The Prolonged Effect of Shift Work and the Impact of Reducing the Number of Nightshifts on Arterial Stiffness-A 4-Year Follow-Up Study.

AIM: To assess changes in blood pressure (BP) and arterial stiffness among 84 rotating shift and 25 dayworkers (control subjects) at two industrial plants during a 4-year follow-up, and to assess changes in outcome variables among shift workers at the two plants after a reduction in the number of night shifts during the last year of follow-up in one of the plants. METHODS: We collected demographic data using a questionnaire, examined systolic and diastolic blood pressure (sBP, dBP), central systolic and diastolic aorta pressure (cSP, cDP), augmentation pressure (AP), central pulse pressure (cPP), and pulse wave velocity (PWV). We registered sleep quality. The last 4-14 months of follow-up one plant implemented a 12-week shift plan reducing the total number of night shifts and consecutive night shifts from 16.8 to 14 and from 7.2 to 4. To assess differences in change of outcomes between study groups we applied linear mixed models. RESULTS: The dayworkers were older, more hypertensive, reported less sleep disturbance, and smoked/snuffed less than the shift workers did. The adjusted annual increase in PWV was 0.34 m/s (95%CI, 0.22, 0.46) among shift workers and 0.09 m/s (95%CI, -0.05, 0.23) in dayworkers, yielding a significant difference of change of 0.25 m/s (95%CI, 0.06, 0.43). No significant differences were found between the two groups of shift workers in any cardiovascular disease (CVD) outcome during the last year of follow-up. CONCLUSIONS: Shift work in industry is associated with arterial stiffness, reflecting an increased risk of future CVD. No significant changes in arterial stiffness were identified as a consequence of a small reduction in the number of night shifts and consecutive night shifts.

Influence of Shift Work on Arterial Stiffness and Systemic Inflammation: A 3-Year Follow-up Study in Industry.

OBJECTIVE: To assess changes in cardiovascular disease risk factors during a 3-year follow-up among 57 rotating shift workers and 29 day workers in industry. METHODS: We collected demographics by questionnaire, examined blood pressure, heart rate, pulse wave velocity, carotid media thickness, and maximal oxygen uptake. We assessed blood samples for determination of lipids, glycosylated hemoglobin, C-reactive protein, markers of inflammation, and particle concentrations/respirable dust. Baseline comparisons were analyzed using logistic regression (plaque) and linear regression for all other outcomes. We applied mixed models to assess differences in change in health outcomes between the shift workers and the day workers. RESULTS: At baseline, the adhesion molecules soluble vascular cell adhesion molecule 1 and soluble P-selectin were elevated among the shift workers compared with that of the day workers. There was a significant difference in change in pulse wave velocity between shift workers (1.29-m/s increase) and day workers (0.11-m/s increase) over the 3-year follow-up. Respirable dust levels were below the Norwegian occupational exposure limit. CONCLUSIONS: Shift work in industry is associated with arterial stiffening reflecting increased risk for future cardiovascular disease. More uncertainly, we found some support for systemic inflammation.

The COVID-19 Pandemic Decreases Cardiorespiratory Fitness: A 3-Year Follow-Up Study in Industry.

BACKGROUND: We aimed to determine if maximal oxygen uptake (V˙O2max), resting heart rate (RHR), and self-reported leisure- time moderate to vigorous physical activity (MVPA) changed over a 3-year follow-up (FU) among industrial workers. METHODS: We assessed cardiorespiratory fitness (CRF) August 2018 and August 2021. The last 17-18 months coincided with the COVID-19 pandemic. Data from 86 participants were collected; demographics by questionnaire and cardiovascular outcomes from medical examination: V˙O2max, RHR, and fat mass (%). Workers reported on their leisure-time MVPA twice. To assess changes in health outcomes we applied a linear mixed model, adjusting for baseline (BL) age, sex, pack-years, shift work, and a 5-month plant shutdown. Further, we adjusted for actual age instead of BL age. RESULTS: V˙O2max decreased from 39.6 mL/kg/min at BL to 34.0 at FU, a reduction of 5.6 mL/kg/min (95%CI, -7.6, -3.7). Adjusted for actual age, the corresponding figure for V˙O2max was 5.4 mL/kg/min, (95%CI, -7.4, -3.4), an annual loss of 4.6%. RHR increased from 61.3 to 64.4 beats per minute (95%CI, 0.8, 5.4). Self-reported MVPA decreased by 43.9 min/week, (95%CI, -73.5, -14.4). CONCLUSIONS: We observed a decrease in V˙O2max, an increase in RHR and a decrease in self-reported MVPA, suggesting physical inactivity during the COVID-19 pandemic.

