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Scope: Fish liver, fish liver oil, oily fish and seagull eggs have been major sources of vitamin D for the coastal population of Norway. They also provide dioxin and polychlorinated dioxin-like compounds (dl-compounds), which may interfere with vitamin D homeostasis. We investigated whether serum 25-hydroxyvitamin D (25(OH)D) might be compromised by concomitant intake of dl-compounds., Methods and Results: We studied 182 adults participating in the Norwegian Fish and Game Study. Participants who consumed fish liver and/or seagull eggs had higher dl-compound intake and blood concentrations than non-consumers (p < 0.001). Vitamin D intake was higher (p < 0.001), whereas serum 25(OH)D was lower (p = 0.029) in consumers than in non-consumers. Among non-consumers, vitamin D intake was associated with serum 25(OH)D (β=1.06; 95% CI: 0.48, 1.63). This association was weaker among consumers (β = 0.52; 95% CI: -0.05, 1.08), but strengthened when adjusted for retinol intake (β = 0.66; 95% CI: 0.12, 1.21). The association between vitamin D intake and serum 25(OH)D did not seem to be compromised by intake of dl-compounds., Conclusion: To secure adequate vitamin D status while keeping the intake of dioxins and dl-polychlorinated biphenyls low, a healthy diet should include both supplemental vitamin D and oily fish. Despite high nutrient content, dietary fish liver and seagull eggs should be restricted, due to dl-compounds and possible vitamin A-D antagonism., (Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Seafood is the predominant food source of several organoarsenic compounds. Some seafood species, like crustaceans and seaweed, also contain inorganic arsenic (iAs), a well-known toxicant. It is unclear whether human biotransformation of ingested organoarsenicals from seafood result in formation of arsenicals of health concern. The present controlled dietary study examined the urinary excretion of arsenic compounds (total arsenic (tAs), iAs, AB (arsenobetaine), dimethylarsinate (DMA) and methylarsonate (MA)) following ingestion of a single test meal of seafood (cod, 780 μg tAs, farmed salmon, 290 μg tAs or blue mussel, 690 μg tAs or potato (control, 110 μg tAs)) in 38 volunteers. The amount of ingested tAs excreted via the urine within 0-72 h varied significantly among the groups: Cod, 74% (52-92%), salmon 56% (46-82%), blue mussel 49% (37-78%), control 45% (30-60%). The estimated total urinary excretion of AB was higher than the amount of ingested AB in the blue mussel group (112%) and also ingestion of cod seemed to result in more AB, indicating possible endogenous formation of AB from other organoarsenicals. Excretion of iAs was lower than ingested (13-22% of the ingested iAs was excreted in the different groups). Although the ingested amount of iAs+DMA+MA was low for all seafood groups (1.2-4.5% of tAs ingested), the urinary DMA excretion was high in the blue mussel and salmon groups, counting for 25% and 11% of the excreted tAs respectively. In conclusion our data indicate a possible formation of AB as a result of biotransformation of other organic arsenicals. The considerable amount of DMA excreted is probably not only due to methylation of ingested iAs, but due to biotransformation of organoarsenicals making it an inappropriate biomarker of iAs exposure in populations with a high seafood intake., (Copyright © 2011 Elsevier Inc. All rights reserved.)

There has been a thrilling development , as well as profound changes, in our understanding of the effect of fetal nutrition on the development and health of the child. The Norwegian Mother and Child Cohort Study (MoBa) is an ongoing nationwide population-based pregnancy cohort study that between 1999 and 2008 recruited 90,723 women with 106,981 pregnancies and 108,487 children. The objective of MoBa is to test specific etiologic hypotheses by estimating the association between exposures and diseases with a special focus on disorders that may originate in early life. An important aspect in this regard is maternal diet and nutritional status during pregnancy. Nutritional factors have long been considered to be important determinants of maternal and fetal health, and dietary information is currently being collected in a number of pregnancy cohorts in Europe and the United States. Thus far, pregnancy complications studied in MoBa are preterm birth, preeclampsia, and fetal growth; and the aim of this article is to report results of recently published studies of dietary factors in relation to these outcomes. Numerous studies are planned using MoBa data, and the aim is to add to the knowledge of the interplay between dietary factors, nonnutrients, and toxic dietary substances and epigenetic modulation on fetal development and health later in life.

Probiotics have been suggested to modify placental trophoblast inflammation, systemic inflammation, and blood pressure, all potentially interesting aspects of preeclampsia. The authors examined the association between consumption of milk-based probiotic products in pregnancy and development of preeclampsia and its subtypes. The study was performed in the Norwegian Mother and Child Cohort Study by using a prospective design in 33,399 primiparous women in the years 2002-2008. The intake of milk-based products containing probiotic lactobacilli was estimated from a self-reported food frequency questionnaire. Preeclampsia diagnoses were obtained from the Norwegian Medical Birth Registry. Intake of probiotic milk products was associated with reduced risk of preeclampsia. The association was most prominent in severe preeclampsia (adjusted odds ratio (OR) = 0.79, 95% confidence interval (CI): 0.66, 0.96). With probiotic intakes divided into categories representing no, monthly, weekly, or daily intake, a lower risk for preeclampsia (all subtypes) was observed for daily probiotic intake (OR = 0.80, 95% CI: 0.66, 0.96). Lower risks for severe preeclampsia were observed for weekly (OR = 0.75, 95% CI: 0.57, 0.98) and daily (OR = 0.61, 95% CI: 0.43, 0.89) intakes. These results suggest that regular consumption of milk-based probiotics could be associated with lower risk of preeclampsia in primiparous women.

Hyperemesis gravidarum (hyperemesis), characterised by severe nausea and vomiting in early pregnancy, has an unknown aetiology. The aim of the present study was to investigate food and nutrient intake before pregnancy and the risk of developing hyperemesis in women participating in the Norwegian Mother and Child Cohort Study. From 1999 to 2002, a total of 7710 pregnant women answered a FFQ about their diet during the 12 months before becoming pregnant and a questionnaire about illnesses during pregnancy, including hyperemesis. Only women who were hospitalised for hyperemesis were included as cases. Nutrient intakes during the year before pregnancy did not differ between the ninety-nine women who developed hyperemesis and the 7611 who did not. However, the intake of seafood, allium vegetables and water was significantly lower among women who developed hyperemesis than among women in the non-hyperemesis group. Relative risks of hyperemesis were approximated as OR, and confounder control was performed with multiple logistic regression. Women in the upper tertile of seafood consumption had a lower risk of developing hyperemesis than those in the lower tertile (OR 0·56, 95 % CI 0·32, 0·98), and women in the second tertile of water intake had a lower risk of developing hyperemesis than those in the first tertile (OR 0·43, 95 % CI 0·25, 0·73). The findings suggest that a moderate intake of water and adherence to a healthy diet that includes vegetables and fish are associated with a lower risk of developing hyperemesis.

