Oral Health Care Behaviors and Periodontal Disease Among Older Adults with Diabetes Mellitus in Northern Thailand

Introduction: Periodontal disease is a major oral health problem among older adults with type 2 diabetes mellitus (T2DM). However, evidence regarding its association with oral health care behaviors in Northern Thailand is limited. This study aimed to assess oral health care behaviors and periodontitis and examine their associated factors among older adults with T2DM. Methods: A cross-sectional study was conducted among 369 older adults with T2DM in Mueang Phayao District, Northern Thailand. Seven subdistricts were selected using simple random sampling, after which eligible participants were recruited through convenience and snowball sampling. Data was collected using structured questionnaires and standardized oral examinations performed by dentists. Results: The mean oral health care behavior score was 29.51 out of 45, and periodontitis was present in 37.4% of the participants. Multivariable linear regression showed that oral health care behavior scores were significantly associated with oral health care knowledge scores (B = 1.052, p < 0.001), diabetes knowledge scores (B = 1.068, p < 0.001), FBS ≥ 126 mg/dL (B = −0.599, p = 0.027), and HbA1c ≥ 6.5% (B = −0.689, p = 0.016). Multivariable logistic regression showed higher odds of periodontitis among participants aged ≥70 years (AOR = 2.38, 95% CI: 1.45–3.89), with a diabetes duration of ≥11 years (AOR = 2.15, 95% CI: 1.21–3.82), who smoked (AOR = 12.62, 95% CI: 4.22–37.75), and with HbA1c ≥ 6.5% (AOR = 1.94, 95% CI: 1.11–3.41), while higher oral health care behavior scores were associated with lower odds (AOR = 0.88, 95% CI: 0.81–0.95). Conclusions: Advanced age, longer diabetes duration, smoking, and poor glycemic control were significantly associated with higher odds of periodontitis, whereas better oral health care behaviors were associated with lower odds. These findings support the integration of periodontal screening into diabetes care and the expansion of community-based oral health promotion for older adults with T2DM in primary care settings.