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Biomedical subjects

Jens Peter Bonde

Publications and source records attributed to Jens Peter Bonde.

At least 19 recordsLinked to original sources
PubMed2007

Cryptorchidism according to maternal gestational smoking.

BACKGROUND: It has been suggested that maternal smoking during pregnancy is a risk factor for low sperm counts and testicular cancer in the offspring. Cryptorchidism is associated with both of these disorders and might share causal mechanisms. METHODS: We used prospective information on prenatal exposures and obstetric information on the birth of 5716 boys, collected from 1984 to 1987. During the 16-19 years of follow-up, 270 cases of cryptorchidism were diagnosed, and 185 of these boys underwent orchiopexy. RESULTS: Compared with nonsmokers, the adjusted risk ratio for being diagnosed with cryptorchidism was 1.1 (95% confidence interval = 0.8-1.6) if the mothers smoked 10-19 cigarettes/day and 2.3 (1.1-5.0) if they smoked > or = 20 cigarettes/day. The risk ratios for orchiopexy were 1.4 (0.9-2.1) and 1.8 (0.6-5.0), respectively. CONCLUSION: An excess risk of cryptorchidism was observed among sons of mothers who smoked 10 cigarettes or more per day during pregnancy. In recognition of the limited power of this study, the findings should be replicated in larger cohorts.

Adult↗
PubMed2006

Thyroid function in Danish greenhouse workers.

BACKGROUND: From animal studies it is known that currently used pesticides can disturb thyroid function. METHODS: In the present study we investigated the thyroid function in 122 Danish greenhouse workers, to evaluate if greenhouse workers classified as highly exposed to pesticides experiences altered thyroid levels compared to greenhouse workers with lower exposure. Serum samples from the greenhouse workers were sampled both in the spring and the fall to evaluate if differences in pesticide use between seasons resulted in altered thyroid hormone levels. RESULTS: We found a moderate reduction of free thyroxine (FT4) (10-16%) among the persons working in greenhouses with a high spraying load both in samples collected in the spring and the fall, but none of the other measured thyroid hormones differed significantly between exposure groups in the cross-sectional comparisons. However, in longitudinal analysis of the individual thyroid hormone level between the spring and the fall, more pronounced differences where found with on average 32% higher thyroid stimulating hormone (TSH) level in the spring compared to the fall and at the same time a 5-9% lower total triiodthyroxin (TT3), free triiodthyroxine (FT3) and FT4. The difference between seasons was not consistently more pronounced in the group classified as high exposure compared to the low exposure groups. CONCLUSION: The present study indicates that pesticide exposure among Danish greenhouse workers results in only minor disturbances of thyroid hormone levels.

Adolescent↗
PubMed2006

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↗
PubMed2006

Prevention of low back pain in female eldercare workers: randomized controlled work site trial.

STUDY DESIGN: Randomized controlled trial. OBJECTIVE: To evaluate the effectiveness of an ergonomic and psychosocial intervention in reducing low back pain (LBP) among health care workers. SUMMARY OF BACKGROUND DATA: LBP and injuries are reported frequently among health care workers worldwide. Improvement of person-transfer techniques is the preferred tool in the prevention of both. Although popular, to our knowledge, any effect has not been documented in controlled trials. METHODS: Study participants were eldercare workers from 19 eldercare groups randomly assigned to the transfer technique, stress management, or reference arm. A total of 163 individuals (79% of the source population) participated in both baseline and follow-up after 2 years. Outcome was intra-individual change in rating of LBP during the past 3 and 12 months. RESULTS: We found no difference in LBP in any of the intervention arms over the study period. CONCLUSION: The study showed no effect of a transfer technique or stress management program targeting LBP. Thus, there is a need for discussing other priorities in the prevention of LBP among health care workers.

Aged↗
PubMed2006

Dioxin-like activities in serum across European and Inuit populations.