The birth cohort BraMat (n = 205; a sub-cohort of the Norwegian Mother and Child Cohort Study (MoBa) conducted by the Norwegian Institute of Public Health) was established to study whether prenatal exposure to toxicants from the maternal diet affects immunological health outcomes in children. We here report on the environmental pollutants polychlorinated biphenyls (PCBs) and dioxins, as well as acrylamide generated in food during heat treatment. The frequency of common infections, eczema or itchiness, and periods of more than 10 days of dry cough, chest tightness or wheeze (called wheeze) in the children during the first year of life was assessed by questionnaire data (n = 195). Prenatal dietary exposure to the toxicants was estimated using a validated food frequency questionnaire from MoBa. Prenatal exposure to PCBs and dioxins was found to be associated with increased risk of wheeze and exanthema subitum, and also with increased frequency of upper respiratory tract infections. We found no associations between prenatal exposure to acrylamide and the health outcomes investigated. Our results suggest that prenatal dietary exposure to dioxins and PCBs may increase the risk of wheeze and infectious diseases during the first year of life., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

Objective: To examine the amount of weight women with eating disorders [anorexia nervosa (AN), bulimia nervosa (BN), and binge eating disorder (BED)] gained during pregnancy and to evaluate the adequacy of total weight gain., Method: Data from the Norwegian Mother and Child Cohort Study were used in a cross-sectional manner, n = 35,148. Descriptive statistics and Generalized Estimating Equations to calculate the relative risk estimates were employed., Results: Mean gestational weight gain for the entire sample was 2.5 kg at 17.0-20.1 weeks gestation, 9.3 kg at 27.4-29.7 weeks gestation and 15.0 kg at delivery. Women with BN and BED gained significantly more weight on average than those with no eating disorders at each time point. Women with AN had a lower risk (AOR = 0.65 (0.24, 1.72) of gaining inadequately while women with BN and BED were more likely to gain excessively, AOR = 1.09 (1.01, 1.18) and 1.11 (1.08, 1.14), respectively., Discussion: The pattern of weight gain identified for each eating disorder subtype may help explain the birth outcomes of women with eating disorders., (Copyright © 2010 Wiley Periodicals, Inc.)

Scope: The aim of this study was to i) characterize dietary polychlorinated biphenyls (PCBs) and dioxin exposure in consumers of fish from the PCB contaminated Lake Mjøsa in Norway ii) examine the influence of demographic factors on blood concentrations and congener composition of dioxins and PCBs, iii) characterize dietary sources and possible exposures above tolerable intake., Methods and Results: Blood samples were analysed for dioxin-like (dl) compounds (PCDD/Fs and dl-PCBs) and non-dl-PCBs (ndl-PCBs). Dietary exposures were calculated using food frequency questionnaires (n=64). Men had higher median intake of dl-compounds than women (1.2 and 0.85 pg TEQ/kg bw/day), but similar blood concentrations (23.3 and 25.8, pg TEQ/g lipid weight (lw)). For non-dl-PCBs, intakes (6.5 and 4.5 ng/kg bw/day) and blood concentrations (381 and 224 ng/g lw) were higher in men than in women. Blood concentrations correlated with dietary intakes in men only. Increasing BMI and age elevated blood concentrations mainly in women. Men and women had different blood congener profiles, with a higher share of PCB-126 in women, despite similar dietary congener profiles. Eleven participants exceeded the tolerable intake for dl-compounds. Fish from Lake Mjøsa was the main dietary source., Conclusion: The higher influence of BMI and age for women than for men may have implications for risk assessment., (Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Objective: Many pregnant women use dietary supplements. Little is known about dietary supplement use during pregnancy in women with eating disorders., Method: We examined dietary supplement use in 37,307 pregnant women, from the Norwegian Mother and Child Cohort Study., Results: Dietary supplement use during pregnancy was as follows: 91.2% of women with anorexia nervosa, 92.2% of women with bulimia nervosa, 93.2% of women with eating disorder not otherwise specified-purging subtype (EDNOS-P), 90.6% of women with binge eating disorder, and 93.5% of the women without eating disorders. Between group differences were not statistically significant. After adjusting for covariates, women with EDNOS-P were more likely to take iron containing supplements (p ≤ .04)., Discussion: Overall dietary supplement use in this sample is similar in women with and without eating disorders., (Copyright © 2010 Wiley Periodicals, Inc.)

Background: Preterm delivery represents a substantial problem in perinatal medicine worldwide. Current knowledge on potential influences of probiotics in food on pregnancy complications caused by microbes is limited., Objective: We hypothesized that intake of food with probiotics might reduce pregnancy complications caused by pathogenic microorganisms and, through this, reduce the risk of spontaneous preterm delivery., Design: This study was performed in the Norwegian Mother and Child Cohort on the basis of answers to a food-frequency questionnaire. We studied intake of milk-based products containing probiotic lactobacilli and spontaneous preterm delivery by using a prospective cohort study design (n = 950 cases and 17,938 controls) for the pregnancy outcome of spontaneous preterm delivery (< 37 gestational weeks). Analyses were adjusted for the covariates of parity, maternal educational level, and physical activity., Results: Pregnancies that resulted in spontaneous preterm delivery were associated with any intake of milk-based probiotic products in an adjusted model [odds ratio (OR): 0.857; 95% CI: 0.741, 0.992]. By categorizing intake into none, low, and high intakes of the milk-based probiotic products, a significant association was observed for high intake (OR: 0.820; 95% CI: 0.681, 0.986)., Conclusion: Women who reported habitual intake of probiotic dairy products had a reduced risk of spontaneous preterm delivery.

Background: Little is known about the use of organic food during pregnancy. The aim of this study was to describe characteristics associated with the use of organic food among pregnant women participating in the Norwegian Mother and Child Cohort Study (MoBa)., Methods: The present study includes 63,561 women who during the years 2002-2007 answered two questionnaires, a general health questionnaire at gestational week 15 and a food frequency questionnaire at weeks 17-22. We used linear binomial regression with frequent versus rare use of organic food as outcome variable and characteristics of the respondent as independent variables. The outcome variable was derived from self-reported frequency of organic food use in six main food groups (milk/dairy, bread/cereal, eggs, vegetables, fruit and meat)., Results: Organic eggs and vegetables were the food items which were most frequently reported to be used "often" or "mostly". The proportion of women reporting frequent intake of organic food was 9.1% (n = 5754). This group included more women in the lower (<25 years) and higher (>40 years) age-groups, with normal or low body mass index, who were vegetarians, exercised regularly (3+times weekly), consumed alcohol and smoked cigarettes during pregnancy (p < 0.001 for all, except alcohol: p=0.044). Further, participants with frequent organic consumption included more women in the lower (≤ 12 years) or higher (17 years +) category of educational attainment, women who were students or had a partner being a student, who belonged to the lowest household income group (both respondent and her partner earned <300,000 NOK), who entered the study 2005-2007, and who lived in an urban area (p < 0.001 for all)., Conclusions: The socio-economic characteristics of pregnant Norwegian women with frequent organic consumption did not unambiguously follow those typically associated with better health, such as higher levels of education and income. Rather, lower household income, and both lowest and highest levels of education were associated with a higher prevalence of frequent organic consumption. The results indicate that personal and socio-economic characteristics are important covariates and need to be included in future studies of potential health outcomes related to organic food consumption during pregnancy.

Objective: First, to describe the prevalence of both full and partial breast-feeding during the first 6 months; second, to study the associations between selected health service-related factors and cessation of full breast-feeding at three time intervals., Design: Retrospective questionnaires, 6 months after birth., Setting: The Norwegian Mother and Child Cohort Study (MoBa)., Subjects: In total, 29 621 women., Results: While 96·6 %, 94·0 %, 90·8 %, 86·9 %, 83·8 % and 80·0 % of the infants were breast-fed at 1, 2, 3, 4, 5 and 6 months, respectively, the corresponding proportions for full breast-feeding were 84·6 %, 79·1 %, 70·9 %, 44·0 %, 16·7 % and 2·1 %. An increased risk of cessation of full breast-feeding during the first month was associated with supplementation during the first week of life with water (relative risk (RR) 1·77; 95 % CI 1·52, 2·06), sugar water (RR 1·73; 95 % CI 1·49, 2·00) or formula (RR 5·99; 95 % CI 5·58, 6·42). An increased risk was also associated with Caesarean delivery (RR 1·08; 95 % CI 1·00, 1·16) and breast-feeding problems (RR 1·56; 95 % CI 1·45, 1·67). Between months 1 and 3, the risk of cessation of full breast-feeding remained elevated in the case of supplementation during the first week of life with water (RR 1·29; 95 % CI 1·14, 1·45), sugar water (RR 1·48; 95 % CI 1·34, 1·64) or formula (RR 1·18; 95 % CI 1·07, 1·29). The same applied to Caesarean delivery (RR 1·15; 95 % CI 1·06, 1·25)., Conclusions: Supplementation during the first week, breast-feeding problems and Caesarean delivery are associated with early cessation of full breast-feeding. The results support a cautious approach to supplementation during the first week of life.

