Biomedical subjects

M Wapniarz

Publications and source records attributed to M Wapniarz.

8 recordsLinked to original sources

PubMed1998

Drinking water fluoridation: bone mineral density and hip fracture incidence.

The role of drinking water fluoride content for prevention of osteoporosis remains controversial. Therefore, we analyzed the influence of drinking water fluoridation on the incidence of osteoporotic hip fractures and bone mineral density (BMD) in two different communities in eastern Germany: in Chemnitz, drinking water was fluoridated (1 mg/L) over a period of 30 years; in Halle, the water was not fluoridated. BMD was measured in healthy hospital employees aged 20-60 years (Halle: 214 women, 98 men; Chemnitz: 201 women, 43 men, respectively) using dual-energy X-ray absorptiometry. Hip fractures in patients > or = 35 years admitted to the local hospitals in the years 1987-1989 were collected from the clinic registers. There was no difference in age, anthropometric, hormonal, or lifestyle variables between the two groups. Mean fluoride exposure in Chemnitz was 25.2 +/- 7.3 years. No correlation was found between fluoride exposure and age-adjusted BMD. We found no significant difference in spinal or femoral BMD between subjects living in Halle and Chemnitz [lumbar spine: 0.997 +/- 0.129 (g/cm2) vs. 1.045 + 0.171 (g/cm2), p = 0.08, for men; 1.055 +/- 0.112 (g/cm2) vs. 1.046 +/- 0.117 (g/cm2), p = 0.47, for women]. The fracture incidence showed an exponential increase with aging in men and women with an incidence about 3.5 times higher for women. In Chemnitz, we calculated an age-adjusted annual incidence of 142.2 per 100,000 for women and 72.5 per 100,000 for men, respectively. In Halle, the incidences were 178.5 per 100,000 for women and 89.2 per 100,000 for men. There was a lower hip fracture incidence after the age of 85 in women in Chemnitz (1391 per 100,000 in Chemnitz vs. 1957 per 100,000) in Halle, p = 0.006). Using the age-adjusted incidences, significantly fewer hip fractures occurred in Chemnitz in both men and women. In conclusion, our study suggests that optimal drinking water fluoridation (1 mg/L), which is advocated for prevention of dental caries, does not influence peak bone density but may reduce the incidence of osteoporotic hip fractures in the very old.

Adult↗

PubMed1997

Determinants of radial bone density as measured by PQCT in pre- and postmenopausal women: the role of bone size.

The aim of the present study was to examine the influence of anthropometric, hormonal, and geometric factors on the variability of radial bone mineral density (BMD) in women. In 583 healthy pre- and postmenopausal females (aged 40-60 years) radial total (BD) and trabecular BMD (TBD) was measured by peripheral quantitative computerized tomography at the nondominant distal forearm. In addition, 29 women who had suffered a Colles' fracture after minor trauma were also evaluated. There was no age-dependent change in radial BD and TBD before menopause. We found a negative correlation between BMD and age and years since menopause (YSM) in postmenopausal women (BD = 422.73 - 2.342 age - 6.308YSM; r = 0.36, p = 0.0001, n = 128). The variation of YSM, body mass index (BMI), and age accounted for 20% of the variability of BD in postmenopausal women. In contrast, in premenopausal women, only 3% of the variability could be explained by anthropometric variables. Bone mineral content (BMC) and bone area, but not BMD at the distal radius, were significantly correlated to grip strength (r = 0.25, p = 0.006 for BMC, r = 0.26, p = 0.003 for area). The cross-sectional bone area of the CT slice showed a significant increase with aging (y = 263.02 + 1.25x; r = 0.14, p = 0.0009). There was a strong negative correlation between bone area and BD and TBD (y = 516.04 - 0.668x; r = -0.57, p < 0.0001 for BD). If BMD is normalized for BA, variation is reduced by 32% (for BD) and 10% (for TBD), respectively. Women with Colles' fracture had a significantly lower TBD normalized for BA (fracture group [-0.71 +/- 0.88] vs. normals (0.03 +/- 0.99]; p = 0.00009). Our results show that YSM and BMI are predictors of postmenopausal BMD. However, radial BMD is influenced strongly by geometric variables such as cross-sectional bone area.

Absorptiometry, Photon↗

PubMed1995

Dual-energy X-ray absorptiometry at the lumbar spine in German men and women: a cross-sectional study.

