RESUMEN
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.
RESUMEN
An important component of cancer control programs for the growing burden in sub-Saharan Africa is a population's awareness of risk factors. Studies thereof have focused on single rather than multiple cancers and carcinogens. During March and April 2015, we undertook a survey to assess awareness of multiple cancer risk factors and symptoms in the Kilimanjaro Region, North Tanzania. General population (n = 620) and attendees at HIV care-and-treatment clinics (CTCs) were included (n = 207). Participants' mean age was 43.8 (interquartile range 30-52) years; 58% were female. Awareness of cancer risk was highest for tobacco (90%) and alcoholic spirits (67%), but tended to be lower for infections (41% for HIV (42.2% and 41.4% for CTC and community group, respectively) and 16% for HPV (16.0% and 16.6% for CTC and community group, respectively)), while that of moldy maize and peanuts was 35% for both. Awareness of specific cancer signs and symptoms ranged between 70% and 90%. Awareness of alcohol and tobacco was higher in men than women (odds ratio = 1.82 (1.38, 2.40) and 3.96 (2.14, 7.31), respectively). In relation to cancer treatment, 70% preferred modern medicine and 10% preferred traditional medicine alone. Sixty percent was not aware of any local cancer early detection services. Only 20% had ever been examined for cancer, and of those screened, CTC group was 1.5 times more likely to screen than community participants. Awareness did not differ by age or HIV status. There are good levels of cancer risk factor awareness for certain lifestyle-related carcinogens in Tanzania; however, increased awareness is needed especially for infections and cancer warning symptom both in the general and HIV-positive population, as well as some myths to be dispelled.