Studies regarding skin color, vitamin D, and racial health disparities:
Conclusion: This article gives an overview of how, for the at least the last 20 years, black people in America have had higher blood pressure compared to white people. People with darker skin make less vitamin D from sun exposure and vitamin D-deficiency has been strongly associated with high blood pressure.
Excerpt: “Autism incidence has also been linked to maternal vitamin D insufficiency in dark-skinned mothers living in northern latitudes. Reports have correlated low concentrations of maternal 25(OH)D3 with increased risk of having a child with behavioral problems associated with autism, such as language impairment and attention-switching difficulties. In addition, Somali mothers who moved to Stockholm have been shown to be severely vitamin D deficient (<20 ng/ml) and have approximately a 4.5 times higher risk of having a child with autism, as compared with native Swedes. This is in contrast to African individuals living in East Africa, who have mean 25(OH)D3 concentrations of 48 ng/ml. Autism incidence in the Somali population living in Minneapolis also appears to be high. In 2008, the Minneapolis school district enrolled 0.94% of Somali children, 0.52% of non-Somali African American children, 0.38% of Hispanic children, and 0.20% of Caucasian children in their citywide ASD preschool program.”
Conclusion: This study of 7,540 autistic children in Los Angeles County, California found that children born from foreign-born black mothers, children born from foreign-born Central/South American mothers, children born from foreign-born Filipino mothers, children born from foreign-born Vietnamese mothers, and children born from U.S.-born Hispanic and black mothers – all demographics with darker skin – have an increased risk for severe autism compared to children from U.S.-born white mothers. Could this be because of the well-documented fact that darker-skinned people are much more likely to suffer from vitamin D-deficiency?
Conclusion: This study of 3,918 autistic children in Sweden found that children born from Sub-Saharan African migrants, children born from North African migrants, children born from Latin American migrants, children born from Caribbean migrants, and children born from southern Asian migrants all had an increased risk for developing low-functioning autism. Could this be because they are all dark skinned people from extremely sunny areas moving to a country that gets very little sunshine in comparison, putting them and their offspring at an extreme risk of developing vitamin D-deficiency – which could be playing the primary role in the development of their autism?
Differences in Vitamin D Status May Account for Unexplained Disparities in Cancer Survival Rates Between African and White Americans (2012)
Conclusion: Compared to white Americans, black Americans generally have significantly lower vitamin D levels, significantly higher rates of vitamin D deficiency, and suffer much more from cancer (which vitamin D-deficiency has been found to be a major culprit in), with worse cancer survival rates than whites.
“This review offers evidence to explain cancer survival differences between AAs [African Americans] and WAs [White Americans]. AAs’ lower serum 25(OH)D concentrations [vitamin D] (mainly from reduced vitamin D photoproduction owing to darker pigmentation) may account for much of the unexplained survival disparity.” Emphasis added.
Conclusion: This study investigated whether or not racial vitamin D level differences may play a role in the hypertension disparity between American blacks and whites by examining the vitamin D levels of 1,984 and 5,156 black and white adult subjects and, indeed, it turns out that vitamin D is a major factor in the hypertension disparity.
Possible Role of Serum 25-Hydroxyvitamin D in Black–White Health Disparities in the United States (2010)
Conclusion: “Given the widespread vitamin D deficiency in the AA [African American] population and the potential widespread health benefits that accompany adequate replacement, we believe that addressing this issue may be the single most important public health measure that can be undertaken.” (Emphasis added)
Demographic Differences and Trends of Vitamin D Insufficiency in the US Population, 1988–2004 (2009)
Conclusion: In this study of 32,252 members of the U.S. general population, using data collected from the 1988-1994 Third National Health and Nutrition Examination Survey and 2001-2004 National Health and Nutrition Examination Survey, the Average vitamin D level of hispanics was significantly lower than that of non-hispanic whites, and the average vitamin D level of non-hispanic blacks was even lower. The prevalence of severe vitamin D-deficiency was exponentially higher for blacks compared to whites and hispanics. The study also found that men have slightly higher vitamin D levels than women (who also have a higher rates of severe deficiency) and that younger people have slightly higher vitamin D levels than older people. Although this study shows the glaring racial disparities in the U.S. population’s vitamin D levels, most alarming is that it also found a large decrease in vitamin D levels for all demographics in the time between the two surveys with 77% of all subjects being found to have inadequate vitamin D levels in the second survey. The lower vitamin D levels of darker-skinned people are attributed to their increased amount melanin in their skin, which acts as a natural sunscreen limiting cutaneous vitamin D synthesis from UVB exposure.