BACKGROUND: Persistent organic pollutants (POPs) such as polychlorinated dibenzo-p-dioxins/furans, polychlorinated biphenyls (PCBs) and organochlorine pesticides can cause a series of adverse effects on e.g. reproduction in animals and humans, many of which involve the aryl hydrocarbon receptor (AhR). The aim of the present study was to compare the integrated serum level of AhR mediated activity among European and Inuit populations, and evaluate whether the activity was associated to the selected POP markers, 2,2',4,4',5,5'-hexachlorobiphenyl (CB-153) and 1,1-dichloro-2,2-bis(p-chlorophenyl)-ethylene (p,p'-DDE). METHODS: The study included 338 males from Greenland (Inuit's), Sweden, Warsaw (Poland) and Kharkiv (Ukraine). The AhR transactivity of serum extracts alone (AhRag) and competitive AhR activity (AhRcomp) upon co-exposure with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) were determined in the lipophilic serum fraction containing the POPs using the AhR mediated luciferase reporter Hepa1.12cR cell assay. RESULTS: The European groups showed higher median level of AhR-TEQ (TCDD toxic equivalents) compared to the Inuit's, whereas higher incidence of Inuits sample further induced AhRcomp activity. Neither AhRag nor AhR-TEQ were correlated to CB-153 or p,p'-DDE for any of the study groups. Multiple regressions showed a significant heterogeneity of association between the CB-153 and the AhRcomp across the study groups, and accordingly a negative association between AhRcomp and CB-153 was found for the Kharkiv group. CONCLUSION: No consistent correlation between AhR activities and two POP markers was found. Although the difference of AhRag between European and Inuit men could not be explained by CB-153 or p,p'-DDE levels alone, we believe that the variation of AhR serum activity reflects different pattern of POP exposure, genetics and/or life style factors.

Adolescent↗
PubMed2006

Xenoestrogenic activity in blood of European and Inuit populations.

BACKGROUND: Human exposure to persistent organic pollutants (POPs) is ubiquitous and found in all individuals. Studies have documented endocrine disrupting effects and impact on reproduction. The aim of the present study was to compare the level of xenoestrogenic activity in serum of groups with varying POP exposure, and to evaluate correlations to the POP biomarkers, 2,2',4,4',5,5'-hexachlorobiphenyl (CB-153) and 1,1-dichloro-2,2-bis (p-chlorophenyl)-ethylene (p,p'-DDE). METHODS: The study included 358 men: Greenlandic Inuit's, Swedish fishermen, and Warsaw (Poland) and Kharkiv (Ukraine) inhabitants. Xenoestrogenicity of serum extracts alone (XER) and XER competitive (XERcomp) effect on 17beta-estradiol induced estrogen receptor (ER) transactivity were assessed in the hormone free, lipophilic serum fraction containing the POPs using the MVLN human breast cancer cell line. RESULTS: No agonistic XER activity was exhibited for Inuit serum samples, while 12 - 24% of the European samples had detectable agonistic XER activity. On the contrary, 71% of Inuit serum samples antagonized XERcomp compared to 7 - 30 % in the other regions. XER and XERcomp were not or weakly correlated to the two POP markers. XER activity of Inuit samples was negatively associated to levels of CB-153 and p,p'-DDE. For the Warsaw group a positive and negative correlation between XER and p,p'-DDE and estradiol equivalence level and CB-153 levels was found. CONCLUSION: No strong consistent association between xenoestrogenic net activity and the two POP markers was found. The results showed that the selected POP markers alone can not predict the integrated xenoestrogenic serum activity. Correlations to the POP markers were found at the extreme edge; the Inuit's and Warsaw study groups eliciting high frequency of samples with ER antagonistic and agonistic activity, respectively. We suggest that the variation in xenoestrogenic serum activity reflects differences in POP exposure mixture, genetic factors and/or life style factors.

Adolescent↗
PubMed2006

Maternal occupational exposure and risk of specific birth defects.

BACKGROUND: Gregg identified the teratogenic effect of maternal rubella infection in 1941 and since then there has been a focus on risk factors for birth defects. In nearly 70% of all birth defects, there is still no known risk factor and close to 30% of all pregnancies end in a foetal loss or spontaneous abortion, often because of a defect in the foetus. A large percentage of the workforce consists of women of reproductive age. METHODS: A search in MEDLINE for original literature and examination of the association between exposure during pregnancy and the risk of birth defects. RESULTS: Five specific birth defects were identified: neural tube defects, cleft lip and cleft palate, congenital heart defects, urinary tract defects and limb defects. The next step was to include studies with information on occupational exposure during pregnancy. CONCLUSION: There seems to be growing concern as to whether organic solvents, including glycol ethers, pesticides and heavy metals may play a teratogenic role. There is no convincing evidence linking occupational exposure during pregnancy and birth defects.

