Heterogeneity of falls among older adults: implications for public health prevention

OBJECTIVES

We examined risk factors for falls among older people according to indoor and outdoor activity at the time of the fall and explored risk factors for seriously injurious falls.

METHODS

Data came from MOBILIZE Boston, a prospective cohort study of 765 community-dwelling women and men, mainly aged 70 years or older. Over 4.3 years, 1737 falls were recorded, along with indoor or outdoor activity at the time of the fall.

RESULTS

Participants with poor baseline health characteristics had elevated rates of indoor falls while transitioning, walking, or not moving. Healthy, active people had elevated rates of outdoor falls during walking and vigorous activity. For instance, participants with fast, rather than normal, gait speed, had a rate ratio of 7.36 (95% confidence interval [CI] = 2.54, 21.28) for outdoor falls during vigorous activity. The likelihood of a seriously injurious fall also varied by personal characteristics, activity, and location. For example, the odds ratio for serious injury from an outdoor fall while walking outside compared to inside a participant's neighborhood was 3.31 (95% CI = 1.33, 8.23).

CONCLUSIONS

Fall prevention programs should be tailored to personal characteristics, activities, and locations.

Reevaluating the implications of recurrent falls in older adults: location changes the inference

OBJECTIVES

To compare characteristics of indoor and outdoor recurrent fallers and explore some implications for clinical practice, in which a fall risk assessment for all recurrent fallers has been recommended.

DESIGN

Prospective cohort study.

SETTING

Maintenance of Balance, Independent Living, Intellect, and Zest in the Elderly of Boston Study, a study of falls etiology in community-dwelling older individuals from randomly sampled households in the Boston, Massachusetts, area.

PARTICIPANTS

Seven hundred thirteen women and men, mostly aged 70 and older, with at least 1 year of follow-up.

MEASUREMENTS

Data at baseline and from an 18-month follow-up examination were collected by questionnaire and comprehensive clinic examination. During follow-up, participants recorded falls on daily calendars. A telephone interview queried location and circumstances of each fall.

RESULTS

One hundred forty-five participants reported recurrent falls (≥2) during the first year. Those who had fallen only outdoors had good health characteristics, whereas those who had fallen only indoors were generally in poor health. For instance, 25.5% of indoor-only recurrent fallers had gait speeds of slower than 0.6 m/s, compared with 2.9% of outdoor-only recurrent fallers; the respective percentages were 44.7% and 8.8% for Berg balance score less than 48. Recurrent indoor fallers generally had poor health characteristics regardless of their activity at the time of their falls, whereas recurrent outdoor fallers who fell during vigorous activity or walking were especially healthy. A report of any recurrent falls in the first year did not predict number of positive findings on a comprehensive or abbreviated fall risk assessment at the 18-month follow-up examination.

CONCLUSION

Characteristics of community-dwelling older people with recurrent indoor and outdoor falls are different. If confirmed, these results suggest that different types of fall risk assessment are needed for specific categories of recurrent fallers.

Nutritional factors that influence change in bone density and stress fracture risk among young female cross-country runners

OBJECTIVE

To identify nutrients, foods, and dietary patterns associated with stress fracture risk and changes in bone density among young female distance runners.

DESIGN AND SETTING

Two-year, prospective cohort study. Observational data were collected in the course of a multicenter randomized trial of the effect of oral contraceptives on bone health.

PARTICIPANTS

One hundred and twenty-five female competitive distance runners ages 18-26 years.

ASSESSMENT OF RISK FACTORS

Dietary variables were assessed with a food frequency questionnaire.

MAIN OUTCOME MEASUREMENTS

Bone mineral density and content (BMD/BMC) of the spine, hip, and total body were measured annually by dual x-ray absorptiometry (DEXA). Stress fractures were recorded on monthly calendars, and had to be confirmed by radiograph, bone scan, or magnetic resonance imaging.

RESULTS

Seventeen participants had at least one stress fracture during follow-up. Higher intakes of calcium, skim milk, and dairy products were associated with lower rates of stress fracture. Each additional cup of skim milk consumed per day was associated with a 62% reduction in stress fracture incidence (P < .05); and a dietary pattern of high dairy and low fat intake was associated with a 68% reduction (P < .05). Higher intakes of skim milk, dairy foods, calcium, animal protein, and potassium were associated with significant (P < .05) gains in whole-body BMD and BMC. Higher intakes of calcium, vitamin D, skim milk, dairy foods, potassium, and a dietary pattern of high dairy and low fat were associated with significant gains in hip BMD.

CONCLUSIONS

In young female runners, low-fat dairy products and the major nutrients in milk (calcium, vitamin D, and protein) were associated with greater bone gains and a lower stress fracture rate. Potassium intake was also associated with greater gains in hip and whole-body BMD.

Indoor and outdoor falls in older adults are different: the maintenance of balance, independent living, intellect, and Zest in the Elderly of Boston Study

OBJECTIVES

To identify risk factors for indoor and outdoor falls.

DESIGN

Prospective cohort study.

SETTING

The MOBILIZE Boston Study, a study of falls etiology in community-dwelling older individuals.

PARTICIPANTS

Seven hundred sixty-five women and men, mainly aged 70 and older, from randomly sampled households in the Boston, Massachusetts, area.

MEASUREMENTS

Baseline data were collected by questionnaire and comprehensive clinic examination. During follow-up, participants recorded falls on daily calendars. The location and circumstances of each fall were asked during telephone interviews.

RESULTS

Five hundred ninety-eight indoor and 524 outdoor falls were reported over a median follow-up of 21.7 months. Risk factors for indoor falls included older age, being female, and various indicators of poor health. Risk factors for outdoor falls included younger age, being male, and being relatively physically active and healthy. For instance, the age- and sex-adjusted rate ratio for having much difficulty or inability to perform activities of daily living relative to no difficulty was 2.57 (95% confidence interval (CI) = 1.69-3.90) for indoor falls but 0.27 (95% CI = 0.13-0.56) for outdoor falls. The rate ratio for gait speed of less than 0.68 m/s relative to a speed of greater than 1.33 m/s was 1.48 (95% CI = 0.81-2.68) for indoor falls but 0.27 (95% CI = 0.15-0.50) for outdoor falls.

CONCLUSION

Risk factors for indoor and outdoor falls differ. Combining these falls, as is done in many studies, masks important information. Prevention recommendations for noninstitutionalized older people would probably be more effective if targeted differently for frail, inactive older people at high risk for indoor falls and relatively active, healthy people at high risk for outdoor falls.

Footwear and Falls in the Home Among Older Individuals in the MOBILIZE Boston Study

BACKGROUND: Whether certain types of footwear, such as slippers, socks without shoes, and going barefoot, increase the risk for falls among the elderly is uncertain. Our purpose was to examine the relationship between footwear and falls within the home in MOBILIZE Boston, a prospective cohort study of falls etiology among non-institutionalized women and men, mainly aged 70 years and older, from the Boston MA, USA area. METHODS: The 765 participants were from households randomly selected from town lists. They were followed for a median of 27.5 months. At baseline, participants were administered a questionnaire that included questions on footwear usually worn, and were given a comprehensive examination that included measurement of many risk factors for falls. During follow-up participants were asked to record each day whether they had fallen; those reporting falls were asked about their footwear when they fell. RESULTS: At the time of in-home falls, 51.9% of people were barefoot, wearing socks without shoes, or wearing slippers; 10.1% of people reported that their usual footwear was one of these types. Among those who fell in their own home, the adjusted odds ratio for a serious injury among those who were shoeless or wearing slippers compared to those who were wearing other shoes at the time of the fall was 2.27 (95% confidence interval 1.21-4.24). CONCLUSIONS: It may be advisable for older individuals to wear shoes in their home whenever possible to minimize the risk of falling. Further research is needed to identify optimal footwear for falls prevention.

