Biomedical subjects

Marit B Veierød

Publications and source records attributed to Marit B Veierød.

12 recordsLinked to original sources

PubMed2006

Test-retest reproducibility of a food frequency questionnaire (FFQ) and estimated effects on disease risk in the Norwegian Women and Cancer Study (NOWAC).

BACKGROUND: The Norwegian Women and Cancer Study (NOWAC) is a national population-based cohort study with 102 443 women enrolled at age 30-70 y from 1991 to 1997. The present study was a methodological sub-study to assess the test-retest reproducibility of the NOWAC food frequency questionnaire (FFQ), and to study how measurement errors in the data can affect estimates of disease risk. METHODS: A random sample of 2000 women aged 46-75 y was drawn from the cohort in 2002. A self-instructive health and lifestyle questionnaire with a FFQ section was mailed to the same subjects twice (test-retest), about three months apart, with a response rate of 75%. The FFQ was designed to assess habitual diet over the past year. We assess the reproducibility of single questions, food groups, energy, and nutrients with several statistical measures. We also demonstrate the method of regression calibration to correct disease risk estimates for measurement error. Alcohol intake (g/day) and high blood pressure (yes/no) is used in the example. RESULTS: For single foods there were some indications of seasonal reporting bias. For food groups and nutrients the reliability coefficients ranged from 0.5-0.8, and Pearson's r, Spearman's rs, and two intraclass correlation coefficients gave similar results. Although alcohol intake had relatively high reproducibility (r = 0.72), odds ratio estimates for the association with blood pressure were attenuated towards the null value compared to estimates corrected by regression calibration. CONCLUSION: The level of reproducibility observed for the FFQ used in the NOWAC study is within the range reported for similar instruments, but may attenuate estimates of disease risk.

Aged↗

PubMed2006

The SCORE risk model applied to recent population surveys in Norway compared to observed mortality in the general population.

AIMS: To compare the predictions of the Systematic Coronary Risk Evaluation (SCORE) high- and low-risk functions applied to a recent population study with observed cardiovascular disease (CVD) mortality estimated from annual official mortality statistics in Norway. METHODS: Data were obtained from large epidemiological surveys conducted in five Norwegian counties in 2000-2003. RESULTS: A total of 32 251 men and women were investigated (aged 30-31, 40-41, 45-46, and 59-61). For men aged >or=59, more than 75% qualified for preventive treatment by having a 10-year risk >or=5%. Few women and practically no men younger than 46 years can be considered at high risk according to the SCORE risk prediction models. For men, the high-risk function overestimated and the low-risk model underestimated the CVD mortality as compared to the 10-year risks calculated from official mortality statistics (1999-2003). For women, however, both functions underestimated mortality in young individuals, whereas in the elderly an overestimation was observed. CONCLUSIONS: The risk predictions depended strongly on age and gender. The SCORE high-risk function overestimates the risk of fatal CVD for men in Norway, and before implementation in clinical practice, proper adjustments to national levels are required.

Adult↗

PubMed2006

Plasma levels of leptin and mammographic density among postmenopausal women: a cross-sectional study.

INTRODUCTION: Obesity has been linked to increased risk of breast cancer in postmenopausal women. Increased peripheral production of estrogens has been regarded as the main cause for this association, but other features of increased body fat mass may also play a part. Leptin is a protein produced mainly by adipose tissue and may represent a growth factor in cancer. We examined the association between leptin plasma levels and mammographic density, a biomarker for breast cancer risk. METHODS: We included data from postmenopausal women aged 55 and older, who participated in a cross-sectional mammography study in Tromsø, Norway. Mammograms, plasma leptin measurements as well as information on anthropometric and hormonal/reproductive factors were available from 967 women. We assessed mammographic density using a previously validated computer-assisted method. Multiple linear regression analysis was applied to investigate the association between mammographic density and quartiles of plasma leptin concentration. Because we hypothesized that the effect of leptin on mammographic density could vary depending on the amount of nondense or fat tissue in the breast, we also performed analyses on plasma leptin levels and mammographic density within tertiles of mammographic nondense area. RESULTS: After adjusting for age, postmenopausal hormone use, number of full-term pregnancies and age of first birth, there was an inverse association between leptin and absolute mammographic density (P(trend) = 0.001). When we additionally adjusted for body mass index and mammographic nondense area, no statistically significant association between plasma leptin and mammographic density was found (P(trend) = 0.16). Stratified analyses suggested that the association between plasma leptin and mammographic density could differ with the amount of nondense area of the mammogram, with the strongest association between leptin and mammographic absolute density in the stratum with the medium breast fat content (P(trend) = 0.003, P for interaction = 0.05). CONCLUSION: We found no overall consistent association between the plasma concentration of leptin and absolute mammographic density. Although weak, there was some suggestion that the association between leptin and mammographic density could differ with the amount of fat tissue in the breast.

