Ambient and at-the-ear occupational noise exposure and serum lipid levels.

OBJECTIVES: Occupational and residential noise exposure has been related to increased risk of cardiovascular disease. Alteration of serum lipid levels has been proposed as a possible causal pathway. The objective of this study was to investigate the relation between ambient and at-the-ear occupational noise exposure and serum levels of total cholesterol, low-density lipoprotein-cholesterol, high-density lipoprotein-cholesterol, and triglycerides when accounting for well-established predictors of lipid levels. METHODS: This cross-sectional study included 424 industrial workers and 84 financial workers to obtain contrast in noise exposure levels. They provided a serum sample and wore portable dosimeters that every 5-s recorded ambient noise exposure levels during a 24-h period. We extracted measurements obtained during work and calculated the full-shift mean ambient noise level. For 331 workers who kept a diary on the use of a hearing protection device (HPD), we subtracted 10 dB from every noise recording obtained during HPD use and estimated the mean full-shift noise exposure level at the ear. RESULTS: Mean ambient noise level was 79.9 dB (A) [range 55.0-98.9] and the mean estimated level at the ear 77.8 dB (A) [range 55.0-94.2]. Ambient and at-the-ear noise levels were strongly associated with increasing levels of triglycerides, cholesterol-HDL ratio, and decreasing levels of HDL-cholesterol, but only in unadjusted analyses that did not account for HPD use and other risk factors. CONCLUSION: No associations between ambient or at-the-ear occupational noise exposure and serum lipid levels were observed. This indicates that a causal pathway between occupational and residential noise exposure and cardiovascular disease does not include alteration of lipid levels.

Morphological diversity of Paramoeba perurans trophozoites and their interaction with Atlantic salmon, Salmo salar L., gills.

Amoebic gill disease (AGD) caused by the ectoparasite Paramoeba perurans affects several cultured marine fish species worldwide. In this study, the morphology and ultrastructure of P. perurans in vitro and in vivo was investigated using scanning and transmission electron microscopy (SEM and TEM, respectively). Amoebae cultures contained several different morphologies ranging from a distinct rounded cell structure and polymorphic cells with pseudopodia of different lengths and shapes. SEM studies of the gills of AGD-affected Atlantic salmon, Salmo salar L., revealed the presence of enlarged swellings in affected gill filaments and fusion of adjacent lamellae. Spherical amoebae appeared to embed within the epithelium, and subsequently leave hemispherical indentations with visible fenestrations in the basolateral surface following their departure. These fenestrated structures corresponded to the presence of pseudopodia which could be seen by TEM to penetrate into the epithelium. The membrane-membrane interface contained an amorphous and slightly fibrous matrix. This suggests the existence of cellular glycocalyces and a role for extracellular products in mediating pathological changes in amoebic gill disease.

Prenatal maternal stress and atopic diseases in the child: a systematic review of observational human studies.

BACKGROUND: A growing number of studies suggest that maternal stress during pregnancy promotes atopic disorders in the offspring. This is the first systematic review to address prenatal maternal stress (PNMS) and the subsequent risk of atopy-related outcomes in the child. METHODS: The review was performed in accordance to the PRISMA criteria. We searched and selected studies in PubMed, Scopus, Embase and PsychINFO until November 2014. RESULTS: Sixteen (with 25 analyses) of 426 identified articles met the review criteria. Five main PNMS exposures (negative life events, anxiety/depression, bereavement, distress and job strain) and five main atopic outcomes (asthma, wheeze, atopic dermatitis, allergic rhinitis and IgE) were assessed across the studies. Overall, 21 of the 25 analyses suggested a positive association between PNMS and atopic outcomes. Of the 11 exposure-response analyses reported, six found statistically significant trends. CONCLUSION: This systematic review suggests a relationship between maternal stress during pregnancy and atopic disorders in the child. However, the existing studies are of diverse quality. The wide definitions of often self-reported stress exposures imply a substantial risk for information bias and false-positive results. Research comparing objective and subjective measures of PNMS exposure as well as objective measures for atopic outcome is needed.

