February 28, 2007

Vitamin D deficiency widespread during pregnancy, Increasing Schizophrenia Risk in Children

Past research has linked Vitamin D deficiency during pregnancy with increased risk of schizophrenia for the child later in life (see research here and here).

Now, new research has come out that suggests that even regular use of prenatal multivitamin supplements is not adequate to prevent vitamin D insufficiency.

The new research found that more than 80 percent of black women and nearly half of white woman tested when their children were born "had levels of vitamin D that were too low, even though more than 90 percent of them used prenatal vitamins during pregnancy," said Lisa Bodnar, assistant professor of epidemiology at the University of Pittsburgh Graduate School of Public Health.

"The numbers also were striking for their newborns - 92.4 percent of African-American babies and 66.1 percent of white infants were found to have insufficient vitamin D at birth."

The research was done by University of Pittsburgh researchers and published in the Journal of Nutrition. In the study vitamin D insufficiency was found to be widespread among women during pregnancy, particularly in the northern latitudes.

In addition to its link to increased risk of schizophrenia, vitamin D is closely associated with bone health, and vitamin D deficiency early in life is associated with rickets - a disorder characterized by soft bones.

"A newborn's vitamin D stores are completely reliant on vitamin D from the mother," observed Dr. Bodnar, who also is an assistant investigator at the university-affiliated Magee-Womens Research Institute (MWRI). "Not surprisingly, poor maternal vitamin D status during pregnancy is a major risk factor for infant rickets, which again is becoming a major health problem."

For their study, Dr. Bodnar and her colleagues evaluated data that was collected on 200 black women and 200 white women who were randomly selected from more than 2,200 women enrolled in the MWRI's Pregnancy Exposures and Preeclampsia Prevention Study between 1997 and 2001. Samples of maternal blood were collected prior to 22 weeks pregnancy and again just before delivery, Samples of newborn umbilical cord blood also were tested for 25 hydroxyvitamin D, an indicator of vitamin D status. Finding such a proliferation of vitamin D insufficiency in spite of prenatal multivitamin use is troubling, she noted, suggesting that higher dosages, differing vitamin formulations or a moderate increase in sunlight exposure might be necessary to boost vitamin D stores to healthier levels.

"In both groups, vitamin D concentrations were highest in summer and lowest in winter and spring," said senior author James M. Roberts, M.D., MWRI director and professor and vice chair of research in the department of obstetrics, gynecology and reproductive sciences at the University of Pittsburgh School of Medicine. "But differences were smaller between seasons for African-American mothers and babies, whose vitamin D deficiency remained more constant."

Since vitamin D is made by the body in reaction to sunlight exposure, it has long been known that vitamin D deficiency is more common among darker-skinned individuals, particularly in more northern latitudes, where less ultraviolet radiation reaches the Earth. Indeed, vitamin D deficiency is more than three times as common in winter than in summer for all women of childbearing age in the United States. Even so, the Pittsburgh researchers' study is cause for concern.

"This study is among the largest to examine these questions in this at-risk population," Marjorie L. McCullough, Sc.D., senior epidemiologist at the American Cancer Society, wrote in an accompanying editorial. "By the end of pregnancy, 90 percent of all women were taking prenatal vitamins and yet deficiency was still common."

Vitamin D is found naturally in fatty fish but few other foods. Primary dietary sources include fortified foods such as milk and some ready-to-eat cereals and vitamin supplements. Sun exposure for skin synthesis of vitamin D also remains critical.

In an interview Dr. Bodnar said, "Our study shows that current vitamin D dietary intake recommendations are not enough to meet the demands of pregnancy," and that "Improving vitamin D status has tremendous capacity to benefit public health."

She suggested that raising the level of dietary supplements might be a relatively safe way to increase vitamin D levels. While many prenatal vitamins contain about 400 international units (iu) of vitamin D, taking perhaps 1,000 units might be preferable, she said.

In an accompanying editorial, Marjorie McCullough, a senior epidemiologist for the American Cancer Society, said the study "illuminates the danger of assuming that prenatal vitamins in their present form are ensuring vitamin D sufficiency in pregnant women and their newborns."

In an unrelated study the following news on Vitamin D levels in Mulsim women was reported:

A study suggests conservative Muslim dress codes are causing vitamin D deficiency by depriving women of sunlight. Researchers "previously found a high prevalence of vitamin D deficiency … in Arab and East Indian women residing in the United Arab Emirates." In a follow-up study of 178 UAE women, "Many dressed to cover their whole bodies, including their hands and faces, while outside of their homes. Only two of the women, one in each group, were not vitamin D deficient." After three months of supplements, only 30 percent of the women who finished the study achieved recommended levels of vitamin D. Researchers' conclusion: These women need higher doses of vitamin D

Source Scientific Journal Article: High prevalence of vitamin D insufficiency in black and white pregnant women residing in the northern United States and their neonates. by Drs. Bodnar and Roberts, study authors include Hyagriv N. Simhan, M.D., Robert W. Powers, Ph.D., Michael P. Frank and Emily Cooperstein, all of MWRI. The study was funded by the National Institutes of Health.

Related Reading:

Season of Birth - Low Sunlight Exposure/Vitamin D deficiency is associated with higher risk of schizophrenia

Vitamin D supplementation in boys during first year of life is associated with lower risk of schizophrenia

Pregnancy-related Schizophrenia Risk Factors - Full List


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