Isosorbide mononitrate increases bone formation and decreases bone resorption in postmenopausal women: a randomized trial

NO regulates bone remodeling in cellular and animal models. We examined the effect of administering ISMO, a NO donor, on bone turnover in 144 postmenopausal women. After 3 months, women randomized to ISMO had a greater decrease in bone resorption and a greater increase in bone formation compared with placebo. NO donors may prevent postmenopausal bone loss.

INTRODUCTION

NO both stimulates bone formation and inhibits bone resorption in vitro. NO donors (nitrates) are inexpensive and widely available, but their value for postmenopausal osteoporosis has never been evaluated in a randomized trial.

MATERIALS AND METHODS

We randomly assigned 144 healthy postmenopausal women with a hip BMD T score between 0 and -2.5 to 5 or 20 mg/day of isosorbide mononitrate (ISMO) or placebo for 12 weeks. We measured urine N-telopeptide (NTx), a marker of bone resorption, and serum bone-specific alkaline phosphatase (BSALP), a marker of bone formation. Markers were measured immediately before randomization and after 12 weeks of treatment. We calculated the percent change in NTx and BSALP for each of the treatment groups (placebo, 5 mg ISMO, and 20 mg ISMO). Our primary outcome was the percent change in NTx and BSALP in the 5- and 20-mg ISMO groups compared with placebo.

RESULTS AND CONCLUSIONS

Compared with women randomized to placebo, women randomized to 20 mg of ISMO had a 45.4% decrease in NTx (95% CI, 25.8-64.9) and a 23.3% increase (95% CI, 8.9-37.8) in BSALP. Women randomized to 5 mg of ISMO had a 36.3% decrease in NTx (95% CI, 14.8-57.8) and a 15.9% increase in BSALP (95% CI, 1.1-30.7). ISMO decreases bone resorption and increases bone formation. These findings suggest that nitrates may be useful for the prevention of postmenopausal osteoporosis.

The moving target: a qualitative study of elderly patients' decision-making regarding total joint replacement surgery

BACKGROUND

Total joint replacement is an accepted, cost-effective, and underutilized treatment for moderate-to-severe hip and knee arthritis. Yet, research has suggested that many patients with arthritis are unwilling to consider total joint replacement surgery. We sought to understand these patients' unwillingness by exploring the nature of their decision-making processes.

METHODS

In-depth interviews were conducted with seventeen individuals with moderate-to-severe arthritis who were appropriate candidates for, but unwilling to consider, total joint replacement. The interviews were analyzed with use of qualitative methods and content analysis techniques.

RESULTS

Symptoms and information sources were the two main factors influencing patient decision-making. Participants engaged in individualized processes of trading off perceived costs and benefits. Accommodation to pain and disability and minimization of the quality-of-life benefit, in view of decreasing life span, led to a process whereby the threshold at which the benefits compared with the risks would tilt in favor of total joint replacement was constantly shifting, a phenomenon we called "the moving target."

CONCLUSIONS AND CLINICAL RELEVANCE

The moving-target characterization sheds light on patients' conceptions of their arthritis and on their unwillingness to consider total joint replacement. This process needs to be considered when developing ways to aid decision-making.

The validity of decision rules for selecting women with primary osteoporosis for bone mineral density testing

The purpose of this study was to determine the validity of the Osteoporosis Risk Assessment Instrument (ORAI), Osteoporosis Self-Assessment Tool (OST) chart and equation, and a criterion based on body weight for identifying women with asymptomatic primary osteoporosis. Prospective recruitment and chart abstractions from family practices of three University affiliated hospitals were completed for women aged 45 years or more with baseline bone mineral density (BMD) testing results by dual energy X-ray absorptiometry. Those taking bone active medication other than hormone therapy, with prior fragility fracture or with risk factors for secondary osteoporosis were excluded. Women were categorized as being normal, osteopenic or osteoporotic by lowest BMD T-score at either the femoral neck or lumbar spine (L1-L4). Sensitivity, specificity and area under the receiver operating characteristic (ROC) curve to identify those with osteoporosis were determined for each decision rule. The positive predictive value (PPV) for detecting osteoporosis after using a second cut point to convert each decision rule into a risk index (low, moderate or high risk) was also determined. The sensitivity of the decision rules to identify women with osteoporosis ranged from 92% to 95% and specificity from 35% to 46%. The area under the ROC curves were significantly better for the ORAI (0.80), OST chart (0.82) and OST equation (0.82) compared with the body weight criterion (0.73). PPV for detecting osteoporosis ranged from 30% to 58% among women deemed at high risk. These data confirm the validity of the ORAI, the OST chart and the OST equation as screening tools for BMD testing. Further evidence is required to confirm the validity of the body weight criterion.

