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Nebraska is Low in D as is Finland
Nebraska is Low in D as is Finland
Journal of the American College of Nutrition,
Vol. 25, No. 5, 395-402 (2006)
Published by the American College of Nutrition
Vitamin D Status in a Rural Postmenopausal Female Population
Joan M. Lappe, PhD, RN, K. Michael Davies, PhD,
Dianne Travers-Gustafson, MS, RN, CS and Robert P. Heaney, MD
Creighton University,
Osteoporosis Research Center,
Omaha, Nebraska
Address reprint requests to: Joan M. Lappe, Ph.D.,
Creighton University Medical Center,
Osteoporosis Research Center,
601 North 30th Street
Suite 4820, Omaha, NE 68131.
E-mail: jmlappe@creighton.edu
Background:
Inadequate vitamin D nutritional status is increasingly
recognized as common in North American and European populations,
but the extent of the shortfall and the parameters of the
distribution for populations of interest remain uncertain.
Purpose:
To report the distribution of values for
serum 25-hydroxyvitamin D [25(OH)D] in a population of
rural postmenopausal women, together with quantification of
factors related to vitamin D status.
Setting:
Nine largely agrarian counties in eastern Nebraska (41° N).
Participants:
A population-based sample of 1,179 women 55 years
of age and older recruited into a four-year trial of calcium
and vitamin D supplementation.
Methods:
Baseline biochemical, dietary, and anthropometric
measurements obtained on entry into trial.
Results: Serum 25(OH)D concentration at baseline varied
cyclically with season, with the solar cycle explaining
2.9% of the total variance (P < 0.001). Mean seasonally
adjusted 25(OH)D concentration was 71.1 nmol/L.
Serum 25(OH)D also exhibited the expected inverse
curvilinear relationship with serum parathyroid hormone (PTH),
with the inflection point of the curve located at
approximately 80 nmol/L. Supplements containing
vitamin D were regularly taken by 59% of the cohort
(median dose: 200 IU/d). Nevertheless, approximately
4% of all women had values below the laboratory reference
range and more than two-thirds fell below 80 nmol/L.
Seasonally adjusted serum 25(OH)D concentration was
positively correlated with the size of daily vitamin D
supplement dose, and negatively with age, weight, and
body mass index (P < 0.01 for all). In stepwise multiple
linear regression models, weight, age, and supplement dose
were independently correlated with seasonally adjusted
serum 25(OH)D, and together explained 19% of the total
variance of adjusted 25(OH)D concentration. Women taking
supplements had only one-sixth the chance of having a
25(OH)D value below the reference limit of the assay,
compared to women who did not use supplements.
Conclusions:
Approximately two-thirds of this rural population fell
below 80 nmol/L, a value considered to be the lower end of
the optimal range. Based on the slope of 25(OH)D on supplement
dose observed in these women, it would require an additional
vitamin D input of nearly 2000 IU/d to reach the goal of an
RDA for vitamin D, i.e., to bring 97.5% of the cohort to levels
of 80 nmol/L or higher.
Key words: vitamin D, 25-hydroxyvitamin D, parathyroid hormone,
calcium intake, supplements, post-menopause
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Journal of the American College of Nutrition,
Vol. 25, No. 5, 429-435 (2006)
Published by the American College of Nutrition
How Much Vitamin D3 Do the Elderly Need?
Heli T. Viljakainen, MSc, Anette Palssa, MSc,
Merja Kärkkäinen, PhD, Jette Jakobsen, MSc and Christel Lamberg-
Allardt, PhD
Calcium Research Unit,
Department of Applied Chemistry and Microbiology,
University of Helsinki, Helsinki, FINLAND
Danish Institute for Food and Veterinary Research,
Søborg, DENMARK
Address reprint requests to: Christel Lamberg-Allardt, Ph.D.,
Department of Applied Chemistry and Microbiology,
P.O. Box 66,
FIN-00014 University of Helsinki, FINLAND.
E-mail: christel.lamberg-allardt@helsinki.fi
Background:
Vitamin D insufficiency poses a problem in many parts of the world,
the elderly being an especially vulnerable group.
This insufficiency results from an inadequate amount of sunshine
and a low dietary intake of vitamin D. Typically, insufficiency
is accompanied with high intact parathyroid hormone, (S-iPTH)
concentrations.