Poor adherence to medications may be associated with falls

BACKGROUND

Poor medication adherence is associated with negative health outcomes. We investigated whether poor medication adherence increases the rate of falls as part of Maintenance of Balance, Independent Living, Intellect, and Zest in the Elderly of Boston (MOBILIZE Boston), a prospective, community-based cohort recruited for the purpose of studying novel risk factors for falls.

METHODS

A total of 246 men and 408 women (mean age, 78 years) were followed for the occurrence of falls (median follow-up, 1.8 years). Adherence was assessed by the Morisky scale based on the following four questions: whether an individual ever forgets, is careless at times, stops taking medications when feels better, or stops taking medications when feels worse. Low adherence was defined as a "yes" answer to one or more questions. High adherence was defined as a "no" answer to every question.

RESULTS

Forty-eight percent of subjects were classified as having low medication adherence. The rate of falls in the low adherence group was 1.1 falls/person-year (95% confidence interval [CI]: 1.0-1.3) compared with 0.7 falls/person-year (95% CI: 0.6-0.8) in the high adherence group. After adjusting for age, sex, race/ethnicity, education, alcohol use, cognitive measures, functional status, depression, and number of medications, low medication adherence was associated with a 50% increased rate of falls compared with high medication adherence (rate ratio = 1.5, 95% CI: 1.2-1.9; p < .001).

CONCLUSIONS

Low medication adherence may be associated with an increased rate of falls among older adults. Future studies should confirm this association and explore whether interventions to improve medication adherence might decrease the frequency of falls and other serious health-related outcomes.

Variation in risk factors for fractures at different sites

Fractures in older people are important medical problems. Knowledge of risk factors is essential for successful preventive measures, but when fracture sites of diverse etiology are combined, risk factors for any one site are difficult to identify and may be missed entirely. Among older people, incidence rates of hip, proximal humerus, and vertebral fractures increase with age, but not rates of distal forearm and foot fractures. Low bone mineral density is strongly associated with hip, distal forearm, vertebral, and proximal humerus fractures, but not foot fracture. Most fractures of the hip, distal forearm, and proximal humerus result from a fall, whereas smaller proportions of fractures of the foot and vertebrae follow a fall. Frail people are likely to fracture their hip or proximal humerus, while healthy, active people tend to fracture their distal forearm. We strongly recommend that studies identify risk factors on a site-specific basis.

Small-area estimation and prioritizing communities for tobacco control efforts in Massachusetts

OBJECTIVES

We developed a method to evaluate geographic and temporal variations in community-level risk factors and prevalence estimates, and used that method to identify communities in Massachusetts that should be considered high priority communities for smoking interventions.

METHODS

We integrated individual-level data from the Behavioral Risk Factor Surveillance System from 1999 to 2005 with community-level data in Massachusetts. We used small-area estimation models to assess the associations of adults' smoking status with both individual- and community-level characteristics and to estimate community-specific smoking prevalence in 398 communities. We classified communities into 8 groups according to their prevalence estimates, the precision of the estimates, and temporal trends.

RESULTS

Community-level prevalence of current cigarette smoking among adults ranged from 5% to 36% in 2005 and declined in all but 16 (4%) communities between 1999 and 2005. However, less than 15% of the communities met the national prevalence goal of 12% or less. High smoking prevalence remained in communities with lower income, higher percentage of blue-collar workers, and higher density of tobacco outlets.

CONCLUSIONS

Prioritizing communities for intervention can be accomplished through the use of small-area estimation models. In Massachusetts, socioeconomically disadvantaged communities have high smoking prevalence rates and should be of high priority to those working to control tobacco use.

Small-area estimation and prioritizing communities for obesity control in Massachusetts

OBJECTIVES

We developed a method to evaluate geographic and temporal variations in community-level obesity prevalence and used that method to identify communities in Massachusetts that should be considered high priority communities for obesity control.

METHODS

We developed small-area estimation models to estimate community-level obesity prevalence among community-living adults 18 years or older. Individual-level data from the Behavioral Risk Factors Surveillance System from 1999 to 2005 were integrated with community-level data from the 2000 US Census. Small-area estimation models assessed the associations of obesity (body mass index >or= 30 kg/m(2)) with individual- and community-level characteristics. A classification system based on level and precision of obesity prevalence estimates was then used to identify high-priority communities.

RESULTS

Estimates of the prevalence of community-level obesity ranged from 9% to 38% in 2005 and increased in all communities from 1999 to 2005. Fewer than 7% of communities met the Healthy People 2010 objective of prevalence rates below 15%. The highest prevalence rates occurred in communities characterized by lower income, less education, and more blue-collar workers.

CONCLUSIONS

Similar to the rest of the nation, Massachusetts faces a great challenge in reaching the national obesity control objective. Targeting high-priority communities identified by small-area estimation may maximize use of limited resources.

Issues in conducting epidemiologic research among elders: lessons from the MOBILIZE Boston Study

Conducting research in elderly populations is important, but challenging. In this paper, the authors describe specific challenges that have arisen and solutions that have been used in carrying out The MOBILIZE Boston Study, a community-based, prospective cohort study in Massachusetts focusing on falls among 765 participants aged 70 years or older enrolled during 2005-2007. To recruit older individuals, face-to-face interactions are more effective than less personal approaches. Use of a board of community leaders facilitated community acceptance of the research. Establishing eligibility for potential participants required several interactions, so resources must be anticipated in advance. Assuring a safe and warm environment for elderly participants and offering a positive experience are a vital priority. Adequate funding, planning, and monitoring are required to provide transportation and a fully accessible environment in which to conduct study procedures as well as to select personnel highly skilled in interacting with elders. It is hoped that this paper will encourage and inform future epidemiologic research in this important segment of the population.

Influence of musculoskeletal conditions on oral health among older adults

Both musculoskeletal disorders and diseases of the oral cavity are common and potentially serious problems among older persons, yet little attention has been given to the links between them. Several musculoskeletal diseases, including osteoporosis, Paget's disease, and arthritic disorders, may directly involve the oral cavity and contiguous structures. Drugs used to treat musculoskeletal diseases, including corticosteroids and bisphosphonates, increase the risk of suppression of the immune system and osteonecrosis of the jaw, respectively. Many people with disabling osteoarthritis, rheumatoid arthritis, and other conditions have difficulty practicing good oral hygiene and traveling to dental offices for professional help. Various inexpensive measures can help such individuals, including education of their caregivers and provision of antimicrobial mouthwashes and special toothbrushes.

