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Vitamin D status of older adults of diverse ancestry living in the Greater Toronto Area.

Ginter JK, Krithika S, Gozdzik A, Hanwell H, Whiting S, Parra EJ - BMC Geriatr (2013)

Bottom Line: Females had significantly higher 25(OH)D concentrations than males (84.5 nmol/L vs. 72.2 nmol/L, p = 0.012).Mean concentration of 25(OH)D in a sample of older adults of diverse ancestry living in the GTA exceeded 80 nmol/L, and there were no significant differences in 25(OH)D levels between ancestral groups.These results sharply contrast with our recent study focused on young adults of diverse ancestry living in the same geographic area, in which we found substantially lower 25(OH)D concentrations (mean 39.5 nmol/L), low supplemental vitamin D intake (114 IU/day), and significant differences in 25(OH)D levels between ancestral groups.

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ABSTRACT

Background: Physiological and lifestyle factors put older adults at an increased risk of vitamin D insufficiency and resulting negative health outcomes. Here we explore the vitamin D status in a sample of community dwelling older adults of diverse ancestry living in the Greater Toronto area (GTA).

Methods: Two hundred and twenty-four (224) adults over 60 years of age were recruited from the Square One Older Adult Centre, in Mississauga, Ontario. Circulating 25-hydroxyvitamin D (25(OH)D) concentrations were measured from dried blood spot cards. Dietary and supplemental intakes of vitamin D were assessed via questionnaires. Skin pigmentation was assessed quantitatively by measuring melanin levels using a reflectometer.

Results: The mean 25(OH)D concentration in the total sample was 82.4 nmol/L. There were no statistically significant differences in serum 25(OH)D concentrations, supplemental or dietary vitamin D intakes between the three major ancestral groups (East Asians, Europeans and South Asians). Females had significantly higher 25(OH)D concentrations than males (84.5 nmol/L vs. 72.2 nmol/L, p = 0.012). The proportion of participants with 25(OH)D concentrations below 50 nmol/L and 75 nmol/L were 12.1%, and 38.8%, respectively. The mean daily supplemental intake of vitamin D was 917 IU/day. Vitamin D intake from supplements was the major factor determining 25(OH)D concentrations (p < 0.001).

Conclusions: Mean concentration of 25(OH)D in a sample of older adults of diverse ancestry living in the GTA exceeded 80 nmol/L, and there were no significant differences in 25(OH)D levels between ancestral groups. These results sharply contrast with our recent study focused on young adults of diverse ancestry living in the same geographic area, in which we found substantially lower 25(OH)D concentrations (mean 39.5 nmol/L), low supplemental vitamin D intake (114 IU/day), and significant differences in 25(OH)D levels between ancestral groups. High daily intake of supplemental vitamin D in this sample of older adults likely accounts for such disparate findings with respect to the young adult sample.

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Correlation of 25(OH)D values obtained from serum and blood spots in the same samples.
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Figure 1: Correlation of 25(OH)D values obtained from serum and blood spots in the same samples.

Mentions: We performed an internal validation by comparing, for 10 blood spot and serum samples obtained from the same individuals, the 25(OH)D concentrations measured with the ZRT blood spot LC-MS/MS method with the values obtained using a previously described serum-based LC-MS/MS method [23]. A scatterplot showing the results of these comparisons is depicted in Figure 1. There was a very strong correlation between the 25(OH)D values obtained with both methods (r2 = 0.91). An analysis using a Bland-Altman plot indicated that the 25(OH)D concentrations measured in the blood spots were slightly higher than those measured in the serum samples (on average, approximately 10 nmol/L higher, Figure 2). We measured three independent blood spots for the same individual with concordant results (110, 115 and 117.5 nmol/L, respectively).


Vitamin D status of older adults of diverse ancestry living in the Greater Toronto Area.

Ginter JK, Krithika S, Gozdzik A, Hanwell H, Whiting S, Parra EJ - BMC Geriatr (2013)

Correlation of 25(OH)D values obtained from serum and blood spots in the same samples.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3721999&req=5

Figure 1: Correlation of 25(OH)D values obtained from serum and blood spots in the same samples.
Mentions: We performed an internal validation by comparing, for 10 blood spot and serum samples obtained from the same individuals, the 25(OH)D concentrations measured with the ZRT blood spot LC-MS/MS method with the values obtained using a previously described serum-based LC-MS/MS method [23]. A scatterplot showing the results of these comparisons is depicted in Figure 1. There was a very strong correlation between the 25(OH)D values obtained with both methods (r2 = 0.91). An analysis using a Bland-Altman plot indicated that the 25(OH)D concentrations measured in the blood spots were slightly higher than those measured in the serum samples (on average, approximately 10 nmol/L higher, Figure 2). We measured three independent blood spots for the same individual with concordant results (110, 115 and 117.5 nmol/L, respectively).

Bottom Line: Females had significantly higher 25(OH)D concentrations than males (84.5 nmol/L vs. 72.2 nmol/L, p = 0.012).Mean concentration of 25(OH)D in a sample of older adults of diverse ancestry living in the GTA exceeded 80 nmol/L, and there were no significant differences in 25(OH)D levels between ancestral groups.These results sharply contrast with our recent study focused on young adults of diverse ancestry living in the same geographic area, in which we found substantially lower 25(OH)D concentrations (mean 39.5 nmol/L), low supplemental vitamin D intake (114 IU/day), and significant differences in 25(OH)D levels between ancestral groups.

View Article: PubMed Central - HTML - PubMed

ABSTRACT

Background: Physiological and lifestyle factors put older adults at an increased risk of vitamin D insufficiency and resulting negative health outcomes. Here we explore the vitamin D status in a sample of community dwelling older adults of diverse ancestry living in the Greater Toronto area (GTA).

Methods: Two hundred and twenty-four (224) adults over 60 years of age were recruited from the Square One Older Adult Centre, in Mississauga, Ontario. Circulating 25-hydroxyvitamin D (25(OH)D) concentrations were measured from dried blood spot cards. Dietary and supplemental intakes of vitamin D were assessed via questionnaires. Skin pigmentation was assessed quantitatively by measuring melanin levels using a reflectometer.

Results: The mean 25(OH)D concentration in the total sample was 82.4 nmol/L. There were no statistically significant differences in serum 25(OH)D concentrations, supplemental or dietary vitamin D intakes between the three major ancestral groups (East Asians, Europeans and South Asians). Females had significantly higher 25(OH)D concentrations than males (84.5 nmol/L vs. 72.2 nmol/L, p = 0.012). The proportion of participants with 25(OH)D concentrations below 50 nmol/L and 75 nmol/L were 12.1%, and 38.8%, respectively. The mean daily supplemental intake of vitamin D was 917 IU/day. Vitamin D intake from supplements was the major factor determining 25(OH)D concentrations (p < 0.001).

Conclusions: Mean concentration of 25(OH)D in a sample of older adults of diverse ancestry living in the GTA exceeded 80 nmol/L, and there were no significant differences in 25(OH)D levels between ancestral groups. These results sharply contrast with our recent study focused on young adults of diverse ancestry living in the same geographic area, in which we found substantially lower 25(OH)D concentrations (mean 39.5 nmol/L), low supplemental vitamin D intake (114 IU/day), and significant differences in 25(OH)D levels between ancestral groups. High daily intake of supplemental vitamin D in this sample of older adults likely accounts for such disparate findings with respect to the young adult sample.

Show MeSH
Related in: MedlinePlus