A cross-sectional, population-based study of 238 randomly selected females and 224 males with German ethnic background (aged 20-80 years) was carried out to establish lumbar spine bone mineral density (BMD) values, using dual X-ray absorptiometry (DXA), for a German population. Comparison was made to the reference range provided by the manufacturer of the DXA equipment. No sex difference in peak spine BMD was found in our study (1.091 +/- 0.114 g/cm2 for males versus 1.070 +/- 0.113 g/cm2 for females, n.s.). Different patterns of bone loss could be detected in both sexes. In premenopausal women there was no significant correlation between age and BMD (y = 1.044 + 0.00047x, r = 0.03, P = 0.73) whereas reduction of female BMD at the spine was demonstrated in postmenopausal women (y = 1.189-0.0041x, r = -0.28, P = 0.01), underscoring the important role of the menopause for later manifestation of spinal osteoporosis in women. In contrast, in males we found no significant change of BMD with aging (y = 1.071-0.0007x, r = -0.08, P = 0.25). Employing commonly used exclusion criteria, BMD values of the study subjects were found mostly within the normal range of BMD. The major finding of our study was good concordance between female data of our study population and the reference data provided by the manufacturer. Clinically significant discrepancies between our data and the Hologic reference range for males could be detected. Our data on males (30-39 years of age) were up to 7% lower than those provided by the manufacturer, probably due to differences in sampling procedures.

Absorptiometry, Photon↗

PubMed1994

Precision of dual X-ray absorptiometry and peripheral computed tomography using mobile densitometry units.

Irrespective of the method used for noninvasive bone mass determination, data comparison between different centers is a major problem as significant interunit variation may occur. We, therefore, have employed mobile densitometry units to reduce interunit variability in two large epidemiologic studies in Germany. Two cars were equipped with either two dual X-ray absorptiometry (DXA) instruments (QDR 1000 Hologic, USA) (car I) or a special purposed scanner for peripheral quantitative computed tomography (pQCT) (XCT 900, Stratec, FRG) (car II). The cars were moved across Germany 11,090 km and 1651 km during the studies over a period of 30 and 7 months, respectively. Precision in vitro was determined using hydroxyapatite phantoms. Forty-eight patients underwent duplicate measurements at the lumbar spine (n = 22) and hip (n = 26) for assessing reproducibility in vivo. Between the two series of scans, the car was moved 63 km. Long-term precision in vitro of the QDR 1000 instruments were 0.41% and 0.59% for BMD with no evidence of machine drift (rate of change per year 0.04% and 0.05%, respectively). Short-term reproducibility in vivo showed a coefficient of variation (cv) of 1.02% for spinal BMD (L2-L4) and 1.72% for femoral neck. Long-term precision in vitro of the pQCT scanner was 0.9%. Our study shows precision in vivo and in vitro and stability of the mobile densitometers similar to that achieved with stationary equipment. In conclusion, mobile densitometry may become a useful tool not only for epidemiologic surveys and clinical trials but also for routine evaluation in less densely populated areas.

Absorptiometry, Photon↗

PubMed1993

Overestimation of osteopenia using standard analysis software for peripheral quantitative computed tomography.

It is well established that measurement of bone mineral density (BMD) can estimate the risk of future fractures. To assess individual fracture risk BMD measurements are compared with a reference range provided by the manufacturer of the respective BMD technology. However, the power of trabecular bone measured by peripheral quantitative computed tomography (pQCT) to predict future fractures has not been shown up to now. We conducted measurements of trabecular bone density (TBD) at the distal radius (pQCT XCT 900, Stratec, Germany) in a sample of 506 healthy white women aged 40-60 years (mean 48) and compared the results with the manufacturer's normal range. We found a remarkable difference in TBD values between our healthy study population and the manufacturer's reference data in all age groups (e.g., age 50-54 years, 143.1 +/- 43.2 mg/cm3 versus 181.1 +/- 39.0 mg/cm3). Compared to the +/- 2 SD limits of the manufacturer's reference range our study population showed mean TBD values that were about 1 SD below the mean of the reference range. About 50% of our healthy cohort were below the -1 SD limit of the reference range. Almost ten times as many normal subjects as expected (22.1%) were found below the -2 SD limit and therefore classified as individuals with increased fracture risk. This overestimation of fracture risk leads to discomfort of the patient, unnecessary therapeutic intervention, and significant costs to the public.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1993

Velocity of ultrasound at the patella: influence of age, menopause and estrogen replacement therapy.