Osteoporosis Health Belief Scale: Minor changes were required after telephone administration among women

OBJECTIVE

The Osteoporosis Health Belief Scale (OHBS) is a 42-item scale designed to measure general health motivation, perceived susceptibility to and seriousness of osteoporosis, and beliefs about calcium intake and exercise in preventing and treating osteoporosis. The purpose of this study was to examine the psychometric properties of the OHBS by telephone administration among older women.

STUDY DESIGN AND SETTING

A convenience sample of 425 women aged 61-93 years participating in a longitudinal arthritis study was recruited by telephone. Item clarity was evaluated and 22 additional items (6 reworded, 16 from other questionnaires) were considered to supplement or replace existing scale items. Multitrait scaling techniques and exploratory factor analysis were used to test scale structure. Construct validity was tested based on theoretical hypothesis between OHBS subscale scores and participant characteristics.

RESULTS

A few modifications to the OHBS scale were suggested, reducing the scale by five items (two redundant, three did not load), rewording one item and moving on item to a different subscale. The modified 37-item OHBS had a seven-factor uncorrelated solution explaining 48% of the model variance with internal consistency ranging from 0.73 to 0.88.

CONCLUSION

Relatively minor changes to the OHBS results in reduced redundancy and improved internal structure of the scale for telephone administration among women over 60 years of age. Further examination is recommended to confirm these findings.

Using publicly available directories to trace survey nonresponders and calculate adjusted response rates

In population-based surveys, sample lists are often out of date by the time data collection begins. Consequently, response rates, and the perceived validity of the survey, may be compromised by the unknowing inclusion of ineligible subjects. A strategy to address this issue is ascertainment of survey nonrespondents' eligibility status, enabling post hoc adjustment of response rates. In 1995-1996, population surveys were carried out in two Ontario, Canada, communities. Despite intensive follow-up, the status of 8949 (18.6%) of the 48218 potential subjects in these surveys remained unknown. In response, 500 "unknowns" from each community were randomly selected for tracing by using publicly available telephone directories and, where applicable, city directories. These tracing efforts classified persons into one of three groups: "ineligible" (moved before the mailing), "true nonresponder" (present when the survey was mailed), and "remains unknown" (no directory listing found). Publicly available directories clarified the status of 76.0% of potential participants, reducing the proportion of "unknowns" from 18.6% to 4.6%. Applying the estimated proportions of "ineligibles" from each area resulted in response rates adjusted from 63.8% to 71.2% and from 72.8% to 74.9% in the survey areas. Publicly available directories were used to successfully trace the majority of survey nonresponders, thus strengthening confidence in the survey's results.

Patient and provider factors related to comprehensive arthritis care in a community setting in Ontario, Canada

OBJECTIVE

To determine factors that correlate with recommendations for nonpharmacologic and pharmacologic interventions (comprehensive therapy) in community dwelling adults.

METHODS

Eligible participants were >/= 55 years of age with hip and knee arthritis symptoms and disability. Comprehensive therapy was classified as a recommendation for exercise and weight loss (if required) and any pharmacotherapy.

RESULTS

Only one-half of participants received a recommendation for comprehensive therapy. Participants who had seen a specialist and a therapist were almost twice as likely to receive a recommendation for comprehensive therapy.

CONCLUSION

In our setting, many people with hip or knee arthritis were not receiving even minimum recommended treatment. Changes in educational and organizational policies are needed to address this situation.

The effect of education and income on need and willingness to undergo total joint arthroplasty

OBJECTIVE

Individuals with lower socioeconomic status (SES) receive less arthritis care, including joint arthroplasty. However, no studies have considered the expectations or needs of the patients. Our objective was to assess the effect of education and income on the potential need for, and the willingness to consider hip and knee arthroplasty.

METHODS

Through a mail/telephone survey of 48,218 persons ages 55 years or older residing in 2 areas of Ontario, Canada, 3,307 individuals with moderate-to-severe hip/knee problems were identified. These individuals received a questionnaire to assess education, income, arthritis severity, and comorbidity. In a subset of these subjects, we conducted interviews to evaluate the willingness to consider arthroplasty, and we also performed clinical and radiographic examinations of the joints to validate self-reports of arthritis. The potential need for arthroplasty was defined as the presence of severe arthritis (as scored by the Western Ontario and McMaster Universities Osteoarthritis Index), with no absolute contraindications to surgery. Separate logistic regression models examined the independent effects of education and income on the potential need for, and definite willingness to consider arthroplasty, after controlling for age, sex, and region of residence. Potential unmet need was estimated as the proportion of subjects with the need for arthroplasty who were not already on a surgery waiting list, who were definitely willing to consider arthroplasty, and who had evidence of arthritis by examination and radiography.

