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Biomedical subjects

K Overvad

Publications and source records attributed to K Overvad.

At least 19 recordsLinked to original sources
PubMed1997

Nicotine patches in smoking cessation: a randomized trial among over-the-counter customers in Denmark.

The authors examined the effect of 24-hour nicotine patches in smoking cessation among over-the-counter customers in Denmark, based on a randomized double-blind placebo-controlled trial. Participants were consecutive customers to whom nicotine patches were offered as the only treatment. Forty-two pharmacies in the areas of Aarhus and Copenhagen in Denmark participated in the trial, and 522 customers who smoked 10 or more cigarettes per day were randomized to either nicotine patches or placebo from January to March 1994. Customers with chronic diseases and pregnant or breastfeeding women were excluded from the trial. Twenty-four-hour patches were offered free of charge during a 3-month period. Those smoking 20 or more cigarettes per day started on a dose of 21-mg/day patches. Customers who smoked less started on patches of 14 mg/day; and for all of the participants, the dose was gradually reduced to 7-mg/day patches during the study period. Smoking behavior and compliance were recorded by means of self-administered questionnaires and telephone interviews. Smoking status was recorded in intervals of 4 weeks, which was fixed to be a treatment period, and 26 weeks after inclusion. There was a significant increase in smoking cessation rates after 8 weeks of follow-up but only among smokers who started on 21-mg/day patches. There was a marked placebo effect at each time of contact during the trial, especially in those smoking fewer than 20 cigarettes per day. Although the noncompliance rate was high overall due to discontinuation in the use of patches by relapsed smokers, noncompliance among successful quitters was low. More side effects were seen in the nicotine group than in the placebo group, but none of the reported side effects were serious. It appears that regular healthy smokers who were customers of nonprescribed nicotine patches and who received 21-mg/day nicotine patches benefited from the active treatment (44.1% stopped smoking after 4 weeks), but almost as many stopped smoking in the placebo group (37.3% after 4 weeks). No significant differences in smoking cessation rates were seen among smokers who started with the low-dose nicotine or placebo patches.

Administration, Cutaneous↗
PubMed1996

Dietary risk factors for renal cell carcinoma in Denmark.

The role of diet in the aetiology of renal cell carcinoma was investigated in a population-based case-control study in Denmark. Cases were 20-79 years old, with a histologically verified diagnosis of renal cell carcinoma. Controls were sampled from the general population and were frequency-matched on age and sex. A total of 351 cases (73% of the eligible) and 340 controls (68% of the eligible) were included in the study. Dietary information was obtained in a self-administered food frequency questionnaire and the information was confirmed in a subsequent interview performed by trained interviewers who also elicited information on other suspected risk factors such as smoking, occupation, medical history, education and reproductive history. Logistic regression models were used to calculate the odds ratios, and, both frequency of consumption of various food stuffs and computed nutrients were examined. A positive association was observed between risk of renal cell carcinoma and total energy intake (odds ratio, OR, for highest quartile compared to lowest: 1.7 (95% confidence interval, CI, 1.0-3.0) for men, and 3.5 (95% CI 1.6-6.5) for women), fat intake (OR for highest quartile compared to lowest: 1.9 (95% CI 1.1-3.5) for men, and 3.3 (95% CI 1.6-6.9) for women). For women, an effect was also seen for intake of carbohydrates (OR for highest quartile compared to lowest: 3.2 (95% CI 1.5-6.8), while no protective effect was seen for vegetables or fruit. Dairy products may be associated with risk of renal cell cancer (OR for women using thickly spread butter compared to thinly spread: 11.4 (95% CI 2.8-45), OR for women who drank more than one glass of milk with 3.5% fat content compared to never drink milk: 3.7 (95% CI 1.2-11). As expected, total energy intake, intake of fat, protein and carbohydrates were closely correlated making it difficult to identify one of the energy sources as more closely associated with risk of renal cell cancer than the other. Several energy sources have been identified as possible risk factors for renal cell carcinoma. It is possible that a high energy intake as such rather than the individual sources are responsible for the increased risk. Furthermore, dairy fats may be associated with renal cell carcinoma risk. The observed associations appeared stronger in women, and did not explain the association with obesity and low socio-economic status previously found in Denmark.

