's approximation to the log-likelihood ratio with a profile log-likelihood method developed by Whitehead. The comparison is partly mathematical, and partly based on computerized simulations. Average sample size for a sequential test is already smaller than for the equivalent fixed sample test. Increasing the number of controls matched per case further reduces the average sample size necessary to come to a decision. We show that, irrespective of the number of controls per case, pre-specified levels of statistical power and significance are respected closely by Whitehead's method, but not by Rushton's SPRT. This last procedure can lead to a significant loss in power. Since, in addition, Whitehead's method has been implemented in a commercially available computer program (PEST), we conclude that this method can be preferred to the methods we described earlier. Moreover, compared with the method of Rushton, Whitehead's method has the advantage that it can also be applied to groupwise inspection of the data and that it can also be converted easily into a truncated procedure.

Breast Neoplasms↗
PubMed1996

Obesity and fat distribution in relation to hot flashes in Dutch women from the DOM-project.

The authors studied obesity and fat distribution in relation to the occurrence of hot flashes in a population-based study comprising 2904 women aged 40-44 and 569 women aged 54-69 presenting for mammographic screening (the DOM-project). Women aged 40-44 in the upper tertiles of Quetelet's index and waist/hip ratio reported hot flashes significantly more often than women in the respective lower tertiles. These associations were independent of each other and independent of age. After adjustment for age, waist/hip ratio and menopausal status, the odds ratio comparing the upper tertile of Quetelet's index to the lower tertile was 1.70 (95% confidence interval, 1.30-2.21). After adjustment for age, Quetelet's index and menopausal status, the odds ratio comparing the upper tertile of waist/hip ratio to the lower tertile was 1.37 (95% CI, 1.05-1.78). In women aged 54-69 no significant associations between Quetelet's index and complaints of hot flashes were observed. Women in the upper tertile of waist/hip ratio reported hot flashes more often than women in the lower tertile, but this result was not significant (OR 1.38; 95% CI, 0.87-2.22).

Adult↗
PubMed1996

Breast arterial calcifications: association with diabetes mellitus and cardiovascular mortality. Work in progress.

PURPOSE: To determine the relationship between breast arterial calcification, diabetes mellitus, and subsequent cardiovascular and noncardiovascular mortality. MATERIALS AND METHODS: A prospective cohort study was carried out in 12,239 women aged 50-68 years who participated in a breast cancer screening program. The screening mammograms were coded for the presence of breast arterial calcification. Diabetes (n = 442) was defined as use of insulin or oral hypoglycemic agents, use of a restricted diet for diabetes, or the presence of glucosuria. Data were available from questionnaires and urine glucose tests. Hazard ratios, which were adjusted for age, smoking, parity, and obesity, were calculated from mortality data after 16-19 years of follow-up. RESULTS: Breast arterial calcification was seen in 9.0% (1,107 of 12,239) of all women and in 15.4% (68 of 442) of the diabetic women. An excess cardiovascular mortality of 40% (hazard ratio = 1.4; 95% confidence interval = 1.1, 1.8) was found for all women with breast arterial calcification. In diabetic women, the presence of breast arterial calcification was associated with a 90% (hazard ratio = 1.9; 95% confidence interval = 1.1, 3.2) increase in cardiovascular mortality. CONCLUSION: Breast arterial calcification represents an independent risk factor for cardiovascular mortality in women over 50 years of age, especially in those with diabetes.

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PubMed1996

Mammograms may convey more than breast cancer risk: breast arterial calcification and arterio-sclerotic related diseases in women of the DOM cohort.

In a cohort of 12,239 women aged 50-69, who participated in a population-based breast cancer screening project (DOM-project) in Utrecht, The Netherlands, as well as being coded for micro-calcifications indicative of breast cancer, the mammograms were also coded for arterial calcifications. This allowed for a secondary analysis of associations between breast arterial calcification (BAC) and the occurrence of arteriosclerosis-associated morbidity (ie diabetes, hypertension, albuminuria, stroke, thrombosis and myocardial infarction). Arterial calcifications were seen on screening mammograms in 9.1% of the women. Significant relations were found between BAC and albuminuria [Relative risk (RR) 2.7; 95% CI 1.0-7.0], BAC and hypertension (RR 1.1; 95% CI 1.0-1.3), transient ischaemic attack (TIA)/stroke (RR 1.4; 95% CI 1.1-1.8), thrombosis (RR 1.5; 95% CI 1.0-2.2) and myocardial infarction (RR 1.8; 95% CI 1.1-2.9). In addition BAC were associated with diabetes in the oldest age-group (RR 1.7; 95% CI 1.2-2.4). All relations were adjusted for age, smoking, parity and Quetelet index. The results of the present study show that BAC as detected on breast cancer screening mammograms are associated with disorders related to increased or accelerated arterio-sclerosis. Where increased parity is associated with a decrease in breast cancer risk, parity increases the occurrence of BAC. The present study suggests that breast-cancer screening mammograms may allow for the early detection of enhanced cardiovascular disease risk among otherwise healthy women.

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PubMed1995

Breast size as a determinant of breast cancer.

OBJECTIVE: To determine whether breast size as reflected in cup size is independently associated with Wolfe's mammographic patterns. DESIGN: Univariate and multivariate associations between the waist/hip ratio (WHR), body mass index (BMI), cup size, age, parity, age at menarche menopausal status and Wolfe's mammographic parenchymal patterns were determined by (multiple) linear logistic regression. SETTING: Population based mammographic breast cancer screening project. SUBJECTS: 7819 women between 39 to 52 years of age. RESULTS: The univariate analysis demonstrated that women in the lowest tertile with respect to BMI and WHR when compared to women in the upper tertile were significantly more likely to display the high risk P2, Dy breast patterns. Cup size showed a similar inverse relation with the P2, Dy patterns. When age, WHR and BMI are entered together in the multivariate model the relation between cup size and the P2 Dy patterns is no longer significant in the upper tertile. CONCLUSION: Breast size is not a major independent determinant of the high risk P2, Dy parenchymal breast patterns when the WHR and BMI are taken into account.

Adult↗