RESULTS

Response rates were at least 72% for all questionnaires and interviews. Less education (adjusted odds ratio [OR] 1.57 for less than high school versus postsecondary education, 95% confidence interval [95% CI] 1.17-2.11) and lower income (adjusted OR 1.83 for </=$20,000 versus >$40,000, 95% CI 1.24-2.70) were independently associated with a greater likelihood of having the potential need for arthroplasty. Among the subjects with potential need, neither education nor income was independently associated with a definite willingness to consider arthroplasty. Thus, taking willingness into consideration, individuals with less education and/or lower income were more likely to have potential unmet need for arthroplasty.

CONCLUSION

Persons with lower SES had a greater need for, and were equally willing to consider arthroplasty, compared with those with higher SES. Thus, observed SES disparities in the rates of performed arthroplasties cannot be explained by a lower need or less willingness to undergo arthroplasty in those with lower SES.

Barriers to providing adequate rheumatology care: implications from a survey of rheumatologists in ontario, Canada

OBJECTIVE

To determine what, if any, barriers exist that prevent rheumatologists from providing adequate rheumatology care.

METHODS

All 158 identified rheumatologists in Ontario were sent a self-administered questionnaire and followed up by telephone.

RESULTS

The response rate was 83%. All but 6 rheumatologists reported at least one barrier to the provision of service. The 3 most commonly reported barriers were the cost of drugs for patients (83%), billing policies and regulations for consultation and followup visits (72%), and long waiting times for patients (61%). Rheumatologists reporting the latter had significantly longer waiting times (12 vs 4 wks) for new non-urgent patients, although there was no difference for new patients with inflammatory arthritis. Nearly three-quarters of respondents had changed the patterns of their practice over the last 3 years, with significant increases in the amount of independent medical services (e.g., third party billing) and pharmaceutical company work. The majority (89%) of responding rheumatologists reported having at least some difficulty in making ends meet from rheumatology practice alone and 28% found it was not possible.

CONCLUSION

These results indicate that the majority of rheumatologists face significant barriers to providing adequate care. Given the recruitment and service provision concerns in Canada, these barriers to service need to be addressed to ensure adequate provision of care.

Correlates of forearm bone mineral density in young Norwegian women: the Nord-Trøndelag Health Study

Maximizing attainment of optimal peak bone mineral density (BMD) is a potential osteoporosis prevention strategy. The main objective of this study was to identify correlates of forearm BMD in young adult women. Population-based data derived from standardized questionnaires administered to healthy women aged 19-35 years in Nord-Trøndelag, Norway (n = 963), were collected in 1995-1997. Forearm BMD was assessed by single x-ray absorptiometry. Multiple linear and logistic regression analyses were used to determine correlates of BMD (g/cm(2)) and lowest quintile of BMD, respectively, at the ultradistal and distal sites. The mean age and weight of the cohort were 29.7 years (standard deviation 4.7) and 68.6 kg (standard deviation 12.5), respectively. Age and weight were positively associated with BMD at both forearm sites. When data were controlled for age and weight, later age at menarche and lack of milk consumption were associated with lower BMD values. In both linear models and logistic models, none of the factors vitamin D intake, physical activity, smoking, alcohol consumption, amenorrhea, oral contraceptive use, number of pregnancies, history of breastfeeding, and family history of osteoporosis were found to be significantly associated with BMD. Prior studies have suggested that calcium supplementation in children is useful for optimizing peak BMD. Further studies exploring the relation between lifestyle factors and BMD are warranted to search for ways to maximize attainment of peak BMD.

A clinical prediction rule to identify premenopausal women with low bone mass

Identifying premenopausal women at risk for osteoporosis and related fractures is a potentially important way to reduce the burden of illness from this disease as low peak bone mass is a risk factor for postmenopausal osteoporosis. We examined predictors of 'low' peak bone mass in 668 healthy, pre-menopausal, Caucasian women ages 18-35 years. Predictors of bone mass were assessed using a detailed, standardized interview. Bone mass was assessed using two measures: dual-energy X-ray absorptiometry (DXA) at the femoral neck and lumbar spine, and quantitative ultrasound (QUS) of the heel, which evaluates stiffness, speed of sound (SOS) and broadband ultrasound attenuation (BUA). Bone mass was considered 'low' if the corresponding Z-score was <-1.00 (DXA values, stiffness) or if values were in the lowest quintile (BUA, SOS). Using multivariate logistic regression modeling, predictors of low bone mass based on QUS, DXA or both were determined. The mean age of the cohort was 27.3 years. Independent predictors of low bone mass by both DXA and QUS were: low body weight, menarche at age 15 years or later and physical inactivity as an adolescent. Individuals with all three risk factors had a 92% chance of having low bone mass using both techniques. This suggests that a simple risk factor assessment can identify most young women with low peak bone mass. Early intervention in this group of women may reduce the risk for osteoporosis in later life.

