J Pediatr Endocrinol Metab 2016; aop
Ping Zhou*, Jinny Cai and Morri Markowitz
Absence of a relationship between thyroid hormones and vitamin D levels DOI 10.1515/jpem-2015-0210 Received May 25, 2015; accepted November 23, 2015
Abstract Background: Vitamin D is an immune modulator that may play a role in thyroid related autoimmunity. Methods: We analyzed a US population based dataset to determine the relationship between serum 25-hydroxyvitamin D (25OHD) and thyroid hormones while assessing the effects of autoimmunity and BMI. Results: 25OHD did not correlate significantly with any thyroid related measure. 25OHD levels stratified by thyroid antibody status were not statistically different between antibody positive and negative groups. The mean 25OHD levels of lean, overweight, and obese groups defined by BMI were lower than those of the normal group. Only the mean thyroid stimulating hormone (TSH) value in the obese group was significantly higher than the normal group. Conclusions: We conclude that thyroid related measures and 25OHD serum levels are not related. Keywords: autoimmunity; obesity; thyroid function; vitamin D.
Introduction The identification of vitamin D (calcitriol) receptors in many tissues led to studies aimed at elucidating its role in those locations. Results of these studies indicate that, in addition to its well-known contributions to calcium homeostasis and bone health, vitamin D plays a part in the regulation of immune function, muscle strength
*Corresponding author: Ping Zhou, MD, Assistant Professor of Pediatrics, Division of Pediatric Endocrinology, Albert Einstein College of Medicine, 3450 Wayne Ave., Bronx, NY 10467, USA Phone: +(718) 920-4664, Fax: +(718) 405-5609, E-mail: [email protected] Jinny Cai: University of Southern California, Los Angeles, CA, USA Morri Markowitz: Division of Pediatric Endocrinology, The Children’s Hospital at Montefiore, Albert Einstein College of Medicine, Bronx, NY, USA
and the prevention of diabetes mellitus and, possibly, cardiovascular disease [1, 2]. Many other possible roles are currently under intense investigation. One of these roles, as suggested by some evidence, is regulation of thyroid hormone levels. For example, low vitamin D and slightly elevated thyroid stimulating hormone (TSH) levels have been described as occurring together in obese populations, a state now considered pro-inflammatory [3, 4]. As an immune modulator, vitamin D may affect thyroid functioning in patients with autoimmune thyroiditis [5–7]. However, population based studies supporting this relationship are lacking. The objective of the study was to examine the relationship between serum 25-hydroxyvitamin D (25OHD) and thyroid related measures based on autoimmune and weight status.
Materials and methods This is a cross-sectional study using National Health and Nutrition Examination Survey (NHANES) data collected between 2001 and 2002. Data on anthropomorphic measures, 25-hydroxyvitamin D (25OHD), TSH, free thyroxine (FT4), anti-thyroglobulin (ATA), and anti-thyroid peroxidase antibodies (ATPO) levels are abstracted from the files DEMO_B, L06VID_B, and SSNH4THY. Statistical analyses were performed using SAS (version 9.2, SAS Institute, Cary, NC, USA). The initial data set included 6619 subjects (3181 males and 3438 females). Pearson correlation matrices were calculated using this data set. After subjects without data in FT4, TSH, 25OHD, ATA, and ATPO were excluded, the remaining data set included 2006 subjects (930 males and 1076 females), all of whom were 12 years of age and older at the time of testing. Data from this group were used for the remaining analyses. To examine the role of autoimmunity specifically, we divided the subjects into two groups: antibody negative group (Group A-Control Group) and antibody positive group (Group B – Test Group). Thyroid antibody reference ranges are taken from the CDC lab procedure manual (based on the NHANES 2007–2008 public release data set information), with the normal range of anti-thyroglobulin being 0–4 and that of anti-thyroid peroxidase antibodies being 0–9. From Group B, a subgroup, Group C, is formed with subjects whose anti-thyroglobulin and anti-thyroid peroxidase antibodies were both positive. The mean 25OHD level of the Control Group was compared to that of both Group B and Group C. Age and BMI were adjusted in the comparison as covariates since they are also associated with 25OHD levels.
