Massey Research Online - Browsing by Author "McLean D"

Browsing by Author "McLean D"

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A longitudinal linkage study of occupation and ischaemic heart disease in the general and Māori populations of New Zealand
(PLOS, 21/01/2022) Barnes LA; Eng A; Corbin M; Denison HJ; 't Mannetje A; Haslett S; McLean D; Ellison-Loschmann L; Jackson R; Douwes J
OBJECTIVES: Occupation is a poorly characterised risk factor for cardiovascular disease (CVD) with females and indigenous populations under-represented in most research. This study assessed associations between occupation and ischaemic heart disease (IHD) in males and females of the general and Māori (indigenous people of NZ) populations of New Zealand (NZ). METHODS: Two surveys of the NZ adult population (NZ Workforce Survey (NZWS); 2004-2006; n = 3003) and of the Māori population (NZWS Māori; 2009-2010; n = 2107) with detailed occupational histories were linked with routinely collected health data and followed-up until December 2018. Cox regression was used to calculate hazard ratios (HR) for IHD and "ever-worked" in any of the nine major occupational groups or 17 industries. Analyses were controlled for age, deprivation and smoking, and stratified by sex and survey. RESULTS: 'Plant/machine operators and assemblers' and 'elementary occupations' were positively associated with IHD in female Māori (HR 2.2, 95%CI 1.2-4.1 and HR 2.0, 1.1-3.8, respectively) and among NZWS males who had been employed as 'plant/machine operators and assemblers' for 10+ years (HR 1.7, 1.2-2.8). Working in the 'manufacturing' industry was also associated with IHD in NZWS females (HR 1.9, 1.1-3.7), whilst inverse associations were observed for 'technicians and associate professionals' (HR 0.5, 0.3-0.8) in NZWS males. For 'clerks', a positive association was found for NZWS males (HR 1.8, 1.2-2.7), whilst an inverse association was observed for Māori females (HR 0.4, 0.2-0.8). CONCLUSION: Associations with IHD differed significantly across occupational groups and were not consistent across males and females or for Māori and the general population, even within the same occupational groups, suggesting that current knowledge regarding the association between occupation and IHD may not be generalisable across different population groups.
Airborne Fumigants and Residual Chemicals in Shipping Containers Arriving in New Zealand
(Oxford University Press on behalf of the British Occupational Hygiene Society, 2022-05) Hinz R; 't Mannetje A; Glass B; McLean D; Douwes J
BACKGROUND: Airborne fumigants and other hazardous chemicals inside unopened shipping containers may pose a risk to workers handling containers. METHODS: Grab air samples from 490 sealed containers arriving in New Zealand were analysed for fumigants and other hazardous chemicals. We also collected grab air samples of 46 containers immediately upon opening and measured the total concentration of volatile organic compounds in real-time during ventilation. Additive Mixture Values (AMV) were calculated using the New Zealand Workplace Exposure standard (WES) and ACGIH Threshold Limit Values (TLV) of the 8-h, time-weighted average (TWA) exposure limit. Regression analyses assessed associations with container characteristics. RESULTS: Fumigants were detectable in 11.4% of sealed containers, with ethylene oxide detected most frequently (4.7%), followed by methyl bromide (3.5%). Other chemicals, mainly formaldehyde, were detected more frequently (84.7%). Fumigants and other chemicals exceeded the WES/TLV in 6.7%/7.8%, and 7.8%/20.0% of all containers, respectively. Correspondingly, they more frequently exceeded '1' for the AMV-TLV compared to the AMV-WES (25.7% versus 7.8%). In samples taken upon opening of doors, fumigants were detected in both fumigated and non-fumigated containers, but detection frequencies and exceedances of the WES, TLV, and AMVs were generally higher in fumigated containers. Detection frequencies for other chemicals were similar in fumigated and non-fumigated containers, and only formaldehyde exceeded both the WES and TLV in both container groups. Volatile compounds in container air reduced rapidly during ventilation. Some cargo types (tyres; personal hygiene, beauty and medical products; stone and ceramics; metal and glass; and pet food) and countries of origin (China) were associated with elevated airborne chemical and fumigant concentrations. CONCLUSION: Airborne chemicals in sealed containers frequently exceed exposure limits, both in fumigated and non-fumigated containers, and may contribute to short-term peak exposures of workers unloading or inspecting containers.
