Emphysema andairway obstruction in non-smoking SouthAfrican goldminers with long exposuretosilica dust

Objective-Occupational exposureto silica dustisassociated withsignificant impairment oflungfunction. Thepresent studyinvestigates whichpathological changes inthelungareassociated with impairment oflungfunction insilica dust exposed workers whowerelife-long nonsmokers. Methods-242 SouthAfrican whitegold minerswho werelifelong non-smokers andwhohada necropsy atdeathwere studied. Thepathological features identified atnecropsy werethedegree andtype ofemphysema, thepresence ofairway disease, andthedegree ofsilicosis inthe lungparenchyma andpleura. Thesefeatureswererelated tolungfunction tests doneafewyearsbefore death, totypeof impairment (obstructive orrestrictive), andtocumulative silica dustexposure. Results-Thedegreeof emphysema foundatnecropsy was notassociated witha statistically significant impairmentoflungfunction orwithdustexposure.Thedegree ofsilicosis inthelung parenchyma andthelargeairways disease(based onmucusglandhyperplasia) wereassociated withastatistically significantimpairment oflungfunction. The largeairwaydisease was,however, not positively associated withdustexposure orsilicosis. Inminerswithamoderate or a higher degree oflimitation ofairflow themainfindings weresilicosis, heart disease, andobesity. The presence of smallairways disease couldnotbeestablished fromthenecropsy material. Conclusion-The results indicate thatthe level ofexposure tosilica dusttowhich theseminerswereexposed, without a confounding effect oftobacco smoking, is notassociated witha degreeofemphysemathatwouldcauseastatistically significant impairment oflungfunction. Silicosis ofthelungparenchyma was associated withlossoflungfunction. Otherfactors thatmay playa partin impairment oflungfunction inthese minersareobesity andheartdisease. (Occup Environ Med1994;51:557-563)