Jennifer L. Kelsey

Risk Factors for Falls as a Cause of Hip Fracture in Women

BACKGROUND Although even in the elderly most falls are not associated with fractures, over 90 percent of hip fractures are the result of a fall. Few studies have assessed whether the risk factors for falls are also important risk factors for hip fracture. METHODS To examine the importance of risk factors for falls in the epidemiology of hip fracture, we performed a case-control study of 174 women (median age, 80 years) admitted with a first hip fracture to 1 of 30 hospitals in New York and Philadelphia. Controls, matched to the case patients according to age and hospital, were selected from general surgical and orthopedic surgical hospital services. Information was obtained by direct interview. RESULTS As measured by the odds ratio, increased risks for hip fracture were associated with lower-limb dysfunction (odds ratio = 1.7; 95 percent confidence interval, 1.1 to 2.8), visual impairment (odds ratio = 5.1; 95 percent confidence interval, 1.9 to 13.9), previous stroke (odds ratio = 2.0; 95 percent confidence interval, 1.0 to 4.0), Parkinsons disease (odds ratio = 9.4; 95 percent confidence interval, 1.2 to 76.1), and use of long-acting barbiturates (odds ratio = 5.2; 95 percent confidence interval, 0.6 to 45.0). Of the controls, 44 (25 percent) had had a recent fall. The case patients were more likely than these controls to have fallen from a standing height or higher (odds ratio = 2.4; 95 percent confidence interval, 1.0 to 5.7). Of those with hip fracture the younger patients (less than 75 years old) were more likely than the older ones (greater than or equal to 75 years old) to have fallen on a hard surface (odds ratio = 1.9; 95 percent confidence interval, 1.04 to 3.7). CONCLUSIONS A number of factors that have been identified as risk factors for falls are also associated with hip fracture, including lower-limb dysfunction, neurologic conditions, barbiturate use, and visual impairment. Given the prevalence of these problems among the elderly, who are at highest risk, programs to prevent hip fracture should include measures to prevent falls in addition to measures to slow bone loss.

Epidemiology of musculoskeletal impairments and associated disability.

Data from the US Health and Nutrition Examination Survey (HANES I) of 1971-1975 confirm the high prevalence of musculoskeletal impairments among United States adults. Musculoskeletal impairments tend to be more prevalent among older persons, and persons with less education and with lower annual family incomes. Prevalence rates are slightly higher in females than in males, while Whites and non-Whites are affected with almost equal frequency. Among persons reporting a history of musculoskeletal symptoms, those who have some disability tend to be older, non-White, of lower education and income, and widowed, separated, or divorced. Persons with multiple parts of the body involved, or reporting that their symptoms are due to accident or injury are also especially likely to report disability. Taken as a whole, the data suggest that medical, social, and economic factors all play a role in determining whether a person with musculoskeletal impairment goes on to develop disability related to his or her impairment.

SWAN: A Multicenter, Multiethnic, Community-Based Cohort Study of Women and the Menopausal Transition

Study of Womens Health Across the Nation (SWAN) is the first national study to describe women at midlife, an understudied age group. Its multidisciplinary approach provides the opportunity to consider the contributions of both culture and biology so that one may better understand health of women. The SWAN employs a prospective design that includes sufficient pre- and postmenopausal observations to ensure the separation of menopause-related and age-related physiological changes. Other attributes include the comprehensive standardized data collection related to biological, behavioral, physiological, social, environmental, and cultural factors; specialized data collection methodologies suitable to address the monthly and yearly variation in behavioral and biological patterns; general ability to community-dwelling populations recruited from major United States population centers; sufficiently large sample size and numbers of data points to ensure reliable estimates of associations and relevant effect sizes; and inclusion of sufficient numbers of racial/ethnic minorities to provide comparative information with the non-Hispanic Caucasian population. Because of these attributes, SWAN can contribute new and substantive knowledge about womens health in general and the menopause transition in particular.

