Neutrophil-to-lymphocyte ratio in periodontitis and after subgingival instrumentation in Cameroon: a controlled observational study with prospective follow-up

Periodontitis is associated with low-grade systemic inflammation, and the neutrophil-to-lymphocyte ratio (NLR) is a low-cost blood-cell-derived inflammatory index. Evidence from sub-Saharan African populations remains limited. This study compared baseline NLR between Cameroonian adults with and without periodontitis and described short-term NLR changes after subgingival instrumentation (SI). This controlled observational study comprised a baseline comparison of 102 adults selected according to pre-existing periodontal status (51 with stage II-IV periodontitis and 51 periodontally healthy controls) and prospective follow-up of the periodontitis group. Clinical and hematological parameters were measured at baseline. Participants with periodontitis received full-mouth SI as clinically indicated care independent of study participation and were reassessed one month after completion of the final session. Baseline NLR was log-transformed and analyzed using multivariable linear regression adjusted for age, sex, and education level, with heteroscedasticity-consistent standard errors. At baseline, median NLR was 1.15 [1.00-1.25] in the periodontitis group and 0.89 [0.70–0.98] in controls. After adjustment, the geometric mean NLR was 1.38 times higher in the periodontitis group (95% CI 1.27–1.50; p < 0.001). One month after SI, mean NLR decreased from 1.13 ± 0.18 to 0.89 ± 0.19 (mean change − 0.24, 95% CI -0.25 to -0.23; p < 0.001). Adults with periodontitis had higher baseline NLR than healthy controls, and a lower NLR was observed one month after SI in the periodontitis group. This temporal finding warrants confirmation in controlled studies evaluating the potential role of NLR in periodontal monitoring.