To Örebro University

BACKGROUND: Chronic kidney disease (CKD) is a growing health issue that is becoming more prevalent globally, increasing financial cost on healthcare systems. The purpose of this study is to investigate the incidence of eye diseases in patients diagnosed with CKD in Sweden and to evaluate which eye diseases are most likely to develop.

METHODS: A longitudinal population-based retrospective case-control study was conducted including all individuals diagnosed with chronic kidney disease during the time period 2001-2019. A total of 19 455 cases and 38 890 controls were included. For each case, two controls were matched with the same sex, age, and county of residence.

RESULTS: CKD patients had a significantly higher risk of contracting any eye disease compared to individuals without kidney disease HR 1.73 (CI 1.67-1.79), with an elevated risk for all blocks of diagnoses except for glaucoma HR 0.95 (CI 0.85-1.06). However, this condition developed earlier in cases than in controls. Subanalyses showed an increased risk for chronic eye disease patients to develop cataract HR 1.70 (CI 1.63-1.78), other retinal disorders HR 1.86 (CI 1.72-2.02), and retinal vascular occlusions HR 2.08 (CI 1.73-2.51). In general, diagnosis of an eye disease occurred earlier in cases than controls.

CONCLUSIONS: The results from this study suggest that CKD patients have an increased risk to develop eye disease. Ocular disease seems to develop considerably earlier in CKD, even without staging the severity of the disease, with particularly high risk of developing retinal diseases and cataracts. Screening for eye disease in CKD should be considered.

Trichloramine is a disinfection by-product in chlorinated swimming pools. It can evaporate into the air and irritate eyes and airways among swimmers and pool workers. This study aimed to evaluate airborne concentrations of trichloramine in different types of indoor swimming pools. Altogether, 72 swimming pools across Sweden were included; 36 exercise pools, 16 instruction pools, seven adventure pools, and 13 rehabilitation pools. In total, 167 sampling sessions were performed with the majority (N = 91) conducted in public exercise pools. Repeated sampling sessions on different days were performed within all pool categories. Airborne trichloramine was measured stationary by the poolside using active sampling on quartz filters. In total, 434 air samples were collected. The geometric mean (GM) concentration of trichloramine for the exercise pools was 0.12 mg/m3 (range GMpool: 0.02-0.29 mg/m3) and for about 30% the GMpool exceeded the Swedish public health guideline value (0.2 mg/m3). The geometric mean for instruction pools was 0.18 mg/m3 and for adventure pools 0.20 mg/m3. Trichloramine concentrations were statistically significantly lower in rehabilitation pools (GM: 0.03 mg/m3) compared with the other pool categories. A statistically significant effect of time of the day for sampling was found for the exercise and instruction pools, with higher trichloramine levels during evenings compared with mornings and afternoons. For the rehabilitation pools, trichloramine was significantly higher during the cold season compared with the warm season. Variability in trichloramine concentrations was attributed to between-pool as well as within-pool variances. The within-pool variability encourages a repeated sampling strategy to capture the variation between different days. These findings have implications for exposure assessment in epidemiological studies as well as for indoor air quality monitoring. Trichloramine can cause acute irritative effects at elevated levels, and since trichloramine concentrations may differ depending on the time of the day it is recommended that full-day stationary measurements are supplemented with short-term samplings to capture these variations.

INTRODUCTION: Disinfection by-products are produced in water disinfected with chlorine-based products. One such group is trihalomethanes, and chloroform is the most abundant trihalomethane in swimming pool areas. Chloroform can be absorbed by inhalation, ingestion, and dermal absorption, and is classified as possibly carcinogenic.

AIM: To investigate if chloroform concentrations in air and water affect the chloroform concentration in urine samples of exposed swimming pool workers. METHODS: Workers from 5 adventure indoor swimming pools carried personal chloroform air samplers and provided up to 4 urine samples during one workday. Chloroform concentrations were analyzed with a linear mixed model analysis to investigate a possible correlation between air and urine concentrations.