Individual and work-unit measures of psychological demands and decision latitude and the use of antihypertensive medication.

PURPOSE: To analyse whether psychological demands and decision latitude measured on individual and work-unit level were related to prescription of antihypertensive medication. METHODS: A total of 3,421 women and 897 men within 388 small work units completed a questionnaire concerning psychological working conditions according to the job strain model. Mean levels of psychological demands and decision latitude were computed for each work unit to obtain exposure measures that were less influenced by reporting bias. Dispensed antihypertensive medication prescriptions were identified in The Danish National Prescription Registry. Odds ratios (OR) comparing the highest and lowest third of the population at individual and work-unit level, respectively, were estimated by multilevel logistic regression adjusted for confounders. Psychological demands and decision latitude were tested for interaction. Supplementary analyses of 21 months follow-up were conducted. RESULTS: Among women, increasing psychological demands at individual (adjusted OR 1.54; 95 % CI 1.02-2.33) and work-unit level (adjusted OR 1.41; 95 % CI 1.04-1.90) was significantly associated with purchase of antihypertensive medication. No significant association was found for decision latitude. Follow-up results supported an association with psychological demands but they were not significant. All results for men showed no association. Psychological demands and decision latitude did not interact. CONCLUSION: High psychological work demands were associated with the purchase of prescribed antihypertensive medication among women. This effect was present on both the work-unit and the individual level. Among men there were no associations. The lack of interaction between psychological demands and decision latitude did not support the job strain model.

The norepinephrine transporter gene is a candidate gene for panic disorder.

Panic disorder (PD) is an anxiety disorder characterized by recurrent panic attacks with a lifetime prevalence of 4.7%. Genetic factors are known to contribute to the development of the disorder. Several lines of evidence point towards a major role of the norepinephrine system in the pathogenesis of PD. The SLC6A2 gene is located on chromosome 16q12.2 and encodes the norepinephrine transporter (NET), responsible for the reuptake of norepinephrine into presynaptic nerve terminals. The aim of the present study was to analyze genetic variants located within the NET gene for association with PD. The case-control sample consisted of 449 patients with PD and 279 ethnically matched controls. All cases fulfilled the ICD-10 diagnostic criteria for PD. Genotyping was performed using the Sequenom platform (Sequenom, Inc, San Diego, USA). To test for allelic and haplotypic association, the PLINK software was used, and COMBASSOC was applied to test for gene-wise association. After quality control 29 single nucleotide polymorphisms (SNPs) spanning the gene-region were successfully analyzed. Seven SNPs located within the 5' end of the gene were significantly associated with PD. Furthermore, the NET gene showed overall evidence for association with the disease (P = 0.000035). In conclusion, the present study indicates that NET could be a susceptibility gene for PD.

Surveillance of noise exposure in the Danish workplace: a baseline survey.

AIMS: To evaluate an epidemiological approach to a national noise hazard surveillance strategy, and report current exposure levels in the Danish workplace. METHODS: A study base of 840 companies in 10 selected high risk industries in the largest county in Denmark was identified from a national register. Noise exposure was measured among manual workers recruited from a random sample of workplaces in each industry. For reference, financial companies and a sample of residents were investigated according to the same protocol. The A-weighted equivalent sound level (L(Aeq)) for a full shift was measured by portable dosimeters worn by 830 workers employed at 91 workplaces (67% of 136 eligible companies). RESULTS: The epidemiological design proved feasible and established a baseline for future noise surveillance. Substantial resources were needed to motivate workplaces to enlist and the final participation rate was less than optimal (66.9%). The L(Aeq (8)) values in the selected industries were highly elevated (mean 83.7 dB(A) (95% CI 83.3 to 84.1) in comparison with residents and office workers (mean 69.9 dB(A), 95% CI 68.8 to 71.0). Some 50% of the workers were exposed to more than 85 dB(A) and some 20% to more than 90 dB(A) in several industries. CONCLUSION: Noise levels in Danish high risk industries remain high. A substantial proportion of workers are exposed to noise levels above the current threshold limit of 85 dB(A). Ongoing surveillance of noise exposure using full shift dosimetry of workers in random samples of workplaces most at risk to high noise levels may help reinforce preventive measures. Such a programme would benefit from compulsory workplace participation.