"You're perfect for the procedure! Why don't you want it?" Elderly arthritis patients' unwillingness to consider total joint arthroplasty surgery: a qualitative study

OBJECTIVE

To explore the process by which elderly persons make decisions about a surgical treatment, total joint arthroplasty (TJA).

METHODS

In-depth interviews with 17 elderly individuals identified as potential candidates for TJA who were unwilling to undergo the procedure.

RESULTS

For the majority of participants, decision making involved ongoing deliberation of the surgical option, often resulting in a deferral of the treatment decision. Three assumptions may constrain elderly persons from making a decision about surgery. First, some participants viewed osteoarthritis not as a disease but as a normal part of aging. Second, despite being candidates for TJA according to medical criteria, many participants believed candidacy required a level of pain and disability higher than their current level. Third, some participants believed that if they either required or would benefit from TJA, their physicians would advise surgery.

CONCLUSION

These assumptions may limit the possibility for shared decision making.

CLINICAL IMPLICATIONS

Emphasis should be directed toward thinking about ways in which discussions about TJA might be initiated (and by whom) and considering how patients' views on and knowledge of osteoarthritis in general might be addressed.

Bone density and heel ultrasound testing do not identify patients with dialysis-dependent renal failure who have had fractures

Patients with dialysis-dependent renal failure are at increased risk for low-trauma fractures. However, the optimal means of identifying patients at high risk for fracture is not known. We assessed the association between fracture history and two tests of bone mineral density (dual x-ray absorptiometry [DEXA] and calcaneal ultrasound) among patients with hemodialysis-dependent renal failure. We evaluated 71 men and 33 women aged 55 years or older who had been receiving hemodialysis for at least 1 year. All patients underwent spinal radiography, DEXA of the hip and lumbar spine, and calcaneal ultrasonography. We assessed risk factors for low-trauma fractures by questionnaire and medical chart review. Of patients, 52% had a fracture on spinal radiographs or a history of a low-trauma fracture, 69% had osteopenia by DEXA, and 26% had a low heel ultrasound measurement. Neither DEXA nor calcaneal ultrasound was associated with fracture history, however. Our findings indicate that fractures among patients with dialysis-dependent renal failure are common. Tests of bone strength do not adequately identify patients with a history of fractures. Prospective studies to determine the optimal method of identifying patients with dialysis-dependent renal failure at high risk for fracture are needed.

Wintertime vitamin D insufficiency is common in young Canadian women, and their vitamin D intake does not prevent it

OBJECTIVE

We asked whether women self-reporting the recommended consumption of vitamin D from milk and multivitamins would be less likely to have low wintertime 25-hydroxyvitamin D (25(OH)D) levels.

METHODS

This cross-sectional study enlisted at least 42 young women each month (age 18-35 y, 796 women total) through one year. We measured serum 25(OH)D and administered a lifestyle and diet questionnaire.

RESULTS

Over the whole year, prevalence of low 25(OH)D (<40 nmol/l) was higher in non-white, non-black subjects (25.6% of 82 women) than in the white women (14.8% of 702 white women, P<0.05). Of the 435 women tested during the winter half of the year (November-April), prevalence of low 25(OH)D was not affected by vitamin D intake: low 25(OH)D occurred in 21% of the 146 consuming no vitamin D, in 26% of the 140 reporting some vitamin D intake, up to 5 microg/day (median, 2.5 microg/day), and in 20% of the 149 women reporting vitamin D consumption over 5 microg/day (median, 10 microg/day).

INTERPRETATION

The self-reported vitamin D intake from milk and/or multivitamins does not relate to prevention of low vitamin D nutritional status of young women in winter. Recommended vitamin D intakes are too small to prevent insufficiency. Vitamin D nutrition can only be assessed by measuring serum 25(OH)D concentration.

Determining the need for hip and knee arthroplasty: the role of clinical severity and patients' preferences

BACKGROUND

Area variation in the use of surgical interventions such as arthroplasty is viewed as concerning and inappropriate.

