The association between water fluoridation and hip fracture among white women and men aged 65 years and older. A national ecologic study.

For the past 45 years, there has been a great deal of debate regarding the health issues surrounding the fluoridation of public water supplies. In order to assess the association between fluoridation and hip fracture, we identified 129 counties across the United States considered to be exposed to public water fluoridation and 194 counties without exposure. Data from the Health Care Financing Administration and the Department of Veterans Affairs were used to calculate the incidence of hip fracture among white persons, aged 65 years or older, in fluoridated and nonfluoridated counties. There was a small statistically significant positive association between fracture rates and fluoridation. The relative risk (95% confidence interval) of fracture in fluoridated counties compared to nonfluoridated counties was 1.08 (1.06 to 1.10) for women and 1.17 (1.13 to 1.22) for men. As comparisons were made at the grouped level, it may be inappropriate at this time to draw inferences at the individual level. The relationship observed at the county level needs to be duplicated at the individual level with more precise measures of fluoride exposure.     

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.     

Effects of long-term fluoride in drinking water on risks of hip fracture of the elderly: an ecologic study based on database of hospitalization episodes]

OBJECTIVES: Fluoridation of drinking water is known to decrease dental caries, particularly in children. However, the effects of fluoridated water on bone over several decades are still in controversy. To assess the risk of hip fracture related to water fluoridation, we evaluated the hip fracture-related hospitalizations of the elderly between a fluoridated city and non-fluoridated cities in Korea. METHODS: Cheongju as a fluoridated area and Chungju, Chuncheon, Suwon, Wonju as non-fluoridated areas were chosen for the study. We established a database of hip fracture hospitalization episode based on the claims data submitted to the Health Insurance Review Agency from January 1995 to December 2002. The hip fracture hospitalization episodes that satisfied the conditions were those that occurred in patients over 65 years old, the injuries had a hip fracture code (ICD-9 820, ICD-10 S72) and the patients were hospitalized for at least 7days. A total of 80,558 cases of hip fracture hospitalization episodes were analyzed. RESULTS: The admission rates for hip fracture increased with the age of the men and women in both a fluoridated city and the non-fluoridated cities (p<0.01). The relative risk of hip fracture increased significantly both for men and women as their age increased. However, any difference in the hip fracture admission rates was not consistently observed between the fluoridated city and the nonfluoridated cities. CONCLUSIONS: We cannot conclude that fluoridation of drinking water increases the risk of hip fracture in the elderly.     

New,or biased,evidence on water fluoridation?

Abstract: The recent review, 'New evidence on fluoridation', by Diesendorf, Colquhoun, Spittle, Everingham and Clutterbuck (Aust N Z J Public Health 1997; 21: 187–90) claims a consistent pattern of evidence pointing to fluoride damaging bone, a negligible benefit in dental caries reduction from ingested fluoride, and any small benefit from fluoride coming from the action of fluoride at the tooth surface. Public health authorities are allegedly reluctant to pursue such evidence. In the interest of scholarly debate, invited by Diesendorf et al., this reaction paper examines six separate areas raised in the original paper: fluoridation and hip fracture; fluoridation and osteosarcomas; pre-eruptive and posteruptive benefits in dental caries reduction; fluoride ingestion; benefit in dental caries reduction for contemporary Australian children; and bias of health authorities and responsible science. Numerous examples of bias in die identification, selection and appraisal of the evidence on water fluoridation presented by Diesendorf et al. are developed. Further, this reaction paper puts forward both studies and appraisal indicating that water fluoridation should continue to be regarded as a safe and effective public health measure     

Influence of parity and lactation on hip fracture risk.

Several studies indicate that parity and lactation are associated with modest, short-term bone loss, but the long-term effect on osteoporotic fracture risk is uncertain. The authors therefore analyzed data from a population-based case-control study among Swedish postmenopausal women aged 50-81 years between October 1993 and February 1995. Mailed questionnaires and telephone interviews were used to collect data on 1,328 incident cases with hip fracture and 3,312 randomly selected controls. In age-adjusted analyses, the risk of hip fracture among all women was reduced by 10% per child (95% confidence interval (CI): 5, 14). After multivariate adjustment including body mass index as a covariate, the risk reduction was 5% per child (95% CI: 0, 10). Oral contraceptive use modified the association of parity with hip fracture risk. Among never users of oral contraceptives, the risk of hip fracture was reduced by 8% per child (95% CI: 2, 13), whereas among ever users of oral contraceptives, the risk was in the opposite direction, with an increase in risk by 19% per child (95% CI: 0, 41). After parity was considered, there was no association of duration of lactation period with fracture risk. The authors conclude that parity is modestly associated with a reduced hip fracture risk among women who had not used oral contraceptives previously.     

