Assessing Significance of Risk Factors

Data on risk factors, which in this study were considered to be confounding variables, were collected from participants’ responses on their original WHI-OS enrollment forms. Risk factors assessed included demographics (age, race/ethnicity, educational level, region of residence), medical history (family history of cancer, history of diabetes), health behaviors (recreational physical activity, smoking status, pack-years of smoking, secondhand smoke exposure), diet and nutrition (alcohol consumption, total dietary energy intake, fruit and vegetable intake, total [dietary and supplement] intake of calcium and vitamin D), and menopausal hormone therapy use.1 Participants’ weight and height were also measured at enrollment, and trained examiners at the clinical centers calculated their body mass index (BMI).


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However, none of those factors increased the risk of developing cancer in an appreciable way — not even smoking.1 A statistically significant increase in total cancer risk of 14% was seen in participants with a history of periodontal disease, making it the most significant risk factor in this study.1 “Our findings demonstrate that periodontal disease history is associated with an increased risk of total cancer in this cohort of postmenopausal women, and persists regardless of smoking status,” reported the researchers.1

In addition to demonstrating the link between breast, esophageal, lung, and melanoma skin cancers and periodontal disease, this study also found a relationship between gallbladder cancer and periodontal disease. Interestingly, periodontal disease was not associated with cancer of the liver, pancreas, or lower digestive tract.

Jean Wactawski-Wende, PhD, dean of the School of Public Health and Health Professions and a SUNY distinguished professor at the University at Buffalo, and senior investigator of the study described results from another study on the risk of cancer related to periodontal disease in women, the OsteoPerio Study, which did not rely on data from self-reports. This ongoing study includes more than 1000 WHI participants from the University at Buffalo center. In this smaller cohort, participants underwent comprehensive periodontal assessments; investigators also found risk of cancer was higher among those with a history of periodontal disease. “However, the small sample size limited our ability to look carefully at specific cancer sites,” said Dr Wactawski-Wende. “We continue to follow these women and are now looking at the microbiome in the plaque samples taken from the women.”6

Dental Hygiene as Preventive Medicine

Research on the association between cancer and periodontal disease is of increasing public health importance. The Centers for Disease Control and Prevention (CDC) estimates that approximately 47.2% of adults aged 30 years and older in the United States have some form of periodontal disease, ranging from mild to severe. Furthermore, 70% of adults aged 65 years and older have moderate to severe periodontal disease.7 Dr Wactawski-Wende advises that proper dental hygiene is the most effective way to mitigate this risk. She said a good resource for both clinicians and patients is the American Academy of Periodontology.

References

1. Nwizu N, Marshall JR, Moysich K, et al. Periodontal disease and incident cancer risk among postmenopausal women: results from the Women’s Health Initiative Observational Cohort. Cancer Epidemiol Biomarkers Prev. 2017;26(8):1255-1265.

2. Wen BW, Tsai CS, Lin CL, et al. Cancer risk among gingivitis and periodontitis patients: a nationwide cohort study. QJM. 2014;107(4):283-290.

3. Michaud DS, Liu Y, Meyer M, Giovannucci E, Joshipura K. Periodontal disease, tooth loss, and cancer risk in male health professionals: a prospective cohort study. Lancet Oncol. 2008;9(6):550-558.

4. Tezal M, Sullivan MA, Hyland A, et al. Chronic periodontitis and the incidence of head and neck

squamous cell carcinoma. Cancer Epidemiol Biomarkers Prev 2009;18(9):2406-2412.

5. Anderson G, Cummings S, Freedman LS, et al. Design of the Women’s Health Initiative clinical trial and observational study. The Women’s Health Initiative Study Group. Control Clin Trials 1998;19(1):61-109.

6. Mai X, LaMonte MJ, Hovey KM, et al. Periodontal disease severity and cancer risk in postmenopausal women: the Buffalo OsteoPerio Study. Cancer Causes Control. 2016;27(2):217-228.

7. CDC: half of American adults have periodontal disease [news release]. Chicago, IL: American Academy of Periodontology; September 4, 2012. https://www.perio.org/consumer/cdc-study.htm.  Accessed August 16, 2017.