The role of oral hygiene in head and neck cancer: Results from International Head and Neck Cancer Epidemiology (INHANCE) Consortium

Dana HASHIM, Icahn School of Medicine at Mount Sinai, United States
SARTORI S. 1 , BRENNAN P. 2 , CURADO M. 3 , WÜNSCH-FILHO V. 3 , OLSHAN A. 4 , ZEVALLOS J. 4 , WINN D. 5 , FRANCESCHI S. 2 , CASTELLSAGUÉ X. 6 , LISSOWSKA J. 7 , RUDNAI P. 8 , MATSUO K. 9 , MORGENSTERN H. 10 , BOFFETTA P. 1

1 Department of Preventive Medicine and Department of Translational Epidemiology, Icahn School of Medicine at Mount Sinai, New York, NY USA
2 Genetic Epidemiology Group, International Agency for Research on Cancer, Lyon, France
3 Epidemiology- CIPE/ACCAMARGO and Faculdade de Saúde Pública, Universidade de São Paulo, Sao Paulo, Brazil
4 Department of Pediatric Dentistry and Department of Epidemiology, University of North Carolina School of Public Health, Chapel Hill, NC, USA
5 Division of Cancer Control and Population Sciences, National Cancer Institute, Bethesda, MD
6 Catalan Institute of Oncology (ICO)-IDIBELL, L'Hospitalet de Llobregat, Catalonia, Spain; CIBER de Epidemiología y Salud Pública (CIBERESP), Spain
7 The M. Skasodowska-Curie Memorial Cancer Center and Institute of Oncology, Dept. of Cancer Epidemiology and Prevention, Warsaw, Poland
8 National Public Health Center, Budapest, Hungary.
9 Division of Molecular Medicine, Aichi Cancer Center Research Institute, Nagoya, Japan
10 Departments of Epidemiology and Environmental Health Sciences, School of Public Health and Comprehensive Cancer Center, University of Michigan, Ann Arbor, MI, USA

Background: Poor oral hygiene has been proposed to contribute to head and neck cancer (HNC) risk although causality and independency of some indicators are uncertain.  This study investigates the relationship of five oral hygiene indicators with incident HNCs.

Methods:  In a pooled analysis of 8399 HNC cases and 9425 controls from 13 studies participating in the International Head and Neck Cancer Epidemiology Consortium, comparable data on good oral hygiene indicators were harmonized.  These included: no denture wear, no gum disease (or bleeding), < 5 missing teeth, tooth brushing at least daily, and visiting a dentist at least once a year.  Logistic regression was used to estimate effects of each oral hygiene indicator and cumulative score on HNC risk, adjusting for tobacco smoking and alcohol consumption.

Results:  Inverse associations with any HNC, in the hypothesized direction, were observed for < 5 missing teeth (OR 0.78; 95% CI: 0.74, 0.82), annual dentist visit (OR 0.82; 95% CI: 0.78, 0.87), daily tooth brushing (OR 0.83; 95% CI: 0.79, 0.88), and no gum disease (OR 0.94; 95% CI: 0.89, 0.99), and no association was observed for wearing dentures.  These associations were relatively consistent across specific cancer sites, especially for tooth brushing and dentist visits.  The population attributable fraction for lacking at least 2 out of 5 good oral hygiene indicators was 8.9(95% CI: 3.3%-14%) for oral cavity cancers.

Conclusion:  Good oral hygiene, as characterized by few missing teeth, annual dentist visits, and daily tooth brushing, may modestly reduce the risk of HNC.

Funding:  This study and the INHANCE consortium are supported by NIH grants NCI R03CA113157 and NIDCR R03DE016611 as well as partially supported by government grants from each of the instituions of individual participating countries.