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Increases in summer serum 25-hydroxyvitamin D (25OHD) concentrations in elderly subjects in São Paulo, Brazil vary with age, gender and ethnicity.

Maeda SS, Kunii IS, Hayashi LF, Lazaretti-Castro M - BMC Endocr Disord (2010)

Bottom Line: In the summer, we noticed an increase only for men (107.6 +/- 31.4 nmol/L) compared to women (76.7 +/- 24.0 nmol/L), and 6.5% showed values < 50 nmol/L.A decrease in the mean PTH in the summer compared to the winter was noticed, with PTH levels showing a relationship with 25OHD concentrations only in the winter (r = -0.208, p = 0.041).This season-dependent increase was noticed only among men, white and who were in the youngest group of individuals.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Medicine, Division of Endocrinology, Universidade Federal de São Paulo (UNIFESP) - Escola Paulista de Medicina (EPM), São Paulo, São Paulo, Brazil. ssetsuo@terra.com.br.

ABSTRACT

Background: Hypovitaminosis D is a common condition among elderly individuals in temperate-climate countries, with a clear seasonal variation on 25 hydroxyvitamin D levels, increasing after summer and decreasing after winter, but there are few data from sunny countries such as Brazil. Many factors can interfere on vitamin D cutaneous synthesis. We aimed at studying the 25OHD variations during winter and summer in an outdoor physically active elderly population living in São Paulo city, and analysed their determining factors.

Methods: Ninety-nine individuals (52 women and 47 men, from 55 to 83 years old) from different ethnic groups were selected from an outdoor physical activity group. Data are reported as Mean +/- SD, and we used Pearson Linear Correlation, Student's t-test for non-related samples, Chi-square (chi(2)) test and One-way ANOVA for analysis.

Results: Mean 25OHD value for the whole group was 78.9 +/- 30.9 nmol/L in the winter and 91.6 +/- 31.7 nmol/L in the summer (p = 0.005). Mean winter serum 25OHD concentrations were not different between men and women (81.2 +/- 30.1 nmol/L vs. 76.7 +/- 31.8 nmol/L, respectively), and 19.2% of the individuals showed values < 50 nmol/L. In the summer, we noticed an increase only for men (107.6 +/- 31.4 nmol/L) compared to women (76.7 +/- 24.0 nmol/L), and 6.5% showed values < 50 nmol/L. A decrease in the mean PTH in the summer compared to the winter was noticed, with PTH levels showing a relationship with 25OHD concentrations only in the winter (r = -0.208, p = 0.041). White individuals showed an increase in mean serum 25OHD in the summer (p = 0.016) which was not noticed for other ethnic groups (Asians, native Brazilians and blacks). An increase in 25OHD values in the summer was observed in the age groups ranging from 51-60 and 61-70 years old (p < 0.05), but not in the age group from 71 years old on.

Conclusions: 25OHD values increased during the summer in elderly residents of São Paulo, but to different extents depending on ethnicity, gender and age. This season-dependent increase was noticed only among men, white and who were in the youngest group of individuals.

No MeSH data available.


Related in: MedlinePlus

Distribution of 25OHD (nmol/L) concentrations according to gender and season.
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Figure 1: Distribution of 25OHD (nmol/L) concentrations according to gender and season.

Mentions: The mean serum 25OHD of the whole group in the winter was 78.9 ± 30.9 nmol/L, without any statistical difference between men and women (81.2 ± 30.1 nmol/L vs. 76.7 ± 31.8 nmol/L, respectively, p = 0.472). In the summer, the mean of the whole group was 91.6 ± 31.7 nmol/L, and only men presented a significant increase in 25OHD levels (107.6 ± 31.4 nmol/L, p < 0.001); consequently, their mean value was higher than that of the women during this season (76.7 ± 24.0 nmol/L, p < 0.001, Table 1). In the samples taken in the winter, 2% of the women and 4.3% of the men showed values < 25 nmol/L, and 25% of the women and 6.4% of the men presented values between 25 and 50 nmol/L. However, in the summer, values < 25 nmol/L were not found in any of the individuals from either gender. On this same occasion, values between 25 and 50 nmol/L were observed in 12.5% of the women and in none of the men (Figure 1). There was only one case of secondary hyperparathyroidism detected in the winter (PTH: 81.0 pg/mL, ionized calcium: 1.28 mM, creatinine: 1.5 mg/dL), which normalized in the sample taken in the summer.


