Pan-American prevalence of smokeless tobacco use and association with oral potentially malignant disorders and head and neck cancer: a systematic review and meta-analysis.

OBJECTIVES: To determine the prevalence of smokeless tobacco (SLT) use and its association with oral potentially malignant disorders (OPMDs) and head and neck cancer (HNC) in the Pan-American Health Organization (PAHO) region. STUDY DESIGN: A literature search was conducted across 9 databases and other sources. The eligibility criteria were pediatric (0-18 years old) and adult (19 years and older) populations consuming any type of SLT. Meta-analysis was performed to determine the prevalence of SLT and the association between its use and OPMDs/HNC in the PAHO region; the Grading of Recommendations Assessment, Development, and Evaluation tool was used to verify the certainty of evidence. RESULTS: Fifty-nine studies from 6 PAHO countries were included, of which 51 were also subjected to quantitative analysis. The pooled SLT prevalence of use was 15% (95%CI: 11.93-18.69) overall, 17% (95%CI: 13.25-22.65) in adults, and 11% (95%CI: 8.54-14.78) in the pediatric population. The highest reported SLT prevalence of use was 33.4% (95%CI: 27.17-39.93) in Venezuela. HNC was positively associated with SLT use (OR = 1.98, 95%CI: 1.54-2.55), with a moderate certainty of evidence. Among OPMDs, only leukoplakia reported a positive association with SLT use (OR = 8.38; 95%CI: 1.05-67.25). However, the quality of the evidence was very low. CONCLUSION: A high consumption of SLT use, chewing tobacco and snuff, is reported among the adult population residing in the PAHO region with a positive association with the development of oral leukoplakia and HNC.