Respiratory symptoms and lung function in relation to wood dust and monoterpene exposure in the wood pellet industry

Figures & data

Table 1. Distribution of background variables among study subjects (n = 39).

	Number	%
Age (years)
<30	7	18
30–39	20	51
≥40	12	31
Smoking habits
Smokers	4	10
Non-smokers	27	69
Ex-smokers	8	21
Time with present working tasks (years)
<5	16	41
5–9	21	54
≥10	2	5
Time at present workplace (years)
<4	15	38
5–9	20	51
≥10	4	10
Part-time farming
Yes	10	26
No	29	74
Part-time forestry
Yes	11	28
No	28	72

Table 2. Prevalence of symptoms from the upper and lower airways among study subjects (n = 39) compared with controls (results shown in percent).

	Exposed	Controls
Nasal symptoms:
Sneezing	26^a	11^b
Irritation	8	7^b
Blockage	28^a	9^b
Dripping	10	8^b
Mucous secretion	8	–
Dryness	20^a	6^b
Impaired sense of smell	8	4^b
Lower airway symptoms:
Asthma attack last year	8	3^c
Doctor-diagnosed asthma	15^a	7^d
Asthma medication	13^a	5^c
Nightly breathlessness	8	6^c
Work-related febrile attacks	0	3^e
Dry cough	41^a	15^e
≥3 months per year	18^a	5^e
Cough with phlegm	26	22^d
≥3 months per year	5	9^d

^a p < 0.05.

^b Åhman et al., 1995, n = 112 (8).

^c Björnsson et al., 1998, n = 6031 (27).

^d Lembke et al., 2004, n = 900 (28).

^e Rask-Andersen and Lemke unpublished data (Swedish report).

Table 3. Pulmonary function (VC, FEV₁, and FEV%) in exposed subjects (n = 38) and foundry worker controls (n = 118) before and after shift.

	Exposed n = 38			Controls n = 118
	Mean (% of predicted)	SD	Range	Mean (% of predicted)	SD	Range
FEV1
before	96.4	13.3	62–129	96.7	11.5	62–128
after	96.5	12.8	59–129	96.9	11.6	63–128
difference	+0.1	3.1	−7–7	+0.2	4.0	−11–11
VC
before	94.9	11.7	67–117	94.2	10.8	72–125
after	94.6	10.1	70–114	93.6	10.5	73–122
difference	−0.2	3.2	−7–6	−0.6	3.1	−8–16
FEV%
before	101.9	8.9	68–121	102.9	8.1	66–118
after	102.2	8.9	64–114	103.7	7.8	66–117
difference	+0.2	2.9	−8–6	+0.8	4.0	−17–11

FEV%: FEV₁/VC; FEV₁: forced vital capacity in 1 second; VC: vital capacity.

Table 4. Pulmonary function (VC, FEV₁, and FEV%) among study subjects (n = 38) before shift in relation to years of employment in current working tasks.

	n	FEV1	VC	FEV%
Current working tasks <5 years	16	98	98	100
Current working tasks ≥5 years	22	95	93	103

FEV%: FEV₁/VC; FEV₁: forced vital capacity in 1 second; VC: vital capacity.

Table 5. Stationary and personal exposure levels of wood dust in the wood pellet industry.

		Wood dust (mg/m^3)
Measurements	Number	GM	AM	Range
Stationary	49	0.56	2.9	<0.10–34
Personal	24	1.7	3.5	0.16–19

AM: arithmetic mean; GM: geometric mean.

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