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Community water fluoridation, bone mineral density, and fractures: prospective study of effects in older women

BMJ 2000; 321 doi: https://doi.org/10.1136/bmj.321.7265.860 (Published 07 October 2000) Cite this as: BMJ 2000;321:860
  1. Kathy R Phipps (phippsk{at}ohsu.edu), associate professora,
  2. Eric S Orwoll, professor of medicineb,
  3. Jill D Mason, associate professora,
  4. Jane A Cauley, associate professor of epidemiologyc
  1. a School of Dentistry, Oregon Health Sciences University, 611 SW Campus Drive, Portland, OR 97201, USA,
  2. b School of Medicine, Oregon Health Sciences University, 3181 SW Sam Jackson Park Road, Portland,
  3. c Department of Epidemiology, School of Public Health, University of Pittsburgh, 130 DeSoto Street, Crabtree A524, Pittsburgh, PA 15261, USA
  1. Correspondence to: K R Phipps
  • Accepted 5 July 2000

Abstract

Objective: To determine whether fluoridation influences bone mineral density and fractures in older women.

Design: Multicentre prospective study on risk factors for osteoporosis and fractures.

Setting: Four community based centres in the United States.

Participants: 9704 ambulatory women without bilateral hip replacements enrolled during 1986-8; 7129 provided information on exposure to fluoride.

Main outcome measures: Bone mineral density of the lumbar spine, proximal femur, radius, and calcaneus plus incident fractures (fractures that occurred during the study) of vertebrae, hip, wrist, and humerus.

Results: Women were classified as exposed or not exposed or having unknown exposure to fluoride for each year from 1950 to 1994. Outcomes were compared in women with continuous exposure to fluoridated water for the past 20 years (n=3218) and women with no exposure during the past 20 years (n=2563). In women with continuous exposure mean bone mineral density was 2.6% higher at the femoral neck (0.017 g/cm2, P<0.001), 2.5% higher at the lumbar spine (0.022 g/cm2, P<0.001), and 1.9% lower at the distal radius (0.007 g/cm2, P=0.002). In women with continuous exposure the multivariable adjusted risk of hip fracture was slightly reduced (risk ratio 0.69, 95% confidence interval 0.50 to 0.96, P=0.028) as was the risk of vertebral fracture (0.73, 0.55 to 0.97, P=0.033). There was a non-significant trend toward an increased risk of wrist fracture (1.32, 1.00 to 1.71, P=0.051) and no difference in risk of humerus fracture (0.85, 0.58 to 1.23, P=0.378).

Conclusions: Long term exposure to fluoridated drinking water does not increase the risk of fracture.

Footnotes

  • Funding United States National Institutes of Health (DE10814, AG05407, AR35582, AG05394, AR35584, AR35583). United States Environmental Protection Agency, Center for Environmental Epidemiology, University of Pittsburgh. The views expressed are those of the authors and do not necessarily reflect the views or policies of the US Environmental Protection Agency.

  • Competing interests None declared.

  • Accepted 5 July 2000
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