Regional Differences in African Americans’ High Risk for Stroke: The Remarkable Burden of Stroke for Southern African Americans (2008)
Conclusion: This article covers how the risk of fatal stroke has been found to be 50-200% higher for black Americans compared to white Americans. Black people tend to have lower vitamin D levels than whites and vitamin D has been found to be a crucial element in cardiovascular health.
Note: Article about the extremely high prevalence of autism among the children of Somali immigrants to Minnesota. Could it be because they are dark-skinned people moving from one of the sunniest areas in the world to an area that gets very weak sunlight, contributing to severe vitamin D deficiency, which may be contributing to the development of autism?
Note: Another article about the extremely high prevalence of autism among the children of Somali immigrants to Minnesota. Could it be because they are dark-skinned people moving from one of the sunniest areas in the world to an area that gets very weak sunlight, contributing to severe vitamin D deficiency, which may be contributing to the development of autism?
Note: And another article about the extremely high prevalence of autism among the children of Somali immigrants to Minnesota. Could it be because they are dark-skinned people moving from one of the sunniest areas of the world to an area that gets very weak sunlight, contributing to severe vitamin D deficiency, which may be contributing to the development of autism?
Conclusion: Black people have lower vitamin D levels and higher rates of vitamin D-deficiency. This is because the increased melanin in their skin acts a natural sunscreen, blocking the UVB radiation from the sun necessary for cutaneous vitamin D synthesis.
Conclusion: Blacks have a much higher rate of stroke incidence and mortality compared to whites in the United States. This disparity has stubbornly persisted over a period of decades despite advances in stroke-preventing medical treatments. Could this be due to, as many other studies suggest, the consistently low vitamin D levels of the black population?
Conclusion: This article covers a multitude of studies that have found American blacks and American hispanics generally suffer much poorer dental health compared to American whites. Maybe it’s a socioeconomic thing and they can’t afford dentist visits. Maybe it’s a lifestyle thing. Or maybe it’s because vitamin D has been proven to be crucially important in dental and skeletal health, as vitamin D is required by the body to absorb calcium, and dark-skinned people in the west generally have lower vitamin D levels, which would contribute to tooth decay and poor oral health.
Conclusion: Black people in America suffer kidney disease at far higher rate than whites do, with the number of black people undergoing dialysis being quadruple that of whites. As blacks also suffer much higher rates of vitamin D-deficiency, might there be a connection between vitamin D levels and kidney function? Diabetes, which blacks also suffer much more from, has been associated with kidney disease and has also been strongly associated with vitamin D-deficiency.
Also see: Studies Regarding Type-1 Diabetes and Vitamin D and Studies Regarding Type-2 Diabetes and Vitamin D
Prevalence and Risk Indicators for Destructive Periodontal Diseases in 3 Urban American Minority Populations (2001)
Conclusion: This study found that American blacks suffer poorer oral and dental health compared to Asians and Hispanics. Although this study did not explore vitamin D as a factor, vitamin D has been proven to be a crucial factor in good oral/dental health and dark-skinned people tend to also suffer disproportionately from vitamin D-deficiency.
Conclusion: In this experiment white and black subjects were exposed to a dose of ultraviolet light B (UVB) radiation and then vitamin D levels changes were measured. White subjects experienced an increase in their vitamin D levels, but the black subjects did not.
Vitamin D Metabolism Is Altered in Asian Indians in the Southern United States: A Clinical Research Center Study (1998)
Conclusion: Asian Indians are known to have much lower pre-vitamin D levels than Caucasians due to their darker skin limiting cutaneous vitamin D synthesis and are also known to suffer higher rates of severe symptoms of vitamin D-deficiency such as osteomalacia. However, this study of Asian Indians living in the United States found that they have a stronger vitamin D endocrine system than whites. 27 Caucasian adults and 18 Asian Indian adults were put on the same controlled diets containing specific amounts of calcium, phosphorus, sodium, potassium, and vitamin D. Although the Asian Indians had lower pre-vitamin D levels, they had significantly higher activated vitamin D levels than the Caucasians. This altered vitamin D endocrine system, the researchers conclude, however, is not enough to compensate for the vitamin D-deficiency-causing reduction in sun exposure Asian Indians experience when the move farther away from the equator.
Seasonal Changes in Plasma 25-Hydroxyvitamin D Concentrations of Young American Black and White Women. (1998)
Conclusion: This study checked the vitamin D levels of 51 black and 39 white Boston women (ages 20-40 years) four times over the course of one year at each season. At all time points, the black women had lower vitamin D levels. All women had the lowest levels at the end of winter and the highest levels during summer. Although both white and black women experienced rising vitamin D levels from spring to summer, the rise was smaller for black women.