Commercially used perfluorinated compounds (PFCs) have been widely detected in wildlife and humans, but the sources of human exposure are not fully characterized. The objectives of this study were to explore possible associations between concentrations of PFCs in serum and consumption of food with particular focus on seafood, and to compare estimated dietary intakes with determined serum PFC concentrations. Concentrations of 19 PFCs were determined in serum from 175 participants in the Norwegian Fish and Game Study and evaluated with respect to food consumption using multiple linear regression analysis. Associations between estimated individual total dietary intakes of PFCs and serum concentrations were also explored. PFC concentrations in serum were significantly associated (p<0.05) with the consumption of lean fish, fish liver, shrimps and meat, as well as age, breastfeeding history and area of residence (R(2) 0.35-0.63). The estimated dietary intakes of perfluorooctanoic acid (PFOA), perfluoroundecanoic acid (PFUnDA) and perfluorooctane sulfonic acid (PFOS) were 0.60, 0.34 and 1.5 ng/kg body weight/day, respectively. Seafood (fish and shellfish) was the major dietary source contributing 38% of the estimated dietary intakes of PFOA, 93% of PFUnDA and 81% of PFOS. The estimated dietary intakes of these three selected PFCs were significantly associated with the corresponding serum PFC concentrations (p<0.05). In conclusion, our results show that consumption of fish and shellfish is a major determinant of serum PFC concentrations. Further, significant relationships between estimated dietary intakes and serum concentrations have been demonstrated for the first time., (Copyright 2010 Elsevier Ltd. All rights reserved.)

The purpose of this study was to compare the prevalence of breastfeeding in women with anorexia nervosa, bulimia nervosa, binge eating disorder and eating disorders not otherwise specified - purging subtype, with mothers with no eating disorders during the first 6 months after birth. The study is based on the Norwegian Mother and Child Cohort Study conducted at the Norwegian Institute of Public Health. Questionnaire-based information on eating disorder diagnoses and breastfeeding in 39 355 women was used to estimate the risk of cessation of breastfeeding with Cox proportional hazards regression. Almost all women (98%) initially breastfeed their infants, with no statistically significant difference between the eating disorders subgroups and women with no eating disorders. However, the risk of early cessation before 6 months post-partum increased for all subgroups of mothers with eating disorders, compared with mothers with no eating disorders. After adjusting for maternal body mass index, age, education, birthweight and pre-term birth, only mothers with anorexia nervosa [hazard ratios (HR), 2.35; 95% confidence interval (CI) 1.22-4.53] and eating disorder not otherwise specified-purging subtype (HR, 1.95; 95% CI 1.08-3.53) had increased risk for cessation of breastfeeding There were no differences in the risk of cessation of exclusive breastfeeding. These results show that some eating disorders may influence mothers' early feeding practices and indicate that additional support may be necessary to assist women with anorexia nervosa in maintaining breastfeeding.

Low iron (Fe) stores may influence absorption or transport of divalent metals in blood. To obtain more knowledge about such associations, the divalent metal ions cadmium (Cd), manganese (Mn), cobalt (Co), copper (Cu), zinc (Zn) and lead (Pb) and parameters of Fe metabolism (serum ferritin, haemoglobin (Hb) and transferrin) were investigated in 448 healthy, menstruating non-smoking women, age 20-55 years (mean 38 years), participating in the Norwegian HUNT 2 study. The study population was stratified for serum ferritin: 257 were iron-depleted (serum ferritin < 12 microg/L) and 84 had iron deficiency anaemia (serum ferritin < 12 microg/L and Hb < 120 g/L). The low ferritin group had increased blood concentrations of Mn, Co and Cd but normal concentrations of Cu, Zn and Pb. In multiple regression models, ferritin emerged as the main determinant of Mn, Co and Cd (p < 0.001), while no significant associations with Cu, Zn and Pb were found. Adjusted r(2) for the models were 0.28, 0.48 and 0.34, respectively. Strong positive associations between blood concentrations of Mn, Co and Cd were observed, also when controlled for their common association with ferritin. Apart from these associations, the models showed no significant interactions between the six divalent metals studied. Very mild anaemia (110 < or = Hb < 120 g/L) did not seem to have any effect independent of low ferritin. Approximately 26% of the women with iron deficiency anaemia had high concentrations of all of Mn, Co and Cd as opposed to 2.3% of iron-replete subjects. The results confirm that low serum ferritin may have an impact on body kinetics of certain divalent metal ions, but not all. Only a fraction of women with low iron status exhibited an increased blood concentration of divalent metals, providing indication of complexities in the body's handling of these metals., (2010 Elsevier Inc. All rights reserved.)

Maternal folate status and smoking are potentially strong risk factors for infant birth size. We assessed the association of several folate indicators and smoking with birth outcomes in a subsample of participants in the Norwegian Mother and Child Cohort Study, consisting of 2934 singleton pregnancies in 2002-2003. Blood plasma folate and cotinine concentrations and self-reported intake of food folate and supplemental folic acid were measured during the second trimester (median 18 wk). Birth outcomes included gestational age, infant birth weight, head circumference, crown-heel length, and small for gestational age (SGA). Mean total dietary folate intake from foods (mean 268.0 microg/d) and supplements (mean 187.7 microg/d) was 455.7 microg/d. Smokers (plasma cotinine > or = 85 nmol/L) had substantially lower supplemental folic acid intake than nonsmokers, but they did not differ regarding folate intake from food only. Nevertheless, smoking was correlated with plasma folate both before and after adjusting for total dietary folate intake (both P < 0.001). We found no significant associations of food folate intake, supplemental folic acid use, total dietary folate intake, or plasma folate with the various birth outcomes after adjustment for potential confounders. Consistent with previous studies, infant birth size was strongly predicted by maternal smoking (adjusted odds ratio for SGA: 2.3; 95% CI: 1.6, 3.3). This study of well-nourished Norwegian pregnant women suggests that dietary folate and plasma folate during the second trimester are not risk factors for infant birth size.

We compared the self-reported frequency of recreational exercise and corresponding metabolic equivalent (MET)-minutes with physical activity measured with a position and motion sensor in pregnant women. One hundred and twelve women in the Norwegian Mother and Child Cohort Study (MoBa) completed questions about weekly participation in recreational exercise by week 17 of pregnancy and participated in the validation study around week 20. Data from a validated motion sensor (ActiReg) that measures physical activity and total energy expenditure (TEE) served as the "gold standard." Self-reported recreational exercise was compared with the following ActiReg-based measures: physical activity energy expenditure (PAEE), minutes of vigorous physical activity (VPA), physical activity level (PAL) and TEE. Pearson's correlations between self-reported weekly exercise and the objectively assessed variables were: rPAEE=0.26, rVPA=0.32, rPAL=0.30 (all P<0.01) and rTEE=0.17 (P=0.07). The partial correlation coefficients between the questionnaire responses and the ActiReg measurements were similar after adjusting for parity, body mass index, education, age, height and smoking, but rTEE increased (r=0.27, P<0.01). We observed significant positive associations between self-reported exercise activities and motion sensor measurements of physical activity, indicating that the questions used for exercise assessment in MoBa may be useful for ranking pregnant women according to the recreational exercise level.

