Effect of dust exposure and nitrogen oxides on lung function parameters of German coalminers: a longitudinal study applying GEE regression 1974-1998.
OBJECTIVE
Workplace limits for dust and nitrogen oxides are under review in Germany and the EU. We conducted a study on German coal miners to determine the effects of exposure on lung function.


METHODS
Longitudinal inception cohort study (1974-1998) on miners who began working underground at two coal mines between 1974 and 1979. We determined the number of shifts worked underground, the exposure to coal mine dust, quartz dust, nitrogen oxides (NO, NO(2)), smoking behavior, and three lung function parameters (FVC, FEV(1), FEV(1)/FVC). General estimation equation (GEE) models were fitted.


RESULTS
1,369 miners worked an average 3,017 shifts (S) underground. The mean respirable coal mine dust concentration was 1.89 mg/m(3) (quartz: 0.067 mg/m(3)), and the nitrogen oxide concentrations were 0.58 ppm (NO) and 0.007 ppm (NO(2)). On average, 9 measurements of lung function were available per miner. Compared to reference values, the findings were unexceptionable (103, 101, and 99%) on average. GEE-regression models did not reveal detrimental dust exposure effects. Nitrogen oxides (NO (x) = NO + NO(2)) showed small but clearly insignificant effects on lung function: delta FVC = -0.0008 ml/(220 ppmS), P = 0.86, delta FEV(1) = -0.003 ml/(220 ppmS), P = 0.50 and delta FEV(1)%FVC = -0.07%/(220 ppmS), P = 0.22.


CONCLUSIONS
The effect of dust exposure on lung function described in older British and American coal miner studies was not confirmed. This can be explained partly by differences in methods (here: longitudinal studies, no prior exposure), but also by lower dust levels. NO (x) exposures showed no relevant influence on lung function-a result confirming findings from British coal mining.
Morfeld
P
P
Institute for Occupational Medicine of Cologne University, Cologne, Germany. peter.morfeld@evonik.com
Noll
B
B
Büchte
S F
SF
Derwall
R
R
Schenk
V
V
Bicker
H J
HJ
Lenaerts
H
H
Schrader
N
N
Dahmann
D
D
D000293:Adolescent; D000328:Adult; D003031:Coal / Q000009:adverse effects* / Q000032:analysis; D003032:Coal Mining; D004391:Dust / Q000032:analysis; D005541:Forced Expiratory Volume / Q000187:drug effects*; D005858:Germany; D006801:Humans; D008137:Longitudinal Studies; D008875:Middle Aged; D009589:Nitrogen Oxides / Q000009:adverse effects* / Q000032:analysis; D016273:Occupational Exposure / Q000009:adverse effects* / Q000032:analysis; D011159:Population Surveillance; D011791:Quartz / Q000009:adverse effects* / Q000032:analysis; D012044:Regression Analysis; D014797:Vital Capacity / Q000187:drug effects*; D055815:Young Adult
D003031:Coal; D004391:Dust; D009589:Nitrogen Oxides; D011791:Quartz