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. 2021 May 15;148(10):2416-2428.
doi: 10.1002/ijc.33433. Epub 2020 Dec 22.

Missing and decayed teeth, oral hygiene and dental staining in relation to esophageal cancer risk: ESCCAPE case-control study in Kilimanjaro, Tanzania

Blandina T Mmbaga  1   2 , Amos Mwasamwaja  1 , Godfrey Mushi  1 , Alex Mremi  1   2 , Gissela Nyakunga  1   2 , Ireen Kiwelu  1   2 , Remigi Swai  1 , Godwin Kiwelu  3 , Sophia Mustapha  3 , Eliawawomy Mghase  3 , Amana Mchome  4 , Redfan Shao  5 , Evarista Mallya  6 , Deogratias S Rwakatema  1   2 , Kajiru Kilonzo  1   2 , Oresto Michael Munishi  1 , Behnoush Abedi-Ardekani  7 , Daniel Middleton  8 , Joachim Schüz  8 , Valerie McCormack  8
Affiliations

Missing and decayed teeth, oral hygiene and dental staining in relation to esophageal cancer risk: ESCCAPE case-control study in Kilimanjaro, Tanzania

Blandina T Mmbaga et al. Int J Cancer. .

Abstract

In the African esophageal squamous cell carcinoma (ESCC) corridor, recent work from Kenya found increased ESCC risk associated with poor oral health, including an ill-understood association with dental fluorosis. We examined these associations in a Tanzanian study, which included examination of potential biases influencing the latter association. This age and sex frequency-matched case-control study included 310 ESCC cases and 313 hospital visitor/patient controls. Exposures included self-reported oral hygiene and nondental observer assessed decayed+missing+filled tooth count (DMFT index) and the Thylstrup-Fejerskov dental fluorosis index (TFI). Blind to this nondental observer TFI, a dentist independently assessed fluorosis on photographs of 75 participants. Odds ratios (ORs) are adjusted for demographic factors, alcohol and tobacco. ESCC risk was associated with using a chewed stick to brush teeth (OR 2.3 [95% CI: 1.3-4.1]), using charcoal to whiten teeth (OR 2.13 [95% CI: 1.3, 4.1]) and linearly with the DMFT index (OR 3.3 95% CI: [1.8, 6.0] for ≥10 vs 0). Nondental observer-assessed fluorosis was strongly associated with ESCC risk (OR 13.5 [95% CI: 5.7-31.9] for TFI 5+ v 0). However, the professional dentist's assessment indicated that only 43% (10/23) of participants assessed as TFI 5+ actually had fluorosis. In summary, using oral charcoal, brushing with a chewed stick and missing/decayed teeth may be risk factors for ESCC in Tanzania, for which dose-response and mechanistic research is needed. Links of ESCC with "dental fluorosis" suffered from severe exposure misclassification, rendering it impossible to disentangle any effects of fluorosis, extrinsic staining or reverse causality.

Keywords: Tanzania; esophageal cancer; fluorosis; oral health.

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Conflict of interest statement

The authors declare no completing interests. Where authors are identified as personnel of the International Agency for Research on Cancer/World Health Organization, the authors alone are responsible for the views expressed in this article, and they do not necessarily represent the decisions, policy or views of the International Agency for Research on Cancer/World Health Organization.

Figures

FIGURE 1
FIGURE 1
Distribution of possible presence of fluorosis assessed on 75 photographs by a professional dentist for categories of Thylstrup‐Fejerskov index originally assessed by the study's nondental observer
FIGURE 2
FIGURE 2
Example of oral health photographs considered as (A) Thylstrup‐Fejerskov score of 4+ by the nondental observer, in agreement with the professional dentist's evaluation of the presence of fluorosis; (B‐D) Thylstrup‐Fejerskov score of 5+ by the nondental observer, for which the dentist did not consider as fluorosis but instead were (B) extrinsic staining; (C) stained roots with exposure cementum and (D) development disturbance affecting central incisors
FIGURE 3
FIGURE 3
Odds ratios (ORs) for oral hygiene, DMFT and nondental observer‐assessed fluorosis in relation to ESCC risk, overall in a risk‐factor defined subsets (values are provided in Supplementary Table 1). ORs are mutually adjusted for age, sex, region of residence, Chagga ethnicity, education, alcohol, tobacco and for all the oral health indicators included in the figure
See this image and copyright information in PMC

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