TABLE 1.

Demographic characteristics of Alaska Native (Yup’ik) participants¹

Time of collection2	n	Age, y	BMI, kg/m2	RBC log10(δ15N value)	Serum 25(OH)D33, ng/mL	Males, n	Females, n	Inland villages, n	Coastal villages, n
August–October	167	40.9 ± 20.2	25.8 ± 5.3	0.934 ± 0.053	36.7 ± 12.1	79	88	117	50
November–January	310	35.5 ± 17.1	26.2 ± 5.8	0.939 ± 0.066	30.9 ± 13.0	171	139	161	149
February–April	48	35.1 ± 20.4	26.3 ± 6.0	0.945 ± 0.058	25.6 ± 12.9	19	29	0	48
May–July	218	34.7 ± 16.5	26.6 ± 6.2	0.935 ± 0.057	27.4 ± 10.6	121	97	63	155
Total	743	36.4 ± 18.0	26.2 ± 5.8	0.937 ± 0.060	30.8 ± 12.6	390	353	341	402

¹Values are means ± SDs unless otherwise indicated. Study participants all self-identified as Yup’ik. The δ¹⁵N value is a biomarker of traditional food intake as defined in Methods.

²Participants were stratified by seasonal quarter of data collection. Seasons, as defined by the range of 3 mo listed, were determined by sunlight exposure and lag time of changes in serum concentrations after vitamin D synthesis.

³25(OH)D₃, 25-hydroxycholecalciferol.