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Biomedical subjects

Lars Rylander

Publications and source records attributed to Lars Rylander.

At least 19 recordsLinked to original sources

Weight and height at 4 and 7 years of age in children born to mothers with a high intake of fish contaminated with persistent organochlorine pollutants.

In Sweden the main exposure route for persistent organochlorine pollutants (POP) is through consumption of fatty fish from the Baltic Sea (off the eastern coast). The present study aimed to investigate whether intrauterine exposure for POP may have negative impact on children's weight and height at 4 and 7 years of age, respectively. The study included 174 fishermen's wives from the Swedish east coast who had given birth to an infant with either low (n=55) or normal (n=119) birth weight, and 88 and 206 corresponding women from the Swedish west coast (where the fish is less polluted). Comparisons between the east and west coast cohorts were performed. In addition, blood samples were collected among the east coast women and the concentrations of 2,2',4,4',5,5'-hexachlorobiphenyl (CB-153) in plasma was analyzed and estimated for the year of childbirth. There were no significant differences between the east and west coast cohorts regarding weight and height at 4 and 7 years of age. There were, however, significant negative associations between the estimated plasma concentrations of CB-153 during year of childbirth and weight at 4 and 7 years of age, respectively, among the normal birth weight children. The study gives only very weak support for the hypothesized association.

Animals↗

Incidence of hand eczema in female Swedish hairdressers.

OBJECTIVE: To estimate the occurrence of hand eczema in hairdressers in Sweden. METHODS: The occurrence of hand eczema was estimated in a Swedish longitudinal retrospective cohort study including all female graduates from vocational schools for hairdressers from 1970 to 1995. A stratified sample from the general population acted as controls. A self-administered questionnaire including questions on the occurrence of hand eczema, skin atopy, working periods and number of hair treatments performed per week was sent to the participants. Incidence rate ratios (IRRs) of hand eczema were estimated. RESULTS: The incidence rate of hand eczema in hairdressers was 23.8 cases/1000 person-years, whereas in hairdressers who were aged <25 years it was 37.1/1000 person-years. The corresponding IRR for hairdressers compared with controls was 2.5 (95% confidence interval (CI) 2.2 to 2.8), and that for younger hairdressers was 3.1 (95% CI 2.6 to 3.5). The mean age at onset of hand eczema was 21.6 years for hairdressers and 21.2 years for controls. The 1-year prevalence of hand eczema was 18.0% for hairdressers and 12.1% for controls. A large number of hair treatments involving exposure to skin irritants and sensitisers were reported. The incidence rate of hand eczema was higher among individuals with a history of childhood eczema, both for hairdressers and for controls, giving an (age-adjusted) IRR of 1.9 and 2.2, respectively. The attributable fraction of hand eczema from skin atopy was 9.6%. A synergistic effect of skin atopy and hairdressing was found on the occurrence of hand eczema. The relative excess risk due to interaction was 1.21 (95% CI 0.21 to 2.21; p = 0.01). CONCLUSION: Hairdressers are highly exposed to skin-damaging substances. The self-reported incidence of hand eczema was substantially higher in female hairdressers than in controls from the general population and than that found previously in register-based studies. For many individuals, onset of hand eczema occurs early in life. Only about 10% of the hand eczema cases among hairdressers would be prevented if no one with skin atopy entered the trade.

Adult↗

Association between exposure to persistent organohalogen pollutants and epididymal and accessory sex gland function: multicentre study in Inuit and European populations.

Exposure to persistent organochlorine pollutants (POPs) may have negative impact on male reproductive function. We, therefore, investigated the association between serum levels of POPs and epididymal and accessory sex gland function. Serum levels of CB-153, p,p'-DDE and seminal markers of epididymal [neutral-alpha glucosidase (NAG)], prostatic [prostate specific-antigen (PSA)] and zinc, and seminal vesicle function (fructose) were measured from 135 Swedish fishermen and fertile men from Greenland (n=163), Warsaw, Poland (n=167) and Kharkiv, Ukraine (n=158). Multiple linear regression analyses, adjusting for potential confounders, were employed using both continuous and categorized exposure variables. Both exposure and outcome variables were log transformed. Considering the consistency between models with either continuous or categorized CB-153 levels, negative associations with the activity of NAG were found among Greenlandic men (mean difference 7.0 mU/ejaculate, 95% CI 3.0, 34), and in the aggregated cohort (mean difference 4.0 mU/ejaculate, 95% CI -0.2, 8.0). A positive association was observed between CB-153 and PSA as well as zinc among Kharkiv men. In the Swedish cohort, a negative association was found between CB-153 and fructose. In conclusion, the negative effects of POP on sperm motility, observed in the same study population might partly be caused by post-testicular mechanisms, involving a decreased epididymal function.