A Cease in Shift Work Reverses Arterial Stiffness but Increases Weight and Glycosylated Hemoglobin A 5-Month Follow-Up in Industry.

BACKGROUND: Literature suggests an association between shift work and cardiovascular disease (CVD). Limited evidence is available on how a cessation of shift work affects CVD risk factors. AIM: We investigated whether a five-month plant shutdown affected CVD risk factors in 30 industrial shift workers. METHODS: We collected demographic data, self-reported data on physical activity (PA) and medical history by questionnaire. Pre- and post-plant shutdown, we measured blood pressure (BP), heart rate, lipids, glycosylated hemoglobin (HbA1c) and C-reactive protein (CRP). Additionally, we collected markers of inflammation, Matrix metalloproteinase-9 (MMP-9), Interleukin-6 (IL-6), Monocyte chemoattractant protein-1 (MCP-1), Tumor necrosis factor-alpha (TNF-α), P-selectin, Interleukin-1 beta (IL-1ß), and Interleukin-23 (IL-23). We also examined arterial stiffness (central blood pressure, augmentation pressure, and pulse wave velocity) by means of SphygmoCor® (AtCor Medical Pty Ltd., Sydney, Australia). We monitored sleep by actigraphy prior to and after plant shutdown, with additional registration of sleep quality and assessment of insomnia symptoms. RESULTS: After five months of plant shutdown, we found that HbA1c increased by 1.9 mmol/mol, weight by 1 kg and MCP-1 by 27.3 pg/mL, all unexpectedly. The other markers of inflammation did not change during shutdown, but CRP decreased close to significant levels. There were no changes in lipids during follow-up. Pulse-wave velocity (PWV) was reduced from 8.1 m/s (SD = 1.5) to 7.6 m/s (SD = 1.5), p = 0.03. The workers reported fewer signs of insomnia after shutdown. CONCLUSIONS: Our findings suggest that a five-month cessation in shift work increases weight and HbA1c, but also improves insomnia symptoms and reverses arterial stiffening.

Sleep Duration, Number of Awakenings and Arterial Stiffness in Industrial Shift Workers: A Five-Week Follow-Up Study.

Shift work may increase the risk for hypertension and arterial stiffness, potentially a consequence of disturbed sleep. The aim of this study was to investigate possible correlations between sleep length and spontaneous awakenings with selected cardiovascular risk factors in shift workers at an industrial plant. We examined 19 shift workers by means of blood pressure and arterial stiffness, measured as pulse wave velocity (PWV), prior to and after a 5-week shift period. Sleep patterns were monitored on a daily basis with the assistance of a smartphone-based sleep diary (the entire test period) and by actigraphy (limited to 2 weeks). The number of awakenings and total sleep time were calculated. Shorter sleep duration was associated with higher blood pressure and partly with higher PWV, indicating an increased risk of cardiovascular disease (CVD) with reduced sleep duration. Unexpectedly, a lower number of awakenings was associated with an increase in blood pressure, indicating a reduced risk of CVD. No other significant associations were determined. The results from the present study among shift workers in Norway could support the hypothesis that short sleep duration is associated with elevated blood pressure and arterial stiffness.

Safety incidents associated with extended working hours. A systematic review and meta-analysis.

OBJECTIVE: We performed a systematic review to assess potential consequences of extended working hours on accidents, near-accidents, safety incidents and injuries (incidents) by considering the overall certainty of evidence. METHODS: We searched five databases systematically (Medline, Embase, PsycINFO, Web of Science, and Proquest Health and safety Science Abstract) and identified 10072 studies published until December 2020. Twenty-two studies met the inclusion criteria. We followed a systematic approach to evaluate risk of bias and synthesize results in a meta-analysis. The certainty of evidence was determined by a modified version of The Grading of Recommendations Assessment, Development and Evaluation (GRADE). RESULTS: Our analyses indicated an association between working >12 hours/day (RR: 1.24, 95%CI: 1.11, 1.40), or working >55 hours/week (RR: 1.24, 95%CI: 0.98, 1.57), and elevated risk of incidents. The certainty of evidence evaluated as low. Weak or no associations were observed for other exposure contrasts: working >8 hours/day (RR: 0.93, 95%CI: 0.72, 1.19), or working overtime (RR: 1.08, 95%CI: 0.75, 1.55), working 41-48 hours/week (RR: 1.02, 95%CI: 0.92, 1.13) or 49-54 hours/week (RR: 1.02, 95%CI: 0.97, 1.07). The certainty of evidence was evaluated as low (very low for 41-48 hours/week). CONCLUSIONS: Daily working hours >12 hours and weekly working hours exceeding 55 hours was associated and increased risk of incidents. The level of evidence was low. Hence, further high-quality research is warranted to elucidate these associations.