Objective: Few biomarkers for dietary intake of various food groups have been established. The aim of the present study was to explore whether selenium (Se), iodine, mercury (Hg) or arsenic may serve as a biomarker for total fish and seafood intake in addition to the traditionally used n-3 fatty acids EPA and DHA., Design: Intake of fish and seafood estimated by an FFQ was compared with intake assessed by a 4 d weighed food diary and with biomarkers in blood and urine., Setting: Validation study in the Norwegian Mother and Child Cohort Study (MoBa)., Subjects: One hundred and nineteen women., Results: Total fish/seafood intake (median 39 g/d) calculated with the MoBa FFQ was comparable to intake calculated by the food diary (median 30 g/d, rS = 0.37, P < 0.001). Erythrocyte DHA and blood Hg, Se and arsenic concentrations were positively correlated with intake of fish and seafood, but the association for DHA was weakened by the widespread use of supplements. The main finding was the consistent positive association between the intake of fish/seafood and blood arsenic concentration. In multivariate analyses, blood arsenic was associated with blood Hg and fish and seafood intake. In these models, arsenic turned out to be the best indicator of intake of fish and seafood, both totally and in subgroups of fish/seafood intake., Conclusions: While DHA reflected the intake of fatty fish and n-3 PUFA supplements, blood arsenic concentration also reflected the intake of lean fish and seafood. Blood arsenic appears to be a useful biomarker for total fish and seafood intake.

Dietary patterns were related to intake and blood concentrations of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/PCDFs), dioxin-like polychlorinated biphenyls (dl-PCBs) and selected non-dioxin-like-PCBs (ndl-PCBs). Intake calculations were based on an extensive food frequency questionnaire and a congener-specific database on concentrations in Norwegian foods. The study (2003) applied a two-step inclusion strategy recruiting representative (n=73) and high consumers (n=111) of seafood and game. Estimated median intakes of sum PCDD/PCDFs and dl-PCBs of the representative and high consumers were 0.78 and 1.25 pg toxic equivalents (TEQ)/kg bw/day, respectively. Estimated median intakes of ndl-PCBs (sum chlorinated biphenyl (CB)-28, 52, 101, 138, 153, 180) were 4.26 and 6.40 ng/kg bw/day. The median blood concentrations of PCDD/PCDFs/dl-PCBs were 28.7 and 35.1 pg TEQ/g lipid, and ndl-PCBs (sum of CB-101, 138, 153 and 180) 252 and 299 ng/g lipid. The Spearman correlations between dietary intake and serum concentration were r=0.34 (p=0.017) for dl-compounds and r=0.37 (p<0.001) for ndl-PCBs. Oily fish was the major source of dl-compounds and ndl-PCBs in high and representative consumers. Four dietary patterns were identified by principal component analysis. Two were related to high intakes, one dominated by oily fish ((Omega-3)), the other by fish liver and seagull eggs ("northern coastal"). Only the latter was closely associated with high blood concentrations of dioxins and PCBs.

Concerns about reproductive and developmental health risks of exposure to organophosphate (OP) pesticides, phthalates, and bisphenol A (BPA) among the general population are increasing. Six dialkyl phosphate (DAP) metabolites, 3,5,6-trichloro-2-pyridinol (TCPy), BPA, and fourteen phthalate metabolites were measured in 10 pooled urine samples representing 110 pregnant women who participated in the Norwegian Mother and Child Birth Cohort (MoBa) study in 2004. Daily intakes were estimated from urinary data and compared with reference doses (RfDs) and daily tolerable intakes (TDIs). The MoBa women had a higher mean BPA concentration (4.50 microg/L) than the pregnant women in the Generation R Study (Generation R) in the Netherlands and the National Health and Nutrition Examination Survey (NHANES) in the United States. The mean concentration of total DAP metabolites (24.20 microg/L) in MoBa women was higher than that in NHANES women but lower than that in Generation R women. The diethyl phthalate metabolite mono-ethyl phthalate (MEP) was the dominant phthalate metabolite in all three studies, with the mean concentrations of greater than 300 microg/L. The MoBa and Generation R women had higher mean concentrations of mono-n-butyl phthalate (MnBP) and mono-isobutyl phthalate (MiBP) than the NHANES women. The estimated average daily intakes of BPA, chlorpyrifos/chlorpyrifos-methyl and phthalates in MoBa (and the other two studies) were below the RfDs and TDIs. The higher levels of metabolites in the MoBa participants may have been from intake via pesticide residues in food (organophosphates), consumption of canned food, especially fish/seafood (BPA), and use of personal care products (selected phthalates).

Background: A recent study showed that nulliparous women who develop preeclampsia had low concentrations of vitamin D in serum sampled in midpregnancy. The aim of the present study was to estimate the association between intake of vitamin D during pregnancy and the risk of preeclampsia in 23,423 nulliparous pregnant women taking part in the Norwegian Mother and Child Cohort Study., Methods: Participating women answered questionnaires at gestational week 15 (general health questionnaire), at week 22 (food frequency questionnaire), and at week 30 (general health questionnaire). Pregnancy outcomes were obtained from the Medical Birth Registry. Nutrient intake was calculated from foods and dietary supplements. We estimated relative risks as odds ratios, and controlled for confounding with multiple logistic regression., Results: The odds ratio of preeclampsia for women with a total vitamin D intake of 15-20 microg/d compared with less than 5 microg/d was 0.76 (95% confidence interval = 0.60-0.95). Considering only the intake of vitamin D from supplements, we found a 27% reduction in risk of preeclampsia (OR = 0.73 [0.58-0.92]) for women taking 10-15 microg/d as compared with no supplements. No association was found between intake of vitamin D from the diet alone and the occurrence of preeclampsia., Conclusions: These findings are consistent with other reports of a protective effect of vitamin D on preeclampsia development. However, because vitamin D intake is highly correlated with the intake of long chain n-3 fatty acids in the Norwegian diet, further research is needed to disentangle the separate effects of these nutrients.

Several dietary substances have been hypothesized to influence the risk of preeclampsia. Our aim in this study was to estimate the association between dietary patterns during pregnancy and the risk of preeclampsia in 23,423 nulliparous pregnant women taking part in the Norwegian Mother and Child Cohort Study (MoBa). Women participating in MoBa answered questionnaires at gestational wk 15 (a general health questionnaire) and 17-22 (a FFQ). The pregnancy outcomes were obtained from the Medical Birth Registry of Norway. Exploratory factor analysis was used to assess the associations among food variables. Principal component factor analysis identified 4 primary dietary patterns that were labeled: vegetable, processed food, potato and fish, and cakes and sweets. Relative risks of preeclampsia were estimated as odds ratios (OR) and confounder control was performed with multiple logistic regression. Women with high scores on a pattern characterized by vegetables, plant foods, and vegetable oils were at decreased risk [relative risk (OR) for tertile 3 vs. tertile 1: 0.72; 95% CI: 0.62, 0.85]. Women with high scores on a pattern characterized by processed meat, salty snacks, and sweet drinks were at increased risk [OR for tertile 3 vs. tertile 1: 1.21; 95% CI: 1.03, 1.42]. These findings suggest that a dietary pattern characterized by high intake of vegetables, plant foods, and vegetable oils decreases the risk of preeclampsia, whereas a dietary pattern characterized by high consumption of processed meat, sweet drinks, and salty snacks increases the risk.