Ischaemic Heart Disease and Occupational Exposures: A Longitudinal Linkage Study in the General and Māori Populations of New Zealand
(Oxford University Press on behalf of the British Occupational Hygiene Society, 2022-05) Barnes LA; Eng A; Corbin M; Denison HJ; 't Mannetje A; Haslett S; McLean D; Ellison-Loschmann L; Jackson R; Douwes J
OBJECTIVES: This study assessed associations between occupational exposures and ischaemic heart disease (IHD) for males and females in the general and Māori populations (indigenous people of New Zealand). METHODS: Two surveys of the general adult [New Zealand Workforce Survey (NZWS); 2004-2006; n = 3003] and Māori population (Māori NZWS; 2009-2010; n = 2107), with information on occupational exposures, were linked with administrative health data and followed-up until December 2018. Cox proportional hazards regression (adjusted for age, deprivation, and smoking) was used to assess associations between organizational factors, stress, and dust, chemical and physical exposures, and IHD. RESULTS: Dust [hazard ratio (HR) 1.6, 95%CI 1.1-2.4], smoke or fumes (HR 1.5, 1.0-2.3), and oils and solvents (HR 1.5, 1.0-2.3) were associated with IHD in NZWS males. A high frequency of awkward or tiring hand positions was associated with IHD in both males and females of the NZWS (HRs 1.8, 1.1-2.8 and 2.4, 1.1-5.0, respectively). Repetitive tasks and working at very high speed were associated with IHD among NZWS females (HRs 3.4, 1.1-10.4 and 2.6, 1.2-5.5, respectively). Māori NZWS females working with vibrating tools and those exposed to a high frequency of loud noise were more likely to experience IHD (HRs 2.3, 1.1-4.8 and 2.1, 1.0-4.4, respectively). Exposure to multiple dust and chemical factors was associated with IHD in the NZWS males, as was exposure to multiple physical factors in males and females of the NZWS. CONCLUSIONS: Exposures associated with an elevated IHD risk included dust, smoke or fumes, oils and solvents, awkward grip or hand movements, carrying out repetitive tasks, working at very high speed, loud noise, and working with tools that vibrate. Results were not consistently observed for males and females and between the general and Māori populations.
Neuropsychological symptoms in workers handling cargo from shipping containers and export logs
(Springer-Verlag GmbH, 2022-10) Hinz R; 't Mannetje A; Glass B; McLean D; Douwes J
PURPOSE: Acute poisonings of workers handling shipping containers by fumigants and other harmful chemicals off-gassed from cargo have been reported but (sub)-chronic neuropsychological effects have not been well studied. METHODS: This cross-sectional study assessed, using standardised questionnaires, current (past 3-months) neuropsychological symptoms in 274 container handlers, 38 retail workers, 35 fumigators, and 18 log workers, all potentially exposed to fumigants and off-gassed chemicals, and a reference group of 206 construction workers. Prevalence odds ratios (OR), adjusted for age, ethnicity, smoking, alcohol consumption, education, personality traits and BMI, were calculated to assess associations with the total number of symptoms (≥ 3, ≥ 5 or ≥ 10) and specific symptom domains (neurological, psychosomatic, mood, memory/concentration, fatigue, and sleep). RESULTS: Compared to the reference group, exposed workers were more likely to report ≥ 10 symptoms, statistically significant only for retail workers (OR 6.8, 95% CI 1.9-24.3) who also reported more fatigue (OR 10.7, 95% CI 2.7-42.7). Container handlers with the highest exposure-duration were more likely to report ≥ 10 symptoms, both when compared with reference workers (OR 4.0, 95% CI 1.4-11.7) and with container handlers with shorter exposure duration (OR 7.5, 95% CI 1.7-32.8). The duration of container handling was particularly associated with symptoms in the memory/concentration domain, again both when compared to reference workers (OR 8.8, 95% CI 2.5-31.4) and workers with the lowest exposure-duration (OR 6.8, 95% CI 1.5-30.3). CONCLUSION: Container handlers may have an increased risk of neuropsychological symptoms, especially in the memory/concentration domain. Retail workers may also be at risk, but this requires confirmation in a larger study.