Aims of the Study: We studied how serum 25-hydroxy vitamin D
(S-25-OHD) concentrations respond to different doses of
vitamin D3 supplementation. Secondly to determine the
smallest efficient dose to maintain serum 25-OHD concentration
above the insufficiency level. We also studied which dose
would be efficient in decreasing S-iPTH concentration in these
subjects.
Subjects and Methods:
Forty-nine 65- to 85-year-old women participated. The women were
randomly assigned into one of four groups receiving 0 (placebo),
5, 10 or 20 µg of vitamin D3 daily for 12 weeks.
Fasting morning blood was drawn at the beginning of the study, and
thereafter every second week. Calciotropic variables were
assessed from serum and urine samples.
Results:
The S-25-OHD concentration increased significantly
(p < 0.001) in all supplemented groups [5 µg: by 10.9 (8.5)
nmol/L, 10 µg: by 14.4 (6.9) nmol/L, 20 µg: by 23.7 (11.9) nmol/L],
whereas it decreased in the placebo group by 8.3 (13.2) nmol/L.
Equilibrium in S-25-OHD concentration was reached in all groups
after 6 weeks of supplementation at 57.7 (8.9) nmol/L, 59.9 (8.9)
nmol/L and 70.9 (8.9) nmol/L in the groups with increasing
vitamin D supplementation. The dose-response to supplementation
decreased with increasing vitamin D status at baseline,
r = 0.513, p = 0.002. S-iPTH tended to decrease in those
with highest dose response to supplementation.
Conclusions:
A clear dose response was noted in S-25-OHD to different doses of
vitamin D3. The recommended dietary intake of 15 µg is adequate
to maintain the S-25-OHD concentration around 40 to 55 nmol/L during
winter, but if the optimal S-25-OHD is higher than that even
higher vitamin D intakes are needed. Interestingly, subjects
with lower vitamin D status at baseline responded more
efficiently to supplementation than those with more
adequate status.
Key words: elderly, vitamin D3 supplementation,
25-hydroxyvitamin D, parathyroid hormone, dose-response
Journal of the American College of Nutrition,
Vol. 25, No. 5, 395-402 (2006)
Published by the American College of Nutrition
Vitamin D Status in a Rural Postmenopausal Female Population
Joan M. Lappe, PhD, RN, K. Michael Davies, PhD,
Dianne Travers-Gustafson, MS, RN, CS and Robert P. Heaney, MD
Creighton University,
Osteoporosis Research Center,
Omaha, Nebraska
Address reprint requests to: Joan M. Lappe, Ph.D.,
Creighton University Medical Center,
Osteoporosis Research Center,
601 North 30th Street
Suite 4820, Omaha, NE 68131.
E-mail: jmlappe@creighton.edu
Background:
Inadequate vitamin D nutritional status is increasingly
recognized as common in North American and European populations,
but the extent of the shortfall and the parameters of the
distribution for populations of interest remain uncertain.
Purpose:
To report the distribution of values for
serum 25-hydroxyvitamin D [25(OH)D] in a population of
rural postmenopausal women, together with quantification of
factors related to vitamin D status.
Setting:
Nine largely agrarian counties in eastern Nebraska (41° N).
Participants:
A population-based sample of 1,179 women 55 years
of age and older recruited into a four-year trial of calcium
and vitamin D supplementation.
Methods:
Baseline biochemical, dietary, and anthropometric
measurements obtained on entry into trial.
Results: Serum 25(OH)D concentration at baseline varied
cyclically with season, with the solar cycle explaining
2.9% of the total variance (P < 0.001). Mean seasonally
adjusted 25(OH)D concentration was 71.1 nmol/L.
Serum 25(OH)D also exhibited the expected inverse
curvilinear relationship with serum parathyroid hormone (PTH),
with the inflection point of the curve located at
approximately 80 nmol/L. Supplements containing
vitamin D were regularly taken by 59% of the cohort
(median dose: 200 IU/d). Nevertheless, approximately
4% of all women had values below the laboratory reference
range and more than two-thirds fell below 80 nmol/L.