The aim of this study was to identify dietary predictors of plasma dioxin-like activity in women from the Danish National Birth Cohort. Associations between exposure and birth weight and infant development at 6 months were also explored. Diet was assessed in mid-pregnancy by a food-frequency questionnaire. One hundred nulliparous 25-35-year-old women of normal pre-pregnancy body-mass-index were chosen according to their intake of fatty fish, as fatty fish is a potential route of exposure. Intake of other foods of animal origin was also explored. Dioxin-like activity was measured in plasma using the Dioxin-Responsive Chemically Activated LUciferase eXpression (DR-CALUX) and quantified in toxic equivalents (CALUX-TEQs). Information on infant attainment of specific milestones was obtained by maternal report in a standardized interview. The sample mean was 46 pg CALUX-TEQ/g lipid. Plasma dioxin-like activity increased by 10.7 pg CALUX-TEQ/g lipid (95% CI: 1.8; 19.7) for the highest compared to the lowest tertile of total dietary fat intake but decreased by -9.8 pg CALUX-TEQ/g lipid (95% CI: -19.4; -0.2) for fatty fish intake. The inverse association for fatty fish was explained by lower intake of high-fat food groups such as red meat, fats and oils, which were also predictors of dioxin-like activity. Plasma dioxin-like activity was not associated with birth weight, but an inverse correlation was observed with total developmental score (Spearman r=-0.23, p=0.046). Our study indicates that dietary patterns associated with high fat intake may lead to increased plasma dioxin-like activity and in utero exposure might be related to early infant development.

In a selected group of women from the Danish National Birth Cohort, the authors investigated the association between intake of fatty fish and plasma concentrations of polychlorinated biphenyls (PCBs) on the one hand and the association between maternal PCB concentrations and fetal growth on the other. Of 70,183 women who filled in a food frequency questionnaire during 1996-2002, 100 nulliparous women aged 25-35 years with normal prepregnancy body mass index were selected according to their intake of fatty fish (low (0 meals/month, n = 34), medium (1-3 meals/month, n = 33), or high (> or = meals/month, n = 33)). Women with a high intake of fatty fish had 50% (95% confidence interval (CI): 31, 72) higher plasma PCB concentrations than women with low intake. Maternal plasma PCB concentrations were inversely associated with birth weight and placental weight. The adjusted mean difference between the 75th and 25th PCB percentiles was -155 g (95% CI: -291, -19) for birth weight and -81 g (95% CI: -135, -26) for placental weight. These results support previous findings from this cohort, where fatty fish intake was inversely associated with fetal growth. Dietary recommendations often encourage weekly consumption of fatty fish. These results suggest that potential exposure to PCBs should be carefully considered before recommending such intakes among women of childbearing age.

BACKGROUND: In many cohort studies, biological specimens are being stored without specific plans for analyses. In the Norwegian Mother and Child Cohort Study biological specimens (DNA, plasma, and whole blood) are stored on 96-well plates and as a result may undergo multiple freeze-thaw cycles. METHODS: To explore the impact of multiple freeze-thaw cycles on chemical constituents, we conducted a quality control study using pooled EDTA-plasma. Over a two-year period, samples stored at -80 degrees C were subjected up to 100 freeze-thaw cycles. Specimens were analyzed in triplicate for sodium, cholesterol, triglycerides, vitamin E, aspartate aminotransferase (AST), and free fatty acids. We assessed the percent change of analyte concentration from the values for the first freeze-thaw cycle, because this is the baseline for all stored specimens. RESULTS: With the exception of free fatty acids, there was little change over the first 10 freeze-thaw cycles. A majority of analytes showed no significant changes until 30 freeze-thaw cycles. After 30 freeze-thaw cycles, the largest percent change was observed for free fatty acids (+32%), AST (+21%), and triglycerides (-19%). CONCLUSIONS: Human plasma can go through several freeze-thaw cycles before analysis without influencing sample integrity for the selected analytes.

We assessed dietary exposure to acrylamide in 119 pregnant Norwegian women. The aim of the study was to explore three different methods for estimation of long-term intake of acrylamide and whether it is possible by a food frequency questionnaire (FFQ) to identify pregnant women with high exposure to acrylamide. Acrylamide excreted as mercapturic acid metabolites in 24-h urine was used as an evaluation tool. Food consumption was assessed by an FFQ and by a 4-day weighed food diary (FD). Acrylamide intake was also estimated by a probabilistic approach based on 2 days from the FD. Primarily, acrylamide concentrations reported from analyses of Norwegian foods were used. The dietary exposure to acrylamide estimated as mug/kg bw/day (median and 95 percentile) was 0.48 (0.92) by the FFQ, 0.41 (0.82) by the FD and 0.42 (0.70) by the probabilistic approach. The amount of acrylamide excreted as urinary metabolites (median and 95 percentile) was 0.16 microg/kg bw/24-h (0.50) in non-smokers, corresponding to a dietary exposure of approximately 0.30 microg/kg bw/day (0.91). Linear regression of acrylamide excreted as urinary metabolites identified crisp bread and potato crisps as significant independent predictors, along with cooking oil and onion/garlic. Dietary exposure to acrylamide calculated by FFQ, FD and probabilistic modelling were comparable. The comparison of FFQ acrylamide estimates with levels of urinary acrylamide metabolites showed that the MoBa FFQ was able to identify participants with high dietary acrylamide exposure. Our findings facilitate future studies on acrylamide exposure and health outcomes in the MoBa study.

Background: Little is known concerning the dietary habits during pregnancy of women with eating disorders that may lie in the causal pathway of adverse birth outcomes., Objective: We examined the nutrient and food group intakes of women with bulimia nervosa and binge-eating disorder during pregnancy and compared these with intakes of women with no eating disorders., Design: Data on 30,040 mother-child pairs from the prospective Norwegian Mother and Child Cohort Study were used in cross-sectional analyses. Dietary information was collected by using a food-frequency questionnaire during the first half of pregnancy. Statistical testing by eating disorder categories with the non-eating-disorder category as the referent group was conducted by using log means adjusted for confounding and multiple comparisons. Food group differences were analyzed by using a Wilcoxon's two-sided normal approximation test that was also adjusted for multiple comparisons., Results: Women with binge-eating disorder before and during pregnancy had higher intakes of total energy, total fat, monounsaturated fat, and saturated fat, and lower intakes of folate, potassium, and vitamin C than the referent (P < 0.02). Women with incident binge-eating disorder during pregnancy had higher intakes of total energy and saturated fat than the referent (P = 0.01). Several differences emerged in food group consumption between women with and without eating disorders, including intakes of artificial sweeteners, sweets, juice, fruit, and fats., Conclusion: Women with bulimia nervosa before and during pregnancy and those with binge-eating disorder before pregnancy exhibit dietary patterns that differ from those in women without eating disorders, that are reflective of their symptomatology, and that may influence pregnancy outcomes.

This study investigates dietary exposure and serum levels of polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecane (HBCD) in a group of Norwegians (n = 184) with a wide range of seafood consumption (4-455 g/day). Mean dietary exposure to Sum 5 PBDEs (1.5 ng/kg body weight/day) is among the highest reported. Since concentrations in foods were similar to those found elsewhere in Europe, this may be explained by high seafood consumption among Norwegians. Oily fish was the main dietary contributor both to Sum PBDEs and to the considerably lower HBCD intake (0.3 ng/kg body weight/day). Milk products appeared to contribute most to the BDE-209 intake (1.4 ng/kg body weight/day). BDE-209 and HBCD exposures are based on few food samples and need to be confirmed. Serum levels (mean Sum 7 PBDEs = 5.2 ng/g lipid) and congener patterns (BDE-47 > BDE-153 > BDE-99) were comparable with other European reports. Correlations between individual congeners were higher for the calculated dietary exposure than for serum levels. Further, significant but weak correlations were found between dietary exposure and serum levels for Sum PBDEs, BDE-47, and BDE-28 in males. This indicates that other sources in addition to diet need to be addressed.