Cost-benefit analysis of fluoridating the public water supply of the city of Málaga]

The aim of the present study was to assess the cost-benefit of the program of fluoridation of the public water supply in the city of Málaga. Marginal benefits and the rate cost/benefit were the two parameters used to evaluate the cost-benefit. We have considered all the information available about similar experiences performed in other countries and about the particular aspects of the city in which this program was going to be set up. The cost of fluoridation per inhabitant per year and the effects of the cost of fluoridation on the price of the water supplied were also estimated. The program for the fluoridation of the public water supply in Málaga is profitable from the first year, as for each peseta spent we will benefit 2.10 pesetas. After 20 years of public water fluoridation the net benefit of this program will reach between 519 and 5,300 millions pesetas.     

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

Objective: To use the technique of metaanalysis 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.     

Water fluoride concentration and fracture of the proximal femur.

STUDY OBJECTIVE--The aim of the study was to examine the relationship between water fluoride concentration and the incidence of hip fracture, since evidence on this is at present inconsistent. DESIGN--Numbers of hospital admissions for fractures of proximal femur were obtained from hospital activity analysis data for the years 1978-1982. The fracture rates were compared with water fluoride concentrations in 39 county districts of England and Wales (fluoride concentrations had been measured in these districts between 1969 and 1973 as part of the British Regional Heart Study). PATIENTS--During the study period, 4121 men and 16,272 women aged 45 years and over were discharged from hospital after hip fracture. RESULTS--Poor correlations were found between discharge rates and both total (r = 0.16, p = 0.34) and natural (r = 0.01, p = 0.95) water fluoride concentrations. CONCLUSIONS--Water fluoridation to levels of around 1 mg/litre is unlikely to reduce hip fracture incidence markedly in this country.     

Blood lead concentrations in children and method of water fluoridation in the United States, 1988-1994

Some have hypothesized that community water containing sodium silicofluoride and hydrofluosilicic acid may increase blood lead (PbB) concentrations in children by leaching of lead from water conduits and by increasing absorption of lead from water. Our analysis aimed to evaluate the relation between water fluoridation method and PbB concentrations in children. We used PbB concentration data (n=9,477) from the Third National Health and Nutrition Examination Survey (1988-1994) for children 1-16 years of age, merged with water fluoridation data from the 1992 Fluoridation Census. The main outcome measure was geometric mean PbB concentration, and covariates included age, sex, race/ethnicity, poverty status, urbanicity, and length of time living in residence. Geometric mean PbB concentrations for each water fluoridation method were 2.40 microg/dL (sodium silicofluoride), 2.34 microg/dL (hydrofluosilicic acid), 1.78 microg/dL (sodium fluoride), 2.24 microg/dL (natural fluoride and no fluoride), and 2.14 microg/dL (unknown/mixed status). In multiple linear and logistic regression, there was a statistical interaction between water fluoridation method and year in which dwelling was built. Controlling for covariates, water fluoridation method was significant only in the models that included dwellings built before 1946 and dwellings of unknown age. Across stratum-specific models for dwellings of known age, neither hydrofluosilicic acid nor sodium silicofluoride were associated with higher geometric mean PbB concentrations or prevalence values. Given these findings, our analyses, though not definitive, do not support concerns that silicofluorides in community water systems cause higher PbB concentrations in children. Current evidence does not provide a basis for changing water fluoridation practices, which have a clear public health benefit.     

