1. Vitamin D Analysis Noelle Pervere OHSU Dietetic Intern

2. Vitamin D Background 1 About 40-50% of circulating 25(OH) vitamin D is derived from skin conversion. 25(OH) Vitamin D concentration is the preferred measurement of levels. Half life of 15 days; takes into account sun exposure, diet, supplements, etc. 1,25 dihydroxyvitamin D circulates in the serum at much lower levels. Useful for endocrine and kidney function

3. Vitamin D Background As people age they are more likely to be deficient in vitamin D due to decreased ability to synthesize it 2. Darker skinned populations have a lower rate of vitamin D synthesis 3,4. Individuals with higher BMI values typically have lower 25(OH) Vitamin D concentrations 1,5. 25(OH) Vitamin D levels change with seasons, exposure to sunlight, and dietary intake 1.

4. Institute of Medicine Guidelines 6 RDA by age groups: 1-70 y/o: 600 IU/day >71 y/o: 800 IU/day Serum 25(OH) Vitamin D level: 20 ng/ml Meets the requirements of 97.5% of the population. No defined upper level although >50 ng/ml is suggested.

5. Vitamin D Data Set ~40,000 participants Info included: ▫ Gender ▫ Age ▫ BMI ▫ 25(OH) Vit D; 1,25 Vit D values ▫ Draw year ▫ Winter or summer  (defined as May 15-Oct 15)

6. Vitamin D Data Set Draws taken between 2007-2010 Deleted duplicate draws Used only 25(OH) Vitamin D values ▫ Left with ~ 20,000 participants PTH data only included whether it was performed or not ▫ Could not use

7. Population Data Gender:

8. Population Data Age Range Distribution:

9. Population Data Race and Ethnicity Distribution: Ethnicity RaceParticipantsHispanic/LatinoNon Hispanic/Latino White2097664020336 Asian8792877 Black5673564 Unknown49316144 More than one race17236136 Am Indian/Ak Nat1307123 Hawaiian/Pac Island39435

10. Population Data Draw year and season:

11. Population Data BMI Distribution: *kg/m 2

12. Population Data 25(OH) Vitamin D values: * ng/ml

13. Questions Asked Do 25(OH) vitamin D values vary with: ▫ Gender? ▫ Age? ▫ Race/Ethnicity? ▫ BMI? ▫ Year drawn and which season?

14. Vitamin D and Gender FemaleMale Mean (ng/ml)30.829.5 Std Dev15.315.9 Variance232.8251.4 P(T<=t) one-tail3.83E-09 Hypothesis: 25(OH) Vitamin D concentrations are marginally higher in women 7. Discussion: Although there is only a slight variance, it was significant. Possible explanations could be higher intake of vitamin D foods or supplement use related to bone health for women.

15. Vitamin D and Age <50 y/o> 50 y/o Mean (ng/ml)28.030.9 Std Dev13.8614.89 Variance192.2221.6 P(T<=t) one-tail2.99786E-50 > 71 y/o Mean (ng/ml)32.2 Std Dev13.9 Hypothesis: As age increases, average 25(OH) Vit D will decrease 2. Discussion: There was an increase in vitamin D levels with higher age groups. This could be related to a higher intake of supplements with older age groups.

16. Vitamin D and Race WhiteBlack # of participants20976567 Mean (ng/ml)30.123.9 Std Dev14.013.9 Variance196.7193.8 P(T<=t) one-tail1.1316E-42 Hypothesis: White populations will have higher average 25(OH) Vit D levels than black populations 3,4. Discussion: Vitamin D levels in the white population is significantly higher than in the black population.

17. Vitamin D and Ethnicity Hispanic/LatinoNon Hispanic/Latino # of participants70822215 Mean (ng/ml)24.130.0 Std Dev12.014.3 Variance144.8205.0 P(T<=t) one-tail3.42075E-61 Hypothesis: Hispanic/Latino populations will have a lower mean 25(OH) Vit D level than non-hispanic populations 3,4,8. Discussion: The Non Hispanic/Latino population had a significantly higher mean vitamin D level than the Hispanic/Latino population. Possibly due to skin color and/or cultural practices.

18. Vitamin D and BMI 18.5-24.99*25-29.99* 30-34.99*35-39.99* >40* Mean (ng/ml)32.829.427.625.422.9 Std Dev15.012.9 11.811.3 Hypothesis: As BMI values increase, there will be a marked decrease in mean 25(OH) Vit D levels 5. Discussion: As BMI increases, average 25(OH) vitamin D levels decrease. * BMI: kg/m 2

19. Vitamin D and Draw Year Year 1Year 2Year 3 # of participants651972388095 Mean (ng/ml)27.429.028.2 Std Dev13.613.815.6 Note: Number of people who had vitamin D draws increased, as well as average vitamin D concentrations.

20. Vitamin D and Season Year 1Year 2Year 3 WinterSummerWinterSummerWinterSummer Mean (ng/ml)27.826.928.030.627.629.3 Std Dev14.212.714.013.315.116.3 Hypothesis: 25(OH) Vitamin D levels should be higher in the summer months than winter months 1. Discussion: With the exception of year 1, summer draws tended to have higher vitamin D concentrations.

21. Future Directions Analyze data with more advanced statistical methods ▫ Multi-variable ▫ Look at factors such as:  Age and gender  Race and gender  Race and BMI  Season and BMI Look at other factors such as PTH values

22. References 1.Rosen, C.J. (2011). Vitamin d insufficiency. The New England Journal of Medicine, 364, 248-54. 2.Need, AG, Morris, HA, Horowitz, M, & Nordin, C. (1993). Effects of skin thickness, age, body fat, and sunlight on serum 25- hydroxyvitamin d. American Journal of Clinical Nutrition, 58, 882-885. 3.Yuen, A.W.C, & Jablonski, N.G. (2009). Vitamin d: in the evolution of human skin color. Medical Hypotheses, 74, 39-44. 4.Holick, M.F., Chen, T.C., Lu, Z, & Sauter, E. (2007). Vitamin d and skin physiology: a d- lightful story. Journal of Bone and Mineral Research, 22(2), 28-33. 5.Konradsen, S, Ag, H, Linberg, F, Hexeberg, S, & Jorde, R. (2008). Serum 1,25- dihydroxyvitamin d is inversely associated with body mass index. European Journal of Nutrition, 41(2), 87-91. 6.Ross AC; Manson JE; Abrams SA; Aloia JF; Brannon PM; Clinton SK; Durazo-Arvizu RA; Gallagher JC; Gallo RL; Jones G; Kovacs CS; Mayne ST; Rosen CJ; Shapses SA. The 2011 report on dietary reference intakes for calcium and vitamin D from the Institute of Medicine: what clinicians need to know. Journal of Clinical Endocrinology & Metabolism 96:53-8 7.Hagenau, T, Vest, R, Gissel, N, Poulsen, C.S., & Erlandsen, M. (2009). Global vitamin d levels in relation to age, gender, skin pigmentation and latitude: an ecologic meta- regression analysis. Osteoperosis International, 20(1), 133-140. 8.Smith, M. (2010). Seasonal, ethnic and gender variations in serum vitamin d3 levels in the local population of peterborough. Bioscience Horizons, 3(2), 124-131.