The effect of oral contraceptives on bone mass and stress fractures in female runners

PURPOSE

To determine the effect of oral contraceptives (OC) on bone mass and stress fracture incidence in young female distance runners.

METHODS

One hundred fifty competitive female runners ages 18-26 yr were randomly assigned to OC (30 microg of ethinyl estradiol and 0.3 mg of norgestrel) or control (no intervention) for 2 yr. Bone mineral density (BMD) and content (BMC) were measured yearly by dual x-ray absorptiometry. Stress fractures were confirmed by x-ray, magnetic resonance imaging, or bone scan.

RESULTS

Randomization to OC was unrelated to changes in BMD or BMC in oligo/amenorrheic (N=50) or eumenorrheic runners (N=100). However, treatment-received analyses (which considered actual OC use) showed that oligo/amenorrheic runners who used OC gained about 1% per year in spine BMD (P<0.005) and whole-body BMC (P<0.005), amounts similar to those for runners who regained periods spontaneously and significantly greater than those for runners who remained oligo/amenorrheic (P<0.05). Dietary calcium intake and weight gain independently predicted bone mass gains in oligo/amenorrheic runners. Randomization to OC was not significantly related to stress fracture incidence, but the direction of the effect was protective in both menstrual groups (hazard ratio [95% CI]: 0.57 [0.18, 1.83]), and the effect became stronger in treatment-received analyses. The trial's statistical power was reduced by higher-than-anticipated noncompliance.

CONCLUSION

OC may reduce the risk for stress fractures in female runners, but our data are inconclusive. Oligo/amenorrheic athletes with low bone mass should be advised to increase dietary calcium and take steps to resume normal menses, including weight gain; they may benefit from OC, but the evidence is inconclusive.

Risk factors for stress fracture among young female cross-country runners

PURPOSE

To identify risk factors for stress fracture among young female distance runners.

METHODS

Participants were 127 competitive female distance runners, aged 18-26, who provided at least some follow-up data in a randomized trial among 150 runners of the effects of oral contraceptives on bone health. After completing a baseline questionnaire and undergoing bone densitometry, they were followed an average of 1.85 yr.

RESULTS

Eighteen participants had at least one stress fracture during follow-up. Baseline characteristics associated (P<0.10) in multivariate analysis with stress fracture occurrence were one or more previous stress fractures (rate ratio [RR] [95% confidence interval]=6.42 (1.80-22.87), lower whole-body bone mineral content (RR=2.70 [1.26-5.88] per 1-SD [293.2 g] decrease), younger chronologic age (RR=1.42 [1.05-1.92] per 1-yr decrease), lower dietary calcium intake (RR=1.11 [0.98-1.25] per 100-mg decrease), and younger age at menarche (RR=1.92 [1.15-3.23] per 1-yr decrease). Although not statistically significant, a history of irregular menstrual periods was also associated with increased risk (RR=3.41 [0.69-16.91]). Training-related factors did not affect risk.

CONCLUSION

The results of this and other studies indicate that risk factors for stress fracture among young female runners include previous stress fractures, lower bone mass, and, although not statistically significant in this study, menstrual irregularity. More study is needed of the associations between stress fracture and age, calcium intake, and age at menarche. Given the importance of stress fractures to runners, identifying preventive measures is of high priority.

Associations between body composition, anthropometry, and mortality in women aged 65 years and older

OBJECTIVES

We examined the relation between measures of body size and mortality in a predominantly White cohort of 8029 women aged 65 years and older who were participating in the Study of Osteoporotic Fractures.

METHODS

Body composition measures (fat and lean mass and percentage body fat) were calculated by bioelectrical impedance analysis. Anthropometric measures were body mass index (BMI; kg/m2) and waist circumference.

RESULTS

During 8 years of follow-up, there were 945 deaths. Mortality was lowest among women in the middle of the distribution of each body size measure. For BMI, the lowest mortality rates were in the range 24.6 to 29.8 kg/m2. The U-shaped relations were seen throughout the age ranges included in this study and were not attributable to smoking or measures of preexisting illness. Body composition measures were not better predictors of mortality than BMI or waist girth.

CONCLUSIONS

Our results do not support applying the National Institutes of Health categorization of BMI from 25 to 29.9 kg/m2 as overweight in older women, because women with BMIs in this range had the lowest mortality.

Menopausal hormone therapy in a health maintenance organization before and after women's health initiative hormone trials termination

BACKGROUND

In July 2002, the Women's Health Initiative (WHI) published results that led to early termination of the randomized controlled trial of estrogen plus progestin in postmenopausal women with an intact uterus. Subsequently, the trial of estrogen only also was terminated early, and the results were published in April 2004. The present study examines the impact of both sets of results on menopausal hormone therapy (MHT) prescription patterns, as well as the characteristics of women who did and did not change their MHT behavior after publication of results.

METHODS

We examined the number of MHT prescriptions filled in the months before and after each set of results was published, using claims data from 24,446 women aged 50-79 years continuously enrolled in a health maintenance organization (HMO) at Henry Ford Health System from January 2000 through December 2004.

RESULTS

After July 2002, a statistically significant (p < 0.05) drop occurred in the rate of MHT prescriptions filled; 29% of the women stopped MHT for at least 4 months, but 24% of these women resumed use by December 2004. Successful stoppers tended to be older. Twenty-one percent of users in April 2004 stopped in May 2004 for at least 4 months; 25% of these had restarted by December. Women continued to initiate MHT after July 2002, but at lower rates in 2003 and 2004 (73% and 77% decreases, respectively, compared with 2001). The types of MHT prescriptions obtained by new users changed after 2001: fewer initiated MHT with oral Premarin (Wyeth, St. David's, PA) and Prempro or Premphase (Wyeth-Ayerst, Philadelphia, PA), and more initiated MHT with Premarin and Estrace (Warner Chilcott, Rockaway, NJ) creams.

CONCLUSIONS

Regardless of the goals of the WHI study, the publication of results on estrogen plus progestin in July 2002 impacted overall rates of MHT use, as did, to a lesser extent, the estrogen only results published in May 2004. Although women continued to initiate MHT after the results were published, they were less likely to use the formulations from the WHI and instead used formulations for which there is less information about effectiveness and long-term health consequences.

Outdoor falls among middle-aged and older adults: a neglected public health problem

OBJECTIVES

Although risk factors for indoor falls among older individuals have been well studied, little is known about the etiology of outdoor falls. We examined risk factors for outdoor falls among middle-aged and older adults.

METHODS

We analyzed data on the most recent fall during the past year among participants aged 45 years and older in the control group (N=2193) of a case-control study of fractures. The study was conducted at 5 Northern California Kaiser Permanente Medical Centers between 1996 and 2001.

RESULTS

Falls occurred outdoors more often than indoors among most age groups. Study participants who reported more leisure-time physical activity had a higher risk for outdoor falls, and participants who were in poorer health had a greater risk for indoor falls. Most outdoor falls (73%) were precipitated by environmental factors, such as uneven surfaces and tripping or slipping on objects, and usually occurred on sidewalks, curbs, and streets. Walking (47.3%) was the most common fall-related activity.

