Smokeless tobacco (snuff) and site-specific cancer risks in adult Black South African women: Findings from the Johannesburg Cancer Study.

in International journal of cancer by Melitah Motlhale, Freddy Sitas, Chantal Babb de Villiers, Hannah Simba, Ariadna Feliu, Wenlong Carl Chen, Joachim Schüz, Mazvita Muchengeti, Valerie McCormack

TLDR

  • A study in South Africa found a link between snuff use and increased risks of certain types of cancer in older African women, particularly cervical and vulva cancer.
  • The study also found unexpected associations between snuff use and lower risks of stomach cancer and Hodgkin Lymphoma.

Abstract

Smokeless tobacco (SLT) use is an established carcinogen to the nasal cavity, lip, and oropharynx, however, few studies have examined cancer risks in older African women among whom SLT use is common. We investigated snuff use and the risk of site-specific cancers among 15,336 newly diagnosed female cancer patients in the Johannesburg Cancer Study, South Africa. We designed case-control comparisons across multiple cancer outcomes: (a) known SLT-associated cancers; (b) other tobacco-related cancers and (c) genital cancers owing to intravaginal snuff use. Controls (n = 2961) comprised all other cancer patients. We also investigated (d) each control cancer type versus the remaining controls to explore possible associations with other cancers. Logistic models were fitted to estimate odds ratios adjusted for age, education, tobacco smoking, alcohol, HIV, and language. Overall, ever use of snuff was 22% among control cancers. Ever snuff use was associated with cervical (OR 1.14 [95%CI 1.00-1.30]) and eye and adnexa cancer (OR 1.95 [95%CI 1.03-3.70]). Associations with vulva cancer were less clear, 95% CI's for the main effects included 1 but a subgroup analysis restricted to never-smokers of current-versus-never users was positive (OR 2.10 [95%CI 1.25-3.50]). Surprisingly SLT users have lower risks of stomach cancer (OR 0.60 [95%CI 0.37-0.99]) and Hodgkin Lymphoma (OR 0.48 [95%CI 0.23-0.97]). Snuff use may increase the risk for cervical and vulva cancer in women, which is plausible via intravaginal use. Further research on the impact of SLT on female genital cancers with more detailed exposure data, including timing, intensity, and routes of use are required.

Overview

  • The study investigated the association between snuff use and the risk of site-specific cancers among 15,336 newly diagnosed female cancer patients in the Johannesburg Cancer Study, South Africa.
  • The study aimed to examine the relationship between snuff use and cancer risk in older African women, who are known to have high rates of snuff use.
  • The study used a case-control design to compare snuff use in patients with different types of cancer to controls who had other types of cancer.

Comparative Analysis & Findings

  • Ever snuff use was associated with increased risks of cervical (OR 1.14) and eye and adnexa cancer (OR 1.95), and may also increase the risk of vulva cancer.
  • Surprisingly, snuff use was associated with lower risks of stomach cancer (OR 0.60) and Hodgkin Lymphoma (OR 0.48).
  • The study found some evidence of a positive association between snuff use and vulva cancer in never-smokers who had used snuff in the past.

Implications and Future Directions

  • The study highlights the need for further research on the impact of snuff use on female genital cancers, including more detailed exposure data on timing, intensity, and routes of use.
  • The findings may have implications for cancer prevention and screening programs in African women, particularly those who use snuff.
  • Future studies could explore the potential mechanisms by which snuff use increases the risk of cervical and vulva cancer.
Read Full Article