Adult↗
PubMed1996

Iodine. Do we need an enrichment program in Denmark?

A working group was established to evaluate the need for iodine enrichment in Denmark. Judged from studies of urinary iodine excretion and one dietary survey the intake of iodine in Denmark is low compared with recommended intakes. The occurrence of non-toxic goitre is relatively high; between 9 and 13% in elderly women. Furthermore, a high occurrence of toxic goitre has been seen in the western part of Denmark. On the other hand, an increased or a high intake of iodine may lead to hyperthyroidism and thyroiditis. The working group concluded that an increase in iodine intake in the Danish population is needed and the best way to achieve this is to iodize all salt. To avoid side effects of a sudden large increase in iodine intake the initial amount of iodine in salt will only be 2 ppm.

Animals↗
PubMed1994

Validity of individual portion size estimates in a food frequency questionnaire.

BACKGROUND: Dietary surveys often rely upon subjects' ability to estimate their portion sizes instead of weighing them, but information on the validity of such estimates is lacking. This study investigated the validity of estimated portion sizes from a self-administered food frequency questionnaire including photos. METHODS: Validity was evaluated by comparison with portion sizes from 14-day weighed food records. Eight sets of photos were included in the study (three meat dishes, one fish dish, three vegetables, potatoes), each set with four options. Subjects (59 men, 85 women) were 40-64 years. RESULTS: The majority of subjects (85-95%) selected the most correct photo or a neighbouring photo. However, regression analyses showed that the relationship between the estimated and the measured portion sizes was relatively weak for most of the foods tested, and correlations were only significant for three of the eight foods. This apparent contradiction was partly due to the pattern of the error: subjects selecting small portions had underestimated their actual portions while subjects selecting large portions had overestimated them. This error pattern could not be explained by the theoretical error resulting from the use of four discrete portion sizes instead of continuous weights, neither was it a simple consequence of the unidirectional errors at the extreme ends. Actual portion sizes varied from day to day, with intra-individual coefficients of variation of 34-40%. CONCLUSIONS: The photos used in the present study were of limited value for ranking individuals correctly according to their actual portion sizes. Whether this is a common feature of photos used in food frequency questionnaires remains to be answered.

Adult↗
PubMed1993

Copper in human mammary carcinogenesis: a case-cohort study.

In 1968-1975, a cohort of 5,100 ostensibly healthy women was established on the island of Guernsey, England, for investigation of the influence of hormonal factors on breast cancer. At the women's entry into the study, blood samples were drawn from each participant, and each woman completed a questionnaire that provided information on established risk indicators in human mammary carcinogenesis. Plasma copper levels were measured in 46 breast cancer cases diagnosed an average of 11 years (standard deviation (SD), 4) after entry into the study cohort and in an age-stratified random sample of 138 women drawn from the total initial cohort at risk. Plasma copper levels were 1.31 mg/liter (SD, 0.37) in the cases and 1.26 mg/liter (SD, 0.36) in the controls; the 95% confidence interval for the overall difference was -0.07 to 0.17. A U-shaped relation between premorbid plasma copper levels and the risk of developing breast cancer was seen. Adjusted odds ratios for breast cancer were 1.8, 1.0, 1.6, and 3.2, respectively, in the four quartiles of the copper distribution. No major changes in the risk estimates were observed when statistical evaluation was restricted to cases diagnosed more than 10 years after collection of blood samples.

Adult↗
PubMed1993

Adipose tissue fatty acids as biomarkers of dietary exposure in Danish men and women.