CONCLUSIONS

Outdoor falls among adults aged 45 years and older were frequently attributable to modifiable environmental factors. With the widespread promotion of active lifestyles among older people, improvements in their outdoor environment are urgently needed.

Risk factors for fracture of the shafts of the tibia and fibula in older individuals

A case-control study to identify risk factors for fracture of the shafts of the tibia and fibula among persons 45 years of age and older was undertaken in five Northern California Kaiser Permanente Medical Centers during 1996-2001. One hundred seventy-nine cases of newly diagnosed fracture of the tibia/fibula shaft and 2,399 controls sampled from the membership lists of the same five medical centers were included. Information on potential risk factors was obtained by a standardized questionnaire administered by trained interviewers. The number of previous fractures was associated with an increased risk [adjusted odds ratio (OR) (95% confidence interval)=1.49 (1.09-2.03) per previous fracture]. Attributes known or thought to be associated with protection against loss of bone mass, including high body mass index [adjusted OR=0.82 (0.69-0.97) per 5 kg/m2 increase], having ever used thiazide diuretics or water pills for at least 1 year [adjusted OR=0.62 (0.38-1.02)], and current use of menopausal hormone therapy among females [adjusted OR=0.84 (0.53-1.32)] tended to show decreased risks. Factors generally associated with lower bone mass, such as current cigarette smoking [OR=1.55 (1.01-2.39)] and, to some extent, lack of physical activity [OR=1.31 (0.87-1.96) for the lowest quartile compared to the upper three quartiles], tended to demonstrate increased risks. The number of falls in the past year and risk factors for falls were not associated with tibia/fibula shaft fractures, and indicators of health status were weakly and inconsistently associated with risk. Thus, this study suggests that risk factors for low bone mass, but not health status or risk factors for falls, may be important in the etiology of fracture of the shaft of the tibia/fibula in older individuals.

Socioeconomic status and childhood leukaemia: a review

BACKGROUND

A long-held view links higher socioeconomic status (SES) to higher rates of childhood leukaemia. Some recent studies exhibit associations in the opposite direction.

METHODS

We reviewed journal literature through August 2002 for associations between childhood leukaemia and socioeconomic measures. We determined the direction of each association and its P-value. We described the results with regard to study design, calendar period, geographic locale, and level of the socioeconomic measures (individual or ecological). For measures with sufficient number of results, we computed summary P-values across studies.

RESULTS

Case-control studies conducted in North America since 1980 have involved subject interviews or self-administered questionnaires and have consistently reported inverse (negative) associations of childhood leukaemia with individual-level measures of family income, mother's education, and father's education. In contrast, associations have been consistently positive with father's occupational class in record-based case-control studies and with average occupational class in ecological studies.

CONCLUSIONS

Connections of SES measures to childhood leukaemia are likely to vary with place and time. Validation studies are needed to estimate SES-related selection and participation in case-control studies. Because different socioeconomic measures (such as income and education) and individual-level and ecological-level measures may represent different risk factors, we advise researchers to report these measures separately rather than in summary indices of social class.

Risk factors for pelvis fracture in older persons

From 1996 to 2001, the authors undertook a case-control study of 192 pelvis fracture cases (men and women) and 2,402 controls aged > or = 45 years at five Kaiser Permanente medical centers in Northern California. Most information on potential risk factors was obtained by means of an interviewer-administered questionnaire. Number of fractures since age 45 years and a maternal history of hip fracture were associated with increased risks. Several factors thought to protect against loss of bone mass, including recent use of menopausal hormone therapy (adjusted odds ratio (OR) = 0.55, 95% confidence interval (CI): 0.33, 0.91) and high body mass index (weight (kg)/height (m)2; per 5-unit increase, adjusted OR = 0.65, 95% CI: 0.52, 0.81), were associated with decreased risks, while cigarette smoking (adjusted OR = 2.17, 95% CI: 1.34, 3.52) and hysterectomy (adjusted OR = 1.75, 95% CI: 1.15, 2.66) were associated with increased risks. Various conditions related to propensity to fall were associated with increased risks. Most indicators of frailty, including use of walking aids and needing help with or being unable to perform various activities of daily living, conferred increased risks. Thus, low bone mass, frailty, and probably a propensity to fall appear to be associated with increased risk of pelvis fracture.

Reducing the risk for distal forearm fracture: preserve bone mass, slow down, and don't fall!

A case-control study of 1,150 female and male distal forearm cases and 2,331 controls of age 45 years and older was undertaken from 1996-2001 in five Northern California Kaiser Permanente Medical Centers. Most information on possible risk factors was obtained by an interviewer-administered questionnaire, supplemented by a few tests of lower extremity neurological function. Previous fractures since 45 years of age, a rough marker of osteoporosis, were associated with an increased risk (adjusted odds ratio [OR] [95% confidence interval] = 1.48 [1.20-1.84 ] per previous fracture). Several factors thought to protect against low bone mass were associated with a reduced risk, including current use of menopausal hormone therapy (adjusted OR = 0.60 [0.49-0.74]), ever used thiazide diuretics or water pills for at least 1 year (adjusted OR = 0.79 [0.64-0.97]), high body mass index (weight in kg/height in m2) (adjusted OR = 0.96 [0.89-1.04] per 5 unit increase), and high dietary calcium intake (adjusted OR = 0.88 [0.75-1.03] per 500 mg/day). Falls in the past year and conditions associated with falling, such as epilepsy and/or use of seizure medication (adjusted OR = 2.07 [1.35-3.17]) and a history of practitioner-diagnosed depression (adjusted OR = 1.40 [1.13-1.73]), were associated with increased risks. Having difficulty performing physical functions and all lower-extremity problems measured in this study were associated with reduced risks. The results from this and other studies indicate that distal forearm fractures tend to occur in people with low bone mass who are otherwise in relatively good health and are physically active, but who are somewhat prone to falling (particularly on an outstretched hand), and whose movements are not slowed by lower extremity problems and other debilities. Thus, measures to decrease fall frequency and to slow down the pace of relatively healthy people with low bone mass should lead to a lower frequency of distal forearm fracture.

Increased falling as a risk factor for fracture among older women: the study of osteoporotic fractures

More frequent falling is associated with a higher risk of fracture among older women, but it is not known whether an increased rate of falling, independent of the average rate, also increases fracture risk. The authors examined the relation between an increase in the rate of falls during the first 4 years of follow-up and the subsequent fracture rate, reported for a median of 6.3 years (1986-1998), in 9,106 US women aged 65 years or more. Women in the upper quartile of increasing falls (>0.44 falls/year/year) had greater risks of subsequent hip fracture (rate ratio = 1.42, 95% confidence interval: 0.99, 2.04) and fracture of the proximal humerus (rate ratio = 1.79, 95% confidence interval: 1.08, 2.95) than women without an increase in falls, after adjustment for age, average rate of falls over 4 years, and known risk factors for fracture. Risks of distal forearm, ankle, or foot fracture were not elevated. The associations between fracture risk and increasing falls were not accounted for by baseline physical or cognitive function. An increase in the rate of falls, independent of the average rate, may be associated with a higher risk of frailty (hip and proximal humerus) fractures but not fractures at other sites.

