Obstructive Lung Disease Linked to Occupational Exposures in Malawian Tobacco Farmers.

Nicotine and pesticide exposure in agricultural settings have been linked to the development of chronic respiratory disease in workers. However, this has not been extensively studied in Africa. The aim of this study was therefore to determine the prevalence of obstructive lung disease and its relationship to concurrent nicotine and pesticide exposure among small-scale tobacco farmers in Malawi. For this purpose, sociodemographic characteristics, occupational and environmental exposures were evaluated in relation to work-related respiratory symptoms and lung function impairment. A cross-sectional study was conducted enrolling 279 workers in flue-cured tobacco farms in Zomba, Malawi. The study instruments used for assessing the health outcomes were a standardised European Community Respiratory Health Survey II (ECRHS) questionnaire and Spirometry testing. The questionnaires were aimed at collecting relevant data on sociodemographic factors and self-reported respiratory health outcomes. Data were also collected on potential pesticide and nicotine exposures. Spirometry was done to evaluate objective respiratory impairment in accordance with American Thoracic Society guidelines. The mean age of participants was 38 years with 68% being male. The prevalence of work-related ocular nasal symptoms, chronic bronchitis, and work-related chest symptoms was 20%, 17%, and 29%, respectively. Airflow limitation (FEV1/FVC <70%) was found in 8% of workers. Self-reported exposure to pesticides varied from 72%- to 83%, whilst the prevalence of recent green tobacco sickness was 26%. Tasks linked to nicotine exposure, such as sowing (OR: 2.5; CI 1.1-5.7) and harvesting (OR: 2.6; CI 1.4-5.1), were significantly associated with work-related chest symptoms. Pesticide application (OR:1.96; CI 1.0-3.7) was associated with an increased risk of work-related oculonasal symptoms. Duration of pesticide exposure was also associated with obstructive impairment FEV1/FVC

Occupational risk factors and exposure-response relationships for airway disease among health workers exposed to cleaning agents in tertiary hospitals.

OBJECTIVES: This study investigated occupational risk factors and exposure-response relationships for airway disease among health workers (HWs) exposed to cleaning agents in two tertiary hospitals in South Africa and Tanzania. METHODS: In this cross-sectional study, 697 participants completed questionnaire interviews while 654 underwent fractional exhaled nitric oxide (FeNO) testing. Asthma Symptom Score (ASS) was computed based on the sum of answers to five questions on asthma-related symptoms in the past 12 months. For exposure-response analyses, cleaning agent-related self-reported exposure variables were categorised into three levels (cleaning product not used; use of a cleaning product for up to 99 min per week and use of a cleaning product for ≥100 min per week). RESULTS: Asthma-related outcomes (ASS and FeNO) demonstrated positive associations with medical instrument cleaning agents (orthophthalaldehyde and enzymatic cleaners) and tasks (instruments precleaning and changing sterilisation solutions) as well as patient care activities (disinfection prior to procedures and disinfecting wounds). A particularly pronounced dose-response relationship was observed between work-related ocular-nasal symptoms and medical instrument cleaning agents (orthophthalaldehyde, glutaraldehyde, enzymatic cleaners, alcohols and bleach) (OR range: 2.37-4.56) and tasks (OR range: 2.92-4.44). A strong association was also observed between ASS and use of sprays for fixed surface cleaning (mean ratio 2.81; 95% CI 1.41 to 5.59). CONCLUSIONS: Specific agents for medical instrument disinfection for example, orthophthalaldehyde and enzymatic cleaners, patient care activities and use of sprays are important occupational risk factors for airway disease among HWs.

Work-related allergy and asthma associated with cleaning agents in health workers in Southern African tertiary hospitals.

BACKGROUND: Health workers (HWs) are exposed to diverse cleaning agents in large hospitals. This study determined the prevalence of work-related symptoms, allergic sensitization, and lung function abnormalities in HWs of two tertiary hospitals in Southern Africa. METHODS: A cross-sectional study of 699 HWs (South Africa: SAH, n = 346; Tanzania: TAH, n = 353) was conducted. Health outcomes were assessed using a standardized ECRHS questionnaire, immunological tests (specific IgE antibody to common aero-allergens and to occupational allergens: natural rubber latex [NRL]  Hev b5 and Hev b6.02, chlorhexidine, and ortho-phthalaldehyde [OPA]), spirometry [pre-and post- bronchodilator], methacholine challenge, and fractional exhaled nitric oxide (FeNO). RESULTS: A large proportion of participants (78%) were women. Median age was 42 years, with 76% nurses, 12% cleaners, and 5% administrative workers. Current smoking was more common in SAHWs (12%) than TAHWs (1%). The overall prevalence of doctor-diagnosed asthma was 7%. Atopy was present in 43% of HWs, while 4% were sensitized to OPA, 2% to NRL, and 1% to chlorhexidine. Prevalence of work-related ocular-nasal symptoms (16%) was higher than skin (12%) and chest (7%) symptoms. TAHWs had significantly lower mean lung volumes, higher degrees of significant airflow obstruction and impaired lung function. The prevalence of bronchial hyperresponsiveness in SAHWs (14%) was high. Overall, 23% of HWs had abnormal FeNO; 6% having high (>50 ppb) levels. FeNO was positively associated with sensitization to occupational allergens, primarily OPA and NRL. CONCLUSIONS: HWs from both hospitals had similar prevalence of work-related respiratory symptoms. Sensitization to OPA and NRL appears to be contributing to allergic airway inflammation in these HWs.

Asthma Phenotypes and Host Risk Factors Associated With Various Asthma-Related Outcomes in Health Workers.

Background: Work-related asthma phenotypes in health workers (HWs) exposed to cleaning agents have not been investigated extensively as other occupational exposures. This study aimed to describe asthma phenotypes and to identify important host risk factors associated with various asthma-related outcomes. Methods: A cross-sectional study of 699 HWs was conducted in two large tertiary hospitals. A total of 697 HWs completed questionnaire interviews. Sera collected from 682 HWs were analyzed for atopy (Phadiatop) and IgE to occupational allergens (NRL-Hev b5, Hev b6.02; chlorhexidine and ortho-phthalaldehyde-OPA). Methacholine (MCT), bronchodilator challenge (BDR) and fractional exhaled nitric oxide (FeNO) were performed. An asthma symptom score (ASS) used five asthma-related symptoms reported in the past 12 months. Current asthma was based on use of asthma medication or an asthma attack or being woken up by an attack of shortness of breath in the past 12 months. Nonspecific bronchial hyperresponsiveness (NSBH) was defined as having either a positive MCT or a significant bronchodilator response. Two continuous indices of NSBH [continuous index of responsiveness (CIR) and dose-response slope (DRS)] were calculated. Results: The prevalence of current asthma was 10%, atopic asthma (6%) and non-atopic asthma (4%). Overall, 2% of subjects had work-related asthma. There was a weak positive association between NSBH and FeNO [CIR: Beta coefficient (ß) = 0.12; CI: 0.03-0.22 and DRS: ß = 0.07; CI: 0.03-0.12]. Combining FeNO ≥ 50 ppb with a BDR [mean ratio (MR) = 5.89; CI: 1.02-34.14] or with NSBH (MR = 4.62; CI: 1.16-18.46) correlated better with ASS than FeNO alone (MR = 2.23; CI: 1.30-3.85). HWs with current asthma were twice as likely to be atopic. FeNO was positively associated with atopy (OR = 3.19; CI: 1.59-6.39) but negatively associated with smoking status (GMR = 0.76; CI: 0.62-0.94). Most HWs sensitized to occupational allergens were atopic. Conclusion: Atopic asthma was more prevalent than non-atopic asthma in HWs. Most asthma-related outcomes were positively associated with allergic predictors suggesting a dominant role for IgE mechanisms for work-related symptoms and asthma associated with sensitization to OPA or chlorhexidine.

Predictors of discordant latent tuberculosis infection test results amongst South African health care workers.

BACKGROUND: The tuberculin skin test (TST) and interferon-gamma-release-assays (IGRAs) are utilized in screening programmes for presumed latent tuberculosis infection (LTBI) in health care workers (HCWs). However, inter-test comparison yields high rates of discordance, which is poorly understood. The aim of the study was therefore to identify factors associated with discordance amongst HCWs in a TB and HIV endemic setting. METHODS: 505 HCWs were screened for LTBI in South Africa using the TST and two IGRA assays (QuantiFERON-TB-Gold-In-Tube (QFT-GIT) and TSPOT.TB). Factors associated with discordance were analyzed using a multinomial logistic regression model. RESULTS: TST-IGRA discordance was negatively associated with longer duration of employment for both TSPOT.TB (OR = 0.92; 95% confidence interval (CI) 0.85-0.99) and QFT-GIT (OR = 0.90; 95% CI 0.84-0.96). Marked test discordance occurred in HIV-infected individuals who were more likely to have TSPOT.TB + ve / TST-ve discordance (OR 4.44; 95% CI 1.14-17.27) or TSPOT.TB + ve / QFT-GIT-ve test discordance (OR 5.72; 95% CI 1.95-16.78). Those engaged in home care were less likely to have QFT-GIT + ve/TSPOT.TB -ve / discordance (OR 0.32; 95% CI 0.10-0.95). CONCLUSION: The marked TST-IGRA and IGRA-IGRA discordance in HIV-infected individuals suggest greater sensitivity of TSPOT.TB in immunocompromised persons or potential greater reactivity of TSPOT.TB in this population.

Environmental factors associated with baseline and serial changes in fractional exhaled nitric oxide (FeNO) in spice mill workers.