Physical activity and the risk of hip fracture in the elderly: a prospective cohort study

Physical activity has been inversely associated with the risk of hip fracture, however, few studies have been conducted on the contributions from different domains of physical activity. This study was performed to investigate the association between daily household activities, leisure time physical activity, work-related physical activity and total physical activity during a 24-h period, and the risk of hip fracture. In the Swedish National March Cohort we followed 23,881 men and women aged of 50 and over from 1997 until 2010. Information on domain-specific physical activity was collected at baseline using a questionnaire. We fitted separate multivariable adjusted Cox proportional hazard models to each domain to obtain hazard ratios (HRs) with 95% confidence intervals (CIs). Each model was mutually adjusted for the other domains of physical activity. During a mean follow-up period of 12.2 years we identified 824 incidents of hip fracture. Subjects who spent less than 1 h per week engaged in daily household activities had an 85% higher risk of hip fracture than subjects spending ≥6 h per week carrying out daily household activities (HR 1.85; 95% CI 1.01–3.38). Subjects engaged in leisure time physical activities for >3.1 MET-h/day had a 24% lower risk of hip fracture (HR 0.76; 95% CI 0.59–0.98) than subjects spending <1.1 MET-h/day performing such activities. No association was found between hip fracture and work-related or total physical activity. We conclude that daily household activities and leisure time physical activity may independently decrease the risk of hip fracture in those aged 50 and over.     

Caffeine and the risk of hip fracture: the Framingham Study

Caffeine increases urinary calcium output and has been implicated as a risk factor for osteoporosis. The authors examined the effect of caffeine on hip fracture risk in 3,170 individuals attending the 12th (1971-1973) Framingham Study examination. Coffee and tea consumption, age, Framingham examination number, weight, smoking, alcohol consumption, and estrogen use were used to evaluate hip fracture risk according to caffeine intake. Hip fractures occurred in 135 subjects during 12 years of follow-up. Fracture risk over each 2-year period increased with increasing caffeine intake (one cup of coffee = one unit of caffeine, one cup of tea = 1/2 unit of caffeine). For intake of 1.5-2.0 units per day, the adjusted relative risk (RR) of fracture was not significantly elevated compared with intake of one or less units per day. Consumption of greater than or equal to 2.5 units per day significantly increased the risk of fracture. Overall, intake of greater than two cups of coffee per day (four cups of tea) increased the risk of fracture. In summary, hip fracture risk was modestly increased with heavy caffeine use, but not for intake equivalent to one cup of coffee per day. Since caffeine use may be associated with other behaviors that are, themselves, risk factors for fracture, the association may be indirect. Further studies should be performed to confirm these findings.     

Alcohol consumption and hip fractures: the Framingham Study

Alcoholics often sustain hip and other fractures. However, a detailed examination of the association between alcohol consumption and hip fractures has not been undertaken. Specifically, the effects of moderate alcohol intake, of alcohol consumption in the elderly, and of changes in consumption have not been studied. Using a retrospective cohort design, the authors evaluated this association in the population-based Framingham Heart Study cohort, a group studied over 35 years and queried repeatedly about their alcohol consumption. In 117,224 person-years of observation, 217 hip fractures occurred. Heavy current alcohol consumption (defined as seven or more ounces (207 ml or more) per week) was associated with a modestly increased risk of hip fracture for women (relative risk (RR) = 1.54) and for men (RR = 1.26) after adjustment for age. In a logistic regression analysis controlling for age, sex, weight, and smoking, current alcohol consumption was associated with a significant (p = 0.01) increase in risk of fracture. The relative risks at different ages were not uniform. For those aged less than 65 years, moderate (2-6 ounces (59.14-177.4 ml) per week) and heavy (seven or more ounces (207 ml or more) per week) were associated with a substantial and significant increased risk, but there was only a marginal and nonsignificant increase in risk in those aged 65 years or more. Examination of the effect of changing alcohol consumption over time indicated that among present heavy alcohol users, past light alcohol consumption reduced the risk (p = 0.03) of fracture, whereas in those with present light consumption, past heavy intake had little effect on fracture risk (p = nonsignificant). In conclusion, alcohol consumption, especially if long-term and heavy, increases the risk of hip fracture.     

