Association of Dental Scaling with Lower Risk of Spontaneous Intracranial Haemorrhage: a Cohort Study in Taiwan

Background and Purpose: Spontaneous intracranial haemorrhage (ICH) has high fatality or varying degrees of disability while has few proven treatments. This study aims at investigating the association between dental scaling (DS) and risk of ICH. Methods: In this cohort study, two cohorts were matched by propensity score based on potential confounders. Data of ICH between January 2008 and December 2014 from Taiwan was analysed. The subjects underwent DS at least 6 times between January 1, 2002 and December 31, 2007, while the matched controls did not undergo any DS during the same period. Cumulative incidences and hazard ratios (HRs) were calculated after adjusting for competing confounders. Results: Each cohort consisted of 681,126 subjects. Compared with the non-DS cohort, the regular-DS cohort had a significantly lower incidence of ICH (0.8% vs 1.2%; P < 0.0001), and the adjusted hazards ratio (aHR) of 7-year ICH was 0.61 (95% confidence interval, CI, 0.59-0.63; P < 0.0001). The 30-39-year age group of regular-DS cohort had the lowest HR (0.57; 95% CI, 0.52-0.61; P < 0.0001) of 7-year ICH when compared with similar controls. Compared with the controls, the regular-DS cohort also had significantly lower HR (0.82; 95% CI, 0.81-0.82; P < 0.0001) of 7-year hypertension. Compared with those without DS, lowest risk of intracerebral haemorrhage was observed in the male participants with regular DS (0.43; 95% CI, 0.40-0.47; P < 0.0001). Conclusions: Adherence to regular DS was consistently associated with lower ICH risk in subjects aged 30-59 years, indicating the role of DS in ICH prophylaxis.