Very high concentrations of polybrominated diphenyl ethers (PBDE) have been reported in fish from Lake Mjøsa in Norway. This study was performed to examine the serum concentrations of PBDE and hexabromocyclododecane (HBCD) in consumers of fish from this lake and to investigate possible relationships between serum concentrations, self-reported fish intake and calculated total dietary PBDE exposure. Serum concentrations of the sum of the seven PBDE (BDE-28, 47, 99, 100, 153, 154 and 183) were significantly higher than those of a reference group of Norwegians eating only food with background levels of contamination (medians: 18 ng/g lipids men, 8.4 ng/g lipids women). The median dietary intake of Sum 7 PBDE was 2549 ng/day (30 ng/kg body weight/day), the highest dietary intake of PBDE reported. The contribution from fish caught from the contaminated lake comprised 98.7% of the total dietary exposure. For men, serum levels of PBDE were strongly correlated with the calculated dietary exposure, except for BDE-209. This suggests that sources other than the diet are important for human BDE-209 exposure. The median serum HBCD concentration was 4.1 and 2.6 ng/g lipids for men and women, respectively, and was also found to be associated with consumption of fish from Lake Mjøsa.

Background: Thus far, few factors with a causal relation to preterm birth have been identified. Many studies have focused on the woman's diet, but most have been discouraging. The aim of the present study was to examine if maternal intake of a Mediterranean-type diet (MD) is associated with reduced risk of preterm birth., Methods: The Danish National Birth Cohort assessed diet in mid-pregnancy by food frequency questionnaires (FFQ). Women consuming MD were those who ate fish twice a week or more, used olive or rape seed oil, consumed 5+ fruits and vegetables a day, ate meat (other than poultry and fish) at most twice a week, and drank at most 2 cups of coffee a day., Results: Of 35,530 non-smoking women, 1,137 (3.2%) fulfilled all MD criteria, and 540 (1.5%) none. Odds ratios for preterm birth and early preterm birth were 0.61 (95% Confidence Interval (CI): 0.35-1.05) and 0.28 (0.11-0.76), respectively, in MD women compared to women fulfilling none of the MD criteria., Conclusion: Shifting towards a MD during pregnancy may reduce the risk of early delivery in Danish women.

Background: Use of dietary supplements during pregnancy may give an important contribution to nutrient intake, and for nutrients like folate and vitamin D supplements are recommended. Our objective was to study use and contribution of dietary supplement to nutrient intake among women participating in the Norwegian Mother and Child Cohort Study (MoBa)., Methods: This study is based on 40,108 women participating in MoBa which is conducted by the Norwegian Institute of Public Health. The women had filled inversion 2 of the food frequency questionnaire in MoBa between February 2002 and February 2005., Results: 81% reported use of one or more dietary supplements. The most commonly used category was cod liver oil/fish oil supplements (59%) followed by singular folic acid supplements (36%) and multivitamin/multimineral supplements (31%). The nutrient contribution of the dietary supplements varied from 65% for folate and vitamin D to 1% for potassium among supplement users. The dietary intake of vitamin D, folate, iodine and iron did not reach the Nordic Recommendations for pregnant women., Conclusions: Use of supplements improved the intake of folate, iron and vitamin D, but not sufficiently to reach the recommended amounts., (2008 S. Karger AG, Basel.)

Background: Mediterranean diet has been shown to reduce the incidence of preterm birth. We wanted to investigate whether a Mediterranean-type diet (MD) could be associated with a lower risk of preterm birth in the Norwegian Mother and Child Cohort Study (MoBa)., Methods: The data collection was conducted as part of MoBa at the Norwegian Institute of Public Health. In MoBa, women answer a Food Frequency Questionnaire (FFQ) at week 18-22 of pregnancy. The MD criteria were intake of fish > or =2 times a week, fruit and vegetables > or =5 times a day, use of olive/canola oil, red meat intake < or = times 2 a week, and < or =2 cups of coffee a day., Results: A total of 569 women (2.2%) met the MD criteria, 25,397 women (97.2%) met 1-4 criteria, and 159 women (0.01%) met none of the MD criteria. The number of preterm births in the MD group was 26 (4.6%), in those who met 1-4 criteria it was 1,148 (4.5%), and in those who met none of the criteria it was 10 (6.3%). The women who met the MD criteria did not have reduced risk of preterm birth compared with women meeting none of the MD criteria (OR: 0.73; 95% CI: 0.32, 1.68). Intake of fish twice or more a week was associated with a lower risk of preterm birth (OR: 0.84; 95% CI: 0.74, 0.95)., Conclusions: The women who fulfilled the criteria of a MD did not have a reduced risk of preterm birth.

The aim of the present study was to examine the relative validity of foods and nutrients calculated by a new food frequency questionnaire (FFQ) in the Norwegian Mother and Child Cohort Study (MoBa). Reference measures were a 4-day weighed food diary (FD), a motion sensor for measuring total energy expenditure, one 24-h urine collection for analysis of nitrogen and iodine excretion, and a venous blood specimen for analysis of plasma 25-hydroxy-vitamin D and serum folate. A total of 119 women participated in the validation study, and 112 completed the motion sensor registration. Overall, the level of agreement between the FFQ and the FD was satisfactory, and significant correlations were found for all major food groups and for all nutrients except vitamin E. The average correlation coefficient between the FFQ and the FD for daily intake was 0.48 for foods and 0.36 for nutrients, and on average, 68% of the participants were classified into the same or adjacent quintiles by the two methods. Estimated total energy expenditure indicated that under-reporting of energy intake was more extensive with the FD than with the FFQ. The biological markers confirmed that the FFQ was able to distinguish between high and low intakes of nutrients, as measured by vitamin D, folate, protein and iodine. This validation study indicates that the MoBa FFQ produces reasonable valid intake estimates and is a valid tool to rank pregnant women according to low and high intakes of energy, nutrients and foods.

The authors examined the relation between fish consumption during pregnancy and fetal growth among 44,824 women from the Danish National Birth Cohort (1996-2002). They evaluated the associations between consumption of total fish, fatty fish, and lean fish in midpregnancy and birth weight, birth length, and head circumference among singleton full-term infants. Fish consumption was ascertained by food frequency questionnaire. The birth of infants classified below the 10th percentile for gestational age and gender was significantly increased among women who consumed more than 60 g of fish per day, as compared with women who consumed 5 g or less per day. Adjusted odds ratios were 1.24 (95% confidence interval (CI): 1.03, 1.49) for birth weight and 1.21 (95% CI: 1.01, 1.43) for head circumference. The adjusted odds ratio was borderline significant for birth length (odds ratio = 1.20, 95% CI: 1.00, 1.45). These increases in risk were followed by small decreases in average values for these growth measures. Furthermore, the inverse association for total fish consumption could be explained by consumption of fatty fish, while no association was found for lean fish. These results indicate that consumption of fatty fish, a known route of exposure to persistent organic pollutants, could be associated with reduced fetal growth.

Background/aims: A food frequency questionnaire (FFQ) and a database for dietary supplements were developed for use in the Norwegian Mother and Child Cohort Study (MoBa). The aim of the present study was to investigate the relation between reported use and biomarkers in supplement and non-supplement users and to validate self-reported intake of dietary supplements in mid pregnancy., Method: 120 women were recruited from MoBa, and 119 subjects completed the MoBa FFQ and a 4-day weighed food diary. Information on supplement use was collected by both methods. Venous blood specimens and 24-hour urine samples were obtained for measurement of dietary biomarkers., Results: Biomarker concentration/excretion and intake differed significantly between supplement and non-supplement users for vitamin D, carotenoids, folate, the n-6/n-3 fatty acid ratio and iodine (p < 0.05 for all variables). Flavonoid excretion was higher in flavonoid-supplement users (p < 0.05). Significant correlations between total dietary intake (food and supplements) and biomarker concentration/excretion were found for vitamin D (r = 0.45, p < 0.001), folate (r = 0.26, p = 0.005), the n-6/n-3 fatty acid ratio (r = 0.36, p < 0.001) and iodine (r = 0.42, p < 0.001)., Conclusion: The biochemical indicators examined in this study confirmed differences in self-reported micronutrient intake between supplement and non-supplement users for vitamin D, beta-carotene, folate, n-3 fatty acids, flavonoids and iodine., (Copyright 2007 S. Karger AG, Basel.)

