Some racial disparities in childbirth more environmental than genetic

March 13, 2014, University of Colorado Denver

A new study investigating racial disparities in birth outcomes shows that contrary to some theories Vitamin D is unlikely to play a role in differences in preterm birth and low birth weight between African-Americans and whites.

"For years there has been this hypothesis that African-Americans have worse because they have more melanin in their skin which reflects the sun and therefore lowers levels of Vitamin D," said study author Zaneta Thayer, PhD, assistant professor of anthropology at the University of Colorado Denver . "But in examining the relationship between ultraviolet exposure and birth outcomes nationwide, there was no evidence to support this."

The study was published in the American Journal of Epidemiology.

The so-called ultraviolet light or UVD theory holds that racial differences in between blacks and whites are associated with the ability to synthesize Vitamin D from ultraviolet light. African-Americans, who have high concentrations of melanin, are less able to absorb Vitamin D from the sun leading some to believe that this contributes to higher rates of negative birth outcomes.

A lack of Vitamin D has been linked to increased risk of pregnancy complications, bone disorders, cardiovascular disease, diabetes and some cancers.

At the same time, differences in socioeconomic status and racial discrimination have also been linked to low birth weights, risk of depression and other ailments.

Thayer collected data on UV exposure in 48 states or territories, using information compiled from the National Oceanic and Atmospheric Administration (NOAA) National Weather Service website. She also used birth outcome data came from the National Centers for Disease Control and Prevention, focusing specifically on incidences of low and preterm births.

The study found that states with the highest income inequalities had higher disparities in birth outcomes across the UV spectrum.

The racial disparity in was greatest among women living in areas with high UV exposure and greater income inequality. The disparity in preterm births was also highest in areas with increased UV exposure and income inequality.

According to the UVD hypothesis, the difference in birth outcomes between whites and blacks should be lower among women in areas with more sunshine or UV radiation. In fact, there was an increase in disparities in those areas.

"Given the UV hypothesis, we would expect that women who live in the South would have better birth outcomes than those living in the North," Thayer said. "However, the present analysis suggests the exact opposite, with both absolute rates as well as in adverse birth outcomes being greatest in southern states."

In fact, the states with the lowest disparities in preterm and low birth weights were North Dakota and Vermont which had the second and third lowest UV Indexes respectively.

"The results suggest that the environment is a stronger contributor to adverse birth outcomes than genes, since there are differences in rates of birth outcomes across states" Thayer said. "That said, it seems unlikely that disparities in birth outcomes in the U.S. are primarily shaped by differences in UV induced vitamin D status."

Thayer said it might be time to stop looking at genes as the primary cause of .

"We need to focus on addressing structural inequalities in society like poverty and discrimination that shape individual experience and health," she said.

Explore further: Preterm infants more likely to have elevated insulin levels in early childhood

Related Stories

Preterm infants more likely to have elevated insulin levels in early childhood

February 11, 2014
Researchers have found that preterm infants are more likely to have elevated insulin levels at birth and in early childhood compared to full-term infants, findings that provide additional evidence that preterm birth may be ...

Higher risk of birth problems after assisted conception

January 8, 2014
A University of Adelaide study has shown that the risk of serious complications such as stillbirth, preterm birth, low birth weight and neonatal death is around twice as high for babies conceived by assisted reproductive ...

Low vitamin D levels during pregnancy associated with preterm birth in non-white mothers

October 30, 2013
African-American and Puerto Rican women who have low levels of vitamin D during pregnancy are more likely to go into labor early and give birth to preterm babies, research led by the University of Pittsburgh Graduate School ...

Working while pregnant won't harm the baby, study finds

March 25, 2013
(HealthDay)—Working during pregnancy does not increase a woman's risk of having a preterm or low birth-weight baby, a new study found.

Daily iron during pregnancy linked to improved birth weight

June 20, 2013
Taking iron daily during pregnancy is associated with a significant increase in birth weight and a reduction in risk of low birth weight, finds a study published in BMJ today.

Experts find link between low doses of vitamin D and adverse pregnancy outcomes

March 26, 2013
There is a link between vitamin D insufficiency and adverse health outcomes such as gestational diabetes and preeclampsia in mothers-to-be and low birth weight in newborns, suggests a paper published in BMJ today.

Recommended for you

Air pollution may shorten telomeres in newborns

January 24, 2018
A study conducted before and after the 2004 closure of a coal-burning power plant in Tongliang, China, found children born before the closure had shorter telomeres than those conceived and born after the plant stopped polluting ...

Number of older people with four or more diseases will double by 2035, say researchers

January 23, 2018
A study published today in Age and Ageing, the scientific journal of the British Geriatrics Society, reports that the number of older people diagnosed with four or more diseases will double between 2015 and 2035. A third ...

Placental accumulation of flame retardant chemical alters serotonin production in rats

January 22, 2018
A North Carolina State University-led research team has shown a connection between exposure to a widely used flame retardant chemical mixture and disruption of normal placental function in rats, leading to altered production ...

Marijuana use does not lower chances of getting pregnant

January 22, 2018
Marijuana use—by either men or women—does not appear to lower a couple's chances of getting pregnant, according to a new study led by Boston University School of Public Health (BUSPH) researchers.

Women run faster after taking newly developed supplement, study finds

January 19, 2018
A new study found that women who took a specially prepared blend of minerals and nutrients for a month saw their 3-mile run times drop by almost a minute.

Americans are getting more sleep

January 19, 2018
Although more than one in three Americans still don't get enough sleep, a new analysis shows first signs of success in the fight for more shut eye. According to data from 181,335 respondents aged 15 and older who participated ...

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

Sherman
not rated yet Mar 18, 2014
This is an important article because with all the attention vitamin D has received in the media over the last decade, it has been built up into a cure-all panacea based largely on simple correlations, which is not the same as causation. Every claimed link, association, or correlation between vitamin D and any disease or condition must be thoroughly researched in order to figure out what the causation direction is, or if vitamin D is just a proxy indicator for some truer cause. One great place where this is all being presented and discussed is a new forum called Vitamin D Explained. I'm a writer for the site, and while it is pro-vitamin D, it is also trying to figure out what is fact and what is fiction. It's at http://www.dexplained.com

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.