Skip to main page content
Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2016 Feb;146(2):318-25.
doi: 10.3945/jn.115.223388. Epub 2015 Dec 9.

Genetics, Diet, and Season Are Associated With Serum 25-Hydroxycholecalciferol Concentration in a Yup'ik Study Population From Southwestern Alaska

Free PMC article

Genetics, Diet, and Season Are Associated With Serum 25-Hydroxycholecalciferol Concentration in a Yup'ik Study Population From Southwestern Alaska

Alison E Fohner et al. J Nutr. .
Free PMC article


Background: Low blood vitamin D concentration is a concern for people living in circumpolar regions, where sunlight is insufficient for vitamin D synthesis in winter months and the consumption of traditional dietary sources of vitamin D is decreasing.

Objective: The objective was to characterize the effects of diet, genetic variation, and season on serum 25-hydroxycholecalciferol [25(OH)D3] concentrations in Yup'ik Alaska Native people living in rural southwest Alaska.

Methods: This study was a cross-sectional design that assessed the associations of traditional diet (via a biomarker, the RBC δ(15)N value), age, gender, body mass index (BMI), community location, and genotype of select single nucleotide polymorphisms (SNPs) in cytochrome P450 family 2, subfamily R, peptide 1 (CYP2R1), 7-dehydrocholesterol reductase (DHCR7), and vitamin D binding protein (GC) with serum 25(OH)D3 concentrations in 743 Yup'ik male and female participants, aged 14-93 y, recruited between September 2009 and December 2013.

Results: Yup'ik participants, on average, had adequate concentrations of serum 25(OH)D3 (31.1 ± 1.0 ng/mL). Variations in diet, BMI, age, gender, season of sample collection, and inland or coastal community geography were all significantly associated with serum 25(OH)D3 concentration. In models not adjusting for other covariates, age, diet, and seasonal effects explained 33.7%, 20.7%, and 9.8%, respectively, of variability in serum 25(OH)D3 concentrations. Of the 8 SNPs interrogated in CYP2R1 and DHCR7, only rs11023374 in CYP2R1 was significantly associated with serum 25(OH)D3, explaining 1.5% of variability. The GC haplotype explained an additional 2.8% of variability. Together, age, diet, gender, season of sample collection, BMI, geography of the community, and genotype at rs11023374 explained 52.5% of the variability in serum 25(OH)D3 concentrations.

Conclusions: Lower consumption of the traditional diet was associated with lower serum concentrations of 25(OH)D3. Younger adults and youth in this community may be at increased risk of adverse outcomes associated with vitamin D insufficiency compared with older members of the community, especially during seasons of low sunlight exposure, because of lower consumption of dietary sources of vitamin D.

Keywords: Alaska Native; American Indian; cholecalciferol; polyunsaturated fatty acid; public health; vitamin D.

Conflict of interest statement

Author disclosures: AE Fohner, Z Wang, J Yracheta, DM O’Brien, SE Hopkins, J Black, J Philip, HW Wiener, HK Tiwari, PL Stapleton, JM Tsai, TA Thornton, BB Boyer, and KE Thummel, no conflicts of interest.


Concentration of serum 25(OH)D3 by RBC log1015N value) in adult Alaska Native (Yup’ik) people [n = 689 participants with data for both serum 25(OH)D3 concentration and RBC log1015N value). Least-squares linear regression, with goodness of fit indicated by the R2 regression coefficient, was used. The P value, as calculated by a likelihood ratio test, was <0.0001. The δ15N value represents a biomarker of traditional food intake as defined in Methods. 25(OH)D3, 25-hydroxycholecalciferol.

Similar articles

See all similar articles

Cited by 7 articles

See all "Cited by" articles

Publication types

MeSH terms