ABSTRACT
OBJECTIVE: To analyze the characteristic changes of cognitive and memory function in young and middle-aged workers occupationally exposed to aluminum. METHODS: By cluster sampling method,358 workers aged 19. 0-55. 0 years and engaged in aluminum electrolytic work for more than 1. 0 year were selected as research objects. The cognitive and memory function were tested and evaluated by Mini-Mental State Examination( MMSE),Clock-drawing Test( CDT),Digit-span Test [DST,including Digit-span Forward Test( DSFT) and Digit-span Backward Test( DSBT) ],Verbal Fluency Test( VFT),Fuld Object Memory Evaluation( FOME) and Simple Reaction Time( SRT). Plasma aluminum was measured using graphite furnace atomic absorption spectrometry and used as internal exposure indicator. The research objects were divided into low-,medium- and high-dose aluminum exposure groups based on the median( M) and the 25 th and the 75 th percentile( P25,P75) of plasma aluminum level. RESULTS: The levels of plasma aluminum M( P25,P75) was135. 47( 87. 42,202. 24) μg / L. The DST,DSFT and VFT scores in the high-dose exposure group were lower than those of low- and medium-dose exposure aluminum groups [DST: 16( 13,19) vs 18( 14,21) scores,16( 13,19) vs 18( 15,20) scores,P < 0. 05; DSFT: 10( 8,12) vs 11( 8,12) scores,10( 8,12) vs 11( 9,12) scores,P < 0. 05; VFT: 36( 26,46) vs 40( 30,50) scores,36( 26,46) vs 40( 30,50) scores,P < 0. 05) ]. Comparison of MMSE,CDT,DSBT,FOME scores and SRT showed no significant difference among all groups( P > 0. 05). The multiple stepwise linear regression analysis results showed that plasma aluminum level was negatively correlated with VFT score( P < 0. 05). The VFT scores dropped with the increase of plasma aluminum level. The scores of MMSE,CDT,FOME and SRT showed no correlation with plasma aluminum level( P > 0. 05). CONCLUSION: Long-term occupational aluminum exposure could induce the damage of cognitive and memory function in young and middle-aged workers. The damage includes auditory attention,auditory memory span and verbal executive function. The mainly damage had a dose-effect relationship.