Idiopathic Pulmonary Fibrosis*

Idiopathic pulmonary fibrosis (IPF) is a relentlessly progressive and typically fatal interstitial lung disease. Besides its grave natural history and prognosis, three aspects of IPF challenge clinicians and investigators: (1) recent changes in the conceptual framework and definition of IPF complicate interpretation of prior clinical investigations; (2) while most patients with suspected IPF do not undergo open-lung biopsy, clinical definitions that do not include biopsy criteria have not been validated prospectively; and (3) available treatments have not been shown to be effective. To optimize clinical care and facilitate clinical investigation, a major goal of IPF research should be to develop validated sets of clinical diagnostic and prognostic criteria. Studies have shown the diagnostic value of high-resolution CT scans and identified important prognostic variables; many of these observations await prospective validation. While previous therapeutic studies have been limited by small sample sizes, lack of a placebo control group, and insufficient attention to patient-centered outcomes, the recent study of interferon gamma-1b demonstrated the feasibility of a large-scale, multicenter clinical trial in IPF. In this article, we discuss how overcoming challenges in IPF research will enable future investigators to conduct well-designed observational studies and clinical trials, whose meaningful results will advance our understanding of IPF, its management, and its impact on patients' lives.

Inconsistencies between self-reported ethnicity and ethnicity recorded in a health maintenance organization

PURPOSE

Information on patient ethnicity in hospital admissions databases is often used in epidemiologic and health services research. However, the extent of consistency of these data with self-reported ethnicity is not well studied, particularly for specific Asian subgroups. We examined agreement between ethnicity in records of a sample of members of five Northern California Kaiser Permanente medical centers with self-reported ethnicity.

METHODS

Subjects were 3168 cases and 2413 controls aged 45 years and older from a study of fractures. Ethnicity recorded in the Kaiser admissions database (primarily inpatient) was compared with self-reported ethnicity from the study interviews.

RESULTS

Among study subjects with available Kaiser ethnicity, sensitivities and positive predictive values of the Kaiser classification were high among blacks (0.95 for both measures) and whites (0.98 and 0.94, respectively), slightly lower among Asians (0.88 and 0.95, respectively), and considerably lower among Hispanics (0.55 and 0.81, respectively) and American Indians (0.47 and 0.50, respectively). Among Asian subgroups, the proportion classified as Asian was high among Chinese (0.94) and Japanese (0.99) but lower among Filipinos (0.79) and other Asians (0.74). Among the 228 (4%) subjects who self-identified with multiple ethnicities, 13 of 18 white + Hispanic subjects were classified as being white, and of the 77 subjects identifying as part American Indian, only one was classified as being American Indian in the Kaiser database.

CONCLUSIONS

Given the importance of ethnicity information, medical facilities should be encouraged to adopt policies toward collecting high quality data.

Immigration and acculturation in relation to health and health-related risk factors among specific Asian subgroups in a health maintenance organization

OBJECTIVES

We sought to determine how risk factors for disease vary among Asian subgroups.

METHODS

Using data from a case-control study conducted at Northern California Kaiser Medical Centers (from 1996 to 2001), we compared prevalence of selected risk factors among Asian subgroups and evaluated the associations of these risk factors with sociodemographic factors.

RESULTS

Chinese and Japanese patients had a lower body mass index (kg/m(2)) than did other Asians. In all subgroups, being born in the United States was associated with having a body mass index greater than 25 kg/m(2). Compared with other Asians, more Japanese and multiple-race Asians smoked, and more Filipino and multiple-race Asian smokers started smoking at 18 years or younger. Filipinos and multiple-race Asians also were more likely to report diabetes.

CONCLUSIONS

These data support the importance of efforts to distinguish among Asian subgroups in public health practice and research.

Risk factors for proximal humerus fracture

This case-control study of proximal humerus fracture included 448 incident female and male cases and 2,023 controls aged 45 years or older identified in five Northern California Kaiser Permanente Medical Centers in 1996-2001. Data were collected by using an interviewer-administered questionnaire. Some factors related to low bone mass, including number of fractures since age 45 years and low dietary calcium intake, were associated with increased risks of fracture, and factors thought to protect against bone loss, such as menopausal hormone therapy and calcium carbonate tablet use, were associated with reduced risks. Fall-related risk factors included previous falls, diabetes mellitus, and difficulty walking in dim light. Possible fall-related risk factors suggested for the first time in this study were seizure medication use (adjusted odds ratio (OR) = 2.80, 95% confidence interval (CI): 1.45, 5.42), depression (OR = 1.34, 95% CI: 0.98, 1.84), almost always using a hearing aid (OR = 1.92, 95% CI: 1.12, 3.31 vs. never prescribed), and left-handedness (OR = 2.36, 95% CI: 1.51, 3.68 vs. right-handedness). Difficulty with activities of daily living and lack of physical activity tended to be associated with increased risk. Prevention of falls among frail, osteoporotic persons would likely reduce the frequency of proximal humerus fracture.

Effect of alendronate on bone mineral density and biochemical markers of bone turnover in type 2 diabetic women: the fracture intervention trial

OBJECTIVE

Alendronate sodium (ALN) increases bone mineral density (BMD) in heterogeneous populations of postmenopausal women, but its effect is unknown in women with type 2 diabetes. The objective of this project was to compare changes in BMD during 3 years of ALN treatment versus placebo in diabetic women.

RESEARCH DESIGN AND METHODS

We used data from the Fracture Intervention Trial, a randomized blinded placebo-controlled trial conducted at 11 centers in which 6458 women aged 54-81 years with a femoral neck BMD of <or=0.68 g/cm(2) were randomly assigned to either placebo or 5 mg/day ALN for 2 years, followed by 10 mg/day for the remainder of the trial. BMD was measured by dual-energy X-ray absorptiometry. Type 2 diabetes (n = 297) was defined by self-report, use of insulin or other hypoglycemic agents, or a random nonfasting glucose value >or=200 mg/dl.

RESULTS

In diabetic women, 3 years of ALN treatment was associated with increased BMD at all sites studied, including 6.6% at the lumbar spine and 2.4% at the hip, whereas women in the placebo group experienced a decrease in BMD at all sites except the lumbar spine. The safety/tolerability of ALN was similar to placebo, except for abdominal pain, which was more likely in the ALN group.

CONCLUSIONS

ALN increased BMD relative to placebo in older women with type 2 diabetes and was generally well tolerated as a treatment for osteoporosis. Increases in BMD with ALN therapy compared with placebo were similar between women with and without diabetes.

