Fluoridation and the Rheumatic Diseases: A Comparison of Rheumatism in Watford and Leigh

A systematic search and narrative review of radiographic definitions of hand osteoarthritis in population-based studies

OBJECTIVE

Currently there is no agreed "gold standard" definition of radiographic hand osteoarthritis (RHOA) for use in epidemiological studies. We therefore undertook a systematic search and narrative review of community-based epidemiological studies of hand osteoarthritis (OA) to identify (1) grading systems used, (2) definitions of radiographic OA for individual joints and (3) definitions of overall RHOA.

METHODS

The following electronic databases were searched: Medline, Embase, Science Citation Index and Ageline (inception to Dec 2006). The search strategy combined terms for "hand" and specific joint sites, OA and radiography. Inclusion and exclusion criteria were applied. Data were extracted from each paper covering: hand joints studied, grading system used, definitions applied for OA at individual joints and overall RHOA.

RESULTS

Titles and abstracts of 829 publications were reviewed and the full texts of 399 papers were obtained. One hundred fifty-two met the inclusion criteria and 24 additional papers identified from screening references. Kellgren and Lawrence (K&L) was the most frequently applied grading system used in 80% (n=141) of studies. In 71 studies defining OA at the individual joint level 69 (97%) used a definition of K&L grade > or = 2. Only 53 publications defined overall RHOA, using 21 different definitions based on five grading systems.

CONCLUSION

The K&L scheme remains the most frequently used grading system. There is a consistency in defining OA in a single hand joint as K&L grade > or = 2. However, there are substantial variations in the definitions of overall RHOA in epidemiological studies.

Water fluoridation, bone mass and fracture: a quantitative overview of the literature

OBJECTIVE

To use the technique of meta-analysis to address the following research questions: Is water fluoridation associated with altered fracture risk at a population level and are the differences between studies consistent with confounding or chance variation between studies?

METHOD

The data sources utilised were Medline 1966-97, reviews and bibliographies. The search terms were fluoridation, bone mass and/or fracture. We included all observational studies published in English relating water fluoridation to bone mass and/or fracture in the initial assessment.

RESULTS

Water fluoridation had no evident effect on fracture risk (RR 1.02, 95% CI 0.96-1.09, n = 18 studies). There was marked heterogeneity between studies which could be explained, in part, by the combination of gender, urbanicity and study quality (R2 0.25, p = 0.05, weighted analysis).

CONCLUSIONS

Water fluoridation both at levels aimed at preventing dental caries and, possibly, at higher naturally occurring levels appears to have little effect on fracture risk, either protective or deleterious, at a population level. The small effect on bone mass seen in studies performed at the individual level is consistent with this finding. Variation between studies is also likely to be due to differences in the distribution of other recognised fracture risk factors between different populations. Confirmation of these findings is required in large studies performed at the individual level.

The association between water-borne fluoride and bone mineral density in older adults

While the benefit of fluoridation in the prevention of dental caries has been overwhelmingly substantiated, the effect of fluoride on bone mineral density is less clear. This cross-sectional study was designed to compare the bone mineral densities of older adults exposed to various levels of fluoride from community water systems. Participants were recruited from 3 rural communities with naturally occurring fluoride in their water systems at 0.03, 0.7, and 2.5 mg/L. All adults, age 60 and over, were eligible if they were ambulatory and had a long-term history (> or = 20 yrs) of ingesting city water. Bone mineral density (BMD) was measured by means of dual-energy x-ray absorptiometry at 3 anatomical sites: lumbar spine, proximal femur, and forearm. A total of 353 white non-Hispanic women and 317 white non-Hispanic men took part in the study. When the data were stratified by city of residence and gender, men and women living in the community with high levels of fluoride in their community water system had significantly higher lumbar spine BMD than their counterparts from the communities with low and moderate fluoride levels. The women in the high-fluoride community had significantly higher proximal femur BMD, but there were no statistically significant differences among men in either proximal femur or forearm BMD. Long-term exposure (> or = 20 yrs) to higher levels of fluoride appears to have a positive impact on lumbar spine and proximal femur BMD. Based on the results of this study, exposure to fluoride at levels considered "optimal" for the prevention of dental caries (from 0.7 to 1.2 mg/L) appears to have no significant impact on bone mineral density. The relationship between higher levels of fluoride exposure and bone mineral density requires further investigation.