Psychometric properties and validation of the Brief NORSCI safety perceptions and climate inventory in the Norwegian waste management industry.

A valid, standardized tool for assessing workplace safety can help organizations and employers to detect potential safety risks. This is crucial to improve safety and protect employees and production against accidents and injuries. As no such tool has so far been developed for the waste management industry, this study aimed to establish the psychometric properties and the concurrent validity of the 11-item Brief Norwegian Safety Climate Inventory (Brief NORSCI). A cross-sectional questionnaire study was conducted with 543 workers from the formal Norwegian waste management industry. Exploratory and confirmatory factor analyses showed that the Brief NORSCI exhibited good psychometric properties. Replicating previous validation studies of the inventory, the findings suggested a three-factor structure reflecting Individual intention and motivation, Management's prioritization of safety, and Safety routines. The three first-order factors of the inventory could be combined in a composite second-order safety climate factor. Both the overall composite score and the three subscales correlated in the expected directions with measures of job characteristics (i.e., job demands and resources), leadership, social climate, and severe accidents, thus indicating high concurrent validity. This study supported the validity and reliability of the Brief NORSCI as an assessment tool to measure both individual safety perceptions and group level safety climate among waste management workers. The findings suggest that application of the Brief NORSCI as a safety assessment tool may contribute to the development of a stronger safety profile among organizations and companies in waste management.

High-Intensity Training Reduces CVD Risk Factors among Rotating Shift Workers: An Eight-Week Intervention in Industry.

Rotating shift work is associated with risk factors for cardiovascular disease (CVD). We have studied the effect of 17 min high-intensity training three times a week over eight weeks on CVD risk factors among shift workers. Sixty-five shift workers from two plants were recruited. They were all deemed healthy at the initial health screening and in 100% work. From plant A, 42 workers, and plant B, 23 workers participated. After the intervention, 56 workers were retested. The intervention group consisted of 19 participants from plant A who had participated in at least 10 sessions. Twenty workers from plant B and 17 workers from plant A that not had taken part in the training were included in the control group. All workers reported physical activity (PA) by questionnaires before and after the training intervention. We measured blood pressure, heart rate, lipids, glycated hemoglobin (HbA1c), and C-reactive protein (CRP) and arterial stiffness. Maximal oxygen uptake (V̇O2max) was assessed by bicycle ergometry. The intervention group favorably differed significantly from the control group in improvement of systolic and diastolic blood pressure and glycated hemoglobin (HbA1c). Short training sessions with 4 min of high-intensity PA, three times a week, for eight weeks among rotating shift workers reduced some CVD risk factors. PA interventions in occupational settings may thus decrease coronary heart disease and stroke incidences in this vulnerable group of workers.

Cardiovascular Health Effects of Shift Work with Long Working Hours and Night Shifts: Study Protocol for a Three-Year Prospective Follow-Up Study on Industrial Workers.

There is a plausible association between shift work and cardiovascular disease (CVD), which may be due to disruption of the circadian rhythm causing hormonal changes and metabolic disturbances, resulting in high blood pressure, atherosclerosis, diabetes, and being overweight. However, few studies have investigated the association between several consecutive long work shifts, including night shifts, and risk factors for developing CVD. Moreover, knowledge is lacking on factors that may modify or enhance this suggested relationship. The study period is planned from the third quarter of 2018 to the fourth quarter of 2021, and will involve 125 industrial employees at two Norwegian enterprises producing insulation. The work schedule is either rotating shiftwork (morning, evening, night) or regular day work. At baseline, we will measure blood parameters, including markers of inflammation, lipids, and glycosylated hemoglobin. We will also collect measures of blood pressure, resting heart rate, arterial stiffness, carotid intima-media thickness, and aerobic fitness. At the end of baseline data collection, a subgroup will undergo a supervised high-intensity interval training intervention for eight weeks, initiated by the Occupational Health Service. At one-year follow-up, we repeat baseline measures with added measures of heart rate variability and additional five weeks monitoring of sleep and physical activity, and assessment of respirable dust. At the two year follow-up, we will measure CVD risk factors before and after a planned three-month shutdown in one of the studied plants. We will also assess respirable dust, monitor sleep, and compile a one-year retrospective detailed overview of working hours. A final data collection, similar to the one at baseline, will be carried out after three years. We will use a comprehensive set of methods to identify the effects of shift work with long working hours and night shifts on cardiovascular health. This will provide new knowledge on the association between early manifestations of CVD and occupational exposure to shift work. Further, we can study whether work organization such as extensive overtime, sleep loss, and dust exposure have detrimental effects, and if a three-month cease in shift work or increased physical activity will modify early manifestations of CVD.