OBJECTIVES

To determine whether area arthroplasty rates reflect patient-related demand factors, we estimated the need for and the willingness to undergo arthroplasty in a high- and a low-use area of Ontario, Canada.

RESEARCH DESIGN

Population-based mail and telephone survey.

SUBJECTS

All adults aged > or =55 years in a high (n = 21,925) and low (n = 26,293) arthroplasty use area.

MEASURES

We determined arthritis severity and comorbidity with questionnaires, established the presence of arthritis with examination and radiographs, and evaluated willingness to have arthroplasty with interviews. Potential arthroplasty need was defined as severe arthritis, no absolute contraindication for surgery, and evidence of arthritis on examination and radiographs. Estimates of need were then adjusted for patients' willingness to undergo arthroplasty.

RESULTS

Response rates were 72.0% for questionnaires and interviews. The potential need for arthroplasty was 36.3/1,000 respondents in the high-rate area compared with 28.5/1,000 in the low-rate area (P <0.0001). Among individuals with potential need, only 14.9% in the high-rate area and 8.5% in the low-rate area were definitely willing to undergo arthroplasty (P = 0.03), yielding adjusted estimates of need of 5.4/1,000 and 2.4/1,000 in the high- and low-rate areas, respectively.

CONCLUSIONS

Demonstrable need and willingness were greater in the high-rate area, suggesting these factors explain in part the observed geographic rate variations for this procedure. Among those with severe arthritis, no more than 15% were definitely willing to undergo arthroplasty, emphasizing the importance of considering both patients' preferences and surgical indications when evaluating need and appropriateness of rates for surgery.

Alleles of the estrogen receptor alpha-gene and an estrogen receptor cotranscriptional activator gene, amplified in breast cancer-1 (AIB1), are associated with quantitative calcaneal ultrasound

Quantitative bone ultrasound (QUS) has a significant heritable component. Because estrogen is required for attainment of peak bone mass, we studied alleles of two genes, estrogen receptor alpha (ER1) and amplified in breast cancer-1 (AIB1), for their association with QUS. In a volunteer sample of 663 white women aged 18-35 years, bone ultrasound attenuation (BUA), speed of sound (SOS), and heel stiffness index (SI), the latter consisting of the component measures of BUA and SOS, were measured at the right calcaneus by QUS. Subjects were genotyped for the ER1 polymorphisms Xba I and Pvu II and for the AIB1 polyglutamine tract polymorphism. In a multiple regression analysis, ER1 genotype was an independent predictor of QUS-SI (p = 0.03). Because AIB1 and ER1 enhance gene expression in a coordinate manner, we also searched for interactions. A gene-by-gene interaction effect was seen for QUS-SI (p = 0.009), QUS-BUA (p = 0.03), and QUS-SOS (p = 0.004). These remained significant after the inclusion of clinically relevant variables into the final regression model. Overall, these clinical and genetic factors accounted for up to 16% of the variance in peak QUS; the genetic markers alone accounted for 4-7%. This is the first demonstration of specific genetic effects on calcaneal QUS encoded by alleles of genes directly involved in mediating estrogen effects on bone.

Differences between men and women in the rate of use of hip and knee arthroplasty

BACKGROUND

Previous studies suggest that, for some conditions, women receive fewer health care interventions than men. We estimated the potential need for arthroplasty and the willingness to undergo the procedure in both men and women and examined whether there were differences between the sexes.

METHODS

All 48,218 persons 55 years of age or older in two areas of Ontario, Canada, were surveyed by mail and telephone to identify those with hip or knee problems. In these subjects, we assessed the severity of arthritis and the presence of coexisting conditions by questionnaire, documented arthritis by examination and radiography, and conducted interviews to evaluate the subjects' willingness to undergo arthroplasty. The potential need for arthroplasty was defined by the presence of severe symptoms and disability, the absence of any absolute contraindications to surgery, and clinical and radiographic evidence of arthritis. The estimates of need were then adjusted for the subjects' willingness to undergo arthroplasty.

RESULTS

The overall response rates were at least 72 percent for the questionnaires and interviews. As compared with men, women had a higher prevalence of arthritis of the hip or knee (age-adjusted odds ratio, 1.76; P<0.001) and had worse symptoms and greater disability, but women were less likely to have undergone arthroplasty (adjusted odds ratio, 0.78; P<0.001). Despite their equal willingness to have the surgery, fewer women than men had discussed the possibility of arthroplasty with a physician (adjusted odds ratio, 0.63). The numbers of people with a potential need for hip or knee arthroplasty were 44.9 per 1000 among women and 20.8 per 1000 among men. After adjustment for willingness to undergo the procedure, the numbers were 5.3 per 1000 for women and 1.6 per 1000 for men.