The status of community water fluoridation in the United States

Community water fluoridation has served the American public extremely well as the cornerstone of dental caries prevention activities for 45 years. The dental and general health benefits associated with the ingestion of water-borne fluorides have been well known by researchers for an even longer period. Continued research has repeatedly confirmed the safety, effectiveness, and efficiency of community water fluoridation in preventing dental caries for Americans regardless of age, race, ethnicity, religion, educational status, or socioeconomic level. Despite the obvious benefits associated with this proven public health measure, slow progress has been made toward achieving the 1990 national fluoridation objectives as listed in "Promoting Health/Preventing Disease: Objectives for the Nation." This paper documents the lagging pace of community fluoridation by reviewing and analyzing data reported in "Fluoridation Census, 1985," a document published in late 1988 by the Public Health Service's Centers for Disease Control. Failure to attain the 1990 objectives is attributable to a combination of circumstances, including their low priority within many local, State, and Federal health agencies, inadequate funding at all levels of government, lack of a coordinated and focused national fluoridation effort, failure of most States to require fluoridation, lack of Federal legislation mandating fluoridation, general apathy of most health professional organizations toward fluoridation, misconceptions by the public about effectiveness and safety and, finally, unrelenting opposition by a highly vocal minority of the lay public.(ABSTRACT TRUNCATED AT 250 WORDS)     

Fractures in the men of a Veterans Administration Nursing Home: relation to 1,25-dihydroxyvitamin D

One hundred fifty-three men, age 48-96, 86% white, had resided in this Nursing Home for an average of 6.3 years (range 1.3-36) as of August 1984. At that time, we reviewed their medical charts to record the numbers and sites of fractures which had been diagnosed during the preceding 1 to 5 years of Nursing Home residence, the duration of this period depending on the duration of institutionalization. In addition, a clinical database was compiled comprising 70 attributes, including diagnoses, drugs, plasma (serum) chemistries, and measures of hematologic, nutritional, and functional status. Fractures during the studied period of Nursing Home residence had occurred in 24 of 153 men; six residents had experienced two or more fractures. Fracture rates in hip, spine, and wrist were 2564, 366, and 549 per 100,000 patient years, respectively. The total fracture rate, hip fracture rate, and limb fracture rate were five to 11 times higher than in the age-matched general population of white men in the United States; in Rochester, MN; in Dundee, England; in Oxford, England; or in Finland. Univariate statistical analysis showed that the rates for hip fracture or for fracture at any site were significantly associated with 13 attributes: directly with age, plasma somatomedin C, blood urea N, serum creatinine, serum uric acid, serum 25-hydroxyvitamin D (25-OH-D), degree of functional impairment, and chronic urinary tract infection, and inversely with serum 1,25-dihydroxyvitamin D [1,25-(OH)2-D], serum albumin, hematocrit, and hemoglobin. There was not a significant correlation with the number of falls/month which occurred during the 7 months after August 1984. After the effect of age was partialed out, somatomedin C, 25-OH-D, 1,25-(OH)2-D, and the diagnosis of urinary tract infection were still significantly related to the occurrence of fractures. The fact that Nursing Home fracture cases had significantly higher blood urea nitrogen and 25-OH-D, and significantly lower 1,25-(OH)2-D, than their non-fracture counterparts suggests that impaired renal production of the latter vitamin D metabolite contributed to the excessive rate of fractures.     

Physical activity and hip fracture: a population-based case-control study. Swedish Hip Fracture Study Group

BACKGROUND: A growing body of literature suggests that physical activity may be a protective factor against hip fracture. METHODS: To study the association between hip fracture risk and recreational physical activity at various ages, changes in activity during adult life, occupational physical activity and how risks vary by adult weight change, we performed a population-based case-control study among postmenopausal women aged 50-81 years residing in six counties in Sweden in 1993-1995. The analysis consisted of 1327 women with hip fracture and 3262 randomly selected controls. Information on leisure physical activity before age 18, at 18-30 years and during recent years was based on a questionnaire. Data on occupational physical activity were collected through an independent classification of job titles obtained from record linkage with census data from 1960, 1970 and 1980. RESULTS: There was a protective effect of recent leisure physical activity. Compared to women who reported no leisure activity, the odds ratios (OR) were 0.79 (95% CI: 0.62-1.00), 0.67 (95% CI: 0.54-0.84) and 0.48 (95% CI: 0.39-0.60) for women who exercised <1 h per week, 1-2 h per week, and 3+ h per week, respectively. These decreased OR were more pronounced in women who had lost weight after 18 years of age than in those who had gained weight. Women with high physical activity at both 18-30 years and during recent years did not have a stronger protection than those with isolated high activity late in life, after accounting for recent activity. Occupational physical activity was not associated with hip fracture risk in this study. CONCLUSIONS: Recent physical activity is protective against hip fracture. The protective effect is most pronounced in women who had lost weight after age 18.     

