A Methodological Problem in Investigation of Pneumoconiosis Epidemiology.
Liu-Z; Xing-C; Zhang-S; Li-J
NIOSH 1990 Sep:796-798
A probabilistic approach for assessing changes in the incidence of pneumoconiosis resulting from changes in occupational dust exposure was described. The method involved constructing right triangles on graph paper. The length of the base of the triangles represented the number of calendar years in which a specific dust exposure occurred. The length of the perpendicular edge of the triangles represented the mean dust concentration occurring up to the time of pneumoconiosis diagnosis. Once the hypotenuses were drawn in the triangles represented time windows of equal area. The number of pneumoconiosis occurring in each time window could be statistically compared. The method was illustrated by applying it to two facilities in Liaoning Province, China. Time windows were constructed for the period 1945 through 1985. From 1945 to 1950 no efforts were made to control dust exposures at either facility. From 1950 to 1955 some efforts, deemed inadequate, were made to control dust. From 1955 to 1960 wet drill techniques and ventilation were used to control dust. From 1960 on comprehensive dust control programs were implemented at both facilities. The numbers of pneumoconiosis cases that occurred during the 1945 to 1965 time window were 320 and 291. The numbers of cases occurring during the 1965 to 1985 window were 0 and 7, respectively, a significant decrease. The authors conclude the method can be used to determine the probability that a change in number of pneumoconiosis cases may occur at a given point in time. The approach can be used when data on exposed populations are missing. The approach should be useful for evaluating prevention programs, medical surveillance, health promotion programs, and the effectiveness of administrative controls.
Epidemiology; Dust-exposure; Dust-suppression; Respiratory-system-disorders; Mathematical-models; Occupational-health; Statistical-analysis;
DHHS (NIOSH) Publication No. 90-108
Asthma and Chronic Obstructive Pulmonary Disease; Disease and Injury; Respiratory-system-disorders;
Proceedings of the VIIth International Pneumoconioses Conference