CONCLUSIONS

There is underuse of arthroplasty for severe arthritis in both sexes, but the degree of underuse is more than three times as great in women as in men.

Use of bone densitometry by Ontario family physicians

A stratified (urban/rural), computer-generated random sample of 797 Ontario members of the College of Family Physicians of Canada received a self-administered questionnaire by mail. The questionnaire examined current use of bone densitometry, focusing on reasons for its use, factors that limit use, and features of the report that are helpful to the family physician in subsequent patient management. The response rate was 64% (457/711) after excluding 77 physicians who no longer practice family medicine. Ninety-two percent of the physicians used densitometry; of these, 97% ordered the test in the past year. Compared with urban physicians, rural physicians were more likely to 'never use densitometry' (p=0.04). Rural physicians who reported using densitometry used it less frequently (p=0.002), were less likely to have local access (p=0.001), and were less confident in its use (p=0.004) than their urban counterparts. Risk factors and hormone replacement therapy decision-making were ranked equally as the most frequent reasons for ordering the test, followed by follow-up. Few physicians identified limits to their use of densitometry. Female physicians used densitometry more frequently (p = 0.03) and were more confident in its use (p = 0.02). Features of the bone density report found to be most helpful were the statement of fracture risk, suggestions for further investigation, management and follow-up, and percent reduction in bone density compared with age-matched controls. The use of bone densitometry by Ontario family physicians is consistent with published guidelines. These physicians identified the estimate of fracture risk and suggestions for investigation and management as the most helpful features of the bone density report. This suggests a role for the incorporation of clinical data in bone density reporting.

Bone mineral density testing and osteoporosis education improve lifestyle behaviors in premenopausal women: a prospective study

One way to decrease the risk of osteoporosis is to maximize peak bone mass. Peak bone mass may be moderately influenced by lifestyle behaviors: increasing calcium and exercise, decreasing alcohol intake and smoking may increase peak bone mass. We examined the effects of osteoporosis education and bone mineral density (BMD) testing on self-reported lifestyle behaviors in 669 premenopausal women enrolled in a prospective study to assess determinants of peak bone mass. Study participants completed a questionnaire that assessed lifestyle behaviors, received pamphlets about osteoporosis, and had BMD testing. One year later, the women completed a similar questionnaire. After education about osteoporosis and BMD testing, women reported that they were less likely to smoke (odds ratio [OR] = 0.55; 95% confidence interval [95% CI]: 0.28-1.0), consume alcohol (OR = 0.13; 95% CI: 0.04-0.34), and caffeinated beverages (OR = 0. 43; 95% CI: 0.27-0.68). Women were more likely to use calcium supplements (OR = 4.3; 95% CI: 3.04-6.2), vitamin D supplements (OR = 12.6; 95% CI: 7.4-22.9), and drink at least one glass of milk a day (OR = 13.3; 95% CI: 7.8-23.9). Further, women with low bone mass were more likely to use calcium supplements (OR = 1.7; 95% CI: 1.2-2.3) and vitamin D supplements (OR = 1.6; 95% CI:1.1-2.2) compared with women who had normal bone mass. Thus, our intervention improved self-reported lifestyle behaviors in premenopausal women. Such behaviors may ultimately increase peak bone mass and decrease the risk of developing osteoporosis.

Physician enthusiasm as an explanation for area variation in the utilization of knee replacement surgery

BACKGROUND

Explanations for regional variation in the use of many medical and surgical treatments is controversial.

OBJECTIVES

To identify factors that might be amenable to intervention, we investigated the determinants of regional variation in the use of knee replacement surgery.

RESEARCH DESIGN

We examined the effect of the following factors: characteristics and opinions of surgeons; family physicians and rheumatologists; patients' severity of disease before knee replacement; access to knee-replacement surgery; surgeons' use of other surgical treatment; and county population characteristics.

OUTCOMES MEASURE

County utilization rates of knee replacement in Ontario, Canada.

RESULTS

Counties that had higher rates of knee replacement had older patients (P = 0.0001), higher percentage of medical school affiliated hospital beds (P = 0.04), with more male (P = 0.02) non-North American trained referring physicians (P = 0.002) and orthopedic surgeons who had higher propensities to operate and better perceptions of outcome (P = 0.0001).

CONCLUSIONS

After controlling for population characteristics and access to care (including the number of hospital beds, and the density of orthopaedic and referring physicians), orthopaedic surgeons' opinions or enthusiasm for the procedure was the dominant modifiable determinant of area variation. Thus, research needs to focus on the opinions of surgeons which may be important in reducing regional variation for knee replacement.