Adult↗

Associations between CB-153 and p,p'-DDE and hormone levels in serum in middle-aged and elderly men.

BACKGROUND: Animal and epidemiologic data indicate that exposure to persistent organochlorine pollutants (POPs) may disrupt the hypothalamus-pituitary-thyroid (HPT) and the hypothalamus-pituitary-gonadal (HPG) axes. We have assessed whether the POP-biomarkers 2,2'4,4',5,5'-hexachlorobiphenyl (CB-153) and 1,1-dichloro-2,2-bis(4-chlorophenyl)-ethene (p,p'-DDE) affect thyrotropin (TSH), thyroid hormones, gonadotropins or sex hormone concentrations in men. METHODS: Lipid adjusted serum concentrations of CB-153, and p,p'-DDE, were determined in 196 men (median age 59 years, range 48-82). Hormone analyses in serum were performed with immunoassays. The effect of CB-153 and p,p'-DDE (as continuous or categorized variables) were evaluated by linear regression models, adjusting for potential confounders. RESULTS: There was a significant positive association between p,p'-DDE and TSH. An increase of 100 ng/g lipid of p,p'-DDE corresponded to an increase of 0.03 mU/l (95% Confidence Interval (CI) 0.01, 0.05) in TSH level. The explanatory value (R(2)) of the multivariate model was only 7%. Moreover, there was a significant negative association between p,p'-DDE and estradiol. An increase of 100 ng/g lipid of p,p'-DDE corresponded to a decrease of 0.57 pmol/l (95% CI -1.0, -0.12) in estradiol level. The R(2)-value was only 4%. No associations were observed between any of the POP biomarkers and the other hormones. CONCLUSIONS: The positive association between p,p'-DDE and TSH and the negative association between p,p'-DDE and estradiol, among middle-aged and elderly men, were not accompanied by associations between the POP-markers and thyroxin, testosterone, and gonadotropins, respectively. The results gives some additional support for that POP exposure may affect HPT- and HPG-axes also in humans, but the overall epidemiological data are still not coherent enough to allow any firm conclusions.

Aged↗

Intra-individual variations and time trends 1991-2001 in human serum levels of PCB, DDE and hexachlorobenzene.

BACKGROUND: An important question is whether human serum levels of persistent organic pollutants has continued to decrease during the last decades. The aim of this study was to assess intra-individual variations over time of serum levels of 2,2',4,4',5,5'-hexachlorobiphenyl (CB-153), 1,1-dichloro-2,2-bis(4-chlorophenyl)-ethene (p,p'-DDE) and hexachlorobenzene (HCB), considering the impact of a number of possible determinants. METHODS: Blood samples were drawn for the same 39 subjects in 1991 and 2001. Interviews were made at both occasions. Lipid adjusted serum concentrations of CB-153, p,p'-DDE and HCB were determined in both sets of blood samples using gas chromatography-mass spectrometry. The fatty acid composition of the serum lipids was analyzed by means of gas-liquid chromatography. RESULT: The CB-153 concentrations in serum had averagely decreased with 34% in between 1991 and 2001 (p<0.001). Of individual determinants only increasing BMI was associated with decreasing CB-153 levels (beta=-1.0, 95% CI -1.8, -0.2, p=0.01), explaining 13% of the variation. The average decrease of p,p'-DDE was 55%, and could only weakly be associated with a relative increase of BMI (beta=-1.0, 95% CI -2.3, 0.2, p=0.09), explaining only 5% of the variation. The average decrease of HCB was 53%, and was associated only with high fish consumption in 1991, explaining 12% of the variation. CONCLUSIONS: The results support a continuing decrease in human body burdens of PCBs, DDE and HCB during the 1990s. The explanatory factors relative change of BMI and fish consumption explained only a minor part of the time-related variations in serum levels.