Increases in summer serum 25-hydroxyvitamin D (25OHD) concentrations in elderly subjects in São Paulo, Brazil vary with age, gender and ethnicity.

Maeda SS, Kunii IS, Hayashi LF, Lazaretti-Castro M - BMC Endocr Disord (2010)

Distribution of 25OHD (nmol/L) concentrations according to gender and season.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2902474&req=5

Figure 1: Distribution of 25OHD (nmol/L) concentrations according to gender and season.
Mentions: The mean serum 25OHD of the whole group in the winter was 78.9 ± 30.9 nmol/L, without any statistical difference between men and women (81.2 ± 30.1 nmol/L vs. 76.7 ± 31.8 nmol/L, respectively, p = 0.472). In the summer, the mean of the whole group was 91.6 ± 31.7 nmol/L, and only men presented a significant increase in 25OHD levels (107.6 ± 31.4 nmol/L, p < 0.001); consequently, their mean value was higher than that of the women during this season (76.7 ± 24.0 nmol/L, p < 0.001, Table 1). In the samples taken in the winter, 2% of the women and 4.3% of the men showed values < 25 nmol/L, and 25% of the women and 6.4% of the men presented values between 25 and 50 nmol/L. However, in the summer, values < 25 nmol/L were not found in any of the individuals from either gender. On this same occasion, values between 25 and 50 nmol/L were observed in 12.5% of the women and in none of the men (Figure 1). There was only one case of secondary hyperparathyroidism detected in the winter (PTH: 81.0 pg/mL, ionized calcium: 1.28 mM, creatinine: 1.5 mg/dL), which normalized in the sample taken in the summer.

Bottom Line: In the summer, we noticed an increase only for men (107.6 +/- 31.4 nmol/L) compared to women (76.7 +/- 24.0 nmol/L), and 6.5% showed values < 50 nmol/L.A decrease in the mean PTH in the summer compared to the winter was noticed, with PTH levels showing a relationship with 25OHD concentrations only in the winter (r = -0.208, p = 0.041).This season-dependent increase was noticed only among men, white and who were in the youngest group of individuals.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Medicine, Division of Endocrinology, Universidade Federal de São Paulo (UNIFESP) - Escola Paulista de Medicina (EPM), São Paulo, São Paulo, Brazil. ssetsuo@terra.com.br.

ABSTRACT

Background: Hypovitaminosis D is a common condition among elderly individuals in temperate-climate countries, with a clear seasonal variation on 25 hydroxyvitamin D levels, increasing after summer and decreasing after winter, but there are few data from sunny countries such as Brazil. Many factors can interfere on vitamin D cutaneous synthesis. We aimed at studying the 25OHD variations during winter and summer in an outdoor physically active elderly population living in São Paulo city, and analysed their determining factors.

Methods: Ninety-nine individuals (52 women and 47 men, from 55 to 83 years old) from different ethnic groups were selected from an outdoor physical activity group. Data are reported as Mean +/- SD, and we used Pearson Linear Correlation, Student's t-test for non-related samples, Chi-square (chi(2)) test and One-way ANOVA for analysis.

Results: Mean 25OHD value for the whole group was 78.9 +/- 30.9 nmol/L in the winter and 91.6 +/- 31.7 nmol/L in the summer (p = 0.005). Mean winter serum 25OHD concentrations were not different between men and women (81.2 +/- 30.1 nmol/L vs. 76.7 +/- 31.8 nmol/L, respectively), and 19.2% of the individuals showed values < 50 nmol/L. In the summer, we noticed an increase only for men (107.6 +/- 31.4 nmol/L) compared to women (76.7 +/- 24.0 nmol/L), and 6.5% showed values < 50 nmol/L. A decrease in the mean PTH in the summer compared to the winter was noticed, with PTH levels showing a relationship with 25OHD concentrations only in the winter (r = -0.208, p = 0.041). White individuals showed an increase in mean serum 25OHD in the summer (p = 0.016) which was not noticed for other ethnic groups (Asians, native Brazilians and blacks). An increase in 25OHD values in the summer was observed in the age groups ranging from 51-60 and 61-70 years old (p < 0.05), but not in the age group from 71 years old on.

Conclusions: 25OHD values increased during the summer in elderly residents of São Paulo, but to different extents depending on ethnicity, gender and age. This season-dependent increase was noticed only among men, white and who were in the youngest group of individuals.

No MeSH data available.


Related in: MedlinePlus