Lene Andersen

Effects of exposure to 17α-ethinylestradiol during early development on sexual differentiation and induction of vitellogenin in zebrafish (Danio rerio)

To determine the critical stage of zebrafish development where exposure to xenoestrogens can affect sex ratio and vitellogenin induction, zebrafish (Danio rerio) were exposed to 17α-ethinylestradiol (actual concentration 15.4±1.4 ng EE2/l) during early development: from fertilisation to hatch; hatch to 10 days post hatch (dph); 10–20 dph; 20–30 dph; 20–40 dph; 20–60 dph; fertilisation to 25 dph; or hatch to 60 dph. Vitellogenin was measured in whole body homogenate 30 dph by ELISA and sex ratio was determined 60 dph by histological examination of the gonads. All exposure periods significantly induced vitellogenin synthesis and affected the sex differentiation leading to development of ovo-testis or complete feminisation of the exposed fish depending on exposure period. Complete sex reversal was obtained in groups exposed from 20 to 60 dph and hatch to 60 dph. The half-life for degradation of vitellogenin was calculated. Juvenile zebrafish were exposed to 15.4±1.4 ng EE2/l (actual concentration) from fertilisation to 25 dph and transferred to clean water, after which weekly measurements of vitellogenin concentration in whole body homogenate were performed until day 46 post hatch. The half-life of vitellogenin was 2.4 days.

Impaired larval development in broods of eelpout (Zoarces viviparus) in Danish coastal waters

Eelpouts (Zoarces viviparus), a viviparous fish, were sampled in Danish coastal waters during October and November 2001 and 2002, in ten different areas, which are receiving effluents from cities and industry to more or minor degree. The presence of gross abnormalities in eelpout broods has been suggested to be a useful biomarker of the impact of hazardous substances on fish reproduction in the marine environment as chronic exposure to various substances has the potential to induce severe developmental defects in fish embryos and larvae. Relatively high frequencies of female eelpouts (20–53) with elevated levels (>5) of larvae with developmental defects in the broods were found in four shallow fjords with effluents from larger cities and industry compared to areas. Deformations like spiral or bend shapes of the spinal axis, cranio-facial defects, eye lesions or loss of eyes were the dominating types. In some of␣the areas with the highest incidences of developmental defects, the adults had significantly enlarged livers, which may also be a possible effect caused by contaminant exposure. In two of the areas, relatively high frequencies of the broods contained larvae, which had died late but without any visible developmental defects. These two areas were affected by severe oxygen depletion prior to sampling time suggesting that examination of broods in the eelpout may include not only impact of hazardous substances but also effect of eutrophication-related problems on fish reproduction in the marine environment.

Use of statins and risk of glioma: a nationwide case–control study in Denmark

Background:Laboratory studies and a single case–control study have suggested a protective effect of statins on the risk of glioma. We wished to investigate the influence of statin use on the risk of glioma in a population-based setting.Methods:We conducted a nationwide case–control study in Denmark based on population-based medical registries. We identified all patients aged 20 to 85 years with a first diagnosis of histologically verified glioma during 2000–2009. These cases were matched on birth year and sex with population controls. Prior use of statins since 1995 was classified into short-term use (<5 years) and long-term use (5+ years). We used conditional logistic regression to compute odds ratios (ORs), with 95% confidence intervals (CIs), for glioma associated with statin use, adjusted for potential confounders.Results:A total of 2656 cases and 18 480 controls were included in the study. The risk of glioma was reduced among long-term statin users (OR=0.76; 95% CI: 0.59–0.98) compared with never users of statins, and was inversely related to the intensity of statin treatment among users (OR=0.71; 95% CI: 0.44–1.15 for highest intensity). The inverse association between long-term statin treatment and glioma risk was more pronounced among men aged ⩽60 years (OR=0.40; 95% CI: 0.17–0.91) compared with men aged 60+ years (OR=0.71; 95% CI: 0.49–1.03). An inverse association was also observed among women aged ⩽60 years (OR=0.28; 95% CI: 0.06–1.25), but not among women over age 60 years (OR=1.23; 95% CI: 0.82–1.85).Conclusion:Long-term statin use may reduce the risk of glioma.

Zebrafish Danio rerio and roach Rutilus rutilus : Two species suitable for evaluating effects of endocrine disrupting chemicals?

