Dietary fluoride intake of 15-19-year-old male adults residing in the United States

Patterns of fluoride intake from 6 to 17 years of age: The Iowa Fluoride Study

OBJECTIVES

This article reports on estimated daily fluoride intake from water, other beverages and selected foods, dentifrice, and dietary fluoride supplements by both individual sources, and all sources combined, among 787 children participating in the Iowa Fluoride Study (IFS) from 6 to 17 years of age.

METHODS

Total daily fluoride intake (mg F) and fluoride intake per kilogram bodyweight (mg F/kg bw) were estimated using responses to questionnaires sent every 3-6 months. Dietary assessments included frequencies and amounts of beverage intake for the previous week from water, milk, ready-to-drink beverages, beverages made by adding water to concentrate or powder, and selected foods with substantial water content. Descriptive statistics and bivariate and multivariable analyses with linear mixed models were used to assess associations with each of mg F and mg F/kg bw.

RESULTS

Mean combined dietary fluoride (mg F) from all sources examined in the study increased slightly with age, whereas the fluoride intake per kg bw decreased with age. Age, sex, and socioeconomic status were significantly associated with fluoride intake (mg F and mg F/kg bw). Each year increase in age was associated with a 0.02-mg increase in fluoride consumption, on average, after adjusting for the effects of covariates.

CONCLUSIONS

Daily mean fluoride intakes from single and combined sources were relatively stable, while the intake of fluoride per kg bw decreased from 6 to 17 years of age. Fluoridated water was the major source of ingested fluoride, contributing over 50% of total daily intake at all ages.

Fluoride exposure and factors affecting dental caries in preschool children living in two areas with different natural levels of fluorides

BACKGROUND

Successful oral health interventions must be based on the specific needs of the population that they serve. Evaluation of habits related to dental caries development and estimation of fluoride exposure in a target group of young patients helps to plan effective and safe caries prevention strategies.

OBJECTIVES

The study aimed to evaluate factors affecting dental caries experience and sources of fluoride exposure in preschool children living in two areas: with optimal and low natural content of fluoride in drinking water.

MATERIALS AND METHODS

The study included a group of 73 children of both sexes aged 4-7 years attending two kindergartens in Środa Wielkopolska and Turek (Wielkopolska Voivodeship, Poland), where the content of fluoride in drinking water according to data obtained in the sanitary station ranged from 0.68 to 0.74 mg/L (optimal concentration of fluoride) and from 0.19 to 0.30 mg/L (low concentration of fluoride), respectively. Parents of patients completed a survey about diet, hygiene, and dental care, taking into account the child's fluoride exposure. The calibrated dentist assessed the oral health condition using a mirror, a CPI probe, and a headlamp. Oral hygiene was recorded using the Silness and Löe plaque index, caries experience by calculating the numbers of decayed, missing, and filled primary, and permanent teeth (dmf and DMF, respectively) while caries frequency by calculating the percentage of children with caries experience above 0. In order to assess the fluoride concentrations in urine and drinking water, parents were asked to provide a urine sample collected on fasting and a tap water sample. Fluoride concentrations were assessed using a 09-37 (MARAT) fluoride ion-selective electrode and a RAE 111 silver-chloride reference electrode. Statistical analysis was conducted using the data analysis software system Statistica (version 12, StatSoft, Inc. 2014), assuming a statistical significance level p < 0.05.

RESULTS

No statistically significant differences were found between caries indices of the examined children in each kindergarten (p > 0.05). Urinary fluoride levels were higher in children who tended to swallow toothpaste or used fluoride rinses and positively correlated with fluoride concentrations in the drinking water. Dental caries experience in the examined children depended on the effectiveness and frequency of oral hygiene procedures and dietary habits.

CONCLUSIONS

The strategy aimed at improving the oral health of the examined group of children should include accomplishing oral hygiene, promoting a non-cariogenic diet, and, finally, controlling fluoride exposure from at-home fluoride products. Caries prevention program ought to be adjusted to individual characteristics of each child, taking into consideration oral hygiene practices, dietary habits and total fluoride intake.

