Fibrous 1 year before Microscope Non-malignant disease seen at Amphibole in 1.1.63 Measurements respiratory disease 11.7 Libby, were scanty associated with year 285=deaths Montana and, until cumulative exposure: about 1970, by SMR=3.09 (95% Cl: Midget 2.30, 4.06). respiratory Impinger respiratory disease deaths method only. disease (n=51): After 1970 Cumulative exposure Membrane of 11.7- (16.7) No smoking Filter Method fibre/mL-year history was used. (deaths=13, expected death =3.7; RR=2.53; Estimating 95%CI: 0.88, 7.24) cumulative exposures Cumulative exposure was to take at 25.2- (53.2) the maximum fibre/mL-year advantage of (deaths=14, expected existing air deaths=3.8; RR=2.62 measurements (95%CI: 0.93, 7.27). and to Cumulative exposure concentrate at 113.8- (393.8) efforts on the fibre/mL-year past dry mill (deaths=19, expected period (before deaths=4.1; RR=3.11; 1975) when 95% CI: 1.15, 8.44). substantial Linear model (per 100 exposures fibre/mL-year) occurred. RR=0.38 (95%CI: Altogether, 0.12, 0.96; p=0.0001) results of 1363 Author’s conclusion: a air statistically significant measurements linear between were available exposure and deaths from non-malignant
Fibrous Amphibole in Libby, Montana 1 year before 1.1.63 285=deaths respiratory disease deaths No smoking history Microscope Measurements were scanty and, until about 1970, by Midget Impinger method only. After 1970 Membrane Filter Method was used. Estimating cumulative exposures was to take the maximum advantage of existing air measurements and to concentrate efforts on the past dry mill period (before 1975) when substantial exposures occurred. Altogether, results of 1363 air measurements were available Non-malignant respiratory disease associated with cumulative exposure: SMR=3.09 (95% Cl: 2.30, 4.06). respiratory disease (n=51): Cumulative exposure of 11.7- (16.7) fibre/mL-year (deaths=13, expected death =3.7; RR=2.53; 95%CI: 0.88, 7.24) Cumulative exposure at 25.2- (53.2) fibre/mL-year (deaths=14, expected deaths=3.8; RR=2.62 (95%CI: 0.93, 7.27). Cumulative exposure at 113.8- (393.8) fibre/mL-year (deaths=19, expected deaths=4.1; RR=3.11; 95% CI: 1.15, 8.44). Linear model (per 100 fibre/mL-year) RR=0.38 (95%CI: 0.12, 0.96; p=0.0001) Author’s conclusion: a statistically significant linear between exposure and deaths from non-malignant disease seen at 11.7 year