Ethiopian lactating women are at risk of vitamin D deficiency due to increased need and limited sun exposure. Serum 25(OH)D concentration was assessed in subjects (n=120) enrolled in a randomized controlled vitamin D supplementation trial (NCT02210884) conducted in Sidama Zone (7N, 38E), Southern Ethiopia. Baseline data from the trial are included in this report.
Plasma 25(OH)D concentration was determined using the VDSP certified IDS manual ELISA kits. Data on dress habits and sun seeking behavior were collected using questionnaires. A portable colorimeter was used to measure skin reflectance.
Plasma 25(OH)D concentrations ranged from 23.0 nmol/L to 102.0 nmol/L. More than half of the participants (55%) had 25(OH)D concentrations inadequate for bone and overall health (30 – 50 nmol/L). Four of the women were Vitamin D deficient (< 30 nmol/L). Plasma 25(OH)D was > 50 nmol/L in 41.7%. Most of the participants (82%) reported avoiding direct sunlight, never wearing sleeveless clothes (78%) and covering their head and most of their upper body when going outside (52%). Mean (SD) 25(OH)D concentration was significantly lower among women that covered most of their upper body compared to those that did not. Furthermore, skin lightness was positively correlated with 25(OH)D. Weight and age were significant negative predictors of 25(OH)D concentrations.
Conservative dress habits and avoiding sun exposure were factors that contributed to vitamin D insufficiency in these rural women residing near the equator. Sunlight abundance did not guarantee adequate vitamin D status in this study population.