Adipose Tissue↗

PubMed2005

The Norwegian School Fruit Programme: evaluating paid vs. no-cost subscriptions.

BACKGROUND: This study reports the effect of providing Norwegian school children with free fruit or vegetables every school day and the effect of an existing fee-based School Fruit Programme. METHODS: Seventh grade pupils and their parents completed questionnaires at baseline (autumn 2001) and at follow-up (spring 2002). Nine schools participated in the School Fruit Programme for free (Free fruit), nine schools took part at standard conditions (Paid fruit), and 20 schools did not take part in the subscription programme (No fruit). A total of 795 7th graders (11 or 12 years old at baseline) participated both at baseline and at follow-up. RESULTS: At follow-up, pupils attending the Free fruit schools had significantly higher intake of fruit and vegetables at school than the pupils at the Paid fruit and No fruit schools (P < 0.001, mean intakes were 1.1, 0.4 and 0.2 portions, respectively). Subscribers at the Paid fruit schools had significantly higher intake than the non-subscribers at the same schools. CONCLUSIONS: Providing a free piece of fruit or a vegetable is an effective strategy to increase school children's fruit and vegetable intake. The existing School Fruit Programme appears to increase the intake among the subscribers, but thereby also tends to increase an existing difference in consumption patterns among subscribers and non-subscribers.

Adolescent↗

PubMed2005

On the effect of misclassification on bias of perfectly measured covariates in regression.

This note clarifies under what conditions a naive analysis using a misclassified predictor will induce bias for the regression coefficients of other perfectly measured predictors in the model. An apparent discrepancy between some previous results and a result for measurement error of a continuous variable in linear regression is resolved. We show that similar to the linear setting, misclassification (even when not related to the other predictors) induces bias in the coefficients of the perfectly measured predictors, unless the misclassified variable and the perfectly measured predictors are independent. Conditional and asymptotic biases are discussed in the case of linear regression, and explored numerically for an example relating birth weight to the weight and smoking status of the mother.

Bias↗

PubMed2005

Plasma levels of enterolactone and percentage mammographic density among postmenopausal women.

AIMS: Certain phytoestrogens, such as lignans, may protect against developing breast cancer. Enterolactone is a lignan metabolite produced by the intestinal flora from dietary precursors such as whole grains, vegetables, and fruits. Enterolactone has been shown to have weak estrogenic and antiestrogenic properties. We decided to examine the association between plasma levels of enterolactone and mammographic density, a biomarker for breast cancer risk. METHODS: We included data from postmenopausal women ages 55 and older who participated in a cross-sectional mammogram study in Tromsø, Norway. Mammograms, plasma enterolactone measurements, as well as information on anthropometric and hormonal/reproduction factors were available on 616 women. We assessed mammographic density using a previously validated computer-assisted method. We estimated correlation coefficients and conducted multiple regression analyses. RESULTS: Mean mammographic density increased slightly across quartiles of enterolactone; the women in the highest quartile had, on average, 3.1% (absolute difference) higher percentage mammographic density compared with the lowest quartile (P(trend) < 0.01). After adjustment for age, body mass index, number of full-term pregnancies, age at first birth, and use of postmenopausal hormone therapy, the mean difference in density was reduced to 2.0% (P(trend) = 0.05). Results were similar when restricted to the 454 current hormone nonusers. The fully adjusted statistical model explained 28.3% of the total variability in mammographic percentage density, with body mass index contributing 18.2% and enterolactone only 0.9%. CONCLUSION: In our study, higher levels of enterolactone were associated with slightly higher percentage mammographic density. Our results suggest that if higher enterolactone levels reduce the risk of developing breast cancer in postmenopausal women, then this effect is not through lowering mammographic density.

4-Butyrolactone↗

PubMed2004

Fear-avoidance beliefs and distress in relation to disability in acute and chronic low back pain.