OCCUPATIONAL EXPOSURE TO ELF-MF AND ELECTRIC SHOCKS AND MOTOR NEURONE DISEASE
(4/09/2016) Chen GX; McLean D; van den Berg L; 't Mannetje A; Pearce N; Kromhout H; D'Souza W; McConnell M; Douwes J
Occupational Exposures and Ischaemic Heart Disease: Results from The Entire New Zealand Population
(Swansea University, 7/12/2020) Eng A; Corbin M; Denison H; Barnes L; t'Mannetje A; McLean D; Laird I; Douwes J
Introduction Ischaemic Heart Disease (IHD) is a leading cause of death in Western countries. Common occupational exposures such as loud noise, long working hours, and sedentary work have been associated with increased IHD risks, but inconsistently. Objectives and Approach This study examines associations between incident IHD and exposure to long working hours, sedentary work, and loud noise. Individual-level microdata from Statistics New Zealand Integrated Data Infrastructure (IDI) were extracted for adults (age 20-64 years) with occupation recorded on the 2013 Census. The number of working hours was extracted from the Census, and exposure to sedentary work and loud noise was assessed through job exposure matrices (JEMs). IHD events (from 2013 to end of 2018) were identified using hospitalisations, prescriptions and deaths. Hazard ratios (HRs) were calculated using cox regression adjusted for age, socioeconomic status, and smoking. Results were stratified by sex and ethnicity. Results A total of 20,610 IHD cases were identified from 1,594,680 individuals employed at time of Census. Both short (<35) and long (55+) working hours were associated with an increased IHD risk in crude analyses, but effects disappeared after adjustment for age and socioeconomic status. For females, sedentary work (>90% of the time compared to <50%) was associated with a reduced risk (HR(Non-Māori)=0.86, 95%CI=0.75-0.99; HR(Māori)=0.71, 95%CI=0.44-1.14). For males, exposure to the highest noise category (>90dBA) compared to no exposure (<80dBA) was associated with elevated HRs without reaching statistical significance (HR(Non-Māori)=1.12, 95%CI=0.96-1.29; HR(Māori)=1.25, 95%CI=0.89-1.75). For females exposure to the 80-85dBA category compared to no exposure also showed elevated HRs (HR(Non-Māori)=1.14; 95%CI=1.04-1.26; HR(Māori)=1.16; 95%CI=0.93-1.46), but too few females were employed in jobs with the highest noise exposure. Conclusion These preliminary analyses do not support sedentary work or long working hours as IHD risk factors, but do suggest a modest increase in IHD risk associated with occupational exposure to noise.
Respiratory symptoms and use of dust-control measures in New Zealand construction workers - A cross-sectional study
(PLOS, 7/04/2022) Keer S; Brooks C; Glass B; McLean D; Harding E; Douwes J
Dust-exposed construction workers have an increased risk of respiratory symptoms, but the efficacy of dust-control measures remains unclear. This study compared respiratory symptoms, using a modified European Community Respiratory Health Survey questionnaire, between construction workers (n = 208) and a reference group of bus drivers and retail workers (n = 142). Within the construction workers, we assessed the effect of collective (on-tool vacuum/'wet-cut' systems) and personal (respirators) exposure controls on symptom prevalence. Logistic regression assessed differences between groups, adjusted for age, ethnicity, and smoking status. Construction workers were more likely to cough with phlegm at least once a week (OR 2.4, 95% CI 1.2-4.7) and cough with phlegm ≥3 months/year for ≥2 years (OR 2.8, CI 1.2-7.0), but they had similar or fewer asthma symptoms. Construction workers who had worked for 11-20 years reported more cough/phlegm symptoms (OR 5.1, 1.7-15.0 for cough with phlegm ≥3 months/year for ≥2 years) than those who had worked <10 years (OR 1.9, 0.6-5.8), when compared to the reference group. Those who used 'wet-cut' methods reported less cough with phlegm, although the evidence for this association was weak (OR 0.4, CI 0.2-1.1 for cough with phlegm at least once a week); use of on-tool extraction showed a similar trend. No associations between respiratory protective equipment-use and symptoms were found. In conclusion, construction workers reported more symptoms suggestive of bronchitis, particularly those employed in the industry for >10 years. Use of collective dust exposure controls might protect against these symptoms, but this requires confirmation in a larger study.
