Vitamin D deficiency is associated with anaemia among African Americans in a US cohort

Abstract

Vitamin D deficiency is highly prevalent in the US population and is associated with numerous diseases, including those characterised by inflammatory processes. We aimed to investigate the link between vitamin D status and anaemia, hypothesising that lower vitamin D status would be associated with increased odds of anaemia, particularly anaemia with inflammation. A secondary aim was to examine the effects of race in the association between vitamin D status and anaemia. We conducted a cross-sectional analysis in a cohort of generally healthy adults in Atlanta, GA (n 638). Logistic regression was used to evaluate the association between vitamin D status and anaemia. Serum 25-hydroxyvitamin D (25(OH)D) < 50 nmol/l (compared to 25(OH)D ≥ 50 nmol/l) was associated with anaemia in bivariate analysis (OR 2·64, 95% CI 1·43, 4·86). There was significant effect modification by race (P= 0·003), such that blacks with 25(OH)D < 50 nmol/l had increased odds of anaemia (OR 6·42, 95% CI 1·88, 21·99), v. blacks with 25(OH)D ≥ 50 nmol/l, controlling for potential confounders; this association was not apparent in whites. When categorised by subtype of anaemia, blacks with 25(OH)D < 50 nmol/l had significantly increased odds of anaemia with inflammation than blacks with serum 25(OH)D ≥ 50 nmol/l (OR 8·42, 95% CI 1·96, 36·23); there was no association with anaemia without inflammation. In conclusion, serum 25(OH)D < 50 nmol/l was significantly associated with anaemia, particularly anaemia with inflammation, among blacks in a generally healthy adult US cohort.

Keywords: African Americans; Anaemia; Hb; Hepcidin; Inflammation; Vitamin D.

Conflict of interest statement

Conflict of Interest: None

Figures

Fig. 1

Correlation between vitamin D status (serum 25-hydroxyvitamin D (25(OH)D)) and total circulating iron concentrations in participants of the Emory/Georgia Tech Predictive Health Initiative cohort (2008 – 2013), n 638. Total serum iron was positively correlated with serum 25(OH)D concentration (Pearson’s r=0.2, P<0.001), and this association remained statistically significant after adjusting for age, sex, race, BMI, CRP, and IL-6 (β ± SE: 0.02 ± 0.01, P=0.006).