Prenatal exposure to polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) may influence birth weight among infants in a Swedish cohort with background exposure: a cross-sectional study

BACKGROUND: Prenatal exposure to persistent organic pollutants, e.g. polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) has been suggested to negatively affect birth weight although epidemiological evidence is still inconclusive. We investigated if prenatal exposure to PCBs and PBDEs is related to birth weight in a Swedish population with background exposure. METHODS: Breast milk was sampled during the third week after delivery from first-time mothers in Uppsala county, Sweden 1996–2010 (POPUP cohort) (N = 413). Samples were analysed for di-ortho PCBs (CB-138, 153, 180) and tetra- to hexa- brominated PBDEs (BDE-47, 99, 100, 153). Simple and multiple linear regression models were used to investigate associations between lipid-adjusted, ln-transformed PCB and PBDE concentrations, and birth weight. Covariates included in the multivariate regression model were PCB and PBDE exposure, maternal age, pre-pregnancy BMI, weight gain during pregnancy, education, smoking, gender of the infant and gestational length. The effect of including fish consumption was also investigated. RESULTS: In the multivariate model, prenatal exposure to di-ortho PCBs was significantly associated with increased birth weight (β = 137; p = 0.02). The result did not change when gestational length was added to the model. An inverse association between PBDE(4) (sum of BDE-47, -99, -100 and −153) and birth weight was observed in the multivariate model including gestational length (β = −106; p = 0.04). Maternal pre-pregnancy BMI and weight gain during pregnancy were important confounders of the association between di-ortho PCBs and birth weight. The associations were not alleviated after adjustment for fish consumption, a major source of PCB and PBDE exposure. The observed associations were stronger for boys than for girls. CONCLUSIONS: Our results indicate that prenatal exposure to di-ortho PCBs and PBDE(4) may influence birth weight in different directions, i.e. PCB exposure was associated with higher birth weight and PBDE exposure with lower birth weight. Maternal pre-pregnancy BMI and weight gain during pregnancy were important confounders that may hide positive association between di-ortho PCB exposure and birth weight if they are not included in the statistical model. We speculate that even small PCB- and PBDE-induced shifts in the distribution of birth weight may influence future public health in populations with background exposure

Determinants of serum concentrations of organochlorine compounds in Swedish pregnant women: a cross-sectional study

BACKGROUND: We performed a cross-sectional study of associations between personal characteristics and lipid-adjusted serum concentrations of certain PCB congeners and chlorinated pesticides/metabolites among 323 pregnant primiparous women from Uppsala County (age 18–41 years) sampled 1996–1999. METHODS: Extensive personal interviews and questionnaires about personal characteristics were performed both during and after pregnancy. Concentrations of organochlorine compounds in serum lipids in late pregnancy were analysed by gas chromatography. Associations between personal characteristics and serum levels of organochlorine compounds were analysed by multiple linear regression. RESULTS: Participation rate was 82% (325 of 395 women). Serum concentrations of PCB congeners IUPAC no. 28, 52, 101, 105 and 167, and o, p'-DDT and -DDE, p, p'-DDT and -DDD, oxychlordane, and γ- and α-HCH were in many cases below the limit of quantification (LOQ). No statistical analysis of associations with personal characteristics could be performed for these substances. Concentrations of PCB congeners IUPAC no. 118, 138, 153, 156 and 180, HCB, β-HCH, trans-nonachlor and p, p'-DDE increased with increased age and were highest in women sampled early during the 4 year study period. This shows that older women and women sampled early in the study had experienced the highest life-time exposure levels, probably mainly during childhood and adolescence. The importance of early exposures was supported by lower PCB concentrations and higher β-HCH and p, p'-DDE concentrations among women born in non-Nordic countries. Moreover, serum concentrations of certain PCBs and pesticide/metabolites were positively associated with consumption of fatty fish during adolescence, and concentrations of CB 156, CB 180 and p, p'-DDE increased significantly with number of months women had been breast-fed during infancy. Short-term changes in bodily constitution may, however, also influence serum concentrations, as suggested by negative associations between concentrations of organochlorine compounds and BMI before pregnancy and weight change during pregnancy. CONCLUSION: Although some of the associations could be caused by unknown personal characteristics confounding the results, our findings suggest that exposures to organochlorine compounds during childhood and adolescence influence the body burdens of the compounds during pregnancy

Immune cell counts and risks of respiratory infections among infants exposed pre- and postnatally to organochlorine compounds: a prospective study