Cleft Lip↗
PubMed2006

The influence of occupational exposure on male reproductive function.

Recently, many studies have found a decrease in semen quality which has increased the focus on male reproductive health. Occupational hazards are by far the best documented in reproductive epidemiological research. Generally, occupational exposures have been divided into physical exposures (heat and radiation), chemical exposures (solvents and pesticides), psychological exposures (distress), exposure to metals and welding. The recent and/or most important epidemiological studies exploring the effect of occupational exposures on semen quality and fecundity, the ability to conceive, are reviewed. The evidence for an adverse effect on male reproduction of several occupational and environmental exposures and toxicants, such as heat, ionizing radiation, inorganic lead, dibromochloropropane, ethylene dibromide, some ethylene glycol ethers, carbon disulfide and welding operations, is strongly supported in well-designed epidemiological studies. For other agents, the association is only suspected or suggested and needs further evaluation before conclusions can be drawn. It is also important to bear in mind that many workers in the non-Western world still are exposed to substances that are banned in the Western world, sometimes in high concentrations.

Fertilization↗
PubMed2006

Genetic and environmental correlates of semen quality: a twin study.

BACKGROUND: The influences of environmental factors on the male reproductive system have been much debated over the last 3 decades. We studied the impact of genes and environment on semen quality, sex hormone levels, and sperm chromatin stability by using a twin design. METHODS: The study population consisted of monozygotic and dizygotic twins from the population-based Danish Twin Registry and a random selection of pairs of singleton brothers from the Danish Civil Registration System. All men were 20 to 45 years of age. The study population comprised 100 monozygotic twin brothers (50 pairs), 102 dizygotic twins (51 pairs), and 102 single-born brothers (51 pairs). A semen sample and blood sample were collected from all participants. RESULTS: Heritability was estimated to account for 20% (95% confidence interval = 0% to 68%) of the variation in sperm density. A higher heritability was found for the hormones reflecting Sertoli cell function (inhibin B, 76% [36% to 84%] and follicle-stimulating hormone, 81% [40% to 88%]) and for percent morphologic normal cells (41% [0% to 60%] and sperm chromatin parameters (mean alphaT, 68% [34% to 81%] and COMP alphaT, 72% [25% to 82%], respectively). CONCLUSION: Our study indicates a substantial hereditary component in plasma levels of hormones reflecting Sertoli cell function and in sperm cell chromatin stability and morphology. The environmental contribution (including the prenatal environment) appeared to be largest for sperm count.

Adult↗
PubMed2006

Work related violence and threats and the risk of depression and stress disorders.

OBJECTIVE: To examine the risk of depression and stress related disorders as a function of occupational exposure to violence and threats. DESIGN: Population based nested case-control study. SETTING: All gainfully employed Danes. Cases and controls: 14 166 hospital inpatients and outpatients, aged 18-65, treated for affective or stress related disorders during 1995-1998 selected from The Danish Psychiatric Central Research Register and 58 060 controls matched for age, sex, and time, drawn from Statistics Denmark's Integrated Database for Labour Market Research. MAIN OUTCOME MEASURE: Clinical psychiatric diagnosis (WHO ICD-10) of affective (F30-39) or stress related (F40-48) disorders compared with controls by the occupation held the year before treatment. The occupation held the year before treatment was used as exposure proxy. RESULTS: Potential exposure to occupational violence is associated with significantly increased relative risks of both disorders in either sex (women: depression RR 1.45 CI 1.27 to 1.65, stress RR 1.32 CI 1.19 to 1.46; men: depression RR 1.48 CI 1.18 to 1.86, stress RR 1.55 CI 1.29 to 1.84). Work related threats are associated with increase in the risk of depression in women (RR 1.48 CI 1.23 to 1.79) and the risk of stress related disorders in men (RR 1.59 CI 1.32 to 1.91). Risks rose with increasing prevalence of violence and threats. The results remain significant and only slightly attenuated after controlling for extent of professional contact with people other than colleagues. CONCLUSIONS: Employment in occupations involving exposure to work related threats and violence is a risk factor for depression and stress related disorders in both sexes. These findings have implications for health and safety at work policies.

