What is the effect of 2 different treatment strategies of Vitamin D supplementation on 25(OH)D3 serum concentration? And what are the benefits for older people? A prospective observational clinical study.

In older people, a vitamin D deficiency is common. Vitamin D deficiency is
associated with osteoporosis, osteomalacia and is related to an increased
fracture risk, because of a decreased bone mineral density and muscle mass and
an increased risk of falling. In addition, a deficiency of vitamin D is
possibly associated with conditions and diseases, beyond bone and
musculoskeletal health. Worldwide and within the Netherlands, there is still no
consensus concerning the optimal dosage of vitamin D supplementation to
optimize reduction of the named health risks. Recent research suggests that a
higher dose of supplementation and reaching a higher serum concentration of
vitamin D (25(OH)D3) is necessary to further decrease the fall and fracture
risk. Our hypothesis is, that a higher maintenance dose of vitamin D induces a
higher steady state blood level, and therefore would increase muscle strength
and functional mobility, which would reduce the risk of falling and fractures.

Primary objective of the study is to determine the effect of 2 different
treatment strategies of vitamin D supplementation on 25(OH)D3 serum
concentration after 12 months of supplementation. Secondary objectives are to
determine the effects on the functional mobility and fall and fracture
frequency. Also the 25(OH)D3 serum concentration will be measured after loading
dosage regimen and after 6 months of supplementation.

A prospective, observational clinical study

The study has negligible risks and minimal impact for participating patients.
Patients need to visit the outpatient clinic 2 more times, at 6 and 12 months
after their initial referral. Within these 2 visits, they will undergo mobility
performance measurements (TGUG, timed-stands test, gait speed) and blood
sampling (25(OH)D3, (corrected) calcium, albuminia en creatinine/MDRD). An
extra blood sample will be collected at 7 weeks after start of supplementation.
At baseline and after 12 months, patients will be asked to fill out an
inventory of falling and fractures in the past year. Also, the patients will be
asked to note down (scoring list) every fall with the date, the circumstances
and if the fall led to bone fractures.
Patients with a vitamin D deficiency who will not participate in this study,
will receive supplementation of vitamin D according to the local protocol of
the clinic.
There are no health related risks with these dosages of vitamin D
supplementation. Maintenance doses up to 4000 IE a day are reported to be safe.
If possible, the visits and tests of the study will be incorporated within the
regular visits to the Geriatrician. There is a need to extend our knowledge
about vitamin D supplementation in elderly, because of the serious consequences
of vitamin D deficiency , and uncertainty about the optimal dosage of vitamin
D supplementation in older patients.