Shift Work Including Night Work and Long Working Hours in Industrial Plants Increases the Risk of Atherosclerosis.

There is an abundance of literature reporting an association between shift work and cardiovascular disease (CVD). Few studies have examined early manifestation of CVD using advanced modern methodology. We established a group of 65 shift workers and 29 day workers (controls) in two industrial plants. For the shift workers, the shift schedule includes rotating shifts with day, evening and nightshifts, some day and nightshifts lasting for 12 h. The current paper describes cross-sectional data in a study running for three years. We collected background data by questionnaire and measured blood pressure, heart rate, lipids, glycosylated hemoglobin (HbA1c) and C-reactive protein (CRP). We examined arterial stiffness (central blood pressure, augmentation pressure and index, and pulse wave velocity) by the use of SphygmoCor® (AtCor Medical Pty Ltd, Sydney, Australia) and the carotid arteries by ultrasound. We assessed VO2max by bicycle ergometry. We applied linear and logistic regression to evaluate associations between total number of years in shift work and cardiovascular outcome measures. The day workers were older and had more pronounced arterial stiffness compared to the shift workers. Number of years as a shift worker was associated with increased carotid intima media thickness (max IMT) (B = 0.015, p = 0.009) and an elevated CRP (B = 0.06, p = 0.03). Within the normal range for this age group, VO2max was 41 (9) ml/kg/min. Rotating shift work including day and night shifts lasting up to 12 h and evening shifts are associated with CVD-risk factors. This could imply an increased risk for coronary heart disease and stroke among these workers. Therefore, preventive measures should be considered for these groups of workers in order to prevent such diseases.

Interaction of smoking with respiratory effects of occupational dust exposure: a prospective population study among Norwegian men.

Dust at work is associated with risk of respiratory symptoms, the population attributable fraction is 19, and smoking is an effect modifier http://ow.ly/w0RF30jUL2Z.

Pneumoproteins and markers of inflammation and platelet activation in the blood of grain dust exposed workers.

PURPOSE: To investigate if blood biomarkers could indicate early signs of lung damage or cardiovascular risk due to exposure to grain dust. MATERIALS AND METHODS: Pneumoproteins and markers of inflammation and platelet activation were analysed in blood samples of 102 grain elevator and compound feed mill workers. Differences between exposed (n = 67) and controls (n = 35), and associations with exposure measurements and respiratory health were investigated by multiple linear regression analyses. RESULTS: Concentrations of CC-16 and IL-6 were higher in exposed workers compared with controls (p < 0.001 for both), whereas fibrinogen was lower (p = 0.005). Concentrations of CRP, TNF-α, sCD40L and sP-selectin were similar in both groups. Serum CC-16 was significantly higher in workers with farm childhood, regardless of exposure. The impact of farm childhood on CC-16 interacted with smoking. None of the biomarkers were associated with exposure measurements or any of the tested respiratory health parameters. CONCLUSION: Dust exposure induced inflammatory and anti-inflammatory reactions, but did not induce systemic inflammation and had no effect on platelet activation. No cause-effect relationship could be established in spite of relatively high exposure levels, particularly to endotoxin. Whether increased serum CC-16 is an early sign of lung damage or a reversible defense reaction remains unclear.

The Effect of a Leisure Time Physical Activity Intervention Delivered via a Workplace: 15-Month Follow-Up Study.