Conclusion: Dark-skinned people living non-equatorial western countries have higher blood pressure than lighter-skinned people in these areas. This is partly because dark-skinned people have extreme difficulty synthesizing adequate amounts of vitamin D from sun exposure in areas like the northern U.S. and Great Britain due to the weakness of the sunlight in those regions and the increased melanin in their skin acting as a natural sun protectant blocking the UVB necessary for vitamin D production.
Conclusion: This study of autism rates in Göteborg, Sweden found that children born from mothers who are Ugandan immigrants to Sweden have a 200x higher risk for autism compared to the general Swedish population. Uganda is literally right on the equator and receives some of the most intense sunlight available on the planet (lots of vitamin D). The sun is so intense that the people there have developed very dark, melanin-rich skin to protect themselves from excess sun exposure. They have more sun than they can handle. Sweden is one of the northernmost territories in the world – rivaled only by Finland, Iceland, Russia, Alaska, and northern Canada. Because of Sweden being so far away from the equator, the country receives very little sunlight compared to Uganda and for months and months out of the year it’s physically impossible to make vitamin D from sunlight. Native Swedes have very light colored skin so they can take full advantage of whatever UVB they do manage to get. It is well-documented that dark-skinned people tend to have lower vitamin D levels than light-skinned people in “developed” countries. In this particular case, you have people with dark-skin living directly at the equator, moving extremely far away north away from the sunny equator in Sweden, where it’s even hard for light-skinned people to get enough vitamin D. If it’s hard for pale native Swede’s to make enough vitamin D, then it’s going to be much, much more difficult, impossible, for dark-skinned people who are used to living at the equator to maintain good health. Indeed, as this study found, their autism rate in Sweden is 200x higher, strongly suggesting that lack of sun exposure is a critical factor in autism development.
Child and Adolescent Psychiatric Presentations of Second-Generation Afro-Caribbeans in Britain (1995)
Conclusion: This study from 1973 to 1989 of second-generation Afro-Caribbean and white children living in a British inner city found that the Afro-Caribbean children had a disproportionately higher rate of autism. Could this be because of the well-documented fact that darker-skinned people are much more likely to suffer from vitamin D-deficiency?
Mild Mental Retardation in Black and White Children in Metropolitan Atlanta: A Case-Control Study (1995)
Conclusion: This study of 893 children in Atlanta, Georgia, U.S. (330 mildly retarded kids and 563 normal controls) found that the rate of mental retardation in black children is nearly double that of white children. Although this study did not explore vitamin D as a factor, it is proven and well-documented that vitamin D is a crucial factor in brain development in utero and during childhood and there is also an overwhelming amount of evidence that blacks disproportionately suffer from vitamin D-deficiency and vitamin D-deficiency-related diseases and disorders due to the high amount of melanin in their skin partially or totally preventing cutaneous vitamin D synthesis from sunlight. It is also well-documented that people with mental disabilities and mental disorders tend to have lower vitamin D levels or have been born from and breastfed by mothers with poor vitamin D levels, and that vitamin D plays a very large role in producing optimal cognitive performance throughout life.
Conclusion: This study of 457 American black people found that those with the darkest skin had the highest blood pressure and that blood pressure increased with increased skin pigmentation. People with darker skin make less vitamin D from sun exposure and vitamin D-deficiency has been strongly associated with high blood pressure.
Conclusion: In this study 12 black adults (7 men, 5 women) and 14 white adults (8 men, 6 women) were put on a diet with identical amounts of calcium, phosphate, magnesium, sodium, and potassium. Despite the black subjects having “significantly lower” pre-vitamin D levels, they had higher activated vitamin D levels and better intestinal calcium absorption than the white subjects. Could it be that dark-skinned people have developed stronger vitamin D endocrine systems to compensate for their reduced ability to cutaneously produce vitamin D from sun exposure?
Conclusion: In this experiment “two lightly pigmented Caucasian and three heavily pigmented Negro volunteers” were exposed to a standard dose of ultraviolet radiation. The UV exposure significantly increased the vitamin D levels of the caucasian subjects, but had no effect at all on the vitamin D levels of the negro volunteers. The experiment was repeated on one of the negros and it ended up taking a UV dose six times larger to produce a vitamin D levels increase similar to that of the caucasian subjects with the original, lower UV dose. According to this study at least, black people need roughly 6x the amount of proper sun exposure to get the same vitamin D level increase as white people.
Conclusion: This survey of 1,000 Detroit adults (ages 25-60) found that those with darker skin had higher blood pressure and that the darker the skin the higher the blood pressure. People with darker skin make less vitamin D from sun exposure and vitamin D-deficiency has been strongly associated with high blood pressure.
Relative Efficiency of Pigment and Horny Layer Thickness in Protecting the Skin of the European and Africans Against Solar Ultraviolet Radiation (1955)
Conclusion: It has been known as far back as 1955 that different skin pigmentations respond differently to solar radiation exposure.