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Epidemiologic studies of the relations between drinking-water fluoride levels and bone mineral density (BMD) and fracture are characterized by disparate conclusions and an absence of information about individual circulating fluoride levels. This study relates serum fluoride concentrations, which reflect individual fluoride exposures, to BMD and bone fractures. Data are from 1300 female residents of 3 small communities in which the water fluoride concentrations were 52.6 or 210.4 [micro]mol/L. Circulating serum fluoride concentrations were assessed by ion-specific electrode. Fluoride intake was estimated from interviews describing water and waterbased beverage consumption and duration of residence in the community. BMD was measured by dual-energy X-ray densitometry and single-photon densitometry. Self-reported fractures were confirmed by medical record abstraction. The mean serum fluoride concentration in the high-fluoride community, 2.11 [+ or -] 0.05 [micro]mol/L, was significantly higher than serum fluoride concentrations in the control and high-calcium communities with water fluoridation to 52.6 [micro]mol/L. The mean serum fluoride concentrations in these latter 2 communities were 1.6 [+ or -] 0.04 and 1.22 [+ or -] 0.05 [micro]mol/L, respectively. Serum fluoride was not significantly related to BMD after adjusting for covariates including age and body size. The mean distal radius BMD, however, was significantly higher in the high-fluoride community. Serum fluoride concentrations were not related to incident osteoporotic fractures with 4 y of observation. Serum fluoride concentrations were not associated with BMD or osteoporotic fractures among female residents of communities with water fluoride concentrations of 52.6 or 210.4 [micro]mol/L. KEY WORDS: * water fluoride * serum fluoride * bone mineral density * bone fracture

Background. In the aging process, loss of muscle is relatively continuous, but the initiation, timing, and amount of muscle loss that relate to functional compromise are poorly described. Also poorly understood is whether strength and functioning in aging are related to the amount of lean mass and its change as well as to the amount of fat mass and its change. Methods. The purpose of the study was to ascertain whether 3-year lean and fat mass change predicted functional status in 712 African American and Caucasian women, aged 34-58 years. Fat and lean mass were assessed with bioelectrical impedance. Lower leg strength (torque) was measured with a portable isometric chair, and two indices of physical functioning, walking velocity and double support (both feet touching the surface while walking), were measured with an instrumented gait mat. Results. Almost 9% of middle-aged women had at least a 6%, loss (>2.5 kg) of lean mass over the 3-year observation period. Women who lost at least 2.5 kg of lean mass had slower walking velocity and less leg strength, although women who simultaneously gained more than 2.5 kg of fat mass (at least 7.5%) did not have less leg strength. Age was significantly associated with less velocity, less leg strength, and more time in double support. Conclusions. Even in middle-aged women, there is loss of lean mass among almost 1 woman in 10, and this loss of lean mass (sarcopenia) is associated with greater compromise in physical functioning.

Bone density appears to decline with extended lactation but subsequently return to normal after weaning. Of 110 women, 20 breast-fed for less than one month, 26 breast-fed for two to five months and 64 breast-fed for six months or more. Initial bone mineral density was measured in the hip and spine and compared with measurements taken six months and 12 months later. Bone mineral density declined an average of 5.1% in the spine and 4.8% in the hip among women who breast-fed for six months or more. This loss was significantly greater than that experienced by women in either of the other two groups. Among women who stopped breast-feeding six to nine months after childbirth, the average bone mineral density values returned to normal by 12 months. Among women who continued breast-feeding past nine months, the average bone mineral density was 3.5% lower than the initial value at the hip and 2% lower at the spine., Objective.--To test the a priori hypotheses that significant bone loss occurs in lactation of greater than 5 months' duration and that bone mass returns to baseline levels when breast-feeding ceases. Design.--Prospective cohort study design of 12 months' duration. Setting.--General community setting with recruitment occurring at birthing education classes. Participants.-- Volunteer sample of 98 healthy women of white (n=95) and Asian (n=3) origin, aged 20 to 40 years, and 0 to 1 parity prior to parturition, grouped according to lactation duration: 0 through 1, 2 through 5, and 6 or more months. Main Outcome Measures.--Bone mineral density (BMD) of the proximal femur was measured by dual-energy x-ray densitometry at 2 weeks (baseline), 2 months, 4 months, 6 months, and 12 months following parturition, and BMD of the lumbar spine was measured at baseline, 6 months, and 12 months after parturition. Results.--Women with lactation duration of 6 months or longer had mean BMD losses of 5.1% and 4.8% at the lumbar spine and femoral neck, respectively, comparing baseline values with those at 6 months post partum. Women who breast-fed 0 through 1 month lost no BMD at either bone site. Bone loss in women who breast-fed 6 months or longer was not explained by differences in age, diet, body size, or physical activity. Among women who breast-fed 6 months or longer, there was evidence of return to baseline levels of the lumbar spine at 12 months after parturition. The BMD of the lumbar spine of those women who continued to breast-feed more than 9 months had increased but was still significantly lower than baseline. Conclusion.--Extended lactation ([greater than or equal to]70% of energy intake is provided for [greater than or equal to]6 months) is associated with bone loss; however, there is evidence of return to baseline BMD measurement at 12 months after parturition.