RESULTS: The geometric mean chloroform concentration was 11 μg/m3 in air and 0.009 µg/g creatinine in urine among individuals with ≤2 h at work, 0.023 µg/g creatinine among those with >2-5 working hours, and 0.026 µg/g creatinine in the group with >5-10 working hours. A risk of higher levels of chloroform in urine was associated with longer hours at work (≤2 h versus >5-10 h, odds ratio [OR] 2.04, 95% confidence interval [CI] 1.25-3.34), personal chloroform concentrations in air (≤17.00 µg/m3 versus >28.00 µg/m3, OR 9.23, 95% CI 3.68-23.13) and working at least half the working day near the swimming pools (OR 3.16, 95% CI 1.33-7.55). Executing work tasks in the swimming pool water was not associated with higher chloroform concentrations in urine compared to only working on land (OR 0.82, 95% CI 0.27-2.45).

CONCLUSION: There is an accumulation of chloroform concentrations in urine during a workday and a correlation between personal air and urine concentrations of chloroform among workers in Swedish indoor swimming pools.

Indoor swimming pool facilities often use chlorine for pool water disinfection. Chlorine can also contribute to the formation of unwanted disinfection byproducts (DBPs). Trichloramine and trihalomethanes (THMs) are DBPs formed in swimming pool water and swimming pool air causing occupational exposure. Trichloramine can cause ocular and airway irritation, while some THMs are potentially carcinogenic. Bacterial endotoxins may also cause adverse respiratory effects among swimming pool workers. 

The overall aim of the study was to measure levels of trichloramine, THMs and endotoxins in the air at conventional, habilitation and rehabilitation, and adventure swimming pool facilities, and to investigate adverse ocular and respiratory effects among indoor swimming pool workers.

Trichloramine and THM levels in air were comparable to previous studies. Endotoxin levels in air were low compared to the reference value. Trichloramine concentrations in personal samples were approximately half as high as those measured in stationary samples - an important consideration for a future Swedish occupational exposure limit. The adventure facilities had the highest trichloramine levels while the conventional facilities had the highest THM levels. The adventure workers also reported more ocular and respiratory symptoms compared to referents (office workers) and had a lower FEV1/FVC ratio indicating airway obstruction. Workers both in conventional, and in habilitation and rehabilitation facilities exhibited a difference in FeNO levels compared to referents, implying airway inflammation.

The occupational exposure and adverse health effects found in indoor swimming pool environments emphasizes the importance of a personal based Swedish occupational exposure limit for trichloramine in air.

Objectives: This study aimed to investigate whether introducing a digital risk assessment tool, the Swedish National Vibration Database, would increase the number of risk assessments on hand-arm and whole-body vibration. Employer and safety representatives from companies where vibration exposure is common were invited.

Methods: Of the 2953 invited companies, 1916 were selected for educational intervention and the remaining 1037 companies served as a control group with no intervention. For the educational intervention, participating companies were further divided into two groups (group A, n = 26; group B, n = 47) that both received information regarding risk assessment, but group B was also informed about the digital tool. Both groups answered a questionnaire on risk assessment before the intervention and at the follow-up, 6 months later; the control group received the same questionnaire but no education (group C, n = 22).

Results: Of the invited companies, only 2% chose to participate and 7% at follow-up. Seventy-eight percent of the participants had made some kind of risk assessment of vibration at follow-up.

Conclusion: Due to the low participation rate among invited companies, this study is not able to draw any conclusions on whether the digital tool can be used to increase the number of risk assessments.

OBJECTIVE: To study occupational exposure to trichloramine and endotoxins in air at adventure and rehabilitation swimming pool facilities from an adverse health effects perspective.

METHODS: Air concentrations of trichloramine and endotoxins were measured in five adventure and 10 rehabilitation facilities. Respiratory and ocular symptoms were self-reported, and spirometry and fraction of exhaled nitric oxide (FENO) were measured.

RESULTS: Compared to rehabilitation facilities, the mean trichloramine concentrations in the adventure facilities were higher, both personal (80 μg/m3 (n = 41) vs 19 μg/m3 (n = 21)) and stationary (183 μg/m3 (n = 51) vs 23 μg/m3 (n = 32)), with higher frequency of ocular and respiratory symptoms. Low stationary endotoxin levels (<0.64 to 25 EU/m3) were found, compared to the reference value (90 EU/m3).

