Objectives Past researches almost explored the relationship between a single gene with a single disease. Our study aims to investigate into the interaction of multi-gene with a single disease by using Genetic Algorithms.

Method Samples in this study are from a lead battery factory in Taiwan. We collected the data of their bone density, blood lead levels and 6 SNPs (ACE, alpha-adducin, Bsm, Tag, Apa, ALAD) from 1990 to 2009. When in 2009, a total of 502 employees in this factory. And we used Genetic Algorithms and logistic regression analysis that the genotype in an individual.

Results In this study, our findings suggest that when people’s genotype combined Bsm bb and ALAD 1–1, it will have a protective effect on bone density. It means the Taiwanese lead worker with genotypes of Bsm bb and ALAD 1–1, would have less chance to have low bone density (OR: 0.58; 95% CI: 0.95–0.35).

Conclusions We found the results by using Genetic Algorithms and logistic regression analysis that the genotype in an individual which are Bsm bb type and ALAD 1–1 type plays an important role in protecting bone density among 245 male employees and 261 female employees. In conclusion, our study found Bsm gene and ALAD gene influence bone density. However, the mechanism and the exact relationship between two genes and bone density need further investigation.