Fractures in the men of a Veterans Administration Nursing Home: relation to 1,25-dihydroxyvitamin D.

One hundred fifty-three men, age 48-96, 86% white, had resided in this Nursing Home for an average of 6.3 years (range 1.3-36) as of August 1984. At that time, we reviewed their medical charts to record the numbers and sites of fractures which had been diagnosed during the preceding 1 to 5 years of Nursing Home residence, the duration of this period depending on the duration of institutionalization. In addition, a clinical database was compiled comprising 70 attributes, including diagnoses, drugs, plasma (serum) chemistries, and measures of hematologic, nutritional, and functional status. Fractures during the studied period of Nursing Home residence had occurred in 24 of 153 men; six residents had experienced two or more fractures. Fracture rates in hip, spine, and wrist were 2564, 366, and 549 per 100,000 patient years, respectively. The total fracture rate, hip fracture rate, and limb fracture rate were five to 11 times higher than in the age-matched general population of white men in the United States; in Rochester, MN; in Dundee, England; in Oxford, England; or in Finland. Univariate statistical analysis showed that the rates for hip fracture or for fracture at any site were significantly associated with 13 attributes: directly with age, plasma somatomedin C, blood urea N, serum creatinine, serum uric acid, serum 25-hydroxyvitamin D (25-OH-D), degree of functional impairment, and chronic urinary tract infection, and inversely with serum 1,25-dihydroxyvitamin D [1,25-(OH)2-D], serum albumin, hematocrit, and hemoglobin. There was not a significant correlation with the number of falls/month which occurred during the 7 months after August 1984. After the effect of age was partialed out, somatomedin C, 25-OH-D, 1,25-(OH)2-D, and the diagnosis of urinary tract infection were still significantly related to the occurrence of fractures. The fact that Nursing Home fracture cases had significantly higher blood urea nitrogen and 25-OH-D, and significantly lower 1,25-(OH)2-D, than their non-fracture counterparts suggests that impaired renal production of the latter vitamin D metabolite contributed to the excessive rate of fractures.     

Timing of surgery for hip fracture and in-hospital mortality: a retrospective population-based cohort study in the Spanish National Health System

Background  

While the benefits or otherwise of early hip fracture repair is a long-running controversy with studies showing contradictory results, this practice is being adopted as a quality indicator in several health care organizations. The aim of this study is to analyze the association between early hip fracture repair and in-hospital mortality in elderly people attending public hospitals in the Spanish National Health System and, additionally, to explore factors associated with the decision to perform early hip fracture repair.     

A comparison of hip fracture incidence among native Japanese, Japanese Americans, and American Caucasians

Hip fracture incidence rates among men and women of Japanese ancestry living on Oahu, Hawaii, from 1979 to 1981 were compared with rates for Japanese living on Okinawa, Japan, from 1984 to 1985. Both rates were further compared with those for various American Caucasian populations, including that of Rochester, Minnesota, from 1978 to 1982. Age-specific and cumulative (age 50-84 years) hip fracture rates among persons of Japanese ancestry were approximately half that of Caucasians for both sexes. Although diet and other cultural attributes of the Oahu group have become more westernized than the Okinawan population, there were no detectable differences in hip fracture rates between Oahu and Okinawa Japanese. Additional studies are needed to determine whether the observed differences in fracture rates between Caucasians and Japanese might be related to differences in bone mass, body size, frequency of falls, or other factors.     

Water and turf: fluoridation and the 20th-century fate of waterworks engineers.

Once central figures in American public health, waterworks engineers are no longer involved in many decisions made about the public water supplies. This paper argues that the profession's response to the early fluoridation movement of the 1940s and 1950s marked a change in the relationship between waterworks engineers and the other constitutive groups in public health and contributed to the disenfranchisement of the waterworks profession. Sensing a potentially divisive issue, two leaders of the profession, Abel Wolman and Linn Enslow, took steps they hoped would prevent a rift within the profession and allow waterworks engineering to continue its association with the wider public health community. Although the leaders saw the fluoridation issue differently, neither encouraged the profession to consider it openly or to take up the broader question of what limits, if any, should be placed on treating water supplies to meet human needs. Instead, they opted to locate authority for fluoridation outside the waterworks profession with dentists, doctors, and public health administrators. As a result, waterworks engineers conceded a great deal of the status and prestige associated with decision-making roles in community health issues and have largely faded from view.