Adult↗

Ethnic differences in occurrence of TDS-- genetics and/or environment?

It has been hypothesized that poor semen quality, testis cancer, undescended testis and hypospadias are symptoms of one underlying entity, the so-called testicular dysgenesis syndrome (TDS). TDS was suggested to be a result of disruption of embryonal programming and gonadal development during foetal life and as aetiological factor, an impact of adverse environmental factors such as hormone disrupters, probably acting upon a susceptible genetic background, was suggested. Extensive studies considering the risk of TDS-related diseases in Denmark compared with Finland, showed higher sperm counts and lower risk of cryptorchidism and testicular cancer among Finns. However, when comparing these two populations, the question arises, to which degree this difference might be due to discrepancy in genetic background. A more obvious example of the impact of genetic factors on the risk of TDS concerns Afro-Americans having significantly lower incidence of testicular cancer when compared with Caucasians living in the USA. A yet unexplored scenario is a possible interaction between genetic and environmental/lifestyle-related factors, certain genotypes making individuals more susceptible to adverse exogenous exposures. Studying such interactions has biological, epidemiological and public health-related implications. It will help us to understand the background for the defects in male reproductive organs, facilitate proper design of epidemiological studies and add to identifying individuals susceptible to certain environmental and lifestyle-related hazards. Such 'susceptibility genes' need to be identified, those involved in the synthesis, action and metabolism of sex steroids being strong candidates.

Cryptorchidism↗

Cancer in persons working in dry cleaning in the Nordic countries.

U.S. studies have reported an increased risk of esophageal and some other cancers in dry cleaners exposed to tetrachloroethylene. We investigated whether the U.S. findings could be reproduced in the Nordic countries using a series of case-control studies nested in cohorts of laundry and dry-cleaning workers identified from the 1970 censuses in Denmark, Norway, Sweden, and Finland. Dry-cleaning work in the Nordic countries during the period when tetrachloroethylene was the dominant solvent was not associated with an increased risk of esophageal cancer [rate ratio (RR) = 0.76; 95% confidence interval (CI), 0.34-1.69], but our study was hampered by some unclassifiable cases. The risks of cancer of the gastric cardia, liver, pancreas, and kidney and non-Hodgkin lymphoma were not significantly increased. Assistants in dry-cleaning shops had a borderline significant excess risk of cervical cancer not found in women directly involved in dry cleaning. We found an excess risk of bladder cancer (RR = 1.44; 95% CI, 1.07-1.93) not associated with length of employment. The finding of no excess risk of esophageal cancer in Nordic dry cleaners differs from U.S. findings. Chance, differences in level of exposure to tetrachloroethylene, and confounding may explain the findings. The overall evidence on bladder cancer in dry cleaners is equivocal.

Case-Control Studies↗

Impact of PCB and p,p'-DDE contaminants on human sperm Y:X chromosome ratio: studies in three European populations and the Inuit population in Greenland.

OBJECTIVE: Recent studies indicate that persistent organohalogen pollutants (POPs) may contribute to sex ratio changes in offspring of exposed populations. Our aim in the present study was to investigate whether exposure to 2,2 ,4,4 ,5,5 -hexachlorobiphenyl (PCB-153) and dichlorodiphenyldichloroethene (p,p -DDE) affects sperm Y:X chromosome distribution. SUBJECTS AND METHODS: We obtained semen and blood for analysis of PCB-153 and p,p -DDE levels from 547 men from Sweden, Greenland, Poland (Warsaw), and Ukraine (Kharkiv), with regionally different levels of POP exposure. The proportion of Y- and X-chromosome-bearing sperm in the semen samples was determined by two-color fluorescence in situ hybridization analysis. RESULTS: Swedish and Greenlandic men had on average significantly higher proportions of Y sperm (in both cohorts, 51.2%) and correspondingly higher lipid-adjusted concentrations of PCB-153 (260 ng/g and 350 ng/g, respectively) compared with men from Warsaw (50.3% and 22 ng/g) and Kharkiv (50.7% and 54 ng/g). In the Swedish cohort, log-transformed PCB-153 and log-transformed p,p -DDE variables were significantly positively associated with Y-chromosome fractions (p-values 0.04 and <0.001, respectively). On the contrary, in the Polish cohort PCB-153 correlated negatively with the proportion of Y-bearing fraction of spermatozoa (p=0.008). CONCLUSIONS: The present study indicates that POP exposure might be involved in changing the proportion of ejaculated Y-bearing spermatozoa in human populations. Intercountry differences, with different exposure situations and doses, may contribute to varying Y:X chromosome ratios.