Medical risk factors for small-bowel adenocarcinoma with focus on Crohn disease: a European population-based case-control study.

BACKGROUND: Crohn disease and biliary diseases have been associated with small-bowel adenocarcinoma (SBA). We examined how medical conditions affect the risk of SBA. METHODS: A population-based European multicentre case-control study during the period 1995-97 including 95 histologically verified cases of SBA along with 3335 population controls; 70 cases (74%) and 2070 (62%) controls were interviewed about previous medical conditions. RESULTS: Crohn disease was identified in two SBA cases (both located in ileum) and two controls; odds ratio (OR) 53.6 (6.0-477) (95% CI in parentheses). Only one case and no controls had had long-standing Crohn disease. Coeliac disease was associated with SBA (2 cases, 0 controls), but one of the cases was diagnosed at the same time as the SBA. Overall, people with a history of gallstones had no increased risk of SBA. The OR was exclusively increased during the 3-year period preceding the SBA diagnosis. Previous gallstone surgery, which may be a sign of severe gallstone disease, was not associated with SBA. Liver cirrhosis, hepatitis or medical treatments with radioactive substances or corticosteroid tablets were not associated with this disease. Cases with SBA had an increased prevalence of anaemia; OR 15.3 (2.5-92.1). An association between low educational level and SBA was found; OR 1.75 (1.0-3.0). CONCLUSION: This study supports Crohn disease and coeliac disease being strong but rare risk factors for SBA. Previous gallstones were unrelated to SBA, and detection bias may account for the findings in earlier studies.

[Audiometric surveillance of occupational environment]. / Audiometrisk overvågning i arbejdsmiljøet.

Noise levels in Danish workplaces at which hearing impairment will occur in more than 10% of the workers are still frequent. Annually 300 cases are compensated for noise induced hearing loss at a national level. This may indicate that the current national hearing protection strategy, which relies on noise reduction only, is insufficient. By audiometric screening early hearing loss will be detected and further progression may be halted. This paper reviews the methods of continuous audiometric screening of noise exposed worker populations. Reliability and validity are discussed, and an overview of quality assurance programmes is given. It is concluded that a national hearing conservation program should be implemented in Denmark.

Is there an association between alcohol intake or smoking and small bowel adenocarcinoma? Results from a European multi-center case-control study.

OBJECTIVE: To discover whether tobacco smoking and intake of different types of alcoholic drinks are associated with small bowel adenocarcinoma (SBA). METHODS: A population-based European multi-center case-control study was conducted from 1995 to 1997. RESULTS: After a histological review using uniform diagnostic criteria, 47 (33%) of the 142 identified cases of SBA were excluded due to reclassification as either tumors of the papilla of Vater (n = 22), stromal tumors, or metastases; 95 cases were accepted for study. In all, 70 cases of SBA together with 2070 controls matched by age, sex, and region were interviewed. A high intake (more than 24 g alcohol per day) of beer or spirits was associated with SBA, an odds ratio (OR) of 3.5 and 95% confidence intervals (CI) of 1.5-8.0 and 3.4 (95% CI 1.3-9.2), respectively). There was no association with wine intake or total alcohol intake. Tobacco smoking was probably unrelated to SBA. CONCLUSIONS: A high intake of beer or spirits seems to be a risk factor for SBA. Since this association was not seen for wine drinkers, protective components of wine may counterbalance a carcinogenic effect of alcohol on the small bowel. Alternatively, the result may be confounded by other factors, e.g. dietary factors.

Occupation and small bowel adenocarcinoma: a European case-control study.