Bias in Completeness of Birthplace Data for Asian Groups in a Population-Based Cancer Registry (United States)

Data on place of birth are routinely collected by population-based cancer registries in the United States and are used to study effects of immigration on cancer patterns in Asian migrants, who comprise about a quarter of the US immigrant population. However, the quality of this research, which has the potential for informing cancer etiology and control, is unclear because registry birthplace information is incomplete, and its accuracy has not been examined. We quantified misclassification of birthplace data for Asian cancer patients in the Greater Bay Area Cancer Registry in northern California by comparing registry birthplace information with self-reported birthplace from interview, and then identified sociodemographic and hospital characteristics associated with birthplace completeness and misclassification. Of the 1836 eligible Asian patients, 649 (35%) had unrecorded registry birthplace. For all except Vietnamese, these persons were less likely than those with recorded birthplace to be foreign-born (OR = 0.5, 95% CI = 0.4-0.7), to be diagnosed in public than private hospitals (OR = 0.7, 95% CI = 0.5-0.8) and in teaching than non-teaching hospitals (OR = 0.8, 95% CI = 0.6-1.1), and were more likely to have been diagnosed at a large regional health maintenance organization (OR = 1.7, 95% CI = 1.3-2.2) and after 1995 (OR = 1.6, 95% CI = 1.1-2.1). Among Asians with registry birthplace information (n = 1187), sensitivity and predictive value positive for birthplace exceeded 90% for both US- and foreign-born, except for Japanese (predictive value positive = 85.7%). Among US-born Asians, those misclassified as foreign-born were more likely than those correctly classified to prefer a non-English primary language (OR = 29.4, 95% CI = 1.9-459.9). These results suggest that cancer registry birthplace data for Asians should not be used if they continue to be differentially incomplete for a large proportion of the subjects.

Characteristics of fallers who fracture at the foot, distal forearm, proximal humerus, pelvis, and shaft of the tibia/fibula compared with fallers who do not fracture

This case-control study examined the relation of circumstances of falls and characteristics of fallers with risk of fractures at five sites among persons 45 years of age or older from five Kaiser Permanente Medical Centers in Northern California from 1996 to 2001. Included were distal forearm (n = 1,016), foot (n = 574), proximal humerus (n = 467), pelvis (n = 150), and shaft of the tibia/fibula (n = 141) cases who fell at the time of their fracture, and controls (n = 512) who reported falling in the year before the interview but did not fracture. Interviewers collected information by using a standardized questionnaire. Medium-/high-heeled shoes and shoes with a narrow heel increased the risk of all fractures, and slip-on shoes (adjusted odds ratio = 2.3, 95% confidence interval: 1.4, 4.0) and sandals (adjusted odds ratio = 3.1, 95% confidence interval: 1.5, 6.3) increased the risk of foot fractures. Falling from more than a standing height increased the risk of all fractures by two- to fivefold, while breaking the fall was associated with lower risks of all fractures except the distal forearm. Physical activity and hormone therapy were associated with lower risks of most fractures. These results suggest ways in which risks of fractures in older persons can be reduced.

Left-handedness as a risk factor for fractures

Left-handedness has been associated with increased fracture risk in a small number of previous studies. This study reports risks for fractures at the proximal humerus, distal forearm, pelvis, foot, and shaft of the tibia/fibula according to handedness in a case-control study conducted from October 1996 to May 2001 among members of Northern California Kaiser Permanente. Handedness was assessed by questionnaire for 2,841 cases and 2,192 controls, and subjects were categorized as left-handed, right-handed, ambidextrous, or forced to switch from the left to the right hand. Compared to right-handedness, left-handedness was most strongly associated with an increased risk for proximal humerus fractures (adjusted odds ratio (OR)=2.00, 95% confidence interval (CI) 1.33 to 3.01) and less definitively with fractures of the distal forearm (adjusted OR=1.28, 95% CI 0.92 to 1.80), foot (adjusted OR=1.17, 95% CI 0.82 to 1.65), and pelvis (adjusted OR=1.40, 95% CI 0.71 to 2.74). Ambidextrous individuals had elevated risks for fractures of the distal forearm (adjusted OR=2.99, 95% CI 1.42 to 6.30), foot (adjusted OR=2.59, 95% CI 1.13 to 5.97), shaft of the tibia/fibula (adjusted OR=3.91, 95% CI 1.01 to 15.17), and proximal humerus (adjusted OR=2.37, 95% CI 0.85 to 6.65) when compared with right-handed individuals. Those individuals forced to use the right hand demonstrated no increased risk for fractures at any site. These results suggest that handedness does influence fracture risk, but the reasons for this increased risk are unclear.

Hormone replacement therapy and risk for foot, distal forearm, proximal humerus, and pelvis fractures

This case-control epidemiologic study examines the relationship between hormone replacement therapy (HRT) and risk for fractures of four sites among women 45 years of age and older. From October 1996 to May 2001, incident patients with distal forearm ( n=744), foot ( n=618), proximal humerus ( n=331), and pelvis ( n=109) fractures were recruited from five Kaiser Permanente Medical Centers in northern California. Controls ( n=1617) were selected at random from the same five medical centers over the same time period within strata defined by 5-year age group, gender, and white versus nonwhite or unknown recorded race/ethnicity. Trained interviewers collected information using a standardized questionnaire. Compared with postmenopausal women who never used HRT, postmenopausal women currently using HRT for at least 3 months had a decreased risk of fracture at the distal forearm (adjusted OR=0.55, 95% CI: 0.43, 0.72), proximal humerus (adjusted OR=0.51, 95% CI: 0.36, 0.74), and pelvis (adjusted OR=0.51, 95% CI: 0.27, 0.95), but not the foot (adjusted OR=1.05, 95% CI: 0.81, 1.35). Past use of HRT for more than 7 years also appeared to be associated with a reduced risk of fracture at the distal forearm and proximal humerus. The longer a woman went without HRT after her last menstrual period, the greater her risk of fracture in the distal forearm, proximal humerus, and pelvis. The findings of this study support long-term, current use of HRT for the prevention of osteoporotic fractures, but other risks and benefits also need to be considered.

Disordered eating, menstrual irregularity, and bone mineral density in female runners

PURPOSE

To examine the relationships between disordered eating, menstrual irregularity, and low bone mineral density (BMD) in young female runners.

METHODS

Subjects were 91 competitive female distance runners aged 18-26 yr. Disordered eating was measured by the Eating Disorder Inventory (EDI). Menstrual irregularity was defined as oligo/amenorrhea (0-9 menses per year). BMD was measured by dual x-ray absorptiometry.

RESULTS

An elevated score on the EDI (highest quartile) was associated with oligo/amenorrhea, after adjusting for percent body fat, age, miles run per week, age at menarche, and dietary fat, (OR [95% CI]: 4.6 [1.1-18.6]). Oligo/amenorrheic runners had lower BMD than eumenorrheic runners at the spine (-5%), hip (-6%), and whole body (-3%), even after accounting for weight, percent body fat, EDI score, and age at menarche. Eumenorrheic runners with elevated EDI scores had lower BMD than eumenorrheic runners with normal EDI scores at the spine (-11%), with trends at the hip (-5%), and whole body (-5%), after adjusting for differences in weight and percent body fat. Runners with both an elevated EDI score and oligo/amenorrhea had no further reduction in BMD than runners with only one of these risk factors.

CONCLUSION

In young competitive female distance runners, (i) disordered eating is strongly related to menstrual irregularity, (ii) menstrual irregularity is associated with low BMD, and (iii) disordered eating is associated with low BMD in the absence of menstrual irregularity.