Background: Patterns and predictors of maternal folic acid supplement use have not been examined in large prospective studies of pregnant women., Objective: We examined the patterns and predictors of maternal folic acid supplement use from 2 mo before pregnancy through the eighth month of pregnancy., Design: Data from 22 500 women in the Norwegian Mother and Child Cohort Study with deliveries recorded in 2000-2003 were analyzed., Results: Folic acid supplement use increased from 11.8% at 2 mo before pregnancy to 46.9% at gestational month 3, but decreased to 26.0% at gestational month 8. Of 16 116 women (71.6%) who had taken folic acid supplements at some time before or during pregnancy, 72.4% had started use after becoming pregnant. Ten percent of the women had used supplements regularly from 1 mo before pregnancy throughout the first trimester. These women more frequently reported higher maternal and paternal education, planned pregnancies, infertility treatments, or chronic diseases. They were also more likely to be older, married, and nonsmokers and to have higher income and lower parity., Conclusions: Most women started folic acid supplementation too late with respect to the prevention of neural tube defects. More effective intervention programs to improve periconceptional intakes of folic acid are needed and should consider both demographic and socioeconomic factors.

Background: In a previous study, a group of coronary heart disease (CHD) patients exhibited positive cardioprotective effects of fatty acids derived from a diet of farmed Atlantic salmon fed fish oil (Seierstad et al. 2005). This follow-up study examines these patients for plasma exposure to selected organic and inorganic contaminants found in seafood that may detract from the benefits of eating oily fish., Methods: The study design was from Seierstad et al. (2005), where 58 patients were allocated into three groups consuming 700 g week(-1) of differently fed Atlantic salmon (Salmo salar) fillets for 6 weeks: 100% fish oil (FO), 100% rapeseed oil (RO), or 50% of each (FO/RO)., Results: Different fillets showed graded levels (FO > FO/RO > RO) of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), dioxin-like polychlorinated biphenyls (DLPCBs), indicator PCBs, polybrominated diphenyl ethers (PBDEs), and arsenic (As). Mercury (Hg) and lead (Pb) levels were similar across the three types of fillets. After 6 weeks of consumption, patient levels of PCDDs, DLPCBs, and PCBs in plasma decreased as the dietary intake of these contaminants increased. Plasma PBDEs only showed increases for the FO patients. Levels of inorganic contaminants in plasma showed only slight changes over the study period., Conclusions: These results show a reduction in the use of marine oils in fish feed reduces organic contaminant levels in farmed salmon while still providing a good dietary source of marine fatty acids.

Introduction: Long-term storage of biological materials is a critical component of any epidemiological study. In designing specimen repositories, efforts need to balance future needs for samples with logistical constraints necessary to process and store samples in a timely fashion., Objectives: In the Norwegian Mother and Child Cohort Study (MoBa), the Biobank was charged with long-term storage of more than 380,000 biological samples from pregnant women, their partners and their children for up to 100 years., Methods: Biological specimens include whole blood, plasma, DNA and urine; samples are collected at 50 hospitals in Norway. All samples are sent via ordinary mail to the Biobank in Oslo where the samples are registered, aliquoted and DNA extracted. DNA is stored at -20 degrees C while whole blood, urine and plasma are stored at -80 degrees C., Results: As of July 2006, over 227,000 sample sets have been collected, processed and stored at the Biobank. Currently 250-300 sets are received daily. An important part of the Biobank is the quality control program., Conclusion: With the unique combination of biological specimens and questionnaire data, the MoBa Study will constitute a resource for many future investigations of the separate and combined effects of genetic, environmental factors on pregnancy outcome and on human morbidity, mortality and health in general.

Collection of urine samples in human studies involves choices regarding shipping, sample preservation, and storage that may ultimately influence future analysis. As more studies collect and archive urine samples to evaluate environmental exposures in the future, we were interested in assessing the impact of urine preservative, storage temperature, and time since collection on nonpersistent contaminants in urine samples. In spiked urine samples stored in three types of urine vacutainers (no preservative, boric acid, and chlorhexidine), we measured five groups of contaminants to assess the levels of these analytes at five time points (0, 24, 48, and 72 h, and 1 week) and at two temperatures (room temperature and 4 degrees C). The target chemicals were bisphenol A (BPA), metabolites of organophosphate (OP), carbamate, and pyrethroid insecticides, chlorinated phenols, and phthalate monoesters, and were measured using five different mass spectrometry-based methods. Three samples were analyzed at each time point, with the exception of BPA. Repeated measures analysis of variance was used to evaluate effects of storage time, temperature, and preservative. Stability was summarized with percent change in mean concentration from time 0. In general, most analytes were stable under all conditions with changes in mean concentration over time, temperature, and preservative being generally less than 20%, with the exception of the OP metabolites in the presence of boric acid. The effect of storage temperature was less important than time since collection. The precision of the laboratory measurements was high allowing us to observe small differences, which may not be important when categorizing individuals into broader exposure groups.

Both laymen and the learned are discussing the need for vitamin and minerals supplements and their eventual preventive and therapeutic potential. Documentation is needed, but this word is most of the time used without clarifying the criteria it is based on. In this article we use vitamin E in order to illustrate that there is generally a long way to go from initial hypothesis to eventual practical advice and recommendations. Promising cell and animal studies combined with epidemiological observation studies are not sufficient as evidence; randomised intervention studies are required before conclusions can be drawn. Because high intakes of vitamins and minerals can have negative health effects, we also present the work carried out to decide upper safe intake levels in the Nordic countries, the EU and the USA. Women of fertile age should under certain circumstance take iron and folate supplements, and everyone in Scandinavia should take a supplement with vitamin D. It is sensible and harmless to take a multivitamin and mineral pill for people in risk groups, e.g. people eating very little or have an unbalanced diet (children, old people, patients). Except for these groups it is poorly documented that vitamins and minerals in large doses have a preventive or therapeutic potential. The largest health potential lies in a healthy diet.

Few scientific fields receive more public attention than food and nutrition and few have more self-proclaimed experts. Many are confused by the jungle of dietary advice, sometimes widely differing, with the media often giving broad attention to isolated results without assessing them in the context of the total body of knowledge within a field. A new hypothesis may be received with enthusiasm by lay people and professionals alike, but the road to a well-documented conclusion on which to build general advice, is most often long. A finding must be seen in the context of other findings and judged in relation to the whole body of theory within a field before conclusions can be drawn. Work is carried out both nationally and internationally in order to reach a shared understanding of the minimum requirements of documentation before advice can be given. Traditional guidelines for evidence-based medicine can be applied to some but not all aspects of the science of nutrition. This article presents the process leading to official dietary guidelines in Norway.

The present study was conducted to determine the iodine concentration in Norwegian-produced milk and a selection of dairy products. The iodine concentration of eighty-five samples of milk and dairy products was analysed by inductively coupled plasma-MS. Low-fat milk and organic milk were sampled from nineteen and seven different locations in Norway, respectively, during the summer and winter season of 2000. Other milk and dairy products were chiefly collected during the summer season. Low-fat milk from the summer season had significantly lower median iodine concentration (88 microg/l, range 63-122 microg/l) compared with low-fat milk from the winter season (232 microg/l, range 103-272 microg/l). The median iodine concentration of organic summer milk (60 microg/l) was significantly lower than the iodine concentration of organic winter milk (127 microg/l). There were no significant differences in the low-fat-milk samples with regard to geographical sampling location. Whey cheese (Tine Gudbrandsdalsost) iodine concentration was significantly higher (803 microg/kg) than the median iodine concentration in casein cheeses such as Jarlsberg and Norvegia of 201 and 414 microg/kg, respectively. With a recommended iodine intake of 150 microg/d for adults, a daily intake of 0.4 litres milk meets the requirement with 25 % during the summer and more than 60 % during the winter season. Thus, milk and dairy products are important determinants of iodine intake in Norway.

