Perinatal vitamin D and calcium status of northern Canadian mothers and their newborn infants.

OBJECTIVE: This study was undertaken to examine the vitamin D and calcium status of mothers and their newborns. METHODS: The intakes of vitamin D and calcium were determined prenatally in 121 women including 33 Caucasians, 51 Inuits, and 37 Native Indians, living in the Inuvik zone of the Northwest Territories. Plasma concentrations of 25-(OH)-D and calcium were also measured in mothers as well as in their offspring at delivery. RESULTS: The daily mean vitamin D intake of native mothers, including Inuits and Indians, with (8.1+/-5.5 microg) and without supplements (3.4+/-2.5 microg) was significantly lower than that of non-native mothers (13.2+/-5.9 microg and 5.8+/-4.3 microg, respectively). According to the predicted prevalence of low vitamin D intake, there existed a higher risk of vitamin D deficiency without supplementation in both native (88.6% vs 48.4%) and non-native (63.5% vs. 15.1%) mothers. The trend for calcium intakes with and without supplementation was similar to vitamin D intake. At the point of delivery, the plasma levels of 25-(OH)-D were lower in native mothers (50.1 19.3 nmol/L) and their offspring (34.2+/-13.1 nmol/L) than their counterparts (59.8+/-29.4 nmol/L and 41.4+/-23.5 nmol/L, respectively). Its plasma levels in newborn infants averaged only 67% of their mothers. None of these infants showed clinical evidence of vitamin D deficiency. In fact, their plasma calcium levels were significantly higher than their mothers. CONCLUSIONS: Plasma 25-(OH)-D concentrations of 60 to 70% of maternal levels may represent a "normal" range for newborn infants. However, a supplementation in native northern Canadian mothers during pregnancy and in their neonates during infancy may have a role to play in the prevention of vitamin D deficiency.

Perinatal vitamin A (retinol) status of northern Canadian mothers and their infants.

Vitamin A (retinol) status was determined in two groups living in the northern part of Canada: native (Indian and Inuit) and non-native (Caucasian). The dietary intake of vitamin A and its plasma concentration were measured prenatally, at delivery and postnatally in mothers. Plasma concentrations were also measured at birth and postnatally in their infants. The mean vitamin A intake of native mothers was significantly lower than that of non-native mothers, 661 +/- 485 versus 1,377 +/- 1,418 retinol equivalents (p < 0.00005), with a higher risk of deficiency without supplementation, 35% versus 8%. Plasma retinol concentrations, although not in the deficient range, were significantly lower in native than non-native mothers prenatally and postnatally. Infant mean plasma retinol concentrations at birth averaged only 52% of those of their mothers and were significantly lower among native than non-native infants although no clinical evidence of vitamin A deficiency was noted. We speculate that vitamin A supplementation in native Northern Canadian mothers during pregnancy and in their neonates during infancy may have a role to play in the prevention of vitamin A deficiency. We also postulate that plasma retinol concentrations of 50-60% of maternal levels and between 0.7 and 2.5 mumol/l represent a 'normal' range for newborn infants.

Vitamin D deficiency in a Manitoba community.

OBJECTIVE: Using a cross-sectional survey, to investigate the vitamin D status of a random sample of 80 mother-child pairs (child age 3-24 months) in a Manitoba community with a high incidence of rickets. METHOD: A questionnaire on feeding habits, gestational history, maternal diet and vitamin supplements was administered to mothers in their homes with the assistance of a local interpreter. Venous blood was collected from both mother and child for serum 25-hydroxyvitamin D levels. RESULTS: Of 91% babies initially breastfed, 36% received no formula or milk after weaning and 40% received no vitamin supplements. 24% of mothers took no vitamin supplements during pregnancy and lactation. Knowledge about rickets was poor. In 43% of children and 76% of mothers, serum 25-hydroxyvitamin D levels were below normal range. CONCLUSIONS: Vitamin D levels are low in this population due to lack of fortified dairy products and vitamin D supplements. A public health program should include counseling on rickets and vitamin D supplementation for all infants and pregnant or lactating women.

PIP: In the isolated Island Lake area of northern Manitoba, which has a high incidence of rickets, interviews were conducted with 80 mothers, each with a child at least 2 years old, living in St. Theresa Point and Garden Hill in their homes during June-July 1987 to determine their knowledge and attitudes towards rickets. Nurses obtained blood samples from the women and their young children so the researchers could determine the vitamin D status of both. The mother-child pairs were native Canadians from the Ojibway linguistic group that speaks its own dialect of Ojibway-Cree. Mothers initially breast fed 91% of the children. After weaning, 1/3 of infants received neither infant formula nor milk. No vitamin supplements were given to 40%. Many of the children who did receive vitamin supplements did not receive them regularly. 70% of the mothers did not drink any milk. 24% were milk-intolerant. 24% took no vitamin supplements during pregnancy and lactation. Mothers who did take supplements did not do so regularly. 17% claimed that their skin was sensitive to sunlight. 84% of mothers in one community had never heard of rickets. Most did not know its cause. Neither mothers nor the children were exposed to the sunlight in the summer. When outside, almost all small infants were completely covered to protect them from the elements. The mean 25-hydroxy-vitamin D level was 26.2 nmol/l for the children and 19.8 nmol/l for the mothers. 43% of children and 76% of mothers had a 25-hydroxy-vitamin D level below the normal range. These high levels of vitamin D insufficiency were even more troublesome given that the blood was taken in late June and July when vitamin D levels would be likely to be at their highest. The dearth of vitamin D fortified dairy products and vitamin supplements greatly contributed to the low level of vitamin D status in this area. The findings show a need for public health officials to include education on rickets and vitamin D supplementation for all infants and pregnant or lactating women.

Iron status and pregnancy in a northern Canadian population: relationship to diet and iron supplementation.

To determine the extent of iron deficiency, the prognostic value of prenatal ferritin levels and the desirability of prenatal iron supplementation in the western Canadian arctic, dietary iron intake was determined in 171 women and ferritin levels determined in 121 women during pregnancy, 79 at delivery and 77 postnatally, as well as in 65 of their infants at birth and 74 postnatally. Iron deficiency (ferritin < 15 ng/ml) was present in 34% of women during the first two trimesters, 25% (20/79) at delivery and in 51.7% (15/29) of mothers and 31% (9/29) of infants beyond four months after delivery. Maternal follow-up ferritin levels correlated poorly with dietary iron intake but well with prenatal ferritin levels, which appeared to be good predictors of the effectiveness of supplementation. Mean infant follow-up ferritin levels were 105.6 +/- 115.2 ng/ml with, and 46.7 +/- 63.5 without maternal prenatal supplementation (p = 0.03); maternal, 45.5 +/- 40.9 ng/ml with, and 12.8 +/- 9.2 without (p < 0.001). Measurement of prenatal ferritin levels to determine risk of iron deficiency and routine prenatal iron supplementation are recommended.