Urinary Fluoride Levels among Canadians with and without Community Water Fluoridation

Abstract

Drinking water is a major source of dietary fluoride intake in communities with water fluoridation. We examined the association between urinary fluoride adjusted for specific gravity (UFSG) and tap water fluoride levels, by age and sex, among individuals living in Canada. Participants included 1629 individuals aged 3 to 79 years from Cycle 3 (2012–2013) of the Canadian Health Measures Survey. We used multiple linear regression to estimate unique associations of tap water fluoride levels, age, sex, ethnicity, body mass index (BMI), use of fluoride-containing dental products, smoking in the home, and tea consumption with UFSG. UFSG concentration was significantly higher among participants who received fluoridated drinking water (mean = 1.06 mg/L, standard deviation = 0.83) than among those who did not (M = 0.58 mg/L, SD = 0.47), p < 0.01. UFSG increased over adulthood (ages 19 to 79). Higher UFSG concentration was associated with being female, tea drinking, and smoking in the home. In conclusion, community water fluoridation is a major source of contemporary fluoride exposure for Canadians. Lifestyle factors including tea consumption, as well as demographic variables such as age and sex, also predict urinary fluoride level, and are therefore important factors when interpreting population-based fluoride biomonitoring data.

Flawed MIREC fluoride and intelligence quotient publications: A failed attempt to undermine community water fluoridation

“…For example, if the individual had just brushed her teeth with fluoridated toothpaste or had just drunk black tea (which has high fluoride levels), then the spot urine test would misrepresent her average fluoride exposure in a day; current or concurrent exposure measurements are not useful because they are so variable. Indeed, some of the MIREC fluoride‐IQ authors, who assert that maternal fluoride exposure is associated with decreased IQ, have conceded that spot urine tests are not useful in estimating the duration and persistence of fluoride exposure, such as here: 15

[U]se of one spot urine sample may have introduced error given the short half‐life of fluoride and the impact of consuming tea or inadvertent ingestion of fluoridated dental products prior to urine sampling. […]Taken together, urinary fluoride level varies substantially depending on participant behaviour prior to sampling and may not be representative of long‐term fluoride exposure.

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Fluoride in the Central Nervous System and Its Potential Influence on the Development and Invasiveness of Brain Tumours—A Research Hypothesis

“…Consequently, drinking water, which may also be artificially fluoridated as a public health measure, and food are major sources of fluoride uptake in humans. The degree of fluoride exposure is affected by the quality of food and water, the amount consumed, as well as individual variability [ 36 , 37 , 38 , 39 ].…”

Strategies and Challenges in the Treatment of Dental Enamel

“…Fluoride ion replacement with hydroxyl is not complete and is limited, significantly reducing tooth decay and remineralising the tooth [Hicks et al, 2003;Ali et al, 2020]. Most fluoride consumed by people comes from food, fluoridated water and beverages made with fluoridated water, and toothpaste and other fluoride-containing dental products [Fernandes et al, 2021;Riddell et al, 2021]. Saliva-soluble fluoride can inhibit bacterial growth, prevent enamel demineralization, and ultimately lead to remineralization.…”