Relationship of fluoride in drinking water with blood pressure and essential hypertension prevalence: a systematic review and meta-analysis

Abstract

Previous studies showed controversial results of the relationship between fluoride exposure through drinking water and elevated blood pressure. We conducted a systematic review and meta-analysis to assess the direct relationship of drinking water fluoride exposure with blood pressure and essential hypertension prevalence in general populations. We conducted a systematic search in databases including Web of Knowledge, PubMed, Scopus, and Embase by MeSH and non-MeSH terms for relevant studies with any design published until August 2019, with no limitation in time and language. The pooled effect measure was calculated within a 95% confidence interval (CI). Our search retrieved 630 journal articles, six of which were eligible for data extraction. The random-effects model found significantly higher systolic blood pressure (mean difference = 6.49mmHg; 95% CI 3.73-9.25; p value < 0.01) and diastolic blood pressure (mean difference = 4.33mmHg; 95% CI 1.39-7.26; p value < 0.01) in groups exposed to high-fluoride drinking water than in groups exposed to normal/low-fluoride drinking water. A significant relationship was also found between high-fluoride drinking water and essential hypertension (odds ratio = 2.14; 95% CI 1.02-4.49; p value = 0.045). The risk of elevated blood pressure increases in the general population of fluoride endemic areas. However, more research is needed to make a firm conclusion about the adverse effects of excess fluoride intake on the cardiovascular system at the individual level.