Adipose tissue fatty acids, it has been proposed, reflect dietary intake. Using data from a validation study preceding a prospective study on diet, cancer, and health in Denmark, we were able to compare fatty acid profiles in adipose tissue biopsies from 86 individuals (23 men and 63 women) aged 40-64 y and dietary intake of fatty acids (as percentage of total fat) assessed by two 7-d weighed-diet records or by a semi-quantitative food frequency questionnaire. Correlation coefficients (Pearson r) between fatty acid concentrations in adipose tissue biopsies (as percentage of total peak area) and dietary intake of fatty acid (percentage of total fat), determined from the diet records for men and women, respectively, were as follows: polyunsaturated fatty acids r = 0.74 and r = 0.46; n - 3 fatty acids of marine origin: eicosapentaenoic acid r = 0.15 and r = 0.61, and docosahexaenoic acid r = 0.47 and r = 0.57. Correlation coefficients obtained by using the food frequency questionnaire were slightly lower for most fatty acids.

Adipose Tissue↗
PubMed1993

Effect of exercise on intestinal tumour development in the male Fischer rat after exposure to azoxymethane.

Thirty-two male Fischer rats were exercised in a treadmill, 2 km daily on weekdays for 38 weeks, after three subcutaneous injections of azoxymethane, 15 mg/kg body weight. Randomly selected control animals were housed in regular 38 x 22 cm cages in groups of no more than three rats per cage. All rats were allowed free access to food and water. The exercising rats ate about 20% more than the sedentary rats, but gained less weight. Fat stores were considerably smaller in the exercised rats whereas the lean body mass and ash content were similar. After 38 weeks significantly fewer rats in the exercise group had developed neoplasia of the colon mucosa.

Animals↗
PubMed1993

The concept of multifactorial etiology of cancer.

The concept of causes is not just for professional philosophers to discuss. The epidemiologists also have to clarify how the concept is used since its meaning has profound implications for understanding basic measures of exposure-disease association. The concept of cause also has importance when designing a study or when analyzing epidemiological data. The paper describes the components cause model and its relationship with the mechanism of disease action. A measure of interaction is also presented which is based upon the components cause model. The common sense concept of causes also plays a fundamental role for the success of a health preventive programme according to the Health Belief Model. The component cause model may clarify causal patterns in situations when only a few of the exposed get the disease which the programme tends to prevent.

Animals↗
PubMed1992

Oxidative DNA damage estimated by 8-hydroxydeoxyguanosine excretion in humans: influence of smoking, gender and body mass index.

Oxidative DNA damage may be implicated in ageing, carcinogenesis and other degenerative diseases. Oxidative DNA damage can be assessed in humans in vivo from the urinary excretion of the DNA-repair product 8-hydroxydeoxyguanosine (8OHdG). We investigated factors influencing the excretion of 8OHdG in 24 h urine from 83 randomly selected healthy subjects (52 women) aged 40-64 years. For 2 weeks prior to urine collection the subjects kept a weighed diet record. 8OHdG was quantified by an automatic three-dimensional HPLC analysis with electrochemical detection. The 8OHdG excretion was 252 +/- 103 (mean +/- SD) pmol kg body weight/24 h with a range from 78 to 527. Multiple regression analysis identified three factors, smoking, body mass index (BMI) and gender, as significant predictors of the 8OHdG excretion. In 30 smokers the 8OHdG excretion was 320 +/- 99 pmol/kg/24 h opposed to 213 +/- 84 pmol/kg/24 h in 53 non-smokers. According to multiple regression analysis smokers excreted 50% (31-69%; 95% confidence interval) more 8OHdG than non-smokers. In 52 women the 8OHdG excretion was 240 +/- 106 pmol/kg/24 h opposed to 271 +/- 96 pmol/kg/24 h in 31 men. According to the multiple regression analysis men excreted 29% (10-48%) more 8OHdG than women. According to multiple regression analysis the 8OHdG excretion decreased with 4% (2-6%) per increment in BMI measured in kg/m2. The dietary distribution of energy demonstrated no important predictive value with respect to 8OHdG excretion. The intake of the antioxidant vitamins C and E and of vitamin A equivalents, including beta-carotene, was not associated with 8OHdG excretion. The results suggest that smoking increases oxidative DNA damage by approximately 50%. This effect implies potential serious health effects adding to the other well-known health hazards of smoking. The higher 8OHdG excretion in men and lean subjects may be related to a higher rate of metabolism with increased availability of reactive oxygen species. The apparent 7-fold individual variation in oxidative DNA damage carries implications regarding the rate of ageing and the risk of cancer and other degenerative diseases. The excretion of 8OHdG into urine offers a valuable tool for testing such hypotheses in humans.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed1992

Influence of individually estimated portion size data on the validity of a semiquantitative food frequency questionnaire.