Number of Pregnancies and the Subsequent Risk of Cardiovascular Disease

BACKGROUND Whether increasing parity or gravidity is a risk factor for coronary heart disease has been debated, but the question remains unresolved. METHODS We tested the association between the number of pregnancies and a variety of cardiovascular end points in two groups of women who had completed childbearing. One group comprised 2357 women who were followed for 28 years through the Framingham Heart Study, and the other 2533 women followed for at least 12 years through the first National Health and Nutrition Examination Survey National Epidemiologic Follow-up Study (NHEFS). RESULTS The rates of coronary heart disease were higher among multigravid women than among women who had never been pregnant, in both the Framingham Heart Study and the NHEFS, but in both studies, the higher rates were statistically significant only in women with six or more pregnancies. For the women in the Framingham Study, the rate ratio adjusted for age and educational level in the group with six or more pregnancies (as compared with women who had never been pregnant) was 1.6 (95 percent confidence interval, 1.1 to 2.2). For the women in the NHEFS, the same adjusted rate ratio was 1.5 (95 percent confidence interval, 1.1 to 1.9). Adjustments for other known cardiovascular risk factors, including weight, did not markedly alter this risk. The rate of total cardiovascular disease was also significantly higher among multigravid women in the Framingham Study than in the women who had never been pregnant. CONCLUSIONS In two prospective American studies, having six or more pregnancies was associated with a small but consistent increase in the risk of coronary heart disease and cardiovascular disease. Whether gravidity itself or some other unmeasured factor accounts for the increase in risk that we observed requires further investigation.

Disordered eating, menstrual irregularity, and Bone minéral 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.

Incidence of hip fractures in the elderly: A cross-national analysis

This paper reviews international data on incidence rates of hip fracture in persons 50 years of age and older, based on a bibliographic search of articles published since 1960. Incidence rates are higher in white populations than in black, Asian, and Hispanic populations. In both sexes and in all ethnic groups and geographic areas, incidence rates increase markedly with age. The steep increase with age, however, occurs later in black, Asiatic and Hispanic populations than in whites. The ratio of female to male incidence rates is higher than 1.0 in whites, while in blacks and Asians it has often been the reverse, with higher rates among men. In recent years in Hong Kong incidence rates in females have increased more rapidly than incidence rates in males, so that now the incidence rates in females are higher than those in males. In addition to the study in Hong Kong, most studies in Northern Europe and North America show an increase in age-adjusted hip fracture incidence rates over time over the past few decades.Methodological differences among the various studies (including differences in the definition of hip fracture, in case ascertainment, and in the selection and sample size of the study population) necessitate cautious interpretation of the findings of this report.

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.

Home hazards and falls in the elderly: The role of health and functional status

OBJECTIVES This study was undertaken to determine whether vigorous and frail older people who identify environmental hazards in their homes have an increased risk for falls. METHODS A 1-year prospective study was conducted among 266 female and 59 male community-dwelling volunteers aged 60 to 93 years who had fallen at least once during the previous year. Composite measures of home safety and of frailty were derived using principal components analysis. Participants were divided into vigorous and frail groups, and associations between baseline home safety measures and falls at home over the follow-up year were compared between the two groups. RESULTS Frail individuals were more than twice as likely as vigorous individuals to fall during follow-up (rate ratio [RR] = 2.24; 95% confidence interval [CI] = 1.54, 3.27). In the study group as a whole, falls were not strongly associated with the presence of home hazards. However, when compared with vigorous older persons living with fewer home hazards, vigorous older persons living with more home hazards were more likely to fall. The increased risk for falls among vigorous elderly was limited to falls where home hazards were present. By contrast, living with more home hazards was not associated with increased likelihood of falls among frail older persons. CONCLUSIONS While frail older persons experience higher overall fall rates, vigorous older persons should not be overlooked in fall prevention projects.

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

Abstract: 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 (men = 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 (ICD9 820) as ‘shaft of femur and other femur fractures’ (ICD9 821) 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.

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.