Vitamin D deficiency in cord plasma from multiethnic subjects living in the tropics.

Abstract

BACKGROUND:

Vitamin D deficiency is commonly reported in high-latitude areas and in dark-pigmented individuals. However, nothing is known about vitamin D in cord blood from multiethnic subjects living in the tropics.

OBJECTIVE:

Our study objective was to determine the prevalence of vitamin D deficiency in summer and winter in cord blood from multiethnic individuals in Hawai'i where sufficient sun irradiance occurs year-round for cutaneous vitamin D production.

METHODS:

25-Hydroxyvitamin D (25(OH)D) levels were quantified by enzyme immunoassay in 100 cord plasma samples from apparently healthy full-term newborns and their mothers. Stratification was performed by birth season and ethnicity.

RESULTS:

Mean 25(OH)D levels were 24.5 ng/mL (9.1-68.3 ng/mL). Overall, 28% of samples were vitamin D deficient (<20 ng/mL) and 50% were insufficient (20-30 ng/mL). 25(OH)D levels (ng/mL) were highest in Caucasians (30.5, n = 19), followed by Asians (25.1, n = 43), Hispanics (21.5, n = 3), Pacific Islanders (20.0, n = 25), and African Americans (19.6, n = 2). Differences among groups were significant (p = 0.008). Cord plasmas from summer versus winter were higher overall (p = 0.001) and among Asians (p = 0.0003). Seasonal changes were correlated with sun irradiance overall (r = 0.43, p = 0.0001), among Caucasians (r = 0.45, p = 0.05), and among Asians (r = 0.45, p = 0.0001).

CONCLUSION:

Our results suggest that prenatal supplement recommendations of 400 IU vitamin D/day do not protect against vitamin D deficiency, even in subjects living in the tropics where ample sun irradiance exists for cutaneous vitamin D synthesis. The high prevalence of vitamin D deficiency we observed emphasizes the necessity for regular 25(OH)D monitoring, particularly during pregnancy and lactation, in dark-pigmented individuals, and during winter months.

• Authors: Brunhild M Halm, Jennifer F Lai, Ian Pagano, William Cooney, Reni A Soon, Adrian A Franke
• Journal: Journal of the American College of Nutrition (J Am Coll Nutr) Vol. 32 Issue 4 Pg. 215-23 ( 2013) ISSN: 1541-1087 [Electronic] United States
• PMID: 24024766 (Publication Type: Journal Article, Research Support, N.I.H., Extramural)

Chemical References

• Vitamin D
• 25-hydroxyvitamin D

Topics

• Adolescent
• Adult
• Black or African American
• Asian People
• Dietary Supplements
• Female
• Fetal Blood (chemistry)
• Hawaii (epidemiology)
• Hispanic or Latino
• Humans
• Infant
• Lactation (physiology)
• Male
• Nonlinear Dynamics
• Pregnancy
• Prevalence
• Prospective Studies
• Seasons
• Socioeconomic Factors
• Sunlight
• Vitamin D (administration & dosage, analogs & derivatives, blood)
• Vitamin D Deficiency (blood, ethnology)
• White People
• Young Adult