Using data from a Danish dietary validity study, we evaluated the influence of including individually estimated portion size data on the validity of a semiquantitative food frequency questionnaire. A total of 144 subjects, aged 40-64 years were included. Correlation coefficients and classification of subjects into quintiles according to their intake of foods and nutrients were used to compare questionnaire data, with and without individually estimated portion size data, with data obtained by 2 x 7 days weighed diet records. For men, the mean correlation coefficient for food group comparisons was 0.47 when information about individually estimated portion sizes for food items that do not come in natural units was included in the analysis. Using a common average portion size reduced the mean correlation coefficient to 0.45. For women, similar changes were observed (0.36 to 0.35). For nutrients the mean values for the comparison changed from 0.51 to 0.49 and from 0.39 to 0.40 for men and women, respectively. For both men and women the classification into quintiles according to their intake of foods and nutrients showed only minor differences. We conclude that little extra information was gained by including individual portion size information for food items that do not come in natural units. This may reflect that portion sizes are of minor importance compared with frequencies or that the relevant individual portion sizes were not estimated correctly.

Adult↗
PubMed1991

Selenium in human mammary carcinogenesis: a case-cohort study.

In a prospective study conducted on the island of Guernsey a cohort of 5162 ostensibly healthy women was enrolled between 1967 and 1976. Blood samples were drawn from each participant, who also completed a questionnaire, which provided information on established risk indicators in human mammary carcinogenesis. Plasma selenium levels were measured in 46 breast cancer cases diagnosed a mean of 11 (S.D. 4) years after entry into the study cohort and in an age-stratified sample of 138 women drawn from the study base. Plasma selenium level in the cases was 109 (28) micrograms/l and in the base sample 103 (22) micrograms/l (95% confidence interval for the overall difference, -2 to 14 micrograms/l). The adjusted relative risk of developing breast cancer in the different quartiles of the selenium distribution was 0.80, 0.79, 0.72 and 1.00, respectively. Thus, in the present study selenium was not a strong indicator of human breast cancer risk.

Adult↗
PubMed1991

Development of a semiquantitative food frequency questionnaire to assess food, energy and nutrient intake in Denmark.

Foods to be included in a Danish self-administered semiquantitative food frequency questionnaire were identified from food tables developed, together with data collected, for the survey 'Dietary habits in Denmark, 1985'. The questionnaire was to be used in a prospective study on diet, cancer and health, and the aim was to rank individuals with regard to intake of 19 different nutrients considered of prime importance in human carcinogenesis. The questionnaire for the dietary survey included 247 foods and recipes. From stepwise multiple regression analyses with the intake of each of the 19 nutrients as the dependent variable and the intake of the 247 foods and recipes as independent variables, the foods in the models explaining 90% of the between-person variability were considered for the final questionnaire. All relevant analyses were performed for the study group as a whole, for men and women separately, and in each gender for subgroups of energy intake. Taken together, the models explaining 90% of the between-person variability identified a total of 74 foods or recipes, which were important predictors of the intake of one or more of the nutrients considered. A few foods were excluded and a few foods were added to the final questionnaire based on common biological background information, and on information on foods providing important amounts of given nutrients, but which failed to contribute to regression analyses. The 92 foods and recipes, which were included in the final questionnaire provided altogether 81% of the average total supply of the nutrients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

Validation of a semiquantitative food frequency questionnaire developed in Denmark.