OBJECTIVES: Because of the rarity of small bowel adenocarcinoma (SBA), little is known about the aetiology of this disease. This study aimed to identify occupational clustering of cases SBA as a systematic approach to new hypotheses on the aetiology of this disease. METHODS: A European multicentre case-control study was conducted in 1995-7, inclusive. Incident cases aged 35-69 years with SBA (n=168) were recruited before acceptance by a pathologist. Altogether 107 cases and 3915 controls were accepted, of which 79 cases, 579 colon cancer controls, and 2070 population controls were interviewed. RESULTS: The strongest industrial risk factors for SBA taking account of 10 years' exposure lag were dry cleaning, manufacture of workwear, mixed farming (women), and manufacture of motor vehicles (men). A significantly increased risk of SBA (odds ratio (OR) and 95% confidence interval (95% CI)) was found among men employed as building caretakers, OR 6.7 (1.7 to 26.0) and women employed as housekeepers, OR 2.2 (1.1 to 4.9); general farm labourers, OR 4.7 (1.8 to 12.2); dockers, OR 2.9 (1.0 to 8.2); dry cleaners or launderers, OR 4.1 (1.2 to 13.6); and textile workers (sewers or embroiderers), OR 2.6 (1.0 to 6.8). For the last four groups, together with welders OR 2.7 (1.1 to 6.6) (men) an exposure-response pattern was found when calculating the ORs for jobs held 1-5 years and >5 years, with never having held the job as reference. The ORs (95% CIs) for 1-5 years and >5 years were 4.3 (0.4 to 44.0) and 3.5 (0.9 to 13.7), 3.0 (0.3 to 26.2) and 4.3 (0.9 to 21.2), 4.6 (0.4 to 48.1) and 11.0 (2.0 to 60.4), 1.3 (0.2 to 11.0) and 5.8 (2.0 to 17.2), and 2.8 (0.3 to 23.8) and 4.6 (1.3 to 16.6), respectively, for each of these occupations. Among welders, people performing semiautomatic arc welding (MIG/MAG) were identified as a high risk group (OR 5.0 (1.3 to 19.6)). CONCLUSIONS: This explorative study suggests an increased occurrence of SBA in certain occupations, which needs further evaluation.

[Stress and fertility. A follow-up study among couples planning the first pregnancy]. / Stress og frugtbarhed. En forløbsundersøgelse blandt par, som forsøger at blive gravide for første gang.

Mental distress has often been suggested as a cause of unexplained infertility. However, the causal direction may well be from infertility to distress, and prospective data are needed. We therefore followed 393 couples, who were planning their first pregnancy, with prospective collection of information on distress from termination of birth control until pregnancy for a maximum of six menstrual cycles. The analyses included 1,475 menstrual cycles, and mental distress was measured in each cycle by the General Health Questionnaire (GHQ). Urine samples from each period of vaginal bleeding were analyzed for human chorionic gonadotrophic hormone, indicating early embryonal loss. We found that for cycles with the highest distress score (GHQ score above the 80 percentile) the probability of conception per cycle was 12.8% compared to 16.5% in other cycles (adjusted OR 0.6; 95% CI 0.4-1.0). The effect of distress was almost exclusively found among women with long menstrual cycles (OR 0.1; 95% CI 0.01-0.4 and OR 0.9; 0.5-1.4 for women with cycles > or = 35 and < 35 days, respectively). An increased incidence of early embryonal loss was also found among highly distressed women with long cycles, but was based on a small number of observations. It is concluded that psychological distress may be a risk factor for reduced fertility in women with long menstrual cycles.

Time to pregnancy among male workers of the reinforced plastics industry in Denmark, Italy and The Netherlands. ASCLEPIOS.

OBJECTIVES: The relationship between occupational styrene exposure and male fecundity was examined. METHODS: Among 1560 Danish, Italian, and Dutch reinforced plastics workers, 220 styrene-exposed workers and 382 unexposed referents who had fathered a child were identified. A total of 768 historical styrene measurements conducted in 1970-1996 in the study companies formed the basis for semiquantitative exposure assessment in combination with measurements of urinary styrene metabolite levels. All the subjects were interviewed about work conditions and other factors potentially related to reduced fecundity. Fecundity was measured as the reported time to pregnancy (number of months a couple needed to conceive their youngest child). RESULTS: A statistically nonsignificantly reduced fecundity was observed for the styrene-exposed workers [fecundity ratio 0.79, 95% confidence interval (95% CI) 0.59-1.05]. But no consistent pattern of a detrimental effect on fecundity was found when time to pregnancy was related to worktasks indicating higher styrene exposure levels or semiquantitative or quantitative measures of styrene exposure. The workers with high exposure showed a fecundity ratio of 1.09 (95% CI 0.69-1.72). CONCLUSIONS: It is unlikely that styrene exposure has a strong effect on male fecundity.

