Term of Award

Fall 2021

Degree Name

Doctor of Public Health in Epidemiology (Dr.P.H.)

Document Type and Release Option

Dissertation (restricted to Georgia Southern)

Copyright Statement / License for Reuse

Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.


Department of Biostatistics, Epidemiology, and Environmental Health Sciences

Committee Chair

Jian Zhang

Committee Member 1

Logan Cowan

Committee Member 2

Lili Yu


Folate plays a crucial role in maintaining the stability and integrity of the cell, among other functions. Despite the positive beneficial postulations, evidence suggests that high doses of folic acid may speed cell division and increase tumor progression in post-neoplastic lesions. We assessed the relationship between dietary and blood folate and the risk of lung cancer death (LCD). Study participants were adults 19 years and older who took part in the Third National Health and Nutrition Examination Survey (1988-1994). After 192,973 person-years of follow-up, Cox regression analysis suggested no significant associations between dietary folate intake, serum and RBC folate, and LCD risk. A time-dependent bidirectional association was, however, observed between serum folate and LCD risk. A high serum folate level was associated with an increased LCD risk among participants who died from lung cancer in the first ten years of the follow-up, HR= 2.87 (1.30 – 6.37). In contrast, high serum folate was associated with a decreased risk of the LCD risk among participants who died after ten years of follow-up, HR = 0.45 (0.24 – 0.86). The current study supports the dual effects of serum folate on the carcinogenesis of lung cancer.

Research Data and Supplementary Material


Available for download on Friday, December 18, 2026