Jeanette H. Magnus

Walking after stroke: Does it matter? Changes in Bone mineral density within the first 12 months after stroke. A longitudinal study

Abstract: Stroke patients have increased risk of hip fractures. Nearly all fractures occur on the hemiplegic side, and reduced bone mineral density (BMD) may be an important predisposing factor. The aim of this study was to investigate the degree of demineralization within the first year after stroke, and to elucidate a possible difference in patients with high versus low ambulatory levels. Forty acute stroke patients were followed (17 initially wheelchair-bound and 23 initially ambulatory). BMD was measured in the proximal femur bilaterally at a mean 6 days, 7 months and 1 year after stroke onset using dual-energy X-ray absorptiometry. Ambulatory status was independently associated with changes in BMD (p≤0.005) 1 year after stroke. The 17 initially wheelchair-bound patients had a significant 10% reduction in BMD at the paretic side and 5% reduction at the non-paretic side (p<0.001), while the 23 patients initially able to walk had a significant loss (3%) only at the paretic side (p = 0.01). The analysis also indicated that the major reduction in BMD took place within the first 7 months. Two months after stroke 12 of the wheelchair-bound patients had relearned to walk. At the paretic side the 1 year changes in BMD in the patients who stayed wheelchair-bound, the patients who relearned to walk within the first 2 months and the patients who were able to walk throughout the study were 13%, 8% and 3%, respectively, and a statistically significant trend with ambulatory level was found (p = 0.007). This study provides clear evidence that lack of mobility and weight-bearing early after stroke is an important factor for the greater bone loss in the paretic leg, but that relearning to walk within the first 2 months after stroke, even with the support of another person, may reduce the bone loss after immobilization.

Physical activity and predisposition for hip fractures : A review

Studies on the association between physical activity and hip fractures are reviewed. All the studies, which comprise four follow-up studies, one nested case-control study and 17 case-control studies, suggest a protective effect of physical activity with regard to hip fractures. The association is strong and consistent with physical activity in leisure, weaker with respect to physical activity at work. The association is present for physical activity from childhood to adult age, and it is consistent in study populations from the USA, Australia, Asia and Northern and Southern Europe, in spite of very different hip fractures incidences in these populations. The magnitude of the association is difficult to assess because of varying criteria for exposure, but to be among the physically active seems to reduce the risk of later hip fracture by up to 50%. It seems that even daily chores, such as climbing stairs and walking, protect against hip fracture.

The Tromsø Study: Physical Activity and the Incidence of Fractures in a Middle-Aged Population

We have studied the relation of occupational and recreational physical activity to fractures at different locations. All men born between 1925 and 1959 and all women born between 1930 and 1959 in the city of Tromsø were invited to participate in surveys in 1979–1980 and 1986–1987 (The Tromsø Study). Of 16,676 invited persons, 12,270 (73.6%) attended both surveys. All nonvertebral fractures (n = 1435) sustained from 1988 to 1995 were registered in the only hospital in the area. Average age in the middle of the follow‐up period (December 31, 1991) was 47.3 years among men and 45.1 years among women, ranging from 32 to 66 years. Fracture incidence increased with age at all locations among women, but it decreased with or was independent of age among men. Low‐energetic fractures constituted 74.4% of all fractures among women and 55.2% among men. When stratifying by fracture location, the most physically active persons among those 45 years or older suffered fewer fractures in the weight‐bearing skeleton (relative risk [RR] 0.6, confidence interval [CI] 0.4–0.9, age‐adjusted), but not in the non–weight‐bearing skeleton (RR 1.0, CI 0.7–1.2, age‐adjusted) compared with sedentary persons. The relative risk of a low‐energetic fracture in the weight‐bearing skeleton among the most physically active middle‐aged was 0.3 (CI 0.1–0.7) among men and 0.9 (CI 0.4–1.8) among women compared with the sedentary when adjusted for age, body mass index, body height, tobacco smoking, and alcohol and milk consumption. It seems that the beneficial effect on the skeleton of weight‐bearing activity is reflected also in the incidence of fractures at different sites.

Rural doctor recruitment: does medical education in rural districts recruit doctors to rural areas?