Male-mediated spontaneous abortion among spouses of stainless steel welders.

OBJECTIVES: Male-mediated spontaneous abortion has never been documented for humans. The welding of stainless steel is associated with the pulmonary absorption of hexavalent chromium, which has genotoxic effects on germ cells in rodents. Clinical and early subclinical spontaneous abortions were examined among spouses of stainless-steel welders. METHODS: A cohort of first-pregnancy planners was recruited from members of the union of metal workers and 3 other trade unions. The cohort was followed for 6 menstrual cycles from the cessation of contraceptive use. Altogether, 280 pregnancies were conceived, of which 35 were detected by human chorionic gonadotrophic hormone analysis and did not survive to a clinically recognized pregnancy. Information on exposure was collected prospectively in relation to the outcome and was available for all cycles resulting in a pregnancy. Information on pregnancy outcome was collected for all 245 clinically recognized pregnancies. RESULTS: Increased risk of spontaneous abortion was found for pregnancies with exposure to paternal stainless-steel welding (adjusted relative risk 3.5, 95% confidence interval 1.3-9.1). The results were consistent in analyses of both biochemically and clinically recognized abortions. There was no increased risk for spontaneous abortion in pregnancies with paternal exposure to the welding of metals other than stainless steel. CONCLUSIONS: Male welding of stainless steel was associated with an increased risk of spontaneous abortion in spouses. A mutagenic effect of hexavalent chromium has been found previously in both somatic and germ cells, and the findings could be due to mutations in the male genome.

Spontaneous abortion and physical strain around implantation: a follow-up study of first-pregnancy planners.

Existing studies of physical strain and spontaneous abortion are mainly retrospective or based only on pregnancies that have survived the first trimester. Furthermore, almost all studies have relied on averaged measures of physical strain, which tend to blur an effect if peak values during short time periods are the relevant measure. We followed a cohort of first pregnancy planners from termination of birth control until pregnancy for a maximum of six menstrual cycles. The analyses include 181 pregnancies, of which 32 were subclinical pregnancies detected by hCG analysis only. During early pregnancy the women recorded physical strain prospectively in a structured diary. Physical strain around the time of implantation was associated with later spontaneous abortion. The adjusted risk ratio for women who reported physical strain higher than average at day 6 to 9 after the estimated date of ovulation was 2.5 (95% CI = 1.3-4.6).

Sperm chromatin damage impairs human fertility. The Danish First Pregnancy Planner Study Team.

OBJECTIVE: To examine the relationship between sperm chromatin defects, evaluated by the flow cytometric (FCM) sperm chromatin structure assay (SCSA), and the probability of a pregnancy in a menstrual cycle (fecundability). DESIGN: Follow-up study. SETTING: The Section of Toxicology and Biomedical Sciences, ENEA Casaccia, Rome, Italy, and the Department of Occupational Medicine, Aarhus University Hospital, Aarhus, Denmark. PATIENT(S): Two hundred fifteen Danish first pregnancy planners with no previous knowledge of their fertility capability. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Semen samples were collected at enrollment to measure semen volume, sperm concentration, motility, and morphology (by microscopy), as well as chromatin susceptibility to in situ, acid-induced partial denaturation by the FCM SCSA. Time to pregnancy was evaluated during a 2-year follow-up period. Demographic, medical, reproductive, occupational, and lifestyle data were collected by questionnaire. Fecundability was correlated with SCSA-derived parameters. RESULT(S): Fecundability declines as a function of the percentage of sperm with abnormal chromatin and becomes small when aberrant cells are >40%. CONCLUSION(S): Optimal sperm chromatin packaging seems necessary for full expression of the male fertility potential. The SCSA emerged as a predictor of the probability to conceive in this population-based study.