Chromosomes, Human, X↗

Reproductive hormone levels in men exposed to persistent organohalogen pollutants: a study of inuit and three European cohorts.

OBJECTIVE: Persistent organohalogen pollutant (POP) exposure may have a negative impact on reproductive function. The objective of this study was to assess the impact of POP exposure on the male hypothalamo-pituitary-gonadal axis. PARTICIPANTS: Participants included 184 Swedish fishermen and spouses of pregnant women from Greenland (n = 258), Warsaw, Poland (n = 113) , and Kharkiv, Ukraine (n = 194). EVALUATIONS/MEASUREMENTS: Serum levels of 2,2,4,4,5,5-hexachlorobiphenyl (CB-153) and dichlorodiphenyl dichloroethene (p,p -DDE) were determined in the four populations, showing different exposure patterns: Swedish fishermen, high CB-153/low p,p -DDE; Greenland, high CB-153/high p,p -DDE; Warsaw, low CB-153/moderate p,p -DDE; Kharkiv, low CB-153/high p,p -DDE. Serum was also analyzed for testosterone, estradiol, sex hormone-binding globulin (SHBG) , inhibin B, luteinizing hormone (LH) , and follicle-stimulating hormone (FSH) . Free testosterone levels were calculated based on testosterone and SHBG. RESULTS: We found significant center-to-center variations in the associations between exposure and the outcomes. The most pronounced effects were observed in Kharkiv, where statistically significant positive associations were found between the levels of both CB-153 and p,p -DDE and SHBG, as well as LH. In Greenland, there was a positive association between CB-153 exposure and LH. In the pooled data set from all four centers, there was positive association between p,p -DDE and FSH levels [beta = 1.1 IU/L; 95% confidence interval (CI), 1.0-1.1 IU/L]. The association between CB-153 levels and SHBG was of borderline statistical significance (beta = 0.90 nmol/L; 95% CI, -0.04 to 1.9 nmol/L). CONCLUSIONS: Gonadotropin levels and SHBG seem to be affected by POP exposure, but the pattern of endocrine response is the subject of considerable geographic variation.

Cohort Studies↗

Fertility among female hairdressers.

OBJECTIVES: The study investigated whether working as a hairdresser has a negative impact on fertility, measured as time to pregnancy and miscarriage risk. METHODS: Self-administered questionnaires were sent to 5289 Swedish hairdressers (response rate 50%) and to 5299 age-matched women from the general Swedish population (response rate 54%). Information was collected on time to pregnancy or trying time for women who had tried, but failed, to conceive at the time of the study. The outcome of the pregnancy was determined and categorized as either miscarriage or stillbirth or live birth. The hairdressers were compared with the referents with respect to these two outcomes. Within the hairdresser cohort, the effects of hair treatments, as well as physical workload and stress were investigated. RESULTS: The hairdressers were less successful than the reference cohort in conceiving (fecundability ratio 0.91, 95% confidence interval 0.83-0.99). The effect was reduced after first-month conceptions were excluded, the indication being that the effect may be the result of birth control bias. Within the hairdresser cohort, a self-perceived stressful work situation seemed to prolong the time to pregnancy. No effects were found for the different chemical hair treatments. There was no cohort difference with respect to miscarriage risk (odds ratio 1.12, 95% confidence interval 0.88-1.42), but miscarriage risks were increased for most of the hair treatments and for self-perceived stressful work situations. However, none of these effects were statistically significant. CONCLUSIONS: The present study indicates a negative impact on time to pregnancy and miscarriage risk for working as a hairdresser".

Abortion, Spontaneous↗

A cross-sectional study of the association between persistent organochlorine pollutants and diabetes.