Summary. The impact of the University of Tromsø Medical School on the distribution of doctors in rural areas in northern Norway was evaluated by a postal questionnaire. The survey covered 11 graduation years (417 doctors), and the response rate was 84.2%. The establishment of a new medical school in northern Norway has clearly had beneficial effects: a total of 56.1% of the graduates stay in these remote areas. Of those who also spent their youth in northern Norway the proportion is 82.0%, compared to graduates who lived in the southern parts of the country while growing up (37.7%). The results clearly demonstrate that one of the main goals for the Medical School at the University in Tromsø, to educate doctors who prefer to work in these rural areas, has been accomplished.

Risk assessment and screening for low bone mineral density in a multi-ethnic population of women and men: does one approach fit all?

Screening for osteoporosis is currently recommended for all women aged 65 years and older in the USA. How to address screening of non-white women and all men is unclear. Osteoporosis risk assessment questionnaires have been designed and tested mostly among postmenopausal white women, and there is a lack of consensus on appropriate bone mineral density (BMD) cut-off values for defining osteoporosis in non-white persons. The objectives of the present study were to identify a set of risk factors from published population-based studies in white women and men and determine the ability of these risk factors to predict osteoporosis and low BMD in African–American (AA), Mexican–American (MA), and white women and men, and to assess the diagnostic accuracy of this set of risk factors for identifying osteoporosis separately in AA, MA, and white women and men by the use of data for 2,590 women and 2,391 men 50–79 years of age from the third National Health and Nutrition Examination Survey (NHANES III). We employed the World Health Organisation (WHO) definition of osteoporosis, using race/ethnic and gender-specific young adult mean values when calculating the T scores. Low body-mass index, low calcium intake, current cigarette smoking, and physical inactivity were independent risk factors identified from population-based studies. The presence of one or more risk factors was associated with having osteoporosis and low BMD in all groups. The strength of these associations was greater when two or more risk factors were present but varied with race/ethnicity, gender, and age. We conclude that this set of osteoporosis risk factors predicts osteoporosis in non-white women and men. Furthermore, as a risk assessment tool, this set of risk factors might be useful for reducing the number of unnecessary BMD tests performed in older women as well as identifying non-white men who do not require BMD testing.

What do Norwegian women and men know about osteoporosis

A survey of a random sample of 1514 Norwegian women and men aged 16–79 years was undertaken to investigate knowledge of osteoporosis and attitudes towards methods for preventing this disease. The interviews were carried out by Central Bureau of Statistics of Norway as part of their monthly national poll using a structured questionnaire. Women knew more about osteoporosis than did men (p<01). In both men and women increased knowledge of osteoporosis was correlated to a high level of education. Furthermore it was clearly demonstrated that knowing someone with osteoporosis or suffering from it oneself increased the knowledge of osteoporosis significantly in both women and men. Multiple regression analysis confirmed the univariate analyses, and education was the strongest predictive factor for knowledge. To a hypothetical question as many as two-thirds of the women answered that they would use long-term hormone replacement therapy (HRT) to prevent osteoporosis on the recommendation of their general practitioner. Their attitudes towards the use of estrogen therapy did not show any significant relation to age, but their reluctance towards HRT increased with education (p<001). When asked a question about their preferences regarding the use of physical activity as a means to prevent osteoporosis, older women preferred walking (p<.001), whereas younger women wanted more organized athletic activity (p<001). The data demonstrated that there was a high degree of general knowledge of osteoporosis and its consequences in the general population.

The Tromsø Study: Body Height, Body Mass Index and Fractures

Abstract: Tall persons suffer more hip fractures than shorter persons, and high body mass index is associated with fewer hip and forearm fractures. We have studied the association between body height, body mass index and all non-vertebral fractures in a large, prospective, population-based study. The middle-aged population of Tromsø, Norway, was invited to surveys in 1979/80, 1986/87 and 1994/95 (The Tromsø Study). Of 16 676 invited to the first two surveys, 12 270 attended both times (74%). Height and weight were measured without shoes at the surveys, and all non-vertebral fractures in the period 1988–1995 were registered (922 persons with fractures) and verified by radiography. The risk of a low-energy fracture was found to be positively associated with increasing body height and with decreasing body mass index. Furthermore, men who had gained weight had a lower risk of hip fractures, and women who had gained weight had a lower risk of fractures in the lower extremities. High body height is thus a risk factor for fractures, and 1 in 4 low-energy fractures among women today might be ascribed to the increase in average stature since the turn of the century. Low body mass index is associated with a higher risk of fractures, but the association is probably too weak to have any clinical relevance in this age category.

