목적: 순천향대학교 산업의학연구소가 관리하는 우리나라의 납 노출 사업장의 근로자들 중 1992년 1월 이후부터 2001년까지의 입사 1년 이내의 약 3, 540명을 대상으로 하여 연구대상자들로부터 채취되어 냉동 보관된 혈액으로 ALAD 및 VDR 유전자 형질을 분석하고, 이들의 유전자 형질이 납 노출에 따른 건강영향에 미치는 영향을 분석한 단면조사 연구이다. 방법: 납 노출에 따른 건강영향 관련 연구변수로는 납 노출 변수로서 혈중 납량, 납 중독 변수로서 혈중 ZPP및 요중 ALA, 조혈기능 변수로서 혈색소를 택하였다. 표준화된 설문지를 이용하여 개인관련 변수인 성, 연령, 근무년수 등을 파악하고 체중 등을 측정하였다. 자료의 분석은 기술적 자료의 분석과 t -검정을 이용하였고, 다변량 분석을 위하여 다중 회귀분석을 이용하였다. 결과: 연구대상 신규입사자 3, 540명중 ALAD 유전형질 정형(1-1형)을 가진 대상자는 3, 204명(90.5%)이었으며, 이형 유전형질(1-2 혹은 2-2형)을 가진 대상자는 336명(9.5%) 이었으며, VDR 유전형질의 정형유전형질(bb 형)을 가진 대상자들은 총 3, 238명중 2, 903명(89.7%) 이었으며, 이형유전형질(bB 혹은 BB )을 가진 대상자는 335명(10.5%) 이었다. ALAD 및 VDR 유전형질이 조혈기능 지표인 혈중 ZPP에 미치는 영향을 본 바 ALAD 유전형질의 이형성은 혈중 ZPP의 감소에 유의한 영향을 나타낸 반면, VDR 이형성은 혈중 ZPP의 증가를 가져와서 서로 상반된 영향을 나타냈다. 또한 ALAD 및 VDR 유전형질은 요중 ALA 및 혈색소에 유의한 영향이 없었다. 결론: 본 연구결과로 미루어서 ALAD 유전형질은 납 근로자들에 대한 보호효과가 있는 것으로 추정되며, VDR 유전형질이 ALAD와는 달리 납에 의한 영향을 더 악화시키는 것으로 추정된다.
Objectives: This study was conducted with new workers who entered lead industries from 1992 to 2001 to evaluate the genetic susceptibility of ALAD (δ-aminolevulinic acid dehydratase) and VDR (vitamin D receptor) gene on health effect of lead exposure. Methods: Among the subjects of the database of lead industries at the Soonchunhyang University Institute of Industrial Medicine, only new workers were selected for this study. The total of eligible workers for this category was 3,540 workers, including non lead exposed workers of same lead industries. From stored blood in specimen bank of Soonchunhyang University, genotype of ALAD and VDR were measured using PCR method. Variables for this study were blood lead as an index of lead exposure, ZPP (zinc protoporphyrin in blood), urine ALA (δ-aminolevulinic acid), and hemoglobin as an index of hematopoietic effect of lead. Information on sex, job duration, and weight were collected for personal information. The data were analyzed using SAS (version 8.2) with descriptive analysis of t-test and multiple regression analysis. Results: Among 3,540 new employed study subjects during period of 1992-2001, 3,204 workers(90.5%) had ALAD genotype 1-1, while 336 workers (9.5%) had variant type of ALAD (1-2 or 2-2). For VDR genotype, 2,903 workers (89.7%) out of total tested 3,238 workers were belonged to type bb and 335 workers (10.5%) were type bB or BB. The distribution of genotype of ALAD and VDR were not different according to the job duration in male workers, but were different in female workers. The effect of ALAD and VDR genotype on blood lead were positively significant in the analysis of all cumulative data of new employed workers for 10 years. The effect of VDR genotype on blood lead were stronger than that of ALAD. While the variant ALAD gene made decrease of mean ZPP and ALA in urine after controlling for blood lead and other covariate, the variant VDR gene made increased the mean ZPP and ALA in urine in all cumulative data analysis and cross sectional analysis by job duration. For hemoglobin, ALAD and VDR genotype did not affect the mean value. Conclusions: From the above our results, we found that ALAD and VDR genotype exerted significant effect in various way. We confirmed that the finding of a cross sectional study of protective effect of variant ALAD on the effect of blood lead on blood ZPP in our retrospective study design. It was found that VDR did not exert protective effect for lead exposure as the variant ALAD did.