Chemical Aspects of Human and Environmental Overload with Fluorine

Over the last 100-120 years, due to the ever-increasing importance of fluorine-containing compounds in modern technology and daily life, the explosive development of the fluorochemical industry led to an enormous increase of emission of fluoride ions into the biosphere. This made it more and more important to understand the biological activities, metabolism, degradation, and possible environmental hazards of such substances. This comprehensive and critical review focuses on the effects of fluoride ions and organofluorine compounds (mainly pharmaceuticals and agrochemicals) on human health and the environment. To give a better overview, various connected topics are also discussed: reasons and trends of the advance of fluorine-containing pharmaceuticals and agrochemicals, metabolism of fluorinated drugs, withdrawn fluorinated drugs, natural sources of organic and inorganic fluorine compounds in the environment (including the biosphere), sources of fluoride intake, and finally biomarkers of fluoride exposure.

Association between fluoride, magnesium, aluminum and bone quality in renal osteodystrophy

INTRODUCTION

Trace elements are known to influence bone metabolism; however, their effects may be exacerbated in renal failure because dialysis patients are unable to excrete excess elements properly. Our study correlated bone quality in dialysis patients with levels of bone fluoride, magnesium, and aluminum. A number of studies have linked trace elements, including fluoride, magnesium, and aluminum, to the development of renal osteodystrophy (ROD). However, little is known about the relationship between trace elements and changes in bone quality in ROD patients. The purpose of this study was to examine bone quality in ROD patients, and correlate differences in bone quality to trace element concentrations in bone. Bone quality encompasses parameters that contribute to the mechanical integrity of the bone.

METHODS

One hundred fifty-three anterior iliac crest bone biopsies from patients with ROD were examined and subdivided into five groups based on the pathological features. Parameters contributing to bone quality, such as bone structure and remodeling, connectivity, mineralization, and microhardness, were assessed and correlated to bone chemical composition. In addition, clinical symptoms of ROD were assessed and correlated with bone composition.

RESULTS AND CONCLUSIONS

There were no differences in bone architecture between the different ROD bone groups; however, differences in bone mineralization and microhardness were observed. Increase in bone fluoride was associated with increased osteoid parameters and decreased bone microhardness. Bone mineralization and microhardness decreased with increasing bone magnesium content and intact parathyroid hormone (PTH) level. Moreover, bone magnesium increased with intact PTH levels. The relationship between PTH, bone magnesium, mineralization, and microhardness was primarily observed in aplastic bone disorder. Furthermore, bone magnesium and aluminum contents were positively associated with bone pain and proximal myopathy in these patients. Most importantly, fluoride, magnesium, and aluminum showed significant correlations with one another. These results suggested that in ROD, bone fluoride may diminish bone microhardness by interfering with mineralization. Magnesium may be involved in the suppression of PTH secretion, lowering bone turnover thus leading to an increase in bone mineralization profile and microhardness in aplastic bone disorder. The effects of fluoride and magnesium on bone quality may be exacerbated by their interaction with aluminum.

The fluoride content of foods and beverages from negligibly and optimally fluoridated communities

In the spring of 1996, foods and beverages most commonly consumed by adolescents were analyzed for fluoride as part of a larger investigation. These foods were selected by interviewing 711 adolescents, 12-14 years of age, who were long-time residents of either an optimally or negligibly fluoridated community. The brand names of the identified foods and beverages most commonly purchased were determined by interviews with the parents. A total of 441 brand-name food and beverage items were purchased from both communities and were individually analyzed for fluoride. These analyses were done in order to estimate the fluoride content of various kinds of foods and beverages and to determine whether or not there was a significant difference between the two communities in the amount of fluoride ingested from these dietary sources. The food and beverage items were classified into dietary groups based on US Department of Agriculture (USDA) guidelines. Overall, the fluoride content of the sampled foods and beverages was low. In addition, there was no significant difference in the fluoride content of the same pre-packaged or ready-to-eat food or beverage items purchased in the two communities. However, a significant difference was found between the two communities in the fluoride content of fountain beverages and in cooked or reconstituted foods prepared using local water from the respective communities. Based on these results, we have estimated the mean daily, dietary fluoride intake for 3-5-year-old children who are more susceptible to developing dental fluorosis.

Salt fluoridation and general health

Salt fluoridation is a systemic form of fluoride supplementation, leaving it to the consumer whether he wants fluoride supplements or not, but thereafter not requiring special dependability for daily compliance. Most German drinking water has low fluoride concentrations. The estimated fluoride intake in German children is between 100 and 300 micrograms/day, and in adults, between 400 and 600 micrograms/day. Male subjects have higher mean intakes than females. From 70 to 90% of the salt intake of 10 to 13.5 g/day in German adults comes from commercially prepared foods. This leaves about 1 to 4 g of salt to be added as table salt at the individual level and to become the source of supplementary fluoride. To increase fluoride intake by at least 500 micrograms/d, and to prevent an additional intake of more than 3000 micrograms/day, it may be necessary to have salt at a fluoride level of around 500 micrograms/g or to include one commercial food to be prepared with fluoridated salt, e.g., bread. A salt fluoride concentration of 250 micrograms/g does not present a risk of dental fluorosis. However, clear recommendations about systemic fluoride supplementation must be given as long as there are fluoride tablets, fluoride-rich mineral waters, and fluoridated table salt available simultaneously. Persons at risk for hypertension from salt consumption require different means of fluoride supplementation. By and large, in areas of low drinking water fluoride, fluoridated table salt has the potential to become a means of systemic supplementation comparable with drinking water fluoridation.

Fluoride supplements: current effectiveness, side effects, and recommendations

A critical review of the literature was conducted to determine the current effectiveness of fluoride supplements in caries prevention and their role as risk factors for dental fluorosis. Use of fluoride supplements by young children is idiosyncratic and all of the studies which investigated the effectiveness of this regimen suffered from a significant drop in the number of participants receiving daily supplements. The scientific evidence supports the efficacy of fluoride supplements in caries prevention but there is weaker support for their effectiveness. Fluoride supplements are a risk factor for dental fluorosis, though their contribution to the increase in fluorosis prevalence is less than that of water fluoridation and fluoridated dentifrices because of their more limited and shorter use. There is also evidence that fluoride supplements are used inappropriately in fluoridated areas. The availability of optimal levels of fluorides in beverages in non-fluoridated communities raises the question of whether fluoride supplements are needed in the 1990s, and whether it is time to consider the total fluoride intake not only from water but also from foods, beverages, and dentifrices, when recommending supplements. A re-evaluation of the need for and dosage schedules of fluoride supplements is warranted.

Water fluoridation: current effectiveness and dental fluorosis

This paper reviewed the literature on the evidence for water fluoridation's effectiveness under current conditions of multiple fluoride use at recommended and at reduced concentrations, the extent of dental fluorosis at different fluoride concentrations, and the "halo" effect of water fluoridation. Using the relative difference in dental caries between communities with low and optimal water fluoride as an indicator, the effectiveness of water fluoridation has decreased over time as the use of other fluorides has increased. Thus the effectiveness of water fluoridation alone cannot now be determined. Compared to the early fluoridation studies, the differences in dental caries and fluorosis prevalence between fluoridated and non-fluoridated areas have markedly narrowed. Both the prevalence and severity of dental fluorosis have increased since 1945; however, the portion of fluorosis due to water fluoridation is now less (40%) than that attributed to other fluoride sources (60%). Research also suggests that the "halo" effect of community water fluoridation may result in a significantly greater intake of fluoride for people in non-fluoridated communities. This review recognized that since water fluoridation has unique advantages from the perspectives of distribution, equity, compliance and cost-effectiveness over other fluoride technologies, it remains as the fundamental base for caries prevention. The increasingly greater contribution that other sources of fluoride make to dental fluorosis suggests that these sources of fluoride, many of which are used on an elective basis, should be more closely examined for needed changes.

Fluoridation effects on periodontal disease among adults

Numerous studies report that water fluoridation reduces caries in children, but little current evidence exists about fluoridation's effects on the periodontal health of adults. To address this issue, we estimated fluoridation effects on periodontal disease among 1066 Washington state employees and their spouses, aged 20 to 34, with current residences divided evenly between fluoridated and nonfluoridated communities. Subjects were interviewed by telephone to collect residence histories, personal characteristics and other data. Each subject's lifetime years of fluoridation exposure (YFE) was calculated from the person's residence history and the U.S. Centers for Disease Control's Fluoridation Census. Oral assessments were conducted to measure the extent of periodontal disease. Relative to adults with no exposure, continuous lifetime exposure reduced the probability of attachment loss from 0.87 to 0.72. Similar benefits were obtained for bleeding gingiva and calculus. The estimates of fluoridation's benefits were not influenced by selection bias due to subjects' nonparticipation in the oral assessments.

The changing patterns of systemic fluoride intake

Fluorosis prevalence has increased in North America since the 1930's-1940's. It may also have increased since 1970, though the evidence for that is less clear. Continued monitoring will help determine whether increased fluorosis prevalence in children in the United States is a cohort effect from the 1970's. This review considers the evidence for an increase in fluoride ingestion from all sources since the 1970's. If an increase has occurred, the most likely sources are fluoride dietary supplements, inadvertent swallowing of fluoride toothpastes, and increased fluoride in food and beverages. For adults, there is no evidence from dietary surveys to show that fluoride intake has increased over the last generation. Dietary surveys for children aged six months to two years are similarly inconclusive, though the great variation in fluoride content of various infant foods might be obscuring real effects. The data on fluoride intake by children from food and beverages, infant foods included, are not strong enough to conclude that an increase in fluoride ingestion has occurred since the 1970's. However, the suggested upper limit of fluoride intake is substantially being reached in many children by ingestion of fluoride from food and drink (0.2-0.3 mg per day) and from fluoride toothpaste (0.2-0.3 mg per day). Two public health issues that arise from this review are: (a) the need for a downward revision in the schedule for fluoride supplementation, and (b) education on the potential for high fluoride concentration of soft drinks and processed fruit juices.

How fluoridation affects adult dental caries

Oral assessments conducted to measure caries experience in adults reveal that, on average, each year of exposure to fluoridated water reduced DFS by 0.29 surfaces. Fluoridation appears to have both pre- and post-eruptive benefits.

Fluoride: benefits and risks of exposure

This summarizes current knowledge of the benefits and risks of fluoride ingestion. The preponderance of evidence indicates that fluoride can reduce the incidence of dental caries and that fluoridation of drinking water can provide such protection. Due to the ubiquitous nature of exposures to fluoride sources other than drinking water, it is currently impossible to draw firm conclusions regarding the independent effect of fluoride in drinking water on caries prevalence using an ecologic study design. Moderate dental fluorosis occurs in 1 to 2% of the population exposed to fluoride at 1 mg/l in drinking water and in about 10% of the population at 2 mg/l; moderate/severe fluorosis occurs in variable percentages ranging up to 33% of the population exposed to fluoride at 2.4 to 4.1 mg/l in drinking water. The issue of whether moderate or severe dental fluorosis represents an adverse health effect is still controversial. There is no evidence of skeletal fluorosis among the general U.S. population exposed to drinking water fluoride concentrations lower than 4 mg/l. Radiographically detected osteosclerosis after chronic exposure to fluoride in drinking water at 8 mg/l was not associated with clinical symptoms. Reports of crippling skeletal fluorosis associated with low concentrations of fluoride in drinking water in tropical countries have been attributed to other dietary factors. The available data suggest that some individuals may experience hypersensitivity to fluoride-containing agents. Further studies on hypersensitivity are required. There is no evidence of increased incidence of renal disease or renal dysfunction in humans exposed to up to 8 mg fluoride per liter in drinking water. Structural changes in kidneys of experimental animals have been detected at doses exceeding 1 to 5 mg fluoride per kilogram per day. Based on four case reports, individuals with renal insufficiency who consume large volumes of naturally fluoridated water at 2 to 8 mg/l are possibly at increased risk of developing skeletal fluorosis. Studies on the effects of fluoride in individuals with renal insufficiency are needed. There is no evidence that chronic exposure to concentrations of fluoride reported to be greater than 2 mg/l in drinking water increases human cancer mortality or incidence. A study of lifetime exposure to fluoride on cancer incidence in rats and mice has been completed, but assessment for cancer has not been completed. There is no evidence that fluoride is genotoxic except in some in vitro assays at cytotoxic concentrations. There is no in vivo evidence that fluoride affects human cellular enzyme activities.(ABSTRACT TRUNCATED AT 400 WORDS)

Trends in the prevalence of dental fluorosis in the United States: a review

This paper assesses, by comparing recent published evidence with Dean's pioneering work, whether an increase in the milder forms of dental fluorosis may have occurred since Dean's time. To the extent that the crude comparisons of recent research with historic studies are valid, the data indicate a slight trend toward more fluorosis today than would be expected based upon findings in the late 1930s and early 1940s. This suggested increase in fluorosis is not as clear-cut nor as widely accepted as the recent decline in the prevalence of dental caries. Thus, further study of the prevalence of fluorosis and caries in relation to fluoride ingestion will be required to help validate the trend, and to allow dental researchers and decision makers to plan for the future.