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2 Zhou et al.: Thyroid hormones and vitamin D levels Table 1: Subject characteristics and Pearson correlations of thyroid related variables with 25(OH)D. Variable
n
Mean±SD
Range
R/25(OH)D
Age, years Height, cm Weight, kg BMI Free T4, ng/dL TSH, mIU/L ATA, IU/mL ATPO, IU/mL 25(OH)D, ng/mL
6619 6580 6562 6542 2006 2001 2001 1990 6619
37.8±21.8 166.8±10.1 74.6±20.1 26.68±6.38 0.78±0.17 2.19±10.46 8.6±76.1 16.39±79.54 18.2±8.1
12–85 122–182 27.5–188.3 13.73–65.41 0.1–4.8 0.002–350.52 0.6–1930.6 0.1–964.2 5.6–44.9
0.035 0.0849 –0.121 –0.183 –0.03 –0.005 0.009 –0.001 1
p 0.004
Ping Zhou*, Jinny Cai and Morri Markowitz
Absence of a relationship between thyroid hormones and vitamin D levels DOI 10.1515/jpem-2015-0210 Received May 25, 2015; accepted November 23, 2015
Abstract Background: Vitamin D is an immune modulator that may play a role in thyroid related autoimmunity. Methods: We analyzed a US population based dataset to determine the relationship between serum 25-hydroxyvitamin D (25OHD) and thyroid hormones while assessing the effects of autoimmunity and BMI. Results: 25OHD did not correlate significantly with any thyroid related measure. 25OHD levels stratified by thyroid antibody status were not statistically different between antibody positive and negative groups. The mean 25OHD levels of lean, overweight, and obese groups defined by BMI were lower than those of the normal group. Only the mean thyroid stimulating hormone (TSH) value in the obese group was significantly higher than the normal group. Conclusions: We conclude that thyroid related measures and 25OHD serum levels are not related. Keywords: autoimmunity; obesity; thyroid function; vitamin D.
Introduction The identification of vitamin D (calcitriol) receptors in many tissues led to studies aimed at elucidating its role in those locations. Results of these studies indicate that, in addition to its well-known contributions to calcium homeostasis and bone health, vitamin D plays a part in the regulation of immune function, muscle strength
*Corresponding author: Ping Zhou, MD, Assistant Professor of Pediatrics, Division of Pediatric Endocrinology, Albert Einstein College of Medicine, 3450 Wayne Ave., Bronx, NY 10467, USA Phone: +(718) 920-4664, Fax: +(718) 405-5609, E-mail: [email protected] Jinny Cai: University of Southern California, Los Angeles, CA, USA Morri Markowitz: Division of Pediatric Endocrinology, The Children’s Hospital at Montefiore, Albert Einstein College of Medicine, Bronx, NY, USA
and the prevention of diabetes mellitus and, possibly, cardiovascular disease [1, 2]. Many other possible roles are currently under intense investigation. One of these roles, as suggested by some evidence, is regulation of thyroid hormone levels. For example, low vitamin D and slightly elevated thyroid stimulating hormone (TSH) levels have been described as occurring together in obese populations, a state now considered pro-inflammatory [3, 4]. As an immune modulator, vitamin D may affect thyroid functioning in patients with autoimmune thyroiditis [5–7]. However, population based studies supporting this relationship are lacking. The objective of the study was to examine the relationship between serum 25-hydroxyvitamin D (25OHD) and thyroid related measures based on autoimmune and weight status.
Materials and methods This is a cross-sectional study using National Health and Nutrition Examination Survey (NHANES) data collected between 2001 and 2002. Data on anthropomorphic measures, 25-hydroxyvitamin D (25OHD), TSH, free thyroxine (FT4), anti-thyroglobulin (ATA), and anti-thyroid peroxidase antibodies (ATPO) levels are abstracted from the files DEMO_B, L06VID_B, and SSNH4THY. Statistical analyses were performed using SAS (version 9.2, SAS Institute, Cary, NC, USA). The initial data set included 6619 subjects (3181 males and 3438 females). Pearson correlation matrices were calculated using this data set. After subjects without data in FT4, TSH, 25OHD, ATA, and ATPO were excluded, the remaining data set included 2006 subjects (930 males and 1076 females), all of whom were 12 years of age and older at the time of testing. Data from this group were used for the remaining analyses. To examine the role of autoimmunity specifically, we divided the subjects into two groups: antibody negative group (Group A-Control Group) and antibody positive group (Group B – Test Group). Thyroid antibody reference ranges are taken from the CDC lab procedure manual (based on the NHANES 2007–2008 public release data set information), with the normal range of anti-thyroglobulin being 0–4 and that of anti-thyroid peroxidase antibodies being 0–9. From Group B, a subgroup, Group C, is formed with subjects whose anti-thyroglobulin and anti-thyroid peroxidase antibodies were both positive. The mean 25OHD level of the Control Group was compared to that of both Group B and Group C. Age and BMI were adjusted in the comparison as covariates since they are also associated with 25OHD levels.
Brought to you by | New York University Bobst Library Technical Services Authenticated Download Date | 1/28/16 8:36 PM
2 Zhou et al.: Thyroid hormones and vitamin D levels Table 1: Subject characteristics and Pearson correlations of thyroid related variables with 25(OH)D. Variable
n
Mean±SD
Range
R/25(OH)D
Age, years Height, cm Weight, kg BMI Free T4, ng/dL TSH, mIU/L ATA, IU/mL ATPO, IU/mL 25(OH)D, ng/mL
6619 6580 6562 6542 2006 2001 2001 1990 6619
37.8±21.8 166.8±10.1 74.6±20.1 26.68±6.38 0.78±0.17 2.19±10.46 8.6±76.1 16.39±79.54 18.2±8.1
12–85 122–182 27.5–188.3 13.73–65.41 0.1–4.8 0.002–350.52 0.6–1930.6 0.1–964.2 5.6–44.9
0.035 0.0849 –0.121 –0.183 –0.03 –0.005 0.009 –0.001 1
p 0.004