Patients with chronic low back pain (LBP) frequently demonstrate high scores for fear-avoidance beliefs and distress. We need better knowledge about fear-avoidance beliefs and distress in early stages of LBP. The objectives of this study were to compare the level of fear-avoidance beliefs and distress in patients with acute LBP to patients with chronic LBP, and to assess the relationship of fear-avoidance beliefs and distress to disability in acute and chronic LBP. Two different back pain groups including 123 patients with acute and 233 patients with chronic LBP were studied. Main outcome measures were Oswestry Disability Index and work loss. The scores for fear-avoidance beliefs and distress in patients with acute LBP were significantly lower than among patients with chronic LBP. The results of the multivariate regression analyses, adjusting for sociodemographic, pain and clinical variables, demonstrated that whereas fear-avoidance beliefs for physical activity and distress were significantly associated with the Oswestry Disability Index, fear-avoidance beliefs for work and distress were significantly associated with work loss. The associations showed the same pattern in acute and chronic LBP. In addition, several of the pain and clinical variables were significantly associated with the Oswestry Disability Index and fingertip-floor distance was associated with work loss. In conclusion, fear-avoidance beliefs and distress influence pain-related disability both in early acute and long-term chronic LBP. The results replicate previous reports on the association between pain experience, fear-avoidance beliefs, distress, and disability in chronic LBP, and extend the findings to patients at an early stage of acute LBP.

Activities of Daily Living↗

PubMed2004

Coagulation factor VII, R353Q polymorphism, and serum choline-containing phospholipids in males at high risk for coronary heart disease.

INTRODUCTION: Elevated levels of coagulation factor VII (FVII) have been associated with increased risk for myocardial infarction (MI). The R353Q polymorphism of the FVII gene has been shown to modify plasma levels of FVII, and has in some studies also been associated with reduced risk for MI. OBJECTIVES: To examine the R353Q polymorphism of the FVII gene and the relation to myocardial infarction (MI), cardiovascular disease (CVD), and diabetes, and furthermore, to elucidate the association between the polymorphism and plasma levels of FVII coagulant activity (FVIIc), FVII antigen (FVIIag), activated FVII (FVIIa), and serum choline-containing phospholipids (PC). METHODS: In 560 elderly men characterised as hypercholesterolemic in 1972, we examined the R353Q polymorphism by melting curve analysis after real-time PCR. In a subgroup of 205 individuals, FVIIc, FVIIag, FVIIa, and PC were analysed. RESULTS: There were no significant associations between genotype and the disease states, although we observed a lower number of MI cases among subjects with the Q allele, compared to the RR individuals (14% vs. 19%). FVIIag and FVIIc levels were lower in RQ compared to RR subjects, whereas for FVIIa the opposite was observed (p<0.001 for all). PC correlated positively with FVIIag (r=0.24, p<0.001), but negatively with FVIIa (r=-0.25, p<0.001). No genotype specific interactions were found for the association between FVII and PC. CONCLUSION: No significant associations between the R353Q polymorphism and MI, CVD, or diabetes were observed, although the polymorphism strongly influenced plasma levels of FVII. Serum PC correlated significantly with FVIIag and inversely with FVIIa, independently of genotype.

Aged↗

PubMed2004

A comparison of the effects of cheese and butter on serum lipids, haemostatic variables and homocysteine.

Milk fat contains considerable amounts of saturated fatty acids, known to increase serum cholesterol. Little is known, however, about the relative effect of different milk products on risk factors for CHD. The aim of the present study was to compare the effects of Jarlsberg cheese (a Norwegian variety of Swiss cheese) with butter on serum lipoproteins, haemostatic variables and homocysteine. A controlled dietary study was performed with twenty-two test individuals (nine men and thirteen women) aged 23-54 years. The subjects consumed three isoenergetic test diets, with equal amounts of fat and protein, and containing either cheese (CH diet), butter + calcium caseinate (BC diet) or butter + egg-white protein (BE diet). The study was a randomised cross-over study and the subjects consumed each diet for 3 weeks, with 1 week when they consumed their habitual diet in between. Fasting blood samples were drawn at baseline and at the end of each period. Serum was analysed for lipids and plasma for haemostatic variables and homocysteine. Total cholesterol was significantly lower after the CH diet than after the BC diet (-0.27 mmol/l; P=0.03), while the difference in LDL-cholesterol was found to be below significance level (-0.22 mmol/l; P=0.06). There were no significant differences in HDL-cholesterol, triacylglycerols, apo A-I, apo B or lipoprotein (a), haemostatic variables and homocysteine between the diets. The results indicate that, at equal fat content, cheese may be less cholesterol increasing than butter.

Adult↗

PubMed2004

Breast-feeding at 12 months of age and dietary habits among breast-fed and non-breast-fed infants.