Determination of apparent velocity of ultrasound (AVU) in bone has been proposed as a valuable tool for discriminating between normal and osteoporotic women. We have studied the influence of age, menopause and estrogen replacement therapy (ERT) on AVU at the patella in a large sample of pre- and postmenopausal women. Three hundred and eighteen woman aged 40-60 year participated in the study (112 women were premenopausal, 21 were perimenopausal and 185 were postmenopausal of whom 110 had received ERT for a minimum of 1 year). AVU was determined as the mean of four measurements at each patella using a Signet instrument (Osteo-Technology, Framingham, MA). An age-dependent decline in AVU was observed only after menopause (r = -0.33, p = 0.0055); in premenopausal women there was a slight but not significant decrease in AVU with age (r = -0.12, p > 0.05). AVU was significantly lower in postmenopausal women compared with premenopausal women (1882 +/- .84 m/s vs 1961 +/- 73 m/s, p < 0.05). ERT prevented the menopause-related fall in AVU. There was a significant positive correlation between the duration of ERT and AVU measurements. Our findings demonstrate a pronounced influence of estrogens on AVU at the patella, supporting the concept of a protective role of ERT in bone stability. AVU measurements therefore merit further investigation as an inexpensive method for predicting fracture risk that does not expose the subject to radiation.

Adult↗

PubMed1993

Apparent velocity of ultrasound (AVU) at the patella in comparison to bone mineral density at the lumbar spine in normal males and females.

It has been reported that apparent velocity of ultrasound (AVU) at the patella discriminates as well between osteoporotic and normal subjects as measurement of bone mineral density (BMD) using dual photon absorptiometry. To investigate the relationship between AVU and peak bone mass, we compared AVU (Signet, Osteo-Technology, Framingham, MA) at the patella and BMD (QDR 1000, Hologic, Waltham, MA) at the lumbar spine in a large sample of healthy males and females. The study population consisted of 153 males (aged 20-60 years) and 129 premenopausal females (aged 20-52 years). Vertebral BMD showed no significant difference between males and females (1.03 +/- 0.16 g/cm2 for males vs. 1.07 +/- 0.14 g/cm2 for females, NS), while AVU values were significantly higher in males compared with females (1967 +/- 64 m/s vs. 1938 +/- 76 m/s, P < 0.05). In men there was a significant decrease in BMD with aging (r = -0.27, P < 0.05), in premenopausal females we found no age-related change in BMD. Similarly in males AVU decreased significantly with age (r = -0.2, P < 0.05), whereas in females AVU values showed relative stability over the age range. There was a significant correlation between AVU and BMD (r = 0.36 for males, r = 0.34 for females, P < 0.05). Our study demonstrates only a weak correlation between AVU at that patella and BMD at the lumbar spine, supporting the view that AVU not only reflects bone quantity but possibly also qualitative properties of bone structure. The sex difference in AVU but not in BMD suggests that the trabecular bone at the patella differs significantly from axial trabecular bone. The identical peak BMD at the lumbar spine for young males and females underscores the importance of the menopause for later manifestation of vertebral fractures.

Absorptiometry, Photon↗

PubMed1992

[Reproducibility of bone density measurements of the distal radius using a high resolution special scanner for peripheral quantitative computed tomography (Single Energy PQCT)].

Reliable determination of bone loss in the skeletal system depends on the accuracy of bone mineral density (BMD) measurements. We investigated short-term and long-term accuracy in vitro and in vivo using a new, commercially available special-purpose computed tomography scanner (Single Energy Peripheral QCT: XCT 900, Stratec FRG) for BMD measurements. Using a phantom, the long-term accuracy (3 months) in vitro yielded a coefficient of variation (cv) of 0.18%. Repeated measurements in 37 patients showed excellent reproducibility, with a cv of 0.71%. The differentiation into groups of low, average and high trabecular bone density demonstrated values of 0.61%, 0.59% and 0.98%, respectively for cv. BMD determination with pQCT is a high-precision method. It seems to be suitable for detection of trabecular bone loss in the range of the annual decrease in bone mass, provided the forearm is positioned with maximum care.

Bone Density↗