The Tromsø Study: Registration of Fractures, How Good are Self-reports, a Computerized Radiographic Register and a Discharge Register?

Abstract: In order to compare different methods of fracture registration, we sought all nonvertebral fractures suffered during 8 years (1988–95) among 21 441 persons invited to a survey in 1979/80. We registered a total of 54 hip fracture cases through three separate sources (self-report, computer linkage to the local radiographic archives, discharge register), whereas forearm fractures (a total of 291 cases) were registered through two separate sources (self-report, computer linkage to the radiographic archives). The registration of fractures at other sites (a total of 1321 cases) were from one source (computer linkage to the local radiographic archives), and we have compared three ways of obtaining data from this single source (no ascertainment, ascertainment of records coded as fracture, ascertainment of all records). Ninety-three percent of all hip fractures and 97% of all wrist fractures in the entire study population were found by computer linkage to the radiographic archives, whereas the discharge register detected 87% of all the hip fractures. Computer linkage with ascertainment gave no overreporting of fractures. Among the 11 626 persons who answered a follow-up questionnaire in 1994/95, 97% (CI 84–100%) of all hip fractures and 72% (CI 66–78%) of all wrist fractures were self-reported. We conclude that a computerized search of radiographic archives is a viable method of fracture registration.

Mortality following the first hip fracture in Norwegian women and men (1999-2008). A NOREPOS study

Hip fractures are associated with increased mortality and their incidence in Norway is one of the highest worldwide. The aim of this nationwide study was to examine short- and long-term mortality after hip fractures, burden of disease (attributable fraction and potential years of life lost), and time trends in mortality compared to the total Norwegian population. Information on incident hip fractures between 1999 and 2008 in all persons aged 50 years and older was collected from Norwegian hospitals. Death and emigration dates of the hip fracture patients were obtained through 31 December 2010. Standardized mortality ratios (SMRs) were calculated and Poisson regression analyses were used for the estimation of time trends in SMRs. Among the 81,867 patients with a first hip fracture, the 1-year excess mortality was 4.6-fold higher in men, and 2.8-fold higher in women compared to the general population. Although the highest excess mortality was observed during the first two weeks post fracture, the excess risk persisted for twelve years. Mortality rates post hip fracture were higher in men compared to women in all age groups studied. In both genders aged 50 years and older, approximately 5% of the total mortality in the population was related to hip fractures. The largest proportion of the potential life-years lost was in the relatively young-old, i.e. less than 80 years. In men, the 1-year absolute mortality rates post hip fracture declined significantly between 1999 and 2008, by contrast, the mortality in women increased significantly relatively to the population mortality.

The Tromsø Study: Artifacts in Forearm Bone Densitometry – Prevalence and Effects

Abstract: Suboptimal performance of bone densitometer, operator and/or subject may cause artifacts of consequence both for individual patient management and research. The prevalence and effects of such artifacts are largely unknown in densitometry. A cross-sectional population-based study was carried out of artifacts in forearm bone densitometry with single X-ray Absorptiometry (SXA) of the nondominant hand (distal and ultradistal site). After the screening, all scans were reviewed for artifact detection and reanalysis. The effect on the bone mineral density (BMD) result was found by comparing artifactual scans with a reanalyzed version or with normal repeat scans. All women aged 50–74 years, all men aged 55–74 years and 5–10% samples of other age groups aged ≥25 years attending the fourth Tromsø health study were invited to have bone densitometry. The response rate from the background population was 80% (n= 7948). Fourteen percent of subjects had a movement artifact at either the distal or ultradistal site. The individual BMD variation was twice as large in scans with a movement artifact (0.94%) compared with normal scans (0.58%) (p= 0.0027). The radial endplate was inaccurately detected in 74% of the scans. Reanalysis of these scans led to a mean 3.8% decrease in the BMD value and an increase in the prevalence of osteoporosis of 10%. Artifacts were thus common, and their effects were clinically relevant in forearm bone densitometry. Artifacts and their effects need to be characterized in other bone densitometry settings also.