OBJECTIVE: To analyse factors associated with breast-feeding and use of sweetened drinks at 12 months, and to compare dietary habits among breast-fed and non-breast-fed infants. DESIGN: Data were collected by a semi-quantitative food-frequency questionnaire filled in by the parents. SETTING: National dietary survey in Norway. SUBJECTS: In total, 1932 12-month-old infants were included. RESULTS: At 12 months, 36% of the infants were breast-fed. The odds of breast-feeding at this age were more than doubled both for mothers > or =35 years compared with mothers <25 years and for mothers in the highest educational group compared with mothers in the lowest. A negative association was found for maternal smoking, and the odds of breast-feeding were 40% lower for mothers who smoked than for non-smokers. Some dietary differences were observed between breast-fed and non-breast-fed infants apart from intake of milk. In particular, breast-fed infants had a significantly lower daily intake of sweetened drinks than non-breast-fed infants and a 16% lower mean daily intake of added sugars (P<0.001). Furthermore, breast-fed infants had 30% higher odds of not receiving sweetened drinks daily, compared with non-breast-fed infants. CONCLUSIONS: Maternal age, education and smoking status were important factors for breast-feeding at 12 months. Breast-fed infants had lower intakes of sweetened drinks and added sugars than non-breast-fed infants. From a public health perspective, continued promotion of breast-feeding is needed to reduce inequalities in breast-feeding. Moreover, prevention of high intakes of sweetened drinks and added sugars should start in infancy.

Adult↗

PubMed2004

The effects of long-term diet and omega-3 fatty acid supplementation on coagulation factor VII and serum phospholipids with special emphasis on the R353Q polymorphism of the FVII gene.

The aim of the present study was to investigate the effect of long-term diet and very long chain n-3 fatty acids (VLC n-3) intervention on plasma coagulation factor VII (FVII), choline-containing phospholipids (PC) and triglycerides (TG), especially related to the R353Q polymorphism of the FVII gene. The present investigation included 219 subjects from the Diet and Omega-3 Intervention Trial on atherosclerosis (DOIT), a 2x2 factorial designed study in elderly men with long-standing hypercholesterolemia. The subjects were randomly allocated to receive placebo capsules (corn oil) (control), placebo capsules and dietary advice ("Mediterranean type" diet), VLC n-3 capsules, or VLC n-3 capsules and dietary advice combined. The R353Q genotype and the levels of FVIIc, FVIIag, FVIIa, PC, and TG at baseline and after 6 months were determined. Diet intervention was followed by a significant reduction of 5.1% in the levels of FVIIag and 2.4 mU/ml in FVIIa (95% CI -7.4, -2.9, and -3.8, -1.1, respectively) (both p<0.001) compared to the no diet group, independent of genotype. No effects of diet intervention on FVIIc, PC or TG were observed. After VLC n-3 supplementation the TG levels were significantly reduced compared to placebo (p=0.01), whereas all FVII levels and PC remained unchanged. Dietary advice towards a "Mediterranean type" diet, but not VLC n-3 supplementation, was shown to reduce the levels of FVIIag and FVIIa after 6 months, independent of genotype. The results indicate the dietary advice to be more favourable in reducing this risk factor for CVD as compared to specific VLC n-3 supplementation.

Aged↗

PubMed2003

Supplementation with fish oil affects the association between very long-chain n-3 polyunsaturated fatty acids in serum non-esterified fatty acids and soluble vascular cell adhesion molecule-1.

We have investigated the effect of fish oil supplementation on the association between serum non-esterified fatty acid (NEFA) pattern and atherosclerotic activity. We studied correlations between serum non-esterified very long-chain eicosapentaenoic (EPA), docosahexaenoic acid (DHA) and arachidonic acid (AA) and biochemical markers of endothelial activation before and after 18-months intervention with fish oil supplementation. The fish oil supplementation consisted of 2.4 g of EPA and DHA per day, with corn oil as placebo. Elderly men ( n =171) with high risk for coronary heart disease were divided into four intervention groups in a factorial design: fish oil supplementation ( n =44), dietary intervention ( n =42), fish oil supplementation+dietary intervention ( n =47) or placebo ( n =38). The composition of fasting NEFA was analysed before and after intervention by GLC. Circulating endothelial markers were analysed by ELISA. A statistically significant positive correlation between the change in serum non-esterified DHA and soluble vascular cell adhesion molecule-1 (sVCAM-1) was found in the pooled group that received fish oil supplementation ( n =91; Spearman's correlation coefficient r =0.24, P =0.02). No such correlation was found in the pooled group without fish oil supplementation ( n =80). Furthermore, there was a significant negative correlation between the change in serum non-esterified EPA and the relative change in sVCAM-1 in the group that did not receive fish oil supplementation ( r =-0.34, P =0.002). No such correlation was found in the group with fish oil supplementation. We conclude that large increase in serum non-esterified EPA and DHA, which can only be attained by supplementation, might increase inflammation in vascular endothelium. A moderate dietary increase in fish oil intake may, however, have an effect on decreasing inflammatory markers.

Aged↗