Determinants of peak bone mass: clinical and genetic analyses in a young female Canadian cohort

Peak bone mass has been shown to be a significant predictor of risk for osteoporosis. Previous studies have demonstrated that skeletal mass accumulation is under strong genetic control, and efforts have been made to identify candidate loci. Determinants of peak bone mass also include diet, physical activity, hormonal status, and other clinical factors. The overall contribution of these factors, genetic and nongenetic, and their interaction in determining peak bone density status have not been delineated. Six hundred and seventy-seven healthy unrelated Caucasian women ages 18-35 years were assessed. A detailed, standardized interview was conducted to evaluate lifestyle factors, menstrual and reproductive history, medical conditions, medication use, and family history of osteoporosis. Bone mineral density (BMD) was measured at the lumbar spine (L2-L4) and the femoral neck (hip) using dual-energy X-ray absorptiometry. Genotyping of the vitamin D receptor (VDR) locus at three polymorphic sites (BsmI, ApaI, and TaqI) was performed. In bivariate analyses, BMD at the lumbar spine and hip was positively correlated with weight, height, body mass index (BMI), and level of physical activity, both now and during adolescence, but negatively correlated with a family history of osteoporosis. Hip, but not spine BMD, correlated positively with dietary intake of calcium, and negatively with amenorrhea of more than 3 months, with caffeine intake, and with age. Spine, but not hip BMD, correlated positively with age and with number of pregnancies. VDR haplotype demonstrated significant associations with BMD at the hip, level of physical activity currently, and BMI. In multivariate analysis, independent predictors of greater BMD (at the hip or spine) were: age (younger for the hip, older for the spine), greater body weight, greater height (hip only), higher level of physical activity now and during adolescence, no family history of osteoporosis, and VDR genotype (hip only). Weight, age, level of physical activity, and family history are independent predictors of peak BMD. Of these factors, weight accounts for over half the explained variability in BMD. VDR alleles are significant independent predictors of peak femoral neck, but not lumbar spine BMD, even after adjusting for family history of osteoporosis, weight, age, and exercise. However, the overall contribution of this genetic determinant is modest. Taken together, these factors explained approximately 17% and 21% of the variability in peak spine and hip BMD, respectively, in our cohort. Future research should be aimed at further evaluation of genetic determinants of BMD. Most importantly, understanding the critical interactive nature between genes and the environment will facilitate development of targeted strategies directed at modifying lifestyle factors as well as earlier intervention in the most susceptible individuals.

A986S polymorphism of the calcium-sensing receptor and circulating calcium concentrations

BACKGROUND

The regulation of extracellular calcium concentration by parathyroid hormone is mediated by a calcium-sensing, G-protein-coupled cell-surface receptor (CASR). Mutations of the CASR gene alter the set-point for extracellular ionised calcium [Ca2+]o and cause familial hypercalcaemia or hypocalcaemia. The CASR missense polymorphism, A986S, is common in the general population and is, therefore, a prime candidate as a genetic determinant of extracellular calcium concentration.

METHODS

We genotyped the CASR A986S variant (S allele frequency of 16.3%) in 163 healthy adult women and tested samples of their serum for total calcium, albumin, total protein, creatinine, phosphate, pH, and parathyroid hormone. A prospectively generated, random subset of 84 of these women provided a whole blood sample for assay of [Ca2+]o.

FINDINGS

The A986S genotype showed no association with total serum concentration of calcium, until corrected for albumin. In a multivariate regression model, biochemical and genetic variables accounted for 74% of the total variation in calcium. The significant predictors of serum calcium were: albumin (p<0.001), phosphate (p=0.02), parathyroid hormone (p=0.007), pH (p=0.001), and A986S genotype (p=0.009). Fasting whole-blood [Ca2+]o also showed an independent positive association with the 986S variant (p=0.013).

INTERPRETATION

The CASR A986S variant has a significant effect on extracellular calcium. The CASR A986S polymorphism is a likely candidate locus for genetic predisposition to various bone and mineral disorders in which extracellular calcium concentrations have a prominent part.

Management of common musculoskeletal problems: a survey of Ontario primary care physicians

BACKGROUND

In Canada, primary care physicians manage most musculoskeletal problems. However, their training in this area is limited, and some aspects of management may be suboptimal. This study was conducted to examine primary care physicians' management of 3 common musculoskeletal problems, ascertain the determinants of management and compare management with that recommended by a current practice panel.