The effects of an arsenic-rich fish diet and selenium (Se) supplementation on blood arsenic (As), Se, and thyroid hormones were studied in 32 women divided into four equal groups. Groups 1 and 4 received 400 microg Se-methionine daily, group 2 received 400 microg selenite daily, and group 3 received placebo tablets for 15 wk. In addition, groups 1-3 increased their fish intake, eating at least three fish dinners weekly. Mean blood Se concentrations (initially 1.68 +/- 0.24 micromol/L) increased twofold in the Se-methionine groups (p < 0.0001) and by 32% in the selenite group (p < 0.01). Group means of blood As concentrations increased by 63% (p < 0.01), 50% (p < 0.01), 106% (p < 0.01), and 29% (p < 0.05) in the four groups, respectively. Analyzed As intake from duplicate portions of consumed fish correlated with final blood As concentrations (r = 0.85, p < 0.001, n = 32). In the group not receiving Se, there was a positive correlation between final blood As concentrations and plasma T4:T3 ratio (r = 0.80, p < 0.02, n = 8). Initially, blood As concentrations correlated negatively with both T3 and T4 in plasma, but this correlation disappeared upon Se supplementation. The results demonstrate that increased intake of fish may influence blood As concentrations and that circulating thyroid hormones may be influenced by Se-As interactions.

The mutual influences of wheat selenium (Se) and n-3 polyunsaturated fatty acids (n-3 PUFA) on plasma Se and indicators of increased oxidative stress were investigated in a randomized, double-blind study with 31 women (23.5 +/- 3.4 yr). Groups 1 and 2 ingested 5.4 g n-3 PUFA daily (as ethyl esters), whereas groups 3 and 4 received placebo capsules. Groups 2 and 3 received 3 slices of high-Se bread daily, providing 115 micrograms Se, in addition to the 77 +/- 26 micrograms Se in the diet. Groups 1 and 4 received placebo slices. Blood samples were drawn at baseline and at 3 and 6 wk. Serum Se concentrations increased in both groups given Se-enriched bread, but significantly less in subjects given n-3 PUFA (group 2). There were no changes in the plasma ratio alpha-tocopherol:mg cholesterol or plasma ascorbic acid levels. In group 1, plasma-conjugated dienes and thiobarbituric acid-reactive substances (TBARS) rose by 130% (p < 0.005) and 126% (p < 0.005), respectively. Two-way ANOVA showed significant interaction effects of Se and n-3 PUFA on changes in conjugated dienes (p = 0.03) and TBARS (p = 0.015), Se treatment apparently modifying the peroxidative effects of n-3 PUFA. In subjects receiving n-3 PUFA, changes in conjugated dienes and TBARS were negatively correlated with changes in serum Se. In summary, n-3 PUFA modified the effect of Se supplementation, whereas Se seemed to modify the peroxidative effects of n-3 PUFA.

The administration of large doses of selenium (Se) to rats leads to reduced serum levels of somatotropin (growth hormone) and insulin-like growth factor-1 (IGF-1), followed by growth retardation. Similar experiments in humans have been contradictory. The effects of wheat Se and selenomethionine supplementation were investigated in healthy, Norwegian women. In study 1, the participants (n = 18) were given Se-rich bread with 100, 200 and 300 micrograms Se daily for 6 weeks. Initial serum Se concentration were 1.5 +/- 0.2 mumol/l (mean +/- SD). Serum Se increased in a dose-dependent manner in the three groups (p < 0.001). There was no effect on somatotropin and IGF-1 at any of the Se doses given. In study 2 (n = 24), the effects of 400 micrograms selenomethionine daily for 15 weeks were studied in a placebo controlled study. In the treatment group, serum Se concentrations increased by more than 100%. There was, however, no effect on serum somatotropin and IGF-1 concentrations, nor was there any effect on IGF-binding proteins 1 and 3. Our results indicate that at normal or slightly increased intakes, Se has no effect on the serum concentrations of these two hormones in healthy individuals.

Fish species may contain considerable amounts of trace elements, such as selenium (Se), arsenic (As), and mercury (Hg). The present study investigated the relationships between dietary intake of these elements and cutaneous bleeding time and blood lipids in 32 healthy volunteers. For 6 wk, one group (n = 11) consumed approx 250 g Se-rich fish daily, providing them with an average Se intake of 115 +/- 31 micrograms Se/d, Hg intake of 18 +/- 8 micrograms/d, and As intake of 806 +/- 405 micrograms/d, all values analyzed in 4-d duplicate food collections. To study the effect of Se alone, one group (n = 11) included Se-rich bread in their normal diet, giving them a Se intake (135 +/- 25 micrograms/d) that was comparable to the fish group. A control group (n = 10) ate their normal diet, providing 77 +/- 25 micrograms Se/d, 3.1 +/- 2.5 micrograms Hg/d, and 101 +/- 33 micrograms As/d. The dietary As load strongly correlated both with bleeding times and changes in bleeding times (r = 0.48, p < 0.01 and r = 0.54, p < 0.002, respectively). Dietary Hg showed a positive correlation with LDL-cholesterol (r = 0.55, p < 0.01), whereas dietary Hg in the fish group showed a strong negative relationship with HDL-cholesterol (r = -0.76, p < 0.01). Selenium seemed to have only a modest effect on bleeding time. Our results suggest that mercury and arsenic from fish may be factors contributing to or modifying some of the known effects of fish ingestion.

A diet rich in fish tends to increase the bleeding time both in patients and healthy controls. Another effect of such a diet is a reduction in serum triglyceride levels in the individuals. It is not known whether these two effects are interrelated. In order to rule out effects of selenium in the fish diet, half of a control group consumed bread enriched with selenium while the other half had a normal diet. This combined control group (n = 21) was compared with healthy volunteers (n = 11) eating 250 g of fish daily for six weeks. Blood tests were performed at the start of the study, after three weeks and at the end. Changes in bleeding time were then related to changes in hemostatic variables and serum lipids. An inverse correlation (r = -0.41, p = 0.001) was present in the controls between serum triglyceride levels and bleeding times, but neither of the two variables changed in the course of the study. A negative correlation was observed in the fish eating group, and a change in the variables mentioned occurred in an orderly manner in the course of the study: a prolongation of the bleeding time from the start of the study to the end was only seen in individuals with low triglyceride levels, i.e. less than 1 mmol/L. Selenium in the diet, on the other hand, did not affect any of the observed variables.(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of an increased intake of wheat selenium (Se) on platelet Se, serum Se, whole-blood Se, and glutathione peroxidase (GSH-Px) levels was investigated in 14 healthy Norwegian females (age 21-53 years). The intake of 60 micrograms Se per day as wheat Se, for six weeks, significantly increased the platelet Se (mean +/- SEM) from 9.1 +/- 1.1 mumol/L to 11.4 +/- 0.9 mumol/L, the serum Se from 1.43 +/- 0.18 mumol/L to 1.63 +/- 0.25 mumol/L, and the whole blood Se from 1.77 +/- 0.18 mumol/L to 2.01 +/- 0.18 mumol/L. The increase in percent of initial Se values was twice as high for platelets as for serum and whole blood. The GSH-Px levels were not altered during the experiment. Platelet Se was not significantly correlated to the Se intake initially. At the end of the experimental period, the Se in platelets reflected the total Se intake, but not with a simple linear correlation. No significant correlation between the total Se intake and the Se concentration in whole blood or serum was found.