BACKGROUND: This study evaluated the determinants of high fractional exhaled nitric oxide (FeNO; >50 ppb) and serial changes in FeNO over a 24-hour period in spice mill workers at risk of work-related allergic respiratory disease and asthma. METHODS: A cross-sectional study of 150 workers used European Community Respiratory Health Survey (ECRHS) questionnaires, Phadiatop, serum-specific IgE (garlic, chilli pepper, wheat; Phadia, ImmunoCAP), spirometry and FeNO. A hand-held portable nitric oxide sampling device (NIOX MINO, Aerocrine AB) measured FeNO before and after the 8-hour shift and after 24 hours from baseline. RESULTS: The mean age of workers was 33 years; 71% were male, 46% current smokers and 45% atopic. Among workers with garlic sensitisation, 13% were monosensitised and 6% were co-sensitised to chilli pepper. Baseline preshift FeNO geometric mean (GM=14.9 ppb) was similar to the mean change across shift (GM=15.4 ppb) and across the 24-hour period (GM=15.8 ppb). In multivariate linear models, smoking (ß=-0.507) and atopy (ß=0.433) were strongly associated with FeNO. High FeNO (>50 ppb) was significantly associated with asthma-like symptoms due to spice dust (OR=5.38, CI 1.01 to 28.95). Sensitisation to chilli pepper was more strongly correlated with FeNO (r=0.32) and FeNO>50 ppb (OR=17.04, p=0.005) than garlic. FeNO increase (>12%) across 24 hours demonstrated a strong association with elevated exposures to spice dust particulate (OR=3.77, CI 1.01 to 14.24). CONCLUSIONS: This study suggests that chilli pepper sensitisation is associated with high FeNO (>50 ppb), more strongly compared with garlic, despite the low prevalence of sensitisation to chilli. Elevated inhalant spice dust particulate is associated with a delayed elevation of FeNO across the 24-hour period.

Sensitisation to cereal flour allergens is a major determinant of elevated exhaled nitric oxide in bakers.

OBJECTIVE: Various studies of the usefulness of fractional exhaled nitric oxide (FeNO) in occupational settings remain inconclusive. The objective was to investigate the determinants of increased FeNO in bakery workers. METHODS: A cross-sectional study of 424 supermarket bakery workers used a questionnaire and serum specific IgE to wheat, rye and α-amylase. FeNO during the work shift were assessed using a hand-held portable sampling device (NIOX MINO). RESULTS: The median FeNO was 15 ppb, in atopics 21 ppb and current smokers 12 ppb. Increased FeNO was strongly associated with IgE to wheat independent of smoking and atopy status. In the multivariate model, IgE to wheat, current smoking, atopy and age were significantly associated with FeNO. Stratified analysis in a subgroup of atopic non-smokers demonstrated the strongest relationship between FeNO and various clinical endpoint such as wheat (OR=9.43) or rye (OR=11.76) sensitisation, work-related allergic rhinitis (OR=8.13) or asthma (OR=5.44), and probable baker's asthma (OR=6.72). CONCLUSIONS: Sensitisation to cereal flour allergens rather than asthma symptoms is a major determinant of elevated FeNO among bakers. This relationship is modified by atopy and current smoking status.

Occupational allergy and asthma among salt water fish processing workers.

BACKGROUND: Fish processing is a common economic activity in Southern Africa. The aim of this study was to determine the prevalence and host determinants of allergic symptoms, allergic sensitization, bronchial hyper-responsiveness and asthma among workers processing saltwater fish. METHODS: A cross-sectional study was conducted on 594 currently employed workers in two processing plants involved in pilchard canning and fishmeal processing. A modified European Community Respiratory Health Survey (ECRHS) questionnaire was used. Skin prick tests (SPT) used extracts of common airborne allergens, fresh fish (pilchard, anchovy, maasbanker, mackerel, red eye) and fishmeal. Spirometry and methacholine challenge tests (MCTs; tidal breathing method) used ATS guidelines. RESULTS: Work-related ocular-nasal symptoms (26%) were more common than asthma symptoms (16%). The prevalence of atopy was 36%, while 7% were sensitized to fish species and 26% had NSBH (PC(20) < or = 8 mg/ml or > or =12% increase in FEV(1) post-bronchodilator). The prevalence of probable occupational asthma was 1.8% and fish allergic rhino-conjunctivitis 2.6%. Women were more likely to report work-related asthma symptoms (OR = 1.94) and have NSBH (OR = 3.09), while men were more likely to be sensitized to fish (OR = 2.06) and have airway obstruction (OR = 4.17). Atopy (OR = 3.16) and current smoking (OR = 2.37), but not habitual seafood consumption were associated with sensitization to fish. CONCLUSIONS: Based on comparison with previous published studies, the prevalence of occupational asthma to salt water fish is lower than due to shellfish. The gendered distribution of work and exposures in fish processing operations together with atopy and cigarette smoking are important determinants of occupational allergy and asthma.