Oral contraceptives and bone mineral density in white and black women in CARDIA. Coronary Risk Development in Young Adults

To examine whether exposure to oral contraceptives (OCs) is associated with bone mineral density (BMD) in young women, we studied, cross-sectionally and longitudinally, 216 white and 260 black women enrolled in the Coronary Artery Risk Development in Young Adults (CARDIA) study. Spine, hip and whole body BMDs were measured by dual-energy X-ray absorptiometry (DXA) when the women were aged 25-37 years, and whole body BMD was remeasured in 369 of the women 3 years later. A comprehensive history of OC use, including dose of ethinyl estradiol (estrogen) and duration of use, was determined from an interviewer-administered questionnaire. After adjustment for other relevant variables, we found that cumulative estrogen from OCs (mg) explained 4.0% of the variation in spine BMD ( p = 0.024) among white women, but did not explain any of the variance in BMD in black women. Cumulative OC estrogen was associated with a decreased risk for low bone density (lowest quartile) at the spine, hip and whole body in white women. The odds ratios (95% CIs) comparing women in the highest quartile of cumulative OC estrogen with those in the lowest quartile were, at the spine: 0.08 (0.02, 0.46); at the hip: 0.23 (0.06, 0.87); and at the whole body: 0.37 (0.11, 1.26). OC exposure was not related to low bone density in black women. OCs did not predict longitudinal changes in whole body BMD in either race. These results suggest that exposure to the estrogen from OCs during the premenopausal years may have a small beneficial effect on the skeleton in white women. Benefit is proportional to the cumulative estrogen exposure, suggesting that previous cross-sectional studies that considered OC use as a dichotomous variable may have lacked the power to detect an association.

Ethnic variation in bone density in premenopausal and early perimenopausal women: effects of anthropometric and lifestyle factors

Bone mineral density (BMD) and fracture rates vary among women of differing ethnicities. Most reports suggest that BMD is highest in African-Americans, lowest in Asians, and intermediate in Caucasians, yet Asians have lower fracture rates than Caucasians. To assess the contributions of anthropometric and lifestyle characteristics to ethnic differences in BMD, we assessed lumbar spine and femoral neck BMD by dual-energy x-ray absorptiometry in 2277 (for the lumbar spine) and 2330 (for the femoral neck) premenopausal or early perimenopausal women (mean age, 46.2 yr) participating in the Study of Women's Health Across the Nation. Forty-nine percent of the women were Caucasian, 28% were African-American, 12% were Japanese, and 11% were Chinese. BMDs were compared among ethnic groups before and after adjustment for covariates. Before adjustment, lumbar spine and femoral neck BMDs were highest in African-American women, next highest in Caucasian women, and lowest in Chinese and Japanese women. Unadjusted lumbar spine and femoral neck BMDs were 7-12% and 14-24% higher, respectively, in African-American women than in Caucasians, Japanese, or Chinese women. After adjustment, lumbar spine and femoral neck BMD remained highest in African-American women, and there were no significant differences between the remaining groups. When BMD was assessed in a subset of women weighing less than 70 kg and then adjusted for covariates, lumbar spine BMD became similar in African-American, Chinese, and Japanese women and was lowest in Caucasian women. Adjustment for bone size increased values for Chinese women to levels equal to or above those of Caucasian and Japanese women. Among women of comparable weights, there are no differences in lumbar spine BMD among African-American, Chinese, and Japanese women, all of whom have higher BMDs than Caucasians. Femoral neck BMD is highest in African-Americans and similar in Chinese, Japanese, and Caucasians. These findings may explain why Caucasian women have higher fracture rates than African-Americans and Asians.

Foot problems as risk factors of fractures

This case-control study examines whether foot problems are risk factors of fractures of five sites among people aged 45 years or older at six Kaiser Permanente Medical Centers in northern California. From October 1996 to May 2001, interviewers collected information through a standardized questionnaire. Incident cases of distal forearm (n = 1,000), foot (n = 827), proximal humerus (n = 448), shaft of the tibia/fibula (n = 168), and pelvis (n = 172) fractures and 1,913 controls from the same medical centers were included. After adjustment for potential confounders and for each additional foot problem, the odds of a foot fracture increased by 8% (adjusted odds ratio = 1.08, 95% confidence interval: 1.03, 1.13). In contrast, each additional foot problem was associated with a reduction in the odds of a forearm fracture (adjusted odds ratio = 0.93, 95% confidence interval: 0.89, 0.98). In general, foot problems were not related to fractures of other sites, although diabetes, which may result in foot problems, increased the odds of a proximal humerus fracture (adjusted odds ratio = 1.65, 95% confidence interval: 1.20, 2.26). If these findings are supported by data from other studies, preventive measures to retard the development of foot problems could reduce the incidence of foot fractures.

Characteristics associated with recent recreational exercise among women 20 to 44 years of age

Data on 1,501 control women from a multi-center, population-based, case-control study of breast cancer were used to examine characteristics associated with recreational exercise during the year prior to the interview among women 20 to 44 years of age. In a univariate analysis, higher levels of recreational exercise were associated with: higher education; higher family income; white race; previous participation in recreational exercise above the median level at ages 12 to 13 and at age 20; being nulliparous; ever lactating; being a never or past smoker; having a low current Quetelet's index (QI: weight in kilograms divided by height in meters squared); and living in Atlanta or Seattle (compared to New Jersey). In a multiple linear regression model, independent predictors of higher levels of recreational exercise were: participation in higher levels of exercise at 20 years of age; having a low current QI; and never having smoked. Though all women should be encouraged to participate in exercise, these findings identity subgroups of women that may need targeting when developing exercise intervention programs.

Household appliance use and residential exposure to 60-hz magnetic fields

We characterized the distribution of exposure to magnetic fields (MFs) during daily activities and during household appliance use, and estimated the relative contribution of various activities and appliances to total daily exposure. One hundred sixty-two subjects provided information on their patterns of appliance use and wore personal monitors for 24 h to collect MF exposure data. Of total exposure, 27% accumulated while subjects were in bed; 41% while at home but not in bed; 9% at work; and 24% elsewhere. Less than 2% of the total MF exposure accumulated during the use of each of the eight individual appliances considered, except computers, during the use of which 9% of the total exposure accumulated. Of the time subjects spent at exposure levels higher than 2 microT, 8% accumulated while they were using microwave ovens, and 4% and 3% while using computers and electric stoves, respectively. Mean MF measurements tended to be lowest when subjects were in bed and highest at work and during the use of microwave ovens, coffee grinders, hair dryers, and electric shavers. Results from questionnaires on household appliance use in the past year were not useful in predicting the total mean exposure level and over-threshold exposures measured by 24-h personal monitors. Significant MF exposure accumulates at home, at work, and elsewhere; therefore, accurate exposure assessment needs to consider residential, occupational, and other sources together. Questionnaire-based information on appliance use has limited value in the assessment of average and over-threshold exposure to MFs.