In 1989, a self-administered food frequency questionnaire, including 92 food items and 40 portion-size photographs, was validated against two times seven days of weighed diet records. A total of 144 subjects, aged 40-64 years, from the general population in Copenhagen were included. Correlations between mean calorie-adjusted intakes from the two-week diet records and the food-frequency questionnaire ranged from 0.27 for vitamin A to 0.71 for calcium. In general, higher correlation coefficients were observed for men than for women. On average, about 70% of subjects were classified in the same (+/- 1) quintile in the food frequency questionnaire and the diet records. Of those subjects belonging to the lowest quintile, estimated from the diet records, 42% fell in the same quintile and 68% into the lowest two quintiles in the food frequency questionnaire. Findings were similar for the upper tail of the distribution. Gross misclassification, observed in the highest and lowest quintile, was found for 4% and 7% of the subjects, respectively. It is concluded that this food frequency questionnaire is a useful instrument for categorizing individuals according to their intake of nutrients and energy.

Adult↗
PubMed1991

Coffee consumption, birthweight, and reproductive failures.

We studied the effect of coffee consumption on birthweight, preterm births, and congenital malformations. From April 1985 to April 1987, 11,858 pregnant women out of 13,815 in two Danish cities responded to a mailed questionnaire on eating and drinking habits during pregnancy. Data on pregnancy outcomes were recorded from medical files. Maternal coffee consumption of four cups a day or more was associated with a moderate decrease in birthweight, especially among smokers. The associations between coffee consumption and preterm births or congenital malformations were very weak.

Abnormalities, Drug-Induced↗
PubMed1991

Selenium in human mammary carcinogenesis: a case-referent study.

In a case-referent study on the possible role of selenium in human mammary carcinogenesis, serum selenium was found to be 79 +/- 12 micrograms/l in 66 cases and 81 +/- 12 micrograms/l in 93 referents. An internal trend in serum selenium was observed among cases (TNM stage I 81 +/- 11 micrograms/l and TNM stage II 76 +/- 13 micrograms selenium/l), indicating disease-mediated changes. The evaluation of selenium as a risk indicator in human breast cancer was therefore restricted to TNM stage I patients (n = 36). Multiple logistic regression analyses including variables associated with selenium levels revealed no association between selenium levels and breast cancer risk.

Adenocarcinoma↗
PubMed1990

Subcutaneous adipose-tissue fatty acids and vitamin E in humans: relation to diet and sampling site.

The influence of diet and sampling site on subcutaneous adipose-tissue fatty acid composition and vitamin E content was examined in 20 healthy subjects. A dietary history and adipose-tissue biopsies from the buttock were obtained from 14 individuals. In another six individuals, samples were taken from both waist and buttock. The relative dietary intake of both polyunsaturated and saturated fatty acids correlated with the relative content in adipose tissue (r = 0.6, p = 0.02). Adipose-tissue vitamin E was strongly associated with dietary intake (r = 0.76, p = 0.004). The content of n - 3 (omega-3) fatty acids in adipose tissue was shown to influence adipose-tissue vitamin E negatively. Waist and buttock fat differed (p less than 0.05) with regard to fatty acid composition whereas no systematic variation was seen in the vitamin E content. The use of adipose-tissue biopsies in epidemiologic studies as measures of the habitual relative intake of fatty acids and vitamin E is suggested.

Adipose Tissue↗
PubMed1989

Adipose tissue levels of fatty acids and tocopherol in young and old women.

Tocopherol concentration and fatty acid composition were determined in samples of subcutaneous adipose tissue from 33 young and 28 old women. Young women exhibited more saturated fatty acids and less monounsaturated fatty acids than old women (p less than 0.01). Adipose tissue tocopherol correlated with plasma tocopherol, with r = 0.49 and p less than 0.01, when the data for young and old were combined. A negative association was found between adipose tissue tocopherol and the n-3/n-6 fatty acid ratio in the old women (r = 0.42; p less than 0.05), suggesting that the tocopherol content of adipose tissue is determined not only by the intake of the nutrient but also by the tissue fatty acid composition.

Adipose Tissue↗