Table 2 Study characteristics of studies with occupational populations
From: Respiratory health effects of exposure to low levels of airborne endotoxin – a systematic review
Occupational populations | |||||||||
|---|---|---|---|---|---|---|---|---|---|
Author (Year) Country | Study designa | Population | Ageb,c | Endotoxin assessment methods | Exposure variables measured | Duration of exposured | Spirometry | Questionnaire | Confounders accounted for |
Kawamoto et al. (1987) US [48] | CS | 128 cotton workers | 35.6–38.6 (±2.47–2.90) | -Area sampling -breathing zone height -LAL assay | Total dust, endotoxin, oil mist and boric acid | 6.3–13.1 (±1.28–2.03) | FVC and FEV1 | Standardized questionnaire | Age, smoking |
Kateman et al. (1990) Netherlands [32] | L: follow up 5 days | 40 textile yarn workers exposed to spray-humidifier, 42 controls exposed to other or no humidifier | 30 | -Personal sampling -Glass fibre filter - 2.0 L/min -LAL assay | Dust, endotoxin, fungi, bacteria | – | FVC, FEV1, PEF, MEF75, MEF50, MEF25, MMEF | Modified MRC questionnaire | Smoking, age, height, standing height |
Dahlqvist et al. (1992) Sweden [52] | CS | 28 wood trimmers, 19 office workers (controls) | S: 37 (±11), C:42 (±8) | -Personal sampling -Millipore filter - 2 L/min -LAL assay | Dust, endotoxin, moulds and bacteria, terpenes | 13 (±11) | FEV1 and FVC, MEF50, MEF25 | Modified MRC questionnaire | Smoking |
Sprince et al. (1997) US [54] | CS | 183 machine workers in automobile industry, 66 assemblers (controls) | 43.2–43.7 (± 7.6–8.4) | -Area and personal sampling -MCE filters -LAL assay | MWF, total aerosol, endotoxin, total fungi, total bacteria, total organisms | S: 12 (±9) years, C: 8 (±8) years (p = 0.023) | FEV1 and FVC | Modified ATS-DLD questionnaire | Smoking status, gender, age, race |
Zock et al. (1998) Netherlands [39] | CS | 57 potato processing workers | 39–41 (±7–10) | -Personal sampling -Glass fibre filter - 2.0 L/min -LAL assay | Endotoxin exposure | 13–14 years (± 7–9) | FVC, FEV1, MMEF and PEF | MRC questionnaire | Smoking |
Mandryk et al. (1999) Australia [53] | CS | 168 wood workers, 30 maintenance workers (controls) | S: 37 (± 12.8), C:39 (±11.7) | -Personal sampling -Polycarbonate filter 25 mm -LAL assay | Airborne dust, endotoxin, micro-organisms, (1- > 3)-B-D-glucan | 11 (±10.6 years) | VC, FEV1 and FVC | Combination of the Organic Dust Questionnaire and the MRC respiratory questionnaire | Age, height, smoking, number of years of exposure |
Mahar et al. (2002) UK [40] | L: follow up 5 years | 87 refuse derived fuel plant workers | 39.9–41.4 (SD 8.0–8.1) | -Personal and area sampling -0.45 μm endotoxin free filters -LAL assay | Airborne endotoxin | 7.7–11 years (SD 5.4–5.9) | FEV1 and FVC | Questionnaire | Smoking, length of employment |
Wouters et al. (2002) Netherlands [59] | CS | 47 waste collecting workers, 15 controls | S:34.0 (SD 10.2) C: 36.4 (SD 6.4) | -Personal sampling -Glass fibre filter -3.5 L/min -LAL assay | Dust, endotoxin, β(1-- > 3)-glucan | Median 5 years | – | Modified MRC questionnaire | - |
Fransman et al. (2003) New Zealand [55] | CS | 112 plywood mill workers, 415 controls of the general population | S: 34.5 (±9.1), C: 32.5 (±7.2) | -Personal sampling -Glass fibre filter -2.0 L/min -LAL assay | Inhalable dust, endotoxin, abietic acid, terpenes, formaldehyde | 4.7 years (±3.5) | – | Combination of ISAAC, MRC and ECRHS questionnaires | Age, gender, ethnicity |
Heldal et al. (2004) Norway [36] | CS | 22 waste collection workers | AM: 32 (range 20–62) | -Personal sampling -25 mm polycarbonate filter -2 L/min -LAL assay | Total dust, endotoxin, bacteria, fungal spores | – | – | Questionnaire | Age, smoking |
Kennedy et al. (2004) Canada [34] | Ee: follow up 1 month | 226 glass bottle recycling workers, 212 ferry workers (controls) | S: 41.2–45.5 (±8.4–9.0) | -Personal sampling -2 L/min -LAL assay | Endotoxin, dust, fungi | 12.0–17.3 years (±7.4–8.4) | – | Modified ATS questionnaire | Age, gender, race, smoking status, history of hay fever and asthma |