BACKGROUND: Experimental evidence supports the hypothesis that persistent organochlorine pollutants (POPs) may cause type 2 diabetes mellitus, whereas there is no fully convincing epidemiological evidence for such an association. In Sweden the most important source of POP exposure is fatty fish. We have assessed the association between serum levels of POPs and prevalence of diabetes in Swedish fishermen and their wives, with high consumption of fatty fish from the Baltic Sea. METHODS: In 196 men (median age 60 years) and 184 women (median age 64 years), we analyzed 2,2',4,4',5,5'-hexachlorobiphenyl (CB-153) and 1,1-dichloro-2,2-bis(p-chlorophenyl)-ethylene (p,p'-DDE) in serum using gas chromatography-mass spectrometry. The participants were asked if they had diabetes and, if so, since which year and about medication and diet. The Odds Ratios (OR) for diabetes with respect to continuous exposure variables were analyzed with logistic regression, adjusting for potential confounders. Moreover trends of diabetes prevalence with respect to trichotomized exposure variables were tested with Jonckheere-Terpstra's test. RESULTS: Six percent of the men and 5% of the women had diabetes. After confounder adjustment CB-153 was significantly associated with diabetes prevalence using both categorized and continuous exposure data (an increase of 100 ng/g lipid corresponded to an OR of 1.16, 95% confidence interval [CI] 1.03, 1.32, p = 0.03). Similar associations were observed for p,p'-DDE (an increase of 100 ng/g lipid corresponded to an OR of 1.05, 95% CI 1.01, 1.09, p = 0.006). Gender stratified analyses showed among men consistent positive associations with CB-153, but a more ambiguous pattern with respect to DDE. In contrast, among the women the associations with p,p'-DDE were stronger than with CB-153. CONCLUSION: The study provides support that POP exposure might contribute to type 2 diabetes mellitus.

Adult↗

Inter-population variations in concentrations, determinants of and correlations between 2,2',4,4',5,5'-hexachlorobiphenyl (CB-153) and 1,1-dichloro-2,2-bis (p-chlorophenyl)-ethylene (p,p'-DDE): a cross-sectional study of 3161 men and women from Inuit and European populations.

BACKGROUND: The study is part of a collaborative project (Inuendo), aiming to assess the impact of dietary persistent organochlorine pollutants (POPs) on human fertility. The aims with the present study are to analyze inter-population variations in serum concentrations of 2,2',4,4',5,5'-hexachlorobiphenyl (CB-153) and 1,1-dichloro-2,2-bis (p-chlorophenyl)-ethylene (p,p'-DDE), to assess inter-population variations in biomarker correlations, and to evaluate the relative impact of different determinants for the inter-individual variations in POP-biomarkers. METHOD: In study populations of 3161 adults, comprising Greenlandic Inuits, Swedish fishermen and their wives, and inhabitants from Warsaw, Poland and Kharkiv, Ukraine, serum concentrations of CB-153 and p,p'-DDE, were analysed by gas chromatography-mass spectrometry. RESULTS: The median serum concentrations of CB-153 were for male and female Inuits 200 and 110, for Swedish fishermen 190 and their wives 84, for Kharkiv men and women 44 and 27, and for Warsaw men and women 17 and 11 ng/g lipids, respectively. The median serum concentrations of p,p'-DDE were for Kharkiv men and women 930 and 650, for male and female Inuits 560 and 300, for Warsaw men and women 530 and 380, and for Swedish fishermen 240 and their wives 140 ng/g lipids, respectively. The correlation coefficients between CB-153 and p,p'-DDE varied between 0.19 and 0.92, with the highest correlation among Inuits and the lowest among men from Warsaw. Men had averagely higher serum concentrations of CB-153 and p,p'-DDE, and there were positive associations between age and the POP-biomarkers, whereas the associations with BMI and smoking were inconsistent. Dietary seafood was of importance only in the Inuit and Swedish populations. CONCLUSION: CB-153 concentrations were much higher in Inuits and Swedish fishermen's populations than in the populations from Eastern Europe, whereas the pattern was different for p,p'-DDE showing highest concentrations in the Kharkiv population. The correlations between the POP-biomarkers varied considerably between the populations, underlining that exposure sources differ and that the choice of representative biomarkers of overall POP exposure has to be based on an analysis of the specific exposure situation for each population. Age and gender were consistent determinants of serum POPs; seafood was of importance only in the Inuit and Swedish populations.

Adult↗

Exposure to CB-153 and p,p'-DDE and bone mineral density and bone metabolism markers in middle-aged and elderly men and women.