Morphological studies of gonads from roach ( Rutilus rutilus ) in a small Swedish lake were performed. The lake is a potential recipient for drainage water from a refuse dumping area. All fishes were macroscopically identified as males, but histological examination of the gonads showed a high incidence of intersex. This high incidence might be caused by endocrine disrupting chemicals. The relationships between exposure to endocrine disrupters and intersex observations in wild fish is unknown and the effect of endocrine disrupters on zebrafish ( Danio rerio ) were evaluated in order to determine whether they might serve as a model laboratory species for effects of endocrine disrupting chemicals in wild fish. Zebrafish were exposed from pre-blastula stage until sexual maturation to either standardised water (controls), 17a-methyltestosterone (1, 10 w g l -1 ) or 17b-estradiol (1, 10 w g l -1 ). Exposure to both concentrations of 17bestradiol caused a significant feminisation, while a significant increase in the proportions of males was found after exposure to 1 mg 17a-methyltestosterone l -1 . Furthermore, exposure to 1 and 10 mg 17a-methyltestosterone l -1 caused development of intersex individuals. Additionally, sexually mature male zebrafish were exposed to 1 w g 17b-estradiol l -1 . After 10 weeks of exposure the fish were transferred to non-contaminated water for two weeks. The control group was kept in standardised water for 12 weeks. At termination of the experiment, measurement of whole-body vitellogenin concentrations were performed. Exposure to 17b-estradiol caused a significant increase in whole body vitellogenin concentrations. After 2 weeks in water without addition of 17b-estradiol, the vitellogenin concentration was reduced by approximately 50%. Roach and zebrafish may share properties which makes these species suitable for further comparisons to evaluate effects of endocrine disrupting chemicals as well as domestic and industrial effluents containing hormone-like substances.

Hormone replacement therapy increases the risk of cranial meningioma.

AIM We investigated the influence of hormone replacement therapy (HRT) use on the risk of meningioma in a population-based setting. METHODS We conducted a nationwide case-control study in Denmark based on population-based administrative and health registries. The study included all female patients aged 55-84 years with a first time diagnosis of meningioma during 2000-2009. The cases were matched on birth year with female population controls. Ever use of HRT since 1995 was defined as ≥2 HRT prescriptions and categorised according to HRT type (oestrogen only, combined oestrogen-progestagen, and progestagen only) and cumulated duration of use (<1, ≥1 to <5, ≥5 to <10, ≥10 years). We used conditional logistic regression to compute odds ratios (ORs), with 95% confidence intervals (CIs), for meningioma associated with HRT use, and adjusting for potential confounders. RESULTS We identified 924 cases and 6122 controls. Ever use of HRT was associated with an increased risk of meningioma (OR, 1.3; 95%CI, 1.1-1.5) compared with non-use (0-1 prescriptions). The risk increased with increasing duration of HRT use, reaching an OR of 1.7 (95% CI, 1.2-2.3) after more than 10 years of use. The risk of meningioma associated with long-term (≥10 years) HRT use was most pronounced for combined oestrogen-progestagen therapy (OR, 2.2; 95% CI, 1.4-3.3), especially when this regimen constituted the sole HRT therapy (OR, 2.7; 95% CI, 0.9-7.5), although the latter estimate was based on small numbers. CONCLUSIONS Long-term HRT use, particularly of combined oestrogen-progestagen therapy, may increase the risk of meningioma.

Vitellogenin induction and brain aromatase activity in adult male and female zebrafish exposed to endocrine disrupters

Adult male and female zebrafish were exposed to ethinylestradiol (EE2), methyltestosterone (MT), and Flutamid (F) for one week. EE2 and MT elevated the vitellogenin (VTG) levels in males significantly compared to controls, while no changes in VTG levels were observed in females. Brain aromatase activity was increased significantly in females exposed to EE2 and F compared to control, where as no significant changes in the activity was found in males.

