RENAL EFFECTS OF NAPHTHA EXPOSURE AMONG AUTOMOTIVE WORKERS

As part of a study on health effects of naphtha exposure, the associat ion between naphtha exposure and urinary excretion of total protein, a lbumin, beta-N-acetyl-D-glucosaminidase (beta-NAG), and beta2-Microglo bulin was assessed prospectively over 1 year among workers at an autom otive plant that used naphtha to calibrate fuel injectors. Participant s consisted of 248 workers who provided spot urine samples in June 198 8 among whom 181 workers provided specimens again in June 1989. Naphth a air concentrations at the plant ranged from 6 to 790 mg/m3 and the l ength of exposure ranged from 0.8 to 7.3 years. In both 1988 and 1989, the overall distribution of the four measures of renal function appea red consistent with that of an unexposed population. In cross-sectiona l analyses, there were no statistically significant associations in th e expected direction between cumulative or recent naphtha exposure and the measures of renal function. In longitudinal analyses, the change in beta-NAG was positively associated with the change in recent naphth a exposure (P = .009). The effect of the naphtha exposure during 1 wor kweek was assessed among 17 workers who provided urine samples Monday preshift, Monday postshift, and Friday postshift. No associations were found. The results of this study do not provide strong evidence of na phtha-associated renal effects at these levels of exposure.