Fluoride and bone health

This paper reviews some of the studies related to the effect of fluoride on the skeletal system of humans and outlines the knowns and unknowns of fluoride and bone health. Current research indicates that, in large enough doses, fluoride stimulates bone formation by osteoblastic stimulation, increases bone formation earlier and to a larger extent in trabecular bone compared to cortical bone, and increases spinal bone density. There is controversy, however, concerning the efficacy of fluoride as a therapeutic agent in the treatment of osteoporosis. Some clinical studies have found a reduction in vertebral fracture rates while others have not. To date, only ecologic studies have been conducted on the association between water fluoridation and hip fractures. The inability of ecologic studies to control for confounding variables makes their interpretation difficult. Based on the literature presented, it is concluded that there are more unknowns than knowns in terms of fluoride's effect on bone, osteoporosis, and fractures. One of the major unknowns in the relationship between fluoride and bone health is dose and duration. Two studies are underway that attempt to describe the dose-response relationship between waterborne fluoride and osteoporosis. These studies will be completed in the near future and their results, while providing new insight into fluoride's effects on bone, will by no means answer all the questions raised on this issue.

The fluoridation of drinking water and hip fracture hospitalization rates in two Canadian communities

OBJECTIVES

The purpose of this study was to compare hip fracture hospitalization rates between a fluoridated and a non-fluoridated community in Alberta, Canada: Edmonton, which has had fluoridated drinking water since 1967, and Calgary, which considered fluoridation in 1991 but is currently revising this decision.

METHODS

Case subjects were all individuals aged 45 years or older residing in Edmonton or Calgary who were admitted to hospitals in Alberta between January 1, 1981, and December 31, 1987, and who had a discharge diagnosis of hip fracture. Edmonton rates were compared with Calgary rates, with adjustment for age and sex using the Edmonton population as a standard.

RESULTS

The hip fracture hospitalization rate for Edmonton from 1981 through 1987 was 2.77 per 1000 person-years. The age-sex standardized rate for Calgary was 2.78 per 1000 person-years. No statistically significant difference was observed in the overall rate, and only minor differences were observed within age and sex subgroups, with the Edmonton rates being higher in males.

CONCLUSIONS

These findings suggest that fluoridation of drinking water has no impact, neither beneficial nor deleterious, on the risk of hip fracture.

Schizophrenia and rheumatoid arthritis: a review

Fourteen epidemiologic studies of the relationship of rheumatoid arthritis to schizophrenia have been conducted between 1934 and 1985. Twelve of the studies report a lower-than-expected rate of rheumatoid arthritis in populations of schizophrenics. Methodologic weaknesses in the studies are assessed. Nutritional, hormonal, psychosocial, genetic, and immunologic data and theories are briefly reviewed which might explain the epidemiologic results. There is sufficient evidence for the negative association between the two disorders to justify further research.

Water-borne fluoride and cortical bone mass: a comparison of two communities

This study investigated the relationship between cortical bone mass in an older female population and their ingestion of fluoride from community water supplies. The study was conducted among lifelong female residents in Lordsburg (3.5 ppm fluoride) and Deming (0.7 ppm fluoride), NM. A total of 151 postmenopausal women ranging in age from 39 to 87 years took part; 69 were residents of the optimal-fluoride community, while the remaining 82 were residents of the high-fluoride community. Although bivariate analyses showed no difference in cortical bone mass between women in the two communities, with multiple regression analyses, significant predictors of bone mass (p less than 0.05) were weight, years since menopause, current estrogen supplementation, diabetes, and fluoride exposure status. Based on a model containing all of these variables, women living in the high-fluoride community had a bone mass ranging from 0.004 to 0.039 g/cm2 less than that of similar women living in the optimum-fluoride community. These results suggest that lifelong ingestion of water containing 3.5 ppm fluoride, compared with water containing 0.7 ppm fluoride, does not increase cortical bone mass in women of similar age, weight, and menopausal status. Under the conditions of this study, cortical bone mass might be reduced in a high-fluoride area.

