Study shows no SES/skin color correlation, and a SES/genetic ancestry correlation

mikemikev · Oct 28, 2013

A current concern in genetic epidemiology studies in admixed populations is that population stratification can lead to spurious results. The Brazilian census classifies individuals according to self-reported color, but several studies have demonstrated that stratifying according to color is not a useful strategy to control for population structure, due to the dissociation between self-reported color and genomic ancestry. We report the results of a study in a group of Brazilian siblings in which we measured skin pigmentation using a reflectometer, and estimated genomic ancestry using 21 Ancestry Informative Markers (AIMs). Self-reported color, according to the Brazilian census, was also available for each participant. This made it possible to evaluate the relationship between self-reported color and skin pigmentation, self-reported color and genomic ancestry, and skin pigmentation and genomic ancestry. We observed that, although there were significant differences between the three color groups in genomic ancestry and skin pigmentation, there was considerable dispersion within each group and substantial overlap between groups. We also saw that there was no good agreement between the color categories reported by each member of the sibling pair: 30 out of 86 sibling pairs reported different color, and in some cases, the sibling reporting the darker color category had lighter skin pigmentation. Socioeconomic status was significantly associated with self-reported color and genomic ancestry in this sample. This and other studies show that subjective classifications based on self-reported color, such as the one that is used in the Brazilian census, are inadequate to describe the population structure present in recently admixed populations. Finally, we observed that one of the AIMs included in the panel (rs1426654), which is located in the known pigmentation gene SLC24A5, was strongly associated with skin pigmentation in this sample.
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The availability of data on SES in this sample made it possible to evaluate the relationship of SES and self-reported color, SES and genomic ancestry, and SES and skin pigmentation. No significant association was found between SES and skin pigmentation. However, there were significant associations between SES and self-reported color and SES and genomic ancestry (Table 6 and table 7, respectively). Participants reporting to be white tend to have higher SES than those reporting other color categories. We also observed that the average European ancestry proportion was higher in individuals with higher SES. Previous studies in other countries in Latin America have reported similar associations between SES and genomic ancestry [36], [37].
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http://www.plosone.org/article/info:doi/10.1371/journal.pone.0027162

Which eliminates discrimination based on skin color as a causal variable for racial SES differences.

waltky · May 6, 2016

Skin bacteria stays largely unchanged over time...

Skin bacteria stay 'stable over time'
Fri, 06 May 2016 - Everyone has their own personal range of bacteria living on their skin that stays largely unchanged over time, a US study suggests.

It found sites of oily skin, such as backs and ears, had the most stable microbial fingerprints. But even exposed dry sites such as palms were relatively stable. Feet were among the areas that changed most in their microbial make-up, perhaps due to factors such as personal hygiene. Human skin is home to a wide range of bacteria, fungi, and viruses. Most are harmless or even beneficial, but some have been linked with skin disorders such as acne, psoriasis and eczema.

possum took dis pic o' Granny's toes with a flower in `em

Research into how skin bugs vary across the body helps explain why eczema tends to affect moist sites such as the bends of the arms, while psoriasis commonly occurs on dry exposed areas such as the elbows. But it has been unclear how communities of bacteria, viