Ågot Irgens

Reproductive outcome in offspring of parents occupationally exposed to lead in Norway

In Norway, great efforts have been made to protect both male and female employees against teratogenic exposures. Associations between occupational lead exposure and reproductive outcome in the offspring were studied. All births in Norway 1970-1993 with possible maternal or paternal occupational lead exposure were compared with a reference population of offspring of parents without occupational lead exposure. Offspring of lead exposed mothers had an increased risk of low birth weight (RR = 1.34; CI = 1.12-1.60) and neural tube defects (RR = 2.87; CI = 1.05-6.38). Effects on birth weight and gestational age showed significant dose-response associations. Offspring of lead exposed fathers had no increased risks of any of the analyzed reproductive outcomes. However, decreased risks were observed of low birth weight (RR = 0.91; CI = 0.86-0.96) and preterm birth (RR = 0.89; CI = 0.86-0.93). Further efforts seem to be needed to protect the offspring of lead-exposed mothers.

Occupational rhinitis: diagnostic criteria, relation to lower airway symptoms and IgE sensitization in bakery workers

Conclusions. The use of different diagnostic criteria has considerable consequences for the prevalence estimates of occupational rhinitis. There is a strong relationship between occupational rhinitis and lower airway symptoms. Storage mites appear to be important occupational allergens in Norwegian bakeries. Objectives. To study the consequences of various diagnostic criteria on the prevalence of occupational rhinitis, assess the prevalence of IgE sensitization and explore the relationships between upper and lower airway symptoms and between symptoms and IgE sensitization. Material and methods. A total of 197 employees in 6 bakeries were interviewed and completed a questionnaire. A skin prick test was performed, total and specific IgE were determined and a histamine release test was performed for relevant allergens. The criteria for the diagnosis of occupational rhinitis were based on the 1994 International Consensus Report on Rhinitis. Results. The prevalence of occupational rhinitis varied between 23% and 50%, depending on the criteria used. The occurrence of nasal symptoms was found to precede the development of lower airway symptoms. Occupational rhinitis, both IgE- and non-IgE-mediated, was associated with asthma symptoms. The most frequent causes of sensitization (20%) were different species of storage mites. Storage mite sensitization was related to occupational rhinitis and work exposure.

Birth defects and paternal occupational exposure. Hypotheses tested in a record linkage based dataset

Main question. To test previously established hypotheses on associations of birth defects with paternal occupation on the basis of a Norwegian registry material.

Male proportion in offspring of parents exposed to strong static and extremely low-frequency electromagnetic fields in Norway

Reduced male proportion in offspring of male carbon setters prompted a study into whether offspring of workers exposed to strong static and extremely low-frequency electromagnetic fields (ELF) had a deviant sex ratio. The study was based on all births in Norway 1970-1993. The reference population was offspring of parents not exposed to ELF. The male proportion in offspring of men in aluminum works was 50.38%, RR 0.98 (0.94-1.03), in manganese works 47.32%, RR 0.92 (0.83-1.02), in factories producing iron 50.03%, RR 0.97 (0.93-1.02), in nickel works 48.27%, RR 0.94 (0.84-1.05), and in electric wire production 47.20%, RR 0.92 (0.80-1.05). In the offspring of women in aluminum works, the male proportion was 37.04%, RR 0.72 (0.59-0.90), in all smelter works grouped together, 45.13%, RR 0.88 (0.79-0.99). The male proportion in the reference population was 51.42%. The male proportion in offspring of men in industries with ELF, was slightly reduced, while offspring of women was significantly reduced.

Reproducibility of transcutaneous oximetry and laser Doppler flowmetry in facial skin and gingival tissue

Laser Doppler flowmetry (LDF) and transcutaneous oximetry (TcPO(2)) are non-invasive techniques, widely used in the clinical setting, for assessing microvascular blood flow and tissue oxygen tension, e.g. recording vascular changes after radiotherapy and hyperbaric oxygen therapy. With standardized procedures and improved reproducibility, these methods might also be applicable in longitudinal studies. The aim of this study was to evaluate the reproducibility of facial skin and gingival LDF and facial skin TcPO(2). The subjects comprised ten healthy volunteers, 5 men, aged 31-68 years. Gingival perfusion was recorded with the LDF probe fixed to a custom made, tooth-supported acrylic splint. Skin perfusion was recorded on the cheek. TcPO(2) was recorded on the forehead and cheek and in the second intercostal space. The reproducibility of LDF measurements taken after vasodilation by heat provocation was greater than for basal flow in both facial skin and mandibular gingiva. Pronounced intraday variations were observed. Interweek reproducibility assessed by intraclass correlation coefficient ranged from 0.74 to 0.96 for LDF and from 0.44 to 0.75 for TcPO(2). The results confirm acceptable reproducibility of LDF and TcPO(2) in longitudinal studies in a vascular laboratory where subjects serve as their own controls. The use of thermoprobes is recommended. Repeat measurements should be taken at the same time of day.