Fluoride in the prevention of osteoporosis and fractures

Age-related fractures, especially hip fractures, produce sufficient morbidity and mortality to make osteoporosis a disease worth preventing, and accurate techniques exist to identify groups at high risk of fracture by virtue of low bone mass. While the need for prevention is evident, no specific program of fluoride use for this purpose has been devised, and epidemiologic data provide little support for the notion that exposure to fluoride reduces hip fracture incidence. At present, fluoride cannot be recommended as a prophylactic agent for the fractures that are the primary adverse health outcome of osteoporosis.

Does fluoridation of drinking-water prevent bone fragility and osteoporosis?

The incidence of femoral-neck fracture was compared in 2 Finnish towns of similar economic structure, Kuopio and Jyväskylä. Kuopio has fluoridated its drinking-water since 1959, whereas Jyväskylä has only trace amounts of fluoride in its drinking-water. The incidence of bone fragility (measured as femoral-neck fractures) was found to be significantly less in Kuopio than in Jyväskylä. This finding seems to be associated with a fluoride content of 1 mg/l in the drinking-water of Kuopio.

The relationship between hip fracture and water fluoridation: an analysis of national data

Data from the 1973-1977 National Health Interview Surveys were used to determine whether water fluoridation prevents hip fractures related to osteoporosis. No protective effect was found for fluoride levels of 0.7 ppm, the level recommended for the prevention of dental caries. There are some indications that higher concentrations of fluoride might have a protective effect for groups with a high incidence of osteoporosis. However, no determination of the actual levels needed or the possible adverse effects of high water fluoride levels could be made.

Ankylosing spondylitis: an important cause of severe disturbances of the cardiac conduction system. Prevalence among 223 pacemaker-treated men

The cause of severe disturbances of the cardiac conduction system is seldom possible to establish clinically at pacemaker implantation, apart from cases of acute myocardial infarction or digitalis intoxication and in relatively rare cases of inflammatory disorders such as sarcoidosis and systemic sclerosis. Since cardiac manifestations, mainly conduction disturbances, occur in patients with ankylosing spondylitis, the prevalence of this disease was determined using radiologic screening for sacroiliitis in a population of 223 men who had permanently implanted pacemakers. Sacroiliitis was found in 19 men (8.5 percent), 15 of whom fulfilled the diagnostic criteria for ankylosing spondylitis. In six patients, sacroiliitis was asymptomatic and two of the patients were completely free of symptoms other than those originating from their heart manifestations. In seven of the 15 patients with ankylosing spondylitis and in the four patients with sacroiliitis without clinical criteria of ankylosing spondylitis, the diagnosis was previously unknown. Uveitis and aortic regurgitation occurred in five patients each, while peripheral arthritis was twice as common. The prevalence of sacroiliitis and ankylosing spondylitis of 8.5 and 6.7 percent, respectively, differ significantly (p less than 0.01) from the frequencies found in general Caucasian populations of 1 to 2 and 0.1 to 0.5 percent, respectively. HLA B27 was present in more than 80 percent of the patients with sacroiliitis and/or ankylosing spondylitis, compared with 8 to 10 percent in the general population. This strong association is in accordance with previous studies of patients with symptomatic sacroiliitis and/or ankylosing spondylitis. Thus sacroiliitis, diagnosed by x-ray, can be considered a marker for this relatively common rheumatic cause of severe disturbances of the cardiac conduction system.

Fluoride therapy for osteoporotic lesions

The clinical research and the metabolic and therapeutic concerns related to the administration of fluoride for osteoporotic lesions are reviewed. Two or three daily administrations of 22.4 mg of sodium fluoride (NaF) have been shown to stimulate osteoblastic activity. When accompanied by supplemental calcium (Ca) new normal bone is deposited leading to an increase in total bone mass. The Ca should be given daily in 600 to 1,000 mg quantity at times separate from the fluoride ingestion to avoid formation of insoluble calcium fluoride. Vitamin D may also be prescribed to aid Ca absorption. The precise mechanism of action is not yet known. Promising clinical results have been obtained with a variety of osteoporotic conditions including “otosclerosis.”

Disc degeneration. Its frequency and relationship to symptoms

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