Serum biomarkers of neuroinflammation and blood-brain barrier leakage in amyotrophic lateral sclerosis
(BioMed Central Ltd, 2022-12) Cao MC; Cawston EE; Chen G; Brooks C; Douwes J; McLean D; Graham ES; Dragunow M; Scotter EL
Amyotrophic lateral sclerosis (ALS) is an incurable and rapidly progressive neurological disorder. Biomarkers are critical to understanding disease causation, monitoring disease progression and assessing the efficacy of treatments. However, robust peripheral biomarkers are yet to be identified. Neuroinflammation and breakdown of the blood-brain barrier (BBB) are common to familial and sporadic ALS and may produce a unique biomarker signature in peripheral blood. Using cytometric bead array (n = 15 participants per group (ALS or control)) and proteome profiling (n = 6 participants per group (ALS or control)), we assessed a total of 106 serum cytokines, growth factors, and BBB breakdown markers in the serum of control and ALS participants. Further, primary human brain pericytes, which maintain the BBB, were used as a biosensor of inflammation following pre-treatment with ALS serum. Principal components analysis of all proteome profile data showed no clustering of control or ALS sera, and no individual serum proteins met the threshold for statistical difference between ALS and controls (adjusted P values). However, the 20 most changed proteins between control and ALS sera showed a medium effect size (Cohen's d = 0.67) and cluster analysis of their levels together identified three sample subsets; control-only, mixed control-ALS, and ALS-only. These 20 proteins were predominantly pro-angiogenic and growth factors, including fractalkine, BDNF, EGF, PDGF, Dkk-1, MIF and angiopoietin-2. S100β, a protein highly concentrated in glial cells and therefore a marker of BBB leakage when found in blood, was unchanged in ALS serum, suggesting that serum protein profiles were reflective of peripheral rather than CNS biofluids. Finally, primary human brain pericytes remained proliferative and their secretome was unchanged by chronic exposure to ALS serum. Our exploratory study suggests that individual serum cytokine levels may not be robust biomarkers in small studies of ALS, but that larger studies using multiplexed analysis of pro-angiogenic and growth factors may identify a peripheral signature of ALS pathogenesis.