The incidence of osteoporotic fractures is rising in western societies, partly due to unknown reasons. Persistent organochlorine compounds (POC) have in animal studies impaired the normal bone metabolism and resulted in increased bone fragility, which might have health implications for POC-exposed human populations. The aim of the present study was to assess whether a high dietary intake of POC through fatty fish from the Baltic may result in decreased bone mineral density (BMD) or disturbances in biochemical markers of bone metabolism. From a study base of fishermen and fishermen's wives from the Swedish east coast who are considerably more POC-exposed than the general Swedish population, 196 men (median age 59 years) and 184 women (median age 62 years) participated in an examination of their forearm BMD, using dual energy x-ray absorptiometry (DXA). Further, POC exposure was assessed by analysis of lipid-adjusted serum levels of 2,2',4,4',5,5'-hexachlorobiphenyl (CB-153) and 1,1-dichloro-2,2-bis(p-chlorophenyl)-ethylene (p,p'-DDE). Cadmium in urine (U-Cd) was also analyzed. Biochemical markers in serum of osteoblastic (osteocalcin) and osteoclastic (CrossLaps) functions were measured. Adjustment for potential confounders was made by employing multiple regression analyses. Univariate analyses showed significant negative associations between CB-153 concentrations and BMD, but after adjustment for age and body mass index, these associations did not remain. None of the POC exposure variables were associated with CrossLaps or osteocalcin. There were no significant associations between U-Cd and BMD or any of the biochemical biomarkers. In conclusion, the results did not provide any support for the hypothesis that the current exposure levels to POC constitute a hazard for impaired bone metabolism in the general Swedish population.

Absorptiometry, Photon↗

A simplified precise method for adjusting serum levels of persistent organohalogen pollutants to total serum lipids.

In order to obtain biomarker values that reflect body burden of persistent organohalogen pollutants (POP), concentrations of lipophilic POP in serum or plasma are generally expressed on a lipid weight basis, and not on a fresh weight basis. There are two different approaches to determine the lipid content in serum and plasma. The gravimetric determination is more expensive, and longer experience is needed as compared with the preferable enzymatic determination. Clinical chemistry laboratories at most hospitals perform enzymatic determinations of cholesterol and triglycerides on a routine basis, whereas analysis of phospholipids is not part of these analyses. In the present study, therefore, we evaluated the association between the sum of measured triglyceride, cholesterol, and phospholipid levels in serum among 617 individuals with the sum of only triglyceride and cholesterol levels. There was a very strong linear association between the sums of serum concentrations of triglycerides and cholesterols and the total lipid concentrations. As much as 97.2% of the variation in total lipid concentrations was explained by the sum of the triglyceride and cholesterol concentrations, with the following regression: Total lipid=0.9+1.3 *(Cholesterol+Triglycerides). Almost identical relationships were recorded in subgroups with men, women and subjects of different age. Thus, total lipid concentrations in blood serum can be accurately estimated by analyzing only cholesterol and triglycerides in the matrix.

Adolescent↗

Exposure to persistent organochlorine pollutants associates with human sperm Y:X chromosome ratio.

BACKGROUND: During the last decades, there has been concern that exposure to endocrine disruptors, such as persistent organochlorine pollutants (POPs), may contribute to sex ratio changes in offspring of exposed populations. METHODS: To investigate whether exposure to 2,2'4,4'5,5'-hexachlorobiphenyl (CB-153) and dichlorodiphenyl dichloroethene (p,p'-DDE) affect Y:X chromosome proportion, semen of 149 Swedish fishermen, aged 27-67 years, was investigated. The men provided semen and blood for analysis of hormone, CB-153 and p,p'-DDE levels. The proportion of Y- and X-chromosome bearing sperm in semen samples was determined by two-colour fluorescence in situ hybridization (FISH) analysis. RESULTS: Log transformed CB-153 as well as log transformed p,p'-DDE variables were both significantly positively associated with Y chromosome fractions (P-values = 0.05 and <0.001, respectively). Neither age, smoking nor hormone levels showed any association with Y-chromosome fractions. CONCLUSIONS: This is the first study to indicate that exposure to POPs may increase the proportion of ejaculated Y-bearing spermatozoa. These data add to the growing body of evidence that exposure to POPs may alter the offspring sex ratio.