Adolescent↗
PubMed2006

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↗
PubMed2006

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↗
PubMed2005

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↗
PubMed2005

Fertility in four regions spanning large contrasts in serum levels of widespread persistent organochlorines: a cross-sectional study.

BACKGROUND: Persistent organochlorine pollutants (POPs) may interfere with reproductive function but direct evidence in humans is very limited. METHODS: Fertility was examined in four regions with contrasting blood levels of POPs. Pregnant women and their partners in Warsaw (Poland), Kharkiv (Ukraine) and Greenland were consecutively enrolled during antenatal visits. Swedish fishermen and their spouses were recruited separately and independently of current pregnancy. Lipid adjusted serum concentrations of 2,2',4,4',5,5'-hexachlorobiphenyl (CB-153) and 1,1-dichloro-2,2-bis (p-chlorophenyl)-ethylene (DDE) were available for both partners. Time to pregnancy interviews were obtained among 2269 women and 798 men provided a semen sample. RESULTS: Inuits had high levels of both POP markers, Swedish fishermen were high in CB-153 but low in DDE, men from Kharkiv were high in DDE and low in CB-153 while men from Warsaw were low in CB-153 and had intermediate DDE levels. Compared to Warsaw couples, fecundability was reduced among couples from Kharkiv [adjusted fecundability ratio (FR) 0.64 (95% CI 0.5-0.8)] and elevated in Swedish fishermen families [FR 1.26 (95% CI 1.0-1.6)]. Adjusted geometric means of sperm counts and morphology did not differ between regions while sperm motility was higher in men living in Warsaw. CONCLUSION: We observed regional differences in time to pregnancy and sperm motility that may be related to regional differences in POP blood levels, but other interpretations are also plausible. In particular, differences in access to safe contraception and in the prevalence of contraceptive failures are most likely to bias comparisons of time to pregnancy.

Biomarkers↗
PubMed2005

Male reproductive disorders in humans and prenatal indicators of estrogen exposure. A review of published epidemiological studies.

Male reproductive disorders in humans and prenatal indicators of estrogen exposure. A review of published epidemiological studies. Reports of an increase in male reproductive disorders in several countries led to the hypothesis that estrogens during fetal life may cause reduced sperm counts, cryptorchidism, hypospadias and testicular cancer. So far the hypothesis is based on animal studies and reports from the wild life. We systematically searched the epidemiological literature for evidence linking indicators of prenatal serum levels of maternal estrogens with sperm density, hypospadias, cryptorchidism and testicular cancer in humans. Indicators of fetal estrogen exposure included direct measurements, recorded intake of hormones (diethylstilbestrol (DES), oral contraceptives (OCs) and estrogens), pregnancy conditions with known deviant estrogen level as for instance twin pregnancies and some environmental exposures. Among 425 papers we reviewed 81 publications with appropriate information. With the possible exception of testicular cancer there is no strong epidemiological evidence to indicate that prenatal exposure to estrogen are linked to disturbed development of the male reproductive organs.

Cryptorchidism↗
PubMed2005

Occupational disorders and return to work: a randomized controlled study.

OBJECTIVE: Goal setting and motivational factors are strongly associated with maintaining a job and return to work after sick leave, but research into the effects of interventions targeting these factors is limited. We conducted a randomized controlled study to examine the vocational effect of intervention focusing on motivation, goal setting and planning for return to work. DESIGN AND METHODS: Of 243 patients at risk of long-term sick leave or job dropout, 184 (76%) provided complete baseline information for the study. After randomization to an intervention group (n=92) and a reference group (n=92), occupational physicians examined the participants in accordance with standard guidelines. The intervention group received additional support from a social worker in order to enhance goal setting, motivation and planning for return to work. After 1 year 163 participants (89%) provided data on general health and employment status. The risk of not being gainfully employed was analysed by logistic regression analysis with adjustment for several covariates. RESULTS: The intervention did not increase the likelihood of gainful employment after 1 year or reduce the average number of days of sick leave. CONCLUSION: A low-cost counselling program addressing motivation, goal setting and planning for return to work did not improve vocational outcomes or reduce sick leave among patients with work-related disorders.

Adult↗