Sports and trauma as risk factors for Motor Neurone Disease: New Zealand case-control study
(John Wiley and Sons Ltd, 2022-06) Chen GX; Douwes J; van den Berg LH; Glass B; McLean D; 't Mannetje AM
OBJECTIVES: To assess whether sports, physical trauma and emotional trauma are associated with motor neurone disease (MND) in a New Zealand case-control study (2013-2016). METHODS: In total, 321 MND cases and 605 population controls were interviewed collecting information on lifetime histories of playing sports, physical trauma (head injury with concussion, spine injury) and emotional trauma (14 categories). ORs were estimated using logistic regression adjusting for age, sex, ethnicity, socioeconomic status, education, smoking status, alcohol consumption and mutually adjusting for all other exposures. RESULTS: Head injury with concussion ≥3 years before diagnosis was associated with MND (OR 1.51, 95% CI: 1.09-2.09), with strongest associations for two (OR 4.01, 95% CI: 1.82-8.86), and three or more (OR 2.34, 95% CI: 1.00-5.45) head injuries. Spine injury was not associated with MND (OR 0.81, 95% CI: 0.48-1.36). Compared to never playing sports, engaging in sports throughout childhood and adulthood increased MND risk (OR 1.81, 95% CI: 1.01-3.25), as was more than 12 years playing football/soccer (OR 2.35, 95% CI: 1.19-4.65). Reporting emotionally traumatic events in more than three categories was associated with MND (OR 1.88, 95% CI: 1.17-3.03), with physical childhood abuse the only specific emotional trauma associated with MND (OR 1.82, 95% CI: 1.14-2.90), particularly for those reporting longer abuse duration (OR(5-8 years) 2.26, 95% CI: 1.14-4.49; OR(>8 years) 3.01, 95% CI: 1.18-7.70). For females, having witnessed another person being killed, seriously injured or assaulted also increased MND risk (OR 2.68, 95% CI: 1.06-6.76). CONCLUSIONS: This study adds to the evidence that repeated head injury with concussion, playing sports in general, and playing football (soccer) in particular, are associated with an increased risk of MND. Emotional trauma, that is physical abuse in childhood, may also play a role.
Wood Dust in Joineries and Furniture Manufacturing: An Exposure Determinant and Intervention Study.
(1/05/2017) Douwes J; Cheung K; Prezant B; Sharp M; Corbin M; McLean D; 't Mannetje A; Schlunssen V; Sigsgaard T; Kromhout H; LaMontagne AD; Pearce N; McGlothlin JD
OBJECTIVES: To assess wood dust exposures and determinants in joineries and furniture manufacturing and to evaluate the efficacy of specific interventions on dust emissions under laboratory conditions. Also, in a subsequent follow-up study in a small sample of joinery workshops, we aimed to develop, implement, and evaluate a cost-effective and practicable intervention to reduce dust exposures. METHODS: Personal inhalable dust (n = 201) was measured in 99 workers from 10 joineries and 3 furniture-making factories. To assess exposure determinants, full-shift video exposure monitoring (VEM) was conducted in 19 workers and task-based VEM in 32 workers (in 7 joineries and 3 furniture factories). We assessed the efficacy of vacuum extraction on hand tools and the use of vacuum cleaners instead of sweeping and dry wiping under laboratory conditions. These measures were subsequently implemented in three joinery workshops with 'high' (>4 mg m-3) and one with 'low' (<2 mg m-3) baseline exposures. We also included two control workshops (one 'low' and one 'high' exposure workshop) in which no interventions were implemented. Exposures were measured 4 months prior and 4 months following the intervention. RESULTS: Average (geometric means) exposures in joinery and furniture making were 2.5 mg m-3 [geometric standard deviations (GSD) 2.5] and 0.6 mg m-3 (GSD 2.3), respectively. In joinery workers cleaning was associated with a 3.0-fold higher (P < 0.001) dust concentration compared to low exposure tasks (e.g. gluing), while the use of hand tools showed 3.0- to 11.0-fold higher (P < 0.001) exposures. In furniture makers, we found a 5.4-fold higher exposure (P < 0.001) with using a table/circular saw. Laboratory efficiency experiments showed a 10-fold decrease in exposure (P < 0.001) when using a vacuum cleaner. Vacuum extraction on hand tools combined with a downdraft table reduced exposures by 42.5% for routing (P < 0.1) and 85.5% for orbital sanding (P < 0.001). Following intervention measures in joineries, a borderline statistically significant (P < 0.10) reduction in exposure of 30% was found in workshops with 'high' baseline exposures, but no reduction was shown in the workshop with 'low' baseline exposures. CONCLUSIONS: Wood dust exposure is high in joinery workers and (to a lesser extent) furniture makers with frequent use of hand tools and cleaning being key drivers of exposure. Vacuum extraction on hand tools and alternative cleaning methods reduced workplace exposures substantially, but may be insufficient to achieve compliance with current occupational exposure limits.

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