<p>Abstract</p> <p>Background</p> <p>Early-life chemical exposure may influence immune system development, subsequently affecting child health. We investigated immunomodulatory potentials of polychlorinated biphenyls (PCBs) and <it>p,p'</it>-DDE in infants.</p> <p>Methods</p> <p>Prenatal exposure to PCBs and <it>p,p'</it>-DDE was estimated from maternal serum concentrations during pregnancy. Postnatal exposure was calculated from concentrations of the compounds in mother's milk, total number of nursing days, and percentage of full nursing each week during the 3 month nursing period. Number and types of infections among infants were registered by the mothers (N = 190). White blood cell counts (N = 86) and lymphocyte subsets (N = 52) were analyzed in a subgroup of infants at 3 months of age.</p> <p>Results</p> <p>Infants with the highest prenatal exposure to PCB congeners CB-28, CB-52 and CB-101 had an increased risk of respiratory infection during the study period. In contrast, the infection odds ratios (ORs) were highest among infants with the lowest prenatal mono-<it>ortho </it>PCB (CB-105, CB-118, CB-156, CB-167) and di-<it>ortho </it>PCB (CB-138, CB-153, CB-180) exposure, and postnatal mono- and di-<it>ortho </it>PCB, and <it>p,p'</it>-DDE exposure. Similar results were found for pre- and postnatal CB-153 exposure, a good marker for total PCB exposure. Altogether, a negative relationship was indicated between infections and total organochlorine compound exposure during the whole pre- and postnatal period. Prenatal exposure to CB-28, CB-52 and CB-101 was positively associated with numbers of lymphocytes and monocytes in infants 3 months after delivery. Prenatal exposure to <it>p,p'</it>-DDE was negatively associated with the percentage of eosinophils. No significant associations were found between PCB and <it>p,p'</it>-DDE exposure and numbers/percentages of lymphocyte subsets, after adjustment for potential confounders.</p> <p>Conclusion</p> <p>This hypothesis generating study suggests that background exposure to PCBs and <it>p,p'</it>-DDE early in life modulate immune system development. Strong correlations between mono- and di-<it>ortho </it>PCBs, and <it>p,p'</it>-DDE exposures make it difficult to identify the most important contributor to the suggested immunomodulation, and to separate effects due to pre- and postnatal exposure. The suggested PCB and <it>p,p'</it>-DDE modulation of infection risks may have consequences for the health development during childhood, since respiratory infections early in life may be risk factors for asthma and middle ear infections.</p

Aspects of Risk-Benefit Assessment of Food Consumption : Directions for the future

During the autumn of 2007, the National Food Administration in Sweden arranged a two-day seminar with the title "Aspects of Risk-Benefit Assessment of Food Consumption - Directions for the Future". The seminar was funded by the Nordic Council of Ministers, and the objective was to provide an overview of methods that have been applied for risk-benefit assessment, and to discuss advantages and limitations of this approach in the food sector. The purpose was also to investigate the possibility to establish a common view, among the Nordic and Baltic countries, for how to proceed with work regarding risk-benefit assessment of food products. Experts from the National Food Administration and other Swedish organizations, the other Nordic countries, and the Baltic countries were present at the seminar. Invited speakers held presentations during the first day. On the second day, risk-benefit activities in the Nordic countries concerning fish consumption were presented, and organised group discussions were also held. The report summarises the different activities and discussions at the Uppsala seminar, and presents the conclusions of the meeting

Bromerade flamskyddsmedel i modersmjölk från förstföderskor i Uppsala - uppdaterad tidstrend 1996-2006

Under perioden 1996 till 2006 har Livsmedelsverket samlat in modersmjölk från förstföderskor i Uppsala län. Ett av syftena med studierna är att undersöka hur halterna av vissa persistenta organiska miljögifter förändras med tiden. I denna rapport utvärderas eventuella tidstrender för bromerade flamskyddsmedel (polybromerade difenyletrar (PBDE) och hexabromcyklododecan (HBCD)). Tidstrender för PBDEer under den aktuella tidsperioden har utvärderats tidigare (Glynn et al. 2007), och resultaten har nu kompletterats med analys av ytterligare 80 prover. Bland PBDE kongenerna uppvisade BDE-47 den högsta medianhalten (1,5 ng/g fett) i modermjölk, följt av BDE-153 (0,57 ng/g fett), BDE-99 (0,32 ng/g fett) och BDE-100 (0,29 ng/g fett). Halterna av BDE-28, -66, -138, -154, -183 och HBCD låg under kvantifierings-gränsen i de flesta av proverna. Inga generella trender observerades beträffande PBDEer i modersmjölk. Multipel linjär regression visade att medianhalterna av BDE-47 och BDE-99 har sjunkit (4,3 % respektive 7,5% per år), medan medianhalten av BDE-153 har ökat (4,9% per år) under den studerade tioårsperioden. Ingen signifikant trend kunde påvisas för BDE-100. En långsamt nedåtgående trend av summaPBDE-koncentrationerna (summan av BDE-47, BDE-99, BDE-100, BDE-153 och BDE-154) observerades. Denna nedåtgående trend är dock osäker eftersom den tid det beräknas ta för medianhalten att halveras (34 år) är betydligt längre än den tid som studien sträcker sig över (10 år). I likhet med våra resultat har en studie av PBDE koncentrationer i poolade mjölkprover från kvinnor i Stockholmsområdet också visat att halterna av lägre bromerade kongener (t.ex. BDE-47 och BDE-99) har minskat från mitten av 1990-talet, medan halterna av BDE-153 har ökat (Fängström et al. 2008). Förklaringen till detta kan vara att användningen av lägre bromerade PBDE kongener har minskat och/eller att BDE-153 är mer persistent i jämförelse med t.ex. BDE-47.