Cerebral diffusion and perfusion deficits in North Sea divers

Background: Diving is associated with a risk of cerebral decompression illness, and the prevalence of neurological symptoms is higher in divers compared with control groups. Microvascular dysfunction due to gas microembolism and exposure to hyperoxia are possible mechanisms, which may result in cerebral diffusion and perfusion deficits. Purpose: To investigate if possible functional derangements of the microvasculature and microstructure would be more prevalent among symptomatic divers. Material and Methods: Magnetic resonance imaging (MRI) was performed in 91 former divers and 45 controls. Individual parametric images of apparent diffusion coefficient (ADC), cerebral blood flow (CBF), cerebral blood volume (CBV), and mean transit time (MTT) were generated on the basis of diffusion- and perfusion-weighted imaging. To identify regions with statistically significant differences between groups (P < 0.05, corrected for false discovery rate), voxel-wise ANCOVA analysis was performed for each of the four parametric images. Results: Significant regional group differences were found in all four parametric comparisons. Gross regional ADC differences were seen throughout the brain, including large frontal and temporal white-matter regions, the hippocampus, and parts of the cerebellum. Differences in the perfusion maps were localized in fewer and smaller clusters, including parts of the cerebellum, the putamen, and the anterior watershed regions. Conclusion: Regional functional abnormalities as measured by diffusion- and perfusion-weighted imaging were identified in the divers, and there was a partial co-localization of the regions identified in the perfusion and the diffusion images. The findings may explain some of the long-term clinical symptoms reported among professional divers.

Pregnancy Outcomes among Female Dental personnel-a registry-based Retrospective Cohort Study

OBJECTIVES The aim of this study was to investigate whether women who have worked as dental personnel in Norway, a group with possible previous exposure to mercury vapor, have had an excess risk of having children with congenital malformations or other adverse pregnancy outcomes compared to the general population. METHODS A cohort of female dental personnel was identified from the archives of the public dental healthcare and the national trade unions in Norway. Data on births and pregnancy outcomes during 1967-2006 were obtained from the Medical Birth Registry of Norway (MBRN). The final cohort of dental personnel consisted of 4482 dental assistants and 1011 dentists. All other women registered in the MBRN were assigned to the control group, in total 1,124,758. Excess risks of several adverse pregnancy outcomes for dental personnel compared to the general population were estimated. Analyses were conducted for the whole time period as well as stratified by 10-year periods. RESULTS Female dental personnel had no observed increased occurrence of congenital malformations (including malformations of the central nervous system, dysplasia of the hip, clubfoot, malformations of the heart and great vessels), low birth weight, preterm birth, small for gestational age, changed gender ratio, multiple birth, stillbirth, or prenatal death. CONCLUSION On a group level, we did not observe any excess risks of congenital malformations or other adverse pregnancy outcomes among female dental personnel in Norway during 1967-2006 compared to the general population.

Clinical characteristics of patients with drug hypersensitivity in Norway: a single‐centre study

Drug hypersensitivity reactions (DHRs) represent an important public health problem. Knowledge of their clinical characteristics will provide improved diagnostic approaches to this topic.

Self-reported skin and respiratory Symptoms related to Latex exposure among 5,087 hospital employees in Norway

Background: Latex allergy has become prevalent among health care workers. Objectives: To determine the prevalence of self-reported symptoms related to latex exposure among hospital personnel. Methods: Questionnaires addressing symptoms and risk factors for latex allergy were distributed to all employees (n = 5,087) at Haukeland University Hospital. Results: Symptoms associated with latex exposure were reported by 23.8% of the participants. Skin symptoms were most frequently reported – flushing/itching/hives: 21.0%, hand eczema: 11.8% – while systemic and respiratory symptoms were reported by 1.4 and 1.2%, respectively. Approximately twice as many women than men reported symptoms (odds ratio 2.55, confidence interval 2.04–3.18). Symptoms were reported by 33.7% of those with atopy and by 20.0% of those without. The occurrence of symptoms increased significantly with the frequency of use of latex gloves but was unrelated to age, years of exposure or number of surgical procedures. Conclusions: The occurrence of self-reported symptoms was associated with the frequent use of latex gloves, atopy and female gender.

Secular trends in sperm variables for groups of men in fertile and infertile couples

OBJECTIVE To assess possible secular trends in sperm variables in men according to previous or subsequent paternity. DESIGN A comparison of secular trends in sperm variables 1975-1994 in men under investigation for infertility in groups according to previous and subsequent paternity, based on data from the Medical Birth Registry of Norway. SETTING University hospital, Sperm laboratory and the Medical Birth Registry of Norway. MATERIAL Samples were obtained from: 1108 men who had fathered at least one child before the analysis. 1786 men who had at least one child after the analysis, and 2286 men with no children registered. MAIN OUTCOME MEASURES Sperm concentration, seminal fluid volume, total number of spermatozoa per ejaculate. RESULTS Analyzed by year of evaluation, men with no child registered had a significant secular decrease of sperm concentration, total number of sperms per ejaculate and seminal volume. The group with subsequent children had significant secular decrease of sperm concentration and total sperm count per ejaculate, while no significant changes were found for the group with previous children. Analyzed by year of birth, a significant decrease of sperm concentration and total sperm count was found for the group without and for the group with subsequent children. CONCLUSION The results are compatible with a cohort effect, exhibiting a trend of deteriorating sperm variables in consecutive birth cohorts.