Seasonally adjusted serum 25(OH)D concentration was
positively correlated with the size of daily vitamin D
supplement dose, and negatively with age, weight, and
body mass index (P < 0.01 for all). In stepwise multiple
linear regression models, weight, age, and supplement dose
were independently correlated with seasonally adjusted
serum 25(OH)D, and together explained 19% of the total
variance of adjusted 25(OH)D concentration. Women taking
supplements had only one-sixth the chance of having a
25(OH)D value below the reference limit of the assay,
compared to women who did not use supplements.
Conclusions:
Approximately two-thirds of this rural population fell
below 80 nmol/L, a value considered to be the lower end of
the optimal range. Based on the slope of 25(OH)D on supplement
dose observed in these women, it would require an additional
vitamin D input of nearly 2000 IU/d to reach the goal of an
RDA for vitamin D, i.e., to bring 97.5% of the cohort to levels
of 80 nmol/L or higher.
Key words: vitamin D, 25-hydroxyvitamin D, parathyroid hormone,
calcium intake, supplements, post-menopause
==========================
==========================
==
==========================
==========================
==
Journal of the American College of Nutrition,
Vol. 25, No. 5, 429-435 (2006)
Published by the American College of Nutrition
How Much Vitamin D3 Do the Elderly Need?
Heli T. Viljakainen, MSc, Anette Palssa, MSc,
Merja Kärkkäinen, PhD, Jette Jakobsen, MSc and Christel Lamberg-
Allardt, PhD
Calcium Research Unit,
Department of Applied Chemistry and Microbiology,
University of Helsinki, Helsinki, FINLAND
Danish Institute for Food and Veterinary Research,
Søborg, DENMARK
Address reprint requests to: Christel Lamberg-Allardt, Ph.D.,
Department of Applied Chemistry and Microbiology,
P.O. Box 66,
FIN-00014 University of Helsinki, FINLAND.
E-mail: christel.lamberg-allardt@helsinki.fi
Background:
Vitamin D insufficiency poses a problem in many parts of the world,
the elderly being an especially vulnerable group.
This insufficiency results from an inadequate amount of sunshine
and a low dietary intake of vitamin D. Typically, insufficiency
is accompanied with high intact parathyroid hormone, (S-iPTH)
concentrations.
Aims of the Study: We studied how serum 25-hydroxy vitamin D
(S-25-OHD) concentrations respond to different doses of
vitamin D3 supplementation. Secondly to determine the
smallest efficient dose to maintain serum 25-OHD concentration
above the insufficiency level. We also studied which dose
would be efficient in decreasing S-iPTH concentration in these
subjects.
Subjects and Methods:
Forty-nine 65- to 85-year-old women participated. The women were
randomly assigned into one of four groups receiving 0 (placebo),
5, 10 or 20 µg of vitamin D3 daily for 12 weeks.
Fasting morning blood was drawn at the beginning of the study, and
thereafter every second week. Calciotropic variables were
assessed from serum and urine samples.
Results:
The S-25-OHD concentration increased significantly
(p < 0.001) in all supplemented groups [5 µg: by 10.9 (8.5)
nmol/L, 10 µg: by 14.4 (6.9) nmol/L, 20 µg: by 23.7 (11.9) nmol/L],
whereas it decreased in the placebo group by 8.3 (13.2) nmol/L.
Equilibrium in S-25-OHD concentration was reached in all groups
after 6 weeks of supplementation at 57.7 (8.9) nmol/L, 59.9 (8.9)
nmol/L and 70.9 (8.9) nmol/L in the groups with increasing
vitamin D supplementation. The dose-response to supplementation
decreased with increasing vitamin D status at baseline,
r = 0.513, p = 0.002. S-iPTH tended to decrease in those
with highest dose response to supplementation.
Conclusions:
A clear dose response was noted in S-25-OHD to different doses of
vitamin D3. The recommended dietary intake of 15 µg is adequate
to maintain the S-25-OHD concentration around 40 to 55 nmol/L during
winter, but if the optimal S-25-OHD is higher than that even
higher vitamin D intakes are needed. Interestingly, subjects
with lower vitamin D status at baseline responded more
efficiently to supplementation than those with more
adequate status.
Key words: elderly, vitamin D3 supplementation,
25-hydroxyvitamin D, parathyroid hormone, dose-response
