Vitamin D
IN COLORECTAL CARCINOMA PATIENTS, SERUM VITAMIN D LEVELS
VARY ACCORDING TO STAGE OF THE CARCINOMA
Raised serum levels of the biologically active form of
vitamin D, 1,25-dihydroxyvitamin D3 (1,25(OH)2D3), have
been associated with considerable reduction in the incidence
of colorectal carcinoma. However, previous to this study,
there had been no research into serum levels of vitamin
D in patients with this neoplasm. Therefore, comparisons
were made between serum levels of 1, 25-dihydroxyvitamin
D3, 25-hydroxyvitamin D3, and parathyroid hormone (PTH),
in patients with colorectal carcinoma and healthy individuals.
Results showed that serum levels of 25-hydroxyvitamin D3
were higher in patients with cancer than controls. Serum
1,25-dihydroxyvitamin D3 levels decreased with advancing
stage of the colorectal cancer, and PTH levels were correspondingly
elevated. No correlation was found between vitamin D metabolite
levels and gender, age, tumour localisation, or histological
grade. The research showed an inverse relationship between
serum levels of 1,25(OH)2D3 and advancing stage of colorectal
carcinoma.
As previous investigations indicate that this vitamin D
metabolite inhibits proliferation of colonic epithelial
cells, lowered serum levels may facilitate the growth of
colorectal carcinoma.
Niv, Y. et al
CANCER 1999, 86 (3), 391-7
VITAMIN D DEFICIENCY IS WIDESPREAD
New research based on a random population of patients entering
hospital has uncovered an almost universal need for more
vitamin D in the diet. A study of 290 consecutive patients
admitted to a general medical ward at Massachusetts General
Hospital found that 57% were deficient, some severely deficient,
and even those taking vitamin D supplements in excess of
the RDA were deficient. The definition of deficiency was
defined as a serum concentration of 25-hydroxy-vitamin D
below 15ng per ml, severe deficiency below 8ng per ml. However,
some specialists think 15ng may be insufficient and the
serum levels should exceed 30ng per ml. If this is so, then
93% of the patients would have been deficient.
NEW ENG. J. MED. 1998, 338, 777, 828
BR. NATUROPATHIC J. 1998, 15 (3)
MORE EFFORT NEEDED TO HALT OSTEOPOROTIC BONE LOSS
At a recent British Society for Rheumatology meeting it
was announced that steroid-induced osteoporosis is a problem
that is not being effectively tackled. About 0.5% of the
general population is receiving long-term steroid therapy,
but a survey showed that only about 14% had taken some form
of preventative treatment for bone loss. It was reported
that the C-terminal (CTX) and N-terminal (NTX) peptides
of type-1 collagen were helpful biochemical markers for
prediction of bone loss in osteoporosis. CTX and free deoxypyridinoline
have also proved highly predictive of hip-fracture rate
in osteoporosis, independent of bone mass. It was suggested
that patients on prednisolone 7.5 mg or more per day for
6 months or longer should be targeted for prophylactic therapy
for bone loss. Vitamin D and calcium supplementation should
be considered in all patients.
Clark, S.
LANCET 1998, 351 (9112) 1335
EFFECT OF CALCIUM AND VITAMIN D SUPPLEMENTATION ON BONE
DENSITY IN MEN AND WOMEN 65 YEARS OF AGE OR OLDER
A study was carried out to determine the effects of three
years of dietary supplementation with calcium and vitamin
D on bone mineral density, biochemical measures of bone
metabolism, and the incidence of nonvertebral fractures
in 176 men and 213 women 65 years of age or older. They
received either 500mg of calcium plus 700 IU of vitamin
D (cholecalciferol) per day or placebo. The mean changes
in bone mineral density in the calcium-vitamin D and placebo
groups were as follows:
femoral neck, +0.50 and -0.70%, respectively; spine, +2.12
and +1.22%;
total body, +0.06 and -1.09%.
The difference between the calcium-vitamin D and placebo
groups was significant at all skeletal sites after one year,
but it was significant only for total-body bone mineral
density in the second and third years.
Dawson-Hughes, B et al.
N. ENGL. J. MED. 1997, 337 (10) 670-6
