29.1. Physical Capacity and Supplementation of Vitamin D and Calcium in Postmenopausal Women

Public examination of a doctoral dissertation in the fields of Orthopedics and Traumatology

Doctoral candidate: Lic Med Matti Kärkkäinen

Date and venue:  29.1.2011 at 12 noon, Snellmania L22, Kuopio Campus

 In general, the fracture risk is highest among those who have osteoporotic bone mineral density (BMD) but nonetheless most fragility fractures occur in subjects who do not have osteoporosis. Their poor physical condition might predispose these individuals both to low BMD and a higher risk for fall-related fractures. Vitamin D has been shown to have also physiological importance outside of bone health and calcium homeostasis, and there is evidence that it plays a role in the prevention of falling and it has been associated with a wide spectrum of diseases.

The present thesis was based on Kuopio Osteoporosis Risk Factor and Prevention study (OSTPRE) and its substudy OSTPRE Fracture Prevention Study (OSTPRE-FPS). Physical capacity tests and fracture validation were performed on the OSTPRE cohort (n=2928). The OSTPRE-FPS was an open-label RCT with a 3-year duration conducted during 2003-6. The OSTPRE-FPS population of 3,432 women was randomly selected from the population-based OSTPRE cohort. The women were randomized into two groups of equal size. The intervention group (n=1,718) obtained daily cholecalciferol 800 IU and calcium carbonate 1000 mg supplementation divided into two daily doses for three years and the control group (n=1,714) received no supplementation. The physical capacity tests and BMD measurements were performed in a pre-defined subsample of 750 women. In addition, falls were self-reported from the entire trial population (n=3432).

It was shown that functional capacity was decreased in women with femoral neck osteoporosis (WHO classification) compared to women with normal or osteopenic BMD: standing-on-one-foot (SOOF) !39% (p=0.001), grip strength (GS) !18% (p<0.001), leg extension strength !19% (p=0.007) and ability to squat down on the floor !40% (p=0.004). Furthermore, the decreased GS, low leg extension strength, inability to perform SOOF 10 seconds and self-assessed ability to walk less than 100 meters were associated with future fractures. Accordingly, it was proposed that GS could be used in medical decision making to identify those women who would benefit from BMD measurements albeit alone it may not represent an accurate enough tool for osteoporosis screening. In addition, being unable to perform SOOF for 10 seconds, GS and a question about ability to walk less than 100 meters may help to predict postmenopausal fractures. It is speculated that the poor physical condition increased both the prevalence of low BMD and the risk for fallrelated fractures.

The OSTPRE-FPS indicated that daily vitamin D 800IU and calcium 1000mg could decrease the risk of multiple falls requiring medical attention in a general population of women aged 65 to 71. In addition, vitamin D and calcium supplementation have a positive effect on the skeleton in women who have adequate nutritional calcium intake. These benefits were gained without any severe side effects from the supplementation. Accordingly, a higher vitamin D intake can be recommended for postmenopausal women aged 65 to 71.

The doctoral dissertation of Licentiate of Medicine Matti Kärkkäinen, entitled Physical capacity and supplementation of vitamin D and calcium in postmenopausal women will be examined at the Faculty of Health Sciences. The opponent in the public examination will be Docent Jari Salo of the University of Helsinki, and the custos will be Professor Heikki Kröger of the University of Eastern Finland.

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Publishing year: 2011

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