Association Between Osteoarthritis and Water Fluoride Among Tongyu Residents, China 2019: A Case-control of Population-based Study
Abstract Background: Fluoride is an environmental chemical that has adverse effects on health, probably increasing osteoarthritis (OA) risk. However, whether fluoride is a serious risk factor for OA is still inconsistent among current evidence. The aim of this study was to determine the relationships between chronic fluoride exposure and OA risk among the residents living in Tongyu County, China 2019.Method: 186 cases and 186 controls aged 26 to 86 years were recruited after x-ray examination with Kellgren and Lawrence criteria by two independent evaluators. Urinary fluoride (UF) in a spot sample was measured by fluoride ion-selective electrode, and water fluoride data were used as community level of exposure. Associations between fluoride exposure and OA risk were examined by the unconditional logistic regression. Covariates included age, gender, body mass index, duration of living, daily water drunk, income, sport and filter use with stratified analysis.Results: Mean UF concentration 2.54 ± 1.22 mg/L was higher than the mean of community water fluoride concentration 1.49 ± 0.32 mg/L. The mean UF concentration 2.73 ± 1.18 mg/L was significantly higher in cases compared to 2.35 ± 1.24 mg/L in controls group (p < 0.02). In full sample analysis, a 1mg/L increase in UF level was associated with a 27% higher risk of OA (95% CI: 1.06 - 1.52, p = 0.008), and 4th quartile participants were associated with higher risk when compared to 1st quartile (OR: 2.46, 95% CI: 1.34 – 4.57, p = 0.003). In stratified analysis, compared to 1st quartile, 4th quartile participants were 4 times more likely to have OA (95% CI: 1.86 – 8.82, p = 0.000) in the non-obese group, 7.7 times more likely to have OA (95% CI: 2.58 – 25.05, p = 0.000) among adults ≤ 60-year and 12 times more likely to have OA (95% CI: 2.15 – 99.65, p = 0.008) in non-obese adult women ≤ 60-year group.Conclusion: Water fluoride exposure may increase OA risk and could have more impact on a specific group such as non-obese and adult ≤ 60-year population.