Circulating IGF-1 may mediate improvements in haemoglobin associated with vitamin A status during pregnancy in rural Nepalese women.
Pregnancy exacerbates vitamin A (VA) deficiency and anaemia among women in developing countries. Improving circulating haemoglobin (Hb) requires erythrocyte production and availability of iron. Insulin-like growth factor- 1 (IGF-1) functions in erythropoiesis, but its association with VA status and pregnancy-associated anaemia has not been studied. The aim of this study was to examine the relationship between serum retinol, IGF-1, and Hb among pregnant women in extant samples collected during a placebo-controlled trial of VA and beta-carotene (BC) supplementation in rural Nepal conducted from 1994 to 1997. Mid-pregnancy serum IGF-1 was measured in serum from n=589 randomly selected women of n=1186 in whom anthropometric, VA (retinol) and iron (Hb, erythrocyte zinc protoporphyrin (ZP), and ferritin) status data were available. Associations of IGF-1 with retinol, Hb or anaemia, and iron status were determined using multiple linear and logistic regression. Path analysis was used to explore the role of IGF-1 as a mediator between retinol and Hb, accounting for iron status. A 2.6 g/L increase in IGF-1 was observed per 0.1 mol/L increment in retinol (p<0.0001). Hb increased with each quartile of IGF-1, and odds of anaemia declined 68.8% from the 1st to 4th quartile. Improved iron status indicators explained only 29.1% of the association between IGF-1 and Hb, while IGF-1 explained 25.6% of the association between retinol and Hb. Increasing IGF-1 was likely one mechanism by which retinol improved circulating Hb in pregnant women of rural Nepal, although IGF-1 worked primarily through pathways independent of improved iron status indicators, perhaps by stimulating erythrocyte production.
Centre for Human Nutrition, Department of International Health, Johns Hopkins Bloomberg School of Public Health, 615 North Wolfe Street, Room W2505, Baltimore, MD 21205, USA.
Margia A
MA
Arguello
Centre for Human Nutrition, Department of International Health, Johns Hopkins Bloomberg School of Public Health, 615 North Wolfe Street, Room W2505, Baltimore, MD 21205, USA. Email: kschulz1@jhu.edu.
Kerry J
KJ
Schulze
Centre for Human Nutrition, Department of International Health, Johns Hopkins Bloomberg School of Public Health, 615 North Wolfe Street, Room W2505, Baltimore, MD 21205, USA.
Lee Sf
LS
Wu
Centre for Human Nutrition, Department of International Health, Johns Hopkins Bloomberg School of Public Health, 615 North Wolfe Street, Room W2505, Baltimore, MD 21205, USA.
Michele L
ML
Dreyfuss
Nepal Nutrition Intervention Study-Sarlahi (NNIPS), Tripureswor, Kathmandu, Nepal.
Subarna K
SK
Khatry
Centre for Human Nutrition, Department of International Health, Johns Hopkins Bloomberg School of Public Health, 615 North Wolfe Street, Room W2505, Baltimore, MD 21205, USA.
Parul
P
Christian
Centre for Human Nutrition, Department of International Health, Johns Hopkins Bloomberg School of Public Health, 615 North Wolfe Street, Room W2505, Baltimore, MD 21205, USA.
Keith P
KP
West
D000328:Adult; D000740:Anemia / Q000097:blood / Q000150:complications; D019587:Dietary Supplements; D004311:Double-Blind Method; D004920:Erythropoiesis / Q000502:physiology; D005260:Female; D005293:Ferritins / Q000097:blood; D005865:Gestational Age; D006454:Hemoglobins / Q000032:analysis*; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000032:analysis / Q000502:physiology*; D007501:Iron / Q000097:blood; D019266:Iron, Dietary / Q000008:administration & dosage; D009390:Nepal; D009752:Nutritional Status; D011247:Pregnancy; D011248:Pregnancy Complications / Q000097:blood*; D012424:Rural Population; D014801:Vitamin A / Q000008:administration & dosage / Q000097:blood; D014802:Vitamin A Deficiency / Q000097:blood*; D055815:Young Adult; D019207:beta Carotene / Q000008:administration & dosage
D006454:Hemoglobins; D019266:Iron, Dietary; D019207:beta Carotene; D014801:Vitamin A; D007334:Insulin-Like Growth Factor I; D005293:Ferritins; D007501:Iron