Syntetiska myskföreningar i bröstmjölk och fisk

Syntetiska myskföreningar förekommer i bl.a. parfym, tvål, tvättmedel, och kosmetika som substitut för den dyra naturliga mysken. De vanligaste syntetiska myskföreningarna tillhör grupperna nitromyskföreningar (t.ex. myskxylen (MX) och myskketon (MK)) och polycykliska myskföreningar (t.ex. HHCB och AHTN). Livsmedelsverket har sedan 1996 kontinuerligt samlat in bröstmjölk och blod från förstföderskor i Uppsalaområdet för att undersöka halter av miljökontaminanter. 44 bröstmjölksprover och 15 blodprover (serum) från dessa insamlingar (1996-2001) har analyserats med avseende på nitromyskföreningar (MX och MK) och polycykliska myskföreningar (främst HHCB och AHTN). Dessutom har fisk från Östersjön och andra svenska vattendrag, insamlade 1996-2001, analyserats. Resultaten visar att MX, MK, AHTN och HHCB förekommer i bröstmjölk från svenska mödrar. Medelhalterna var 21,8 (MX), 12,4 (MK), 125 (HHCB) respektive 23,8 (AHTN) μg/kg mjölkfett. Myskhalterna i serumproverna var låga. Inget samband mellan myskhalter i bröstmjölk och parametrarna ålder, BMI eller viktnedgång efter förlossning observerades. Däremot kunde en negativ tidstrend påvisas, d.v.s. halterna HHCB, AHTN och MX har sjunkit från 1998 till 2001. Antalet analyserade prover är dock litet, och för att kunna bekräfta den nedåtgående trenden krävs ytterligare analyser. Förstföderskor som deltog i bröstmjölksinsamlingen under 2000-2001 (N=23) svarade på frågor om användning av parfymerade produkter (parfym, deodorant, hudkräm, tvättmedel, handdiskmedel). Kvinnor med regelbunden användning av parfym hade högre halter HHCB i bröstmjölken än kvinnor med liten parfymanvändning. Kvinnor som använde parfymerad deodorant eller parfymerat tvättmedel hade högre halter AHTN i bröstmjölken än kvinnor som inte använde dessa produkter. P.g.a. det begränsade underlaget är resultaten osäkra, men ett samband mellan användning av parfymerade produkter och myskhalt i bröstmjölk kan inte uteslutas. En intagsberäkning visar att intaget av HHCB, AHTN, MX och MK hos spädbarn via bröstmjölk motsvarar 0,12-1,3 % av föreslagna PTDI-värden (provisional tolerable daily intake). Beaktas bör dock att variationen i halt mellan kvinnor är stor och att spädbarns exponeringen från andra källor, t.ex. parfymerade blöjor, tvättlappar och salvor, är okänd. Dessutom baseras de PTDI-värden som använts på en bristfällig toxikologisk dokumentation. Det begränsade antal analyser som gjorts av fiskprover tyder på att fisk från Östersjön och andra svenska vattendrag innehåller förhållandevis låga halter syntetiska myskföreningar. Resultaten bekräftar tidigare studier som tyder på att vatten från reningsverk är en källa till kontamination av miljön med syntetiska myskföreningar. Även fisk från vatten som anses vara relativt oförorenade, utan direkta utsläpp från industrier eller reningsverk, innehöll detekterbara halter av syntetiska myskföreningar. En intagsberäkning visar att även för storkonsumenter av fisk är marginalerna mellan exponering och föreslagna PTDI-värden stora