Hormone replacement therapy and risk of glioma: A nationwide nested case–control study

AIM Several studies indicate that use of hormone replacement therapy (HRT) is associated with an increased risk of intracranial meningioma, while associations between HRT use and risk of other brain tumors have been less explored. We investigated the influence of HRT use on the risk of glioma in a nationwide setting. METHODS Using population-based registries we conducted a case-control study nested in the Danish female population. We identified all women aged 55-84 years with a first diagnosis of histologically verified brain glioma during 2000-2009. Using risk-set sampling, each case was matched on birth year to eight population controls. Ever use of HRT was defined as ≥2 HRT prescriptions and categorized according to type (oestrogens only, combined oestrogen-progestagen and progestagen only) and duration of use (<1, ≥1 to <5, ≥5 to <10, and ≥10 years). We used conditional logistic regression to compute odds ratios (ORs), with 95% confidence intervals (CIs), for glioma associated with HRT use, adjusting for potential confounders. RESULTS We identified 658 cases and 4350 controls. Ever use of HRT was associated with an OR of 0.9 (95% CI: 0.8-1.1) for glioma. For long-term use (≥10 years) we found ORs of 1.1 (95% CI: 0.7-1.7) for HRT overall, 1.6 (95% CI: 0.9-2.6) for oestrogen only, 0.8 (0.4-1.6) for combined oestrogen-progestagen, and 2.2 (0.9-5.5) for progestagen. Tests for trends were statistically non-significant in all strata. CONCLUSION Use of HRT overall was not associated with an increased risk of glioma. However, our findings indicate that prolonged use of oestrogen only or progestagen may be associated with an increased risk of glioma.

The risk of offspring developing substance use disorders when exposed to one versus two parent(s) with alcohol use disorder: A nationwide, register-based cohort study

AIM Few population-based, family studies have examined associations between exposure to one vs. two parent(s) with alcohol use disorder (AUD) and the risk of offspring developing substance use disorder (SUD). Moreover, these studies have focused solely on the development of AUD, and not SUD, in offspring. The purpose of this study was to investigate whether exposure to one vs. two parent(s) with AUD increases the risk of offspring developing SUD. METHODS A population-based, cohort study was conducted in which offspring born in Denmark between 1983 and 1989 were followed through national registries until 2011. Register-based data were obtained from the: Psychiatric Central Research Register, National Patient Registry, Civil Registration System, Fertility Database, and Cause of Death Register. Adjusted hazard ratios were calculated using multivariate Cox-regression models. FINDINGS A total of 398,881 offspring were included in this study. Of these, 3.9% had at least one parent with AUD. Parental AUD was significantly associated with the development of SUD in offspring. Having one parent with AUD was linked to a 1.44-fold increased risk (95% CL, 1.29-1.61), while having two parents with AUD was linked to a 2.29-fold increased risk (95% CI, 1.64-3.20). No significant differences were found in relation to either parental or offspring gender. CONCLUSIONS Exposure to parental AUD is linked to an increased risk of offspring developing SUD. This risk is additive for offspring exposed to double parental AUD. The findings have important implications for clinical assessment and intervention strategies, as well as the management of offspring exposed to parental AUD.

Hormonal contraceptive use and risk of glioma among younger women a nationwide case-control study

AIM Oral contraceptive use influences the risk for certain cancers. However, few studies have examined any link with risk of central nervous system tumours. We investigated the association between hormonal contraceptive use and glioma risk among premenopausal women in a population-based setting. METHODS Using national administrative and health registries in Denmark to conduct a nationwide case-control study, we identified all women ages 15 to 49 years with a first time diagnosis of histologically verified glioma between 2000 and 2009. Each case was age-matched to eight population controls using risk set sampling. Based on prescription data, exposure until 2 years prior to the index date was categorized according to hormonal contraceptive type, i.e. combined oestrogen-progestagen or progestagen only, and duration of use (<1, 1 to <5, ≥5 years). We used conditional logistic regression to compute odds ratios (ORs) with 95% confidence intervals (CIs) for glioma associated with hormonal contraceptive use, adjusting for potential confounders. RESULTS We identified 317 cases and 2126 controls. Ever use of hormonal contraceptive was associated with an OR of 1.5 (95% CI 1.2, 2.0) and the OR increased with duration of use (long term, ≥5 years: OR 1.9; 95% CI 1.2, 2.9). The association between long term hormonal contraceptive use and glioma risk was most pronounced for progestagen only therapy (OR 2.4; 95% CI 1.1, 5.1), especially when this regimen constituted the sole hormonal contraceptive therapy (OR 4.1; 95% CI 0.8, 20.8). CONCLUSION Long term hormonal contraceptive use may increase the risk of glioma.