In line with recommendations from both the World Health Organization and the European Union some employers encourage workplace health promotion through physical activity (PA) facilities and leisure time PA-initiatives. The current study describes a 15-month follow-up after an 8-week workplace delivered PA-initiative, investigates if improvements in cardiovascular risk status are sustainable, and elucidates differences according to educational level. One hundred and twenty one employees (43 women) were examined before and after the 8-week PA-initiative and 94 at the 15-month follow-up. PA-levels, blood pressure, resting heart rate, lipids, glycosylated hemoglobin (HbA1c), C-reactive protein (CRP), and selected markers of inflammation were registered at baseline, immediately after the 8-week PA-initiative, and 15 months after baseline. At the end of follow-up (15-month), PA-levels-increased during the 8-week intervention-had returned to baseline values. None of the five improvements in cardiovascular markers (total cholesterol, low density lipoprotein (LDL), P-selectin, CD40Ligand (CD40L) and Monocyte chemoattractant protein-1 (MCP-1)) seen at the 8-week follow-up were sustained. At the 15-month follow-up as compared to baseline HbA1c, CRP (log) and interleukin-6 (IL-6) were reduced by 0.06 mmol/L (95% CI -0.11,-0.01), 0.25 mg/L (95% CI -0.46,-0.04) and 0.39 pg/mL (95% CI -0.75, -0.04), respectively. At baseline, there were differences in cardiovascular risk factors comparing men with low versus high levels of education. No differences in changes in outcomes between these groups of men were found during follow-up. In this study highly educated men generally have lower levels of cardiovascular risk factors, but the effect of PA on such markers in this group do not differ from the effects seen in less educated men.

Physical activity initiated by employer induces improvements in a novel set of biomarkers of inflammation: an 8-week follow-up study.

PURPOSE: We investigated the level of pro- and anti-inflammatory biomarkers before and after 8 weeks of unsupervised physical activity (PA) initiated by employer. METHODS: During autumn 2014, background data, blood samples and self-reported exercise level were collected from 76 men and 41 women in a Norwegian road maintenance company. Monocyte chemoattractant protein-1 (MCP-1), tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), leptin, adiponectin, p-selectin and CD40 ligand (CD40L) were analyzed. [Formula: see text] was measured in a subgroup of 50 subjects. RESULTS: With reference point of exercise ≤1 time/week, we found that participants who exercised 2-3 times/week had higher [Formula: see text] values (5.6 mL kg-1 min-1; 95% CI [1.3, 9.9]). MCP-1 was lower in those who exercised ≥ 4 times/week (-81.98 pg/ml [-142.9, -21.0]). IL-6 and p-selectin levels were lower in females who exercised ≥4 times/week (-1.04 pg/ml [-2.04, -0.03] and -13.75 ng/ml [-24.03, -3.48]). Leptin was lower in participants who exercised 2-3 times/week (-0.39 µg/ml ln [-0.68, -0.09]) and ≥4 times/week (-0.69 µg/ml ln [-1.10, -0.28]). During follow-up, [Formula: see text] increased (2.9 mL kg-1 min-1 [1.5, 4.3]), while p-selectin and CD40L decreased (-2.33 ng/ml [-3.78, -0.87] and 718.14 ng/ml [-1368, -68]). MCP-1 levels decreased among men (-32.70 pg/ml [-51.21, -14.19]). A joint analysis of all biomarkers (inversed adiponectin) showed that those who exercised ≥4 times/week at baseline had lower total levels of biomarkers and that total biomarker levels decreased during follow-up. CONCLUSIONS: Exercising several times a week was associated with less inflammation compared to exercising once a week or less. During the 8-week follow-up, total levels of biomarkers of inflammation improved.

Noise-induced hearing loss in a longitudinal study of Norwegian railway workers.

OBJECTIVE: The aim of this study was to analyse longitudinal data to assess the risk of noise-induced hearing loss (NIHL) in Norwegian railway workers. DESIGN: Longitudinal. SETTING: A major Norwegian railway company. METHODS: We examined data from the first and last audiograms for the period 1991-2014, from 9640 railway workers with varying occupational noise exposure and with an average observation period of 10 years. The course of hearing acuity in seven groups of railway workers (train drivers, conductors, bus drivers, traffic controllers, train maintenance workers, track maintenance workers and others) were compared with each other and with ISO standards (ISO 1999). RESULTS: The change in hearing threshold during the observation period was 2-3 dB in the 0.5-4 kHz range and 6-7 dB in the 3-6 kHz range adjusted for age and sex, for all occupational groups, which is slightly less than expected (8 dB) according to ISO 1999. CONCLUSIONS: The risk of NIHL in Norwegian railway workers during the period 1991-2014 has been negligible.

Cross-shift study of exposure-response relationships between bioaerosol exposure and respiratory effects in the Norwegian grain and animal feed production industry.