Adult↗

Urinary phthalate metabolites and biomarkers of reproductive function in young men.

BACKGROUND: High exposure to phthalates, which are ubiquitous contaminants, has been shown in animal studies to produce detrimental effects on male reproductive functions. A recent study in humans reported dose-response relations between low phthalate levels in urine and human semen parameters, which raises the question whether humans are more sensitive to phthalate exposure than animals. METHODS: Urine, serum, and semen samples were collected from 234 young Swedish men at the time of their medical conscript examination. Semen volume, sperm concentration, and motility were measured, together with sperm chromatin integrity (sperm chromatin structure assay) and biochemical markers of epididymal and prostatic function. We analyzed reproductive hormones in serum, and mono ethyl phthalate (MEP), mono ethylhexyl phthaltale (MEHP), mono benzyl phthalate (MBzP), mono butyl phthalate (MBP), and phthalic acid in urine. RESULTS: For MBP, MBzP, and MEHP, no clear pattern of associations were observed with any of the reproductive biomarkers. Subjects within the highest quartile for MEP had fewer motile sperm (mean difference = 8.8%; 95% confidence interval = 0.8-17), more immotile sperms (8.9%; 0.3-18), and lower luteinizing hormone values (0.7 IU/L; 0.1-1.2), but there was no suggestion of harmful effects for most other endpoints. Phthalic acid actually was associated with improved function, as measured by several markers. CONCLUSIONS: The observed weak associations between 1 phthalate biomarker and impairment of a few aspects of reproductive function biomarkers were not consistent with results from a recent U.S. study. It is not yet possible to conclude whether phthalate exposure may reflect a hazard for human male reproduction.

Adolescent↗

Exposure to PCBs and p,p'-DDE and human sperm chromatin integrity.

Persistent organochlorine pollutants (POPs) such as polychlorinated biphenyls (PCBs) and dichlorodiphenyldichloroethylene (p,p'-DDE), the major metabolite of dichlorodiphenyltrichloroethane (DDT), are stable lipophilic compounds widely found in the environment and in the general population. They can enter the food chain, and their negative impact on male reproduction is currently under active scrutiny. To explore the hypothesis that environmental exposure to these compounds is associated with altered sperm chromatin structure integrity in human sperm, we conducted a study of 176 Swedish fishermen (with low and high consumption of fatty fish, a very important exposure source of POPs). We determined serum levels of 2,2',4,4',5,5'-hexachlorobiphenyl (CB-153) and p,p'-DDE, and we used the sperm chromatin structure assay (SCSA) to assess sperm DNA/chromatin integrity. When CB-153 serum levels (individual dose range, 39-1,460 ng/g lipid) were categorized into equally sized quintiles, we found an association with the DNA fragmentation index (%DFI). A significantly lower %DFI was found in the lowest CB-153 quintile (< 113 ng/g lipid) compared with the other quintiles; there was a similar tendency, although not statistically significant, between %DFI and p,p'-DDE. These results suggest that POP exposure may have a slight negative impact on human sperm chromatin integrity.

Adult↗

Reproductive outcomes among hairdressers.

OBJECTIVES: The present study aimed at examining the possible risk of working as a hairdresser during pregnancy in relation to reproductive outcomes. METHODS: The Swedish Medical Birth Register, which includes almost every infant born in Sweden, has, since 1983, collected information prospectively about occupation in early pregnancy. This information is given at the first visit to a prenatal center. During the period 1983-2001, 12 046 infants were born to female hairdressers working either full- or part-time during early pregnancy. For comparison, all other deliveries during the same period were used in which the mother had worked either part-time or full-time. RESULTS: The full-time hairdressers more often had intrauterine growth-retarded infants (ie, small for gestational age) as compared with referents with a corresponding worktime [adjusted odds ratio (OR) 1.20, 95% confidence interval (95% CI) 1.06-1.36]. The pattern was similar for part-time hairdressers (adjusted OR 1.16, 95% 0.93-1.46). The fraction of malformations did not differ from those among the referents. The gender ratio for the infants of hairdressers was similar to that for the overall Swedish population. CONCLUSIONS: The findings concerning infants small for their gestational age in the present study is in accordance with previous findings. The reason for these findings remains unknown. Studies with more-specific exposure information during pregnancy are needed.

Adolescent↗