Vitamin A Concentration in Umbilical Cord Blood of Infants from Three Separate Regions of the Province of Quebec (Canada)

Article excerpt

ABSTRACT

Background: Inuit women from Northern Quebec have been shown to consume inadequate quantities of vitamin A. This study was conducted to evaluate the prevalence of blood vitamin A deficiency in newborns from 3 distinct populations of the province of Quebec.

Methods: 594 newborns were included in this study (375 Inuit newborns from northern Quebec (Nunavik), 107 Caucasian and Native newborns from the Lower Northern Shore of the Saint-Lawrence River (LNS) and 112 newborns from Southern Quebec where clinical vitamin A deficiency is uncommon). Mothers were recruited at delivery and vitamin A (retinol) was analyzed from umbilical cord blood samples by reversed-phase high-pressure liquid chromatography.

Results: Nunavik and LNS newborns had significantly lower mean vitamin A concentrations in cord blood compared to Southern Quebec participants (15.7 [mu]g/dL, 16.8 [mu]g/dL and 20.4 [mu]g/dL respectively). The differences observed were similar when adjusted for sex and birthweight. Results also showed that 8.5% of Nunavik newborns and 1 2.2% of LNS newborns were below 1 0.0 [mu]g/dL, a level thought to be indicative of blood vitamin A deficiency in neonates.

Conclusion: These data suggest that a carefully planned vitamin A supplementation program during pregnancy in Nunavik and LNS might be indicated to promote healthy infant development.

Vitamin A influences the expression many genes and is essential for normal growth. Its involvement in infant development, vision and cell differentiation is well known. Adequate maternal stores of vitamin A are essential during pregnancy to meet the needs of the fetus. Vitamin A deficiency during development and early childhood delays growth, impairs vision and increases the severity of infections, ultimately leading to many otherwise preventable deaths.1-4

Vitamin A deficiency among children is an important public health problem primarily in developing countries.4,5 In Canada, Inuit infants are also at risk of vitamin A deficiency because Inuit women of childbearing age have been shown to consume inadequate quantities of vitamin A.6-8 Canadian Inuit preschool children have been shown to have a high incidence of infections.9,10 It is therefore important to determine if vitamin A deficiency, an important risk factor for infectious diseases, is prevalent in this population. This study attempts to document the prevalence of blood vitamin A deficiency in Inuit neonates. Comparison of vitamin A concentrations between studies has proven difficult because of variations in analytical methods. In this study, we compare the vitamin A concentrations in umbilical cord serum samples of Inuit neonates from the northern part of the province of Quebec (Nunavik) with cord blood levels of two different populations from Quebec, with all samples being analyzed in the same laboratory.

Methods

Populations and recruitment

The participants in this study were recruited between 1993 and 1997 and came from three different populations in the province of Quebec (Canada): 1) mothers and newborns from 14 small Inuit communities of Nunavik - a vast and remote area in northernmost Quebec (Figure 1), 2) 15 villages in the Lower North Shore (LNS) region of the St-Lawrence River - remote and isolated from the rest of the province, and 3) women admitted for delivery in one of the 10 participating hospitals from 10 administrative regions of Quebec, thought to be representative of the southern portion of the province where clinical vitamin A deficiency is uncommon.

The women were recruited originally for the evaluation of prenatal exposure to food-chain contaminants (heavy metals and organochlorines),11-13 and a subset of each population were randomly selected and agreed to participate in the present study (Population 1: 419/491 (85.3%), Population 2: 108/467 (23.1%), Populations: 112/1109 (10.1%)).

Data collection and sample analysis

After signing the appropriate consent forms, all mothers answered a short questionnaire relating to their sociodemographic characteristics. …