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- Englund, Undis, 1957-
(författare)
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Physical activity, bone density, and fragility fractures in women
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Scandinavia has among the highest incidence of fragility fractures in the world. The reasons for this are unknown, but might involve differences in genetic and/or environmental factors, such as sunlight exposure and levels of physical activity. Weight-bearing exercise is thought to have a beneficial effect on bone health in the young, but few studies have evaluated whether exercise in older subjects affects bone density and protects against fragility fractures. The initial objective of this thesis was to evaluate whether a combined weight-bearing training programme twice a week would be beneficial as regards bone mineral density (BMD) and neuromuscular function in older women. Forty-eight community living women with a mean age of 73 years were recruited for this 12-month prospective, randomised controlled trial, and were randomly assigned to an intervention group (n=24) or a control group (n=24). The intervention group displayed significant increments in BMD at the Ward’s triangle, maximum walking speed, and isometric grip strength compared to the control group. The second objective was to investigate if training effects were retained in older women five years after the cessation of training. The 40 women who completed the first study included in this thesis were invited to take part in a follow-up assessment five years later, and 34 women (~79 years) agreed to participate. During these five years both groups had sustained significant losses in hip BMD and in all neuromuscular function tests, and the previous exercise-induced intergroup differences were no longer seen. The third and fourth objective of this thesis was to investigate whether exercise and weight-bearing leisure activities in middle-aged women are associated with a decreased risk of sustaining hip or wrist fractures at a later stage. A cohort of women participating in the Umeå Fracture and Osteoporosis (UFO) study, a longitudinal, nested case-control study investigating associations between bone markers, lifestyle, and osteoporotic fractures, was used for the purpose of this investigation. Eighty-one hip fracture cases and 376 wrist fracture cases, which had reported lifestyle data before they sustained their fracture, were identified. These cases were compared with age-matched controls identified from the same cohort. Using conditional logistic regression analysis with adjustments for height, BMI, smoking, and menopausal status, results showed that moderate frequency of leisure physical activities such as gardening and berry/mushroom picking, were associated with reduced hip fracture risk (OR 0.28; 95% CI 0.12 – 0.67), whereas active commuting (especially walking) along with dancing and snow shoveling in leisure time, reduced the wrist fracture risk (OR 0.48; 95% CI 0.27 – 0.88, OR 0.42; 95% CI 0.22 – 0.80 and OR 0.50; 95% CI 0.32 – 0.79 respectively). In summary, this thesis suggests that weight-bearing physical activity is beneficial for BMD and neuromuscular functions such as muscle strength and gait in older women, and that a physically active lifestyle, with outdoor activities, in middle age is associated with reduced risk of both hip and wrist fractures. Possible mechanisms underlying this association include improved muscle strength, coordination, and balance, resulting in a decreased risk of falling and perhaps also direct skeletal benefits.
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| 2. |
- Bergström, Ulrica, 1970-
(författare)
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Fragility fractures in fragile people : epidemiology of the age quake
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Osteoporosis-related fracture is already today a major public health problem and the number of hip fractures is expected to double to 2030. Sweden has one of the highest hip fracture incidences worldwide. This may be explained by several factors: e.g. age, genetic, climatologic, geographic and a relative vitamin D deficiency, secondary to the limited sunlight exposure especially during winter months. Intrinsic and extrinsic factors contribute to a fracture, although a prior low energy fracture is one of the strongest predictors for a subsequent one and this should be a target for secondary fracture prevention in an orthopaedic setting. Since 1993 all injured patients admitted to the emergency floor and all in-hospital fractures at Umeå University Hospital, Sweden, were registered according to the Injury Data Base, former EHLASS. There were 31,173 fracture events (one or more fractures at the same time), of which 13,931 were in patients’ ≥ 50 years old. The fracture database was co analyzed with the Northern Sweden Health and Disease Study cohort in a nested case-control study for investigations of associations between osteoporotic fracture and serum markers, lifestyle data, nutrition etc. We found that there were differences in fracture pattern depending on age and sex. Both injury mechanism and fracture site were strongly dependent of age. The most severe fragility fracture, hip fracture, had a decreasing incidence. However, the incidence curve was right-shifting leading to an increase, both in numbers and in incidence of hip fractures among the oldest female. To identify people at high risk for fractures, re-fracture patients are useful. No less than 21% of the fracture patients had suffered more than one fracture event, accounting for 38% of all fracture events. The total risk ratio for a subsequent fracture was 2.2 (2.1-2.3 95% CI). In males the highest risk for re fracture was in the age cohort 70-79 years (RR 2.7, 2.3-3.2 95% CI), in females > 90 years (RR 3.9, 3.2-4.8 95% CI). Another possible risk factor in this subarctic population is the lack of sunlight, leading to a vitamin D deficit. The overall adjusted risk of sustaining a hip fracture in this population was 2.7 (95%CI:1.3-5.4) in subjects with a serum 25 hydroxyvitamin D below 50 nmol/l. The association was, however, different according to age at baseline. Thus in subjects aged 60 years and above at baseline, the adjusted odds ratio of sustaining a hip fracture was 6.2 (1.2-32.5 95%CI) for the group of individuals with a serum 25OHD below 50 nmol/l, whereas no significant association was found in the youngest age group. In the next 30 years the ongoing demographic changes will accelerate. The World War II baby boomers will cause an age quake. We can already see signs heralding a new fracture pattern: an increasing cohort of mobile but fragile elderly, with considerable co-morbidity is now at risk for fragility fractures. In fracture patients, clinical information is sufficient to pinpoint patients with a high risk for re-fractures. It is therefore clinically important to use the information provided by the fracture event. We suggest that trauma units and primary care units should screen for risk factors and inform patients about the treatment options, and to organize fracture liaison services. This seems to be especially cost-efficient for our oldest and frailest patients. Secondary prophylaxis and follow-up treatment after cardiovascular disorders are now a matter of course worldwide, but the screening for risk factors, in order to prevent a second fracture, is often neglected. This is one of the most important issues of fracture care in the future in order to improve general health.
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