Sigsgaard et al. (2004) Denmark [33] | L: follow up 11 years | 97 paper mill workers, 55 water-supply workers (controls) | 39–43 (±7–9) | -Personal sampling - 37 micropore filters -LAL assay | Total dust, endotoxin, micro-organisms | – | FVC and FEV1 | – | Age, smoking, atopy |
Smit et al. (2005) Netherlands [41] | CS | 371 waste water workers; 97 office staff, 2698 general population members (controls) | 43.4–47.3 (± 9.9–10.1) | -Personal sampling -Glass fibre filter - 3.5 L/min -LAL assay | Endotoxin | 12.6–14.9 years (±9.0–10.2) | – | Questionnaire specifically developed for bioaerosol related health effects in waste recycling and composting industry | Age, gender and smoking habits |
Widmeier et al. (2007) Switzerland [42] | CS | 409 wastewater-and garbage workers, 369 public transport and forestry workers (controls) | median 41–47 (5th–95th% 22–58) | -Personal and area sampling -LAL assay | Endotoxin exposure | – | FVC and FEV1 | Questions from SAPALDIA-study questionnaire | Age, gender, height, packyears, BMI, serum creatinine, job change, smoking history |
Rusca et al. (2008) Switzerland [60] | CS | 111 sawmill workers | group 1: 26.5 (±9.5), group 2: 36.7 (±8.5), group 3: 47.7 (±8.2) | -Area sampling -Glass fibre filter - 2.0 L/min -LAL assay | Airborne dust, endotoxin, fungi and bacteria | group 1: 1–5 years, group 2: 5–20 years, group 3: > 20 years | FVC and FEV1 | Combination of the Organic Dust Questionnaire and the MRC respiratory questionnaire | Height and packyears of cigarette smoking |
Dang et al. (2010) US [49] | CS | 69 water resort workers, 74 office workers (controls) | S: 20 (range 16–50), C: 31 (range 15-61) | -Area sampling -Polyvinyl-chloride filters - 2 L/min - LAL assay | Chloramines, endotoxin, Legionella, Mycobacterium | 2.8 months | – | Questionnaire | Smoking, asthma status |
Renström et al. (2011) Sweden [50] | CS | 59 pet shop workers | 31.4 (±9.9) | -Personal sampling -1 μm filter - 2.0 L/min -LAL assay | Endotoxin and aeroallergens | 9.4 (±7.4) | VC, FVC and FEV1 | Questionnaire | Smoking, gender, |
Schlünssen et al. (2011) Denmark [57] | CS | 232 woodchip and straw workers, 107 workers in oil/gas power plants (controls) | S: 45.9–47.7(SD 8.6–9.3), C:48.1 (SD 10.0) | -Stationary air sampling -Teflon filters - 1.9 L/min -LAL assay | Endotoxin, total dust and fungi | 7–10.9 years | FVC and FEV1 | Modified ECRHS questionnaire | Gender, height, weight, atopy, age and smoking |
Meza et al. (2013) US [56] | CS | 183 aircraft workers exposed to MWF, 224 office workers (controls) | S: 95% > 45 C: 92% > 45 | -Area air sampling - 0.45 μm filter -2 L/min -LAL assay | Metal working fluids, endotoxin, bacteria | – | – | Questionnaire based on the ECRHS | Age, gender, smoking status and hours worked per week |
Shiryaeva et al. (2014) Norway [58] | CS | 70 salmon processing workers | 40.1 (±11.5) | -Personal sampling -Glass fibre filter - 2.5 L/min -LAL assay | Endotoxin, parvalbumin and total protein | – | FEV1 | Modified MRC questionnaire | Age, gender, asthma, smoking and height |
Cyprowski et al. (2015) Poland [43] | CS | 78 sewage workers | 43 | -Personal sampling -25 mm glass-fibre filter -2 L/min -LAL assay | Endotoxin in inhalable dust | 8.5 years | FEV1 and FVC | – | Inhalable dust, smoking habits |
Heldal et al. (2015) Norway [51] | CS | 47 compost workers, 37 office controls | S: 41–42 (± 9–11), C: 43 (±10) | -Personal sampling -Glass fibre filter - 2.0 L/min -LAL assay | Dust, endotoxin, bacteria, fungal spores, actinomycetes | – | FEV1/FVC and FEV1 | Questionnaire | Smoking packyears, age, atopy |
Ghani et al. (2016) Pakistan [44] | CS | 100 textile mill workers, 100 controls | 3 groups: < 30, 30–40, > 40 | -Area air sampling -Glass fibre filter -LAL assay | Airborne endotoxin | ≥5 years | FEV1, FVC, FEV1/FVC, PEF | Modified ATS questionnaire | Age, duration of exposure |