OBJECTIVE: We have studied cross-shift respiratory responses of several individual bioaerosol components of the dust in the grain and feed industry in Norway. METHODS: Cross-shift changes in lung function and nasal congestion, as well as in respiratory and systemic symptoms of 56 exposed workers and 36 referents, were recorded on the same day as full-shift exposure to the inhalable aerosol fraction was assessed. Exposure-response associations were investigated by regression analysis. RESULTS: The workers were exposed on average to 1.0 mg/m(3) of grain dust, 440 EU/m(3) of endotoxin, 6 µg/m(3) of ß-1,3-glucans, 17×10(4)/m(3) of bacteria and 4×10(4)/m(3) of fungal spores during work. The exposure was associated with higher prevalence of self-reported eye and airway symptoms, which were related to the individual microbial components in a complex manner. Fatigue and nose symptoms were strongest associated with fungal spores, cough with or without phlegm was associated with grain dust and fungal spores equally strong and wheeze/tight chest/dyspnoea was strongest associated with grain dust. Bioaerosol exposure did not lead to cross-shift lung function decline, but several microbial components had influence on nose congestion. CONCLUSIONS: Exposure to fungal spores and dust showed stronger associations with respiratory symptoms and fatigue than endotoxin exposure. The associations with dust suggest that there are other components in dust than the ones studied that induce these effects.

Physical activity initiated by employer and its health effects; an eight week follow-up study.

BACKGROUND: While the health benefits of physical activity are well established, little is known about health effects of physical activity programs initiated by employer. METHODS: Background data and level of physical activity were collected by questionnaire among 78 men and 43 women working in road maintenance pre and post an 8-week physical activity motivational program. As a part of the program steps measured by accelerometer were registered online where team and individual performances could be continuously monitored. The physical activity levels were registered as 1) those physical active ≤1 time per week, 2) 2-3 times per week and 3) ≥4 times a week. Maximal oxygen uptake (VO2max), blood pressure, resting heart rate (RHR) and blood samples (glycosylated hemoglobin, lipids and C-reactive protein) were obtained at baseline and after eight weeks. Mixed models were applied to evaluate associations between physical activity and health parameters. RESULTS: With ≤1 time per week as reference, exercising 2-3 times per week at baseline was associated with higher levels of VO2max. During follow-up, VO2max increased with 2.8 mL ∙ kg(-1)∙ min(-1) (95 % CI = 1.4, 4.3). Women had more favorable body mass index (BMI), blood pressure, RHR and lipid profile than men. Total cholesterol, low density lipoprotein (LDL), RHR and diastolic blood pressure (dBP) were lower among participants who exercised 2-3 times per week or ≥4 times a week, compared with those with ≤1 time per week. Half of the participants reported increased daily PA during follow-up, with high intensity PA such as jogging by 8.6 min (SD 14.6) and 8.3 min (SD 18.2), among women and men, respectively. During follow-up dBP increased among men. Further, total cholesterol and LDL were reduced by 0.12 mmol/L and 0.13 mmol/L, respectively (95 % CI = -022, -0.01 and -0.22,-0.04). CONCLUSIONS: Exercise several times a week was associated with lower blood pressure and a favorable lipid status compared to lower weekly activity. During the 8-week follow-up of an employer initiated exercise program VO2max increased, while total cholesterol and LDL were reduced. TRIAL REGISTRATION: Current Controlled Trials ISRCTN13033050 . Registered 21 August 2015.

Thoracic dust exposure is associated with lung function decline in cement production workers.

We hypothesised that exposure to workplace aerosols may lead to lung function impairment among cement production workers.Our study included 4966 workers in 24 cement production plants. Based on 6111 thoracic aerosol samples and information from questionnaires we estimated arithmetic mean exposure levels by plant and job type. Dynamic lung volumes were assessed by repeated spirometry testing during a mean follow-up time of 3.5 years (range 0.7-4.6 years). The outcomes considered were yearly change of dynamic lung volumes divided by the standing height squared or percentage of predicted values. Statistical modelling was performed using mixed model regression. Individual exposure was classified into quintile levels limited at 0.09, 0.89, 1.56, 2.25, 3.36, and 14.6 mg·m(-3), using the lowest quintile as the reference. Employees that worked in administration were included as a second comparison group.Exposure was associated with a reduction in forced expiratory volume in 1 s (FEV1), forced expiratory volume in 6 s and forced vital capacity. For FEV1 % predicted a yearly excess decline of 0.84 percentage points was found in the highest exposure quintile compared with the lowest.Exposure at the higher levels found in this study may lead to a decline in dynamic lung volumes. Exposure reduction is therefore warranted.