Long-term exposure to ambient NO2 increase oral cancer prevalence in Southern China: A 3-year time-series analysis

Hongbin Peng ¹ Xiaoxia Wang ^1,2 Ying Liao ² Lichong Lan ² Danni Wang ² Yaohuan Xiong ² Ling Xu ² Yinxia Liang ^1,3 Xia Luo ¹ Yunan Xu ⁴ Feiyan Li ^2* Hao Chen ^4* Chuanyi Ning ^1,3,5*

• ¹ School of Nursing, Guangxi Medical University, Nanning, China
• ² College & Hospital of Stomatology, Guangxi Medical University, Nanning, China
• ³ The Second Affiliated Hospital, Guangxi Medical University, Nanning, China
• ⁴ School of Public Health, Guangxi Medical University, Nanning, Guangx, China
• ⁵ Key Lab of AIDS Prevention and Treatment, Life Sciences Institute, Guangxi Medical University, Nanning, China

Background While the correlation between cancer and air pollutants is well-established, research on the delayed effects of nitrogen dioxide (NO2) on oral cancer remains limited.Methods We collected data on NO2 along with diagnosed cases of oral cancer in Guangxi, China, and analyzed the correlation between exposure to NO2 and the prevalence of oral cancer.Results The study included 1,841 participants diagnosed with oral malignancies, consisting of 1,179 males (64.0%) and 662 females (36.0%), with a mean age of 55.9±14.0 years. The NO2 concentration is 20.2±10.4µg/m3. The highest cumulative effects of NO2 exposure were observed at a 3-year cumulative lag, with a relative risk (RR) of 1.072 (95% CI: 1.063–1.082). For males, the most pronounced effect of NO2 also occurred at a 3-year lag (RR=1.110, 95% CI: 1.094–1.127). Similarly, among females, the significant cumulative impact of NO2 was found at a 3-year lag (RR=1.123, 95% CI: 1.112–1.152). For individuals under 60 years of age, the cumulative impact of NO2 peaked at the same 3-year lag (RR=1.102, 95% CI: 1.101–1.145). For individuals aged 60 and above, the highest cumulative impact of NO2 was also detected at a 3-year lag (RR=1.132, 95% CI: 1.112–1.152). For the group with normal BMI, the highest cumulative effect of NO2 exposure was also observed at the 3-year lag period(RR=1.289, 95% CI: 1.217-1.365), consistent with the findings for other groups.Conclusions These findings suggest a significant lagged effect of long-term NO2 exposure on oral cancer, with varying associations between NO2 and oral cancer across different ages and genders.