METHODS

A stratified computer-generated random sample of 798 Ontario members of the College of Family Physicians of Canada received a self-administered questionnaire by mail. Respondents selected various items in the management of 3 hypothetical patients: a 77-year-old woman with a shoulder problem, a 64-year-old man with osteoarthritis of the knee and a 30-year-old man with an acutely hot, swollen knee. Scores reflecting the proportion of recommended investigations, interventions and referrals selected for each scenario were calculated and examined for their association with physician and practice characteristics and physician attitudes.

RESULTS

The response rate was 68.3% (529/775 eligible physicians). For the shoulder problem, all of the recommended items were chosen by the majority of respondents. However, of the items not recommended, ordering blood tests was selected by almost half (242 [45.7%]) as was prescribing an NSAID (236 [44.7%]). For the knee osteoarthritis the majority of respondents chose the recommended items except exercise (selected by only 175 [33.1%]). Of the items not recommended, tests were chosen by about half of the respondents and inappropriate referrals (chiefly for orthopedic surgery) were chosen by a quarter. For the acutely hot knee, the majority of physicians chose all of the recommended items except use of ice or heat (selected by only 188 [35.6%]). Although most (415 [78.5%]) of the respondents selected the recommended joint aspiration for this scenario, 84 (15.9%) omitted this investigation or referral to a specialist. The selection of recommended items was strongly associated with training in musculoskeletal specialties during medical school and residency.

INTERPRETATION

Primary care physicians' management of 3 common musculoskeletal problems was for the most part in accord with panel recommendations. However, the unnecessary use of diagnostic tests, inappropriate prescribing of NSAIDs, low use of patient-centred options such as exercise, and lack of diagnostic suspicion of infectious arthritis are cause for concern. The results point to the need for increased exposure to musculoskeletal problems during undergraduate and residency training and in continuing medical education.

Accuracy of administrative data for assessing outcomes after knee replacement surgery

OBJECTIVE

To assess the accuracy of information in an administrative database (Canadian Institute for Health Information; CIHI) compared with the hospital record for patients undergoing knee replacement (KR).

METHODS

A stratified random sample of 185 KR recipients from 5 Ontario hospitals were chosen. Their hospital records and corresponding CIHI files were compared to assess percent complete agreement, false negative (FN) and false positive (FP) rates for demographic data, procedures, and diagnoses.

RESULTS

Of 185 records, 175 (95%) were reviewed. Percent complete agreement was greater than 94% for each of patient demographics and procedures (mean FN rates: 0%; mean FP rates: 0-5%). For comorbidities and complications, although mean percent complete agreement was high, and FP rates were low, mean FN rates were 63% for specific comorbid conditions and 70% for organ systems.

CONCLUSIONS

High FN rates have been found in documentation of comorbidities and in-hospital complications for CIHI data compared with the hospital record. Under-coding of comorbidities and in-hospital complications has potential implications for researchers using administrative databases.

Management of the early and late presentations of rheumatoid arthritis: a survey of Ontario primary care physicians

OBJECTIVE

To examine primary care physicians' management of rheumatoid arthritis, ascertain the determinants of management and compare management with that recommended by a current practice panel.

DESIGN

Mail survey (self-administered questionnaire).

SETTING

Ontario.

PARTICIPANTS

A stratified computer-generated random sample of 798 members of the College of Family Physicians of Canada.

OUTCOME MEASURES

Proportions of respondents who chose various items in the management of two hypothetical patients, one with early rheumatoid arthritis and one with late rheumatoid arthritis. Scores for investigations, interventions and referrals for each scenario were generated by summing the recommended items chosen by respondents and then dividing by the total number of items recommended in that category. The scores were examined for their association with physician and practice characteristics and physician attitudes.

RESULTS

The response rate was 68.3% (529/775 eligible physicians). Recommended investigations were chosen by more than two thirds of the respondents for both scenarios. Referrals to physiotherapy, occupational therapy and rheumatology, all recommended by the panel, were chosen by 206 (38.9%), 72 (13.6%) and 309 (58.4%) physicians respectively for early rheumatoid arthritis. These proportions were significantly higher for late rheumatoid arthritis (p < 0.01). In multiple regression analysis, for early rheumatoid arthritis, internship or residency training in rheumatology was associated with higher investigation and intervention scores, for late rheumatoid arthritis, older physicians had higher intervention scores and female physicians had higher referral scores.

CONCLUSIONS

Primary care physicians' investigation of rheumatoid arthritis was in accord with panel recommendations. However, rates of referral to rheumatologists and other health care professionals were very low, especially for the early presentation of rheumatoid arthritis. More exposure to rheumatology and to the role of physiotherapy, occupational therapy and social work during primary care training is strongly recommended.