Relation of demographic and lifestyle factors to symptoms in a multi-racial/ethnic population of women 40-55 years of age

A community-based survey was conducted during 1995-1997 of factors related to menopausal and other symptoms in a multi-racial/ethnic sample of 16,065 women aged 40-55 years. Each of seven sites comprising the Study of Women's Health across the Nation (SWAN) surveyed one of four minority populations and a Caucasian population. The largest adjusted prevalence odds ratios for all symptoms, particularly hot flashes or night sweats (odds ratios = 2.06-4.32), were for women who were peri- or postmenopausal. Most symptoms were reported least frequently by Japanese and Chinese (odds ratios = 0.47-0.67 compared with Caucasian) women. African-American women reported vasomotor symptoms and vaginal dryness more (odds ratios = 1.17-1.63) but urine leakage and difficulty sleeping less (odds ratios = 0.64-0.72) than Caucasians. Hispanic women reported urine leakage, vaginal dryness, heart pounding, and forgetfulness more (odds ratios = 1.22-1.85). Hot flashes or night sweats, urine leakage, and stiffness or soreness were associated with a high body mass index (odds ratios = 1.15-2.18 for women with a body mass index > or =27 vs. 19-26.9 kg/m2). Most symptoms were reported most frequently among women who had difficulty paying for basics (odds ratios = 1.15-2.05), who smoked (odds ratios = 1.21-1.78), and who rated themselves less physically active than other women their age (odds ratios = 1.24-2.33). These results suggest that lifestyle, menstrual status, race/ethnicity, and socioeconomic status affect symptoms in this age group.

Reliability of proxy-reported and self-reported household appliance use

Exposure assessment presents a major challenge for studies evaluating the association between household exposure to electric and magnetic fields and adverse health outcomes, especially the reliance on proxy respondents when study subjects themselves have died. We evaluated the reliability of proxy- and self-reported household appliance exposure. We recruited 92 healthy couples through either random-digit dialing or newspaper advertisements. Trained interviewers administered questionnaires to each member of a couple independently to assess the reliability of proxy-reported household appliance use. Eighty-five couples completed a second interview 2 months later to assess the reliability of self-reported appliance use. Reliability of proxy-reported appliance exposure was good when we inquired about having any exposure to each of the eight indicator appliances during the past year (range of kappa coefficients = 0.63-0.85; median = 0.76) but was lower with increased time to recall or increased detail. Reliability of self respondents reporting 2 months apart was excellent (range of kappa coefficients = 0.75-0.94; median = 0.87) for having any exposure to the eight indicator appliances during the past year, but reliability was again lower with increased detail. When we used self reports at the first interview as the standard, little systematic over- or underreporting occurred for proxy respondents or for self respondents reporting 2 months later. Because this study did not include cases of specific disease, these findings of no systematic differences in reporting do not refer to case or control status. In summary, reliability of self respondents' reports of appliance use is very good for recent time periods and good for broad aspects of exposure in distant time periods. Proxy respondents can provide information regarding broad aspects of appliance exposure in the past year, but detailed aspects of exposure or exposure in more distant time periods is not reliable.

Relationship of neurological function and age in older women. The study of osteoporotic fractures

The decline of neurological and neuromuscular function with age in older women and in subgroups of older women with selected risk factors for poor function is described using cross- sectional analyses of data on 8,080 women from the multicenter Study of Osteoporotic Fractures. All twelve performance-based tests of muscle strength, balance, gait, somatosensory discrimination and reaction time declined with increasing age. On a percentage scale, vibration threshold declined the most rapidly with age. Participants who were smokers, physically inactive, nonconsumers of alcohol, diabetics and more frequent fallers had poorer age-adjusted performance than those without these attributes. However, with a few exceptions, the rate of decline in performance with age for those with and without these characteristics did not differ significantly.

Oral contraceptive and benign ovarian tumors

Whether use of combined oral contraceptives (OC) protects against benign ovarian tumors is unknown. A case-control study of pathologically confirmed benign ovarian tumors was conducted in the New York City area and included cases diagnosed from January 1, 1992, to December 31, 1993, and controls identified by random digit dialing. There were 196 cases with serous adenomas, 176 with teratomas, 311 with endometriomas, and 65 with mucinous adenomas. Interview data were used to determine contraceptive use. Ever use of OC was associated with a decreased risk of these benign tumors (age- and hospital-adjusted odds ratio = 0.79, 95% confidence interval: 0.60, 1.05). In histologic subgroup analyses, the risk of ovarian tumors was reduced for both current and past OC users. Among tumor subtypes, the risk reduction was greatest for women who had endometriotic lesions. The risk reduction also was greater for women who had used OC for more than 24 months. Protection against benign ovarian tumors may be an additional noncontraceptive benefit of OC use.

Falls in older Mexican-American women

OBJECTIVE

To determine the frequency of falls and identify risk factors for falls among older Mexican-American women.

DESIGN

A prospective cohort study with an average follow-up of 2.7 years.

SETTING

A clinical center at the Palo Alto Veterans Affairs Medical Center, California.

PARTICIPANTS

152 community-dwelling Mexican-American Caucasian women aged 59 years or older.

OUTCOME MEASURES

Falls and injurious falls, as determined by monthly telephone interviews.

RESULTS

The rate of falls was 508 per 1000 person-years (95% confidence interval (CI), 440-577). Injurious falls requiring medical attention occurred at a rate of 79 per 1000 person-years (95% CI, 52-107). Factors that were associated independently with an increased risk of falling were older age, a history of arthritis or rheumatism, a history of high thyroid, having fainted at least once in the year before baseline, current use of psychotropic medications, and walking fewer than 5 blocks a day. Those persons with an average time for the chair stand test had a lower risk of falling than those with the slowest times or the fastest times.

CONCLUSIONS

The frequency of falls and injurious falls in this cohort of 152 relatively acculturated, healthy, older Mexican-American women was similar or slightly higher than previously reported rates for non-Hispanic Caucasian(s). Many of the factors associated with falls in this study were similar to those reported for non-Hispanic Caucasian women, suggesting that fall prevention measures tested mainly among non-Hispanic Caucasian women would also be appropriate for Mexican-American women.

International variation in the incidence of hip fractures: cross-national project on osteoporosis for the World Health Organization Program for Research on Aging

A cross-national study of hip fracture incidence was carried out in five geographic areas--Beijing, China; Budapest, Hungary; Hong Kong; Porto Alegre, Brazil; and Reykjavik, Iceland--during the years 1990-1992. Cases of hip fracture among women and men of age 20 years and older were identified using hospital discharge data in conjunction with medical records, operating room logs, and radiology logs. Estimated incidence rates varied widely, with Beijing reporting the lowest rates (age-adjusted rate per 100,000 population for men 20 years and older = 45.4; women = 39.6) and Reykjavik the highest rates (man = 141.3; women = 274.1). Rates were higher for women than for men in every area except Beijing. In every area except Budapest, review of the operating room or radiology logs identified additional cases that were not reported in the discharge list, increasing the estimated number of hip fractures by 11% to 62%, depending on the area. Review of medical records identified miscoding of hip fractures (ICD 9820) as 'shaft of femur and other femur fractures' (ICD 9821) in the discharge lists of every area except Budapest, increasing the estimated number of hip fractures by 1% to 30%. The final estimates of hip fracture incidence taking into account all investigated sources of undercount and overcount ranged from 15% lower to 89% higher than an estimate based on the discharge diagnoses alone. Although these results indicate substantial limitations in relying on hospital discharge data alone to estimate hip fracture incidence rates, the extent of errors found in the discharge lists is smaller than the large international variation found here and previously reported in incidence rates. The findings support the conclusion that the differences reported among countries mainly reflect genuine variation in the hip fracture incidence rates.