CONCLUSIONS: Higher trichloramine concentrations in air and more ocular and respiratory symptoms in adventure facilities call for adequate occupational exposure limits.

Personnel in swimming pool facilities typically experience ocular, nasal, and respiratory symptoms due to water chlorination and consequent exposure to disinfection by-products in the air. The aim of the study was to investigate exposure to trichloramine and trihalomethanes (chloroform, bromodichloromethane, dibromochloromethane, and bromoform) from the perspective of adverse health effects on the personnel at Swedish habilitation and rehabilitation swimming pools. The study included ten habilitation and rehabilitation swimming pool facilities in nine Swedish cities. The study population comprised 24 exposed swimming pool workers and 50 unexposed office workers. Personal and stationary measurements of trichloramine and trihalomethanes in air were performed at all the facilities. Questionnaires were distributed to exposed workers and referents. Spirometry, fraction of exhaled nitric oxide (FE_NO) and peak expiratory flow (PEF) were measured. Personal and stationary measurements yielded trichloramine levels of 1-76 µg/m³ (average: 19 µg/m³) and 1-140 µg/m³ (average: 23 µg/m³), respectively. A slightly higher, but not significant, prevalence of reported eye- and throat-related symptoms occurred among the exposed workers than among the referents. A significantly increased risk of at least one ocular symptom was attributed to trichloramine exposure above the median (20 µg/m³). Lung function (FVC and FEV1) was in the normal range according to the Swedish reference materials, and no significant change in lung function before and after shift could be established between the groups. Average FE_NO values were in the normal range in both groups, but the difference in the values between the exposed workers and referents showed a significant increase after shift. Hourly registered PEF values during the day of the investigation did not show any unusual individual variability. In conclusion, the increased risk of developing at least one ocular symptom at personal trichloramine concentrations over 20 µg/m³ combined with an increase in the difference in FE_NO during the work shift of the exposed workers should not be neglected as an increased risk of respiratory inflammation in the habilitation and rehabilitation swimming pool environment.

Occupational exposure in swimming pool facilities related to disinfection by-products (DBPs) has been an issue for the last 15 years. Trichloramine (NCl3) and trihalomethanes (THMs) are DBPs formed in swimming pool water following a reaction between organic matter containing nitrogen or organic or inorganic matter, and chlorine. Due to its volatility, trichloramine can easily evaporate into the air and cause nausea and irritation of the eyes and upper airways. Symptoms are likely to be particularly pronounced in those suffering from asthma. Chloroform is the dominant THM in swimming pool atmospheres and is classified by the International Agency for Research on Cancer (IARC) as being possibly carcinogenic to humans. There are no adverse health effects reported among swimming pool employees due to occupational exposure levels of THMs found in the air at swimming pools.

There is no OEL for trichloramine adapted in Sweden, but some reference values and recommendations based on stationary measurements at the pool side are available. In 2006, the World Health Organisation (WHO) recommended a reference value for trichloramine of 500 μg/m3. The Swedish OEL for chloroform is 10 000 μg/m3.

This thesis describes research into the occupational exposure to airborne trichloramine and THMs in eight Swedish indoor swimming pool facilities and the investigation into the prevalence of adverse health effects, manifesting primarily as ocular and respiratory symptoms.

Concentrations of trichloramine and chloroform in Swedish indoor swimming pool facilities were found to be in the same range or lower compared to previous studies in other countries. The trichloramine concentrations varied between <1 and 240 μg/m3 for the personal sampling and between <1 and 640 μg/m3 for the stationary sampling. Personal trichloramine levels in the high-exposure group were more than 60% higher compared to the corresponding stationary measurements. The exposed group had a higher frequency of self-reported ocular and nasal symptoms compared to the controls. A significant difference in the concentration of exhaled FENO over a work shift with an increase in the exposed group, indicated acute airway inflammation due to respiratory irritant agent exposure. Although a dose-response effect could not be established, the results indicate an elevated risk of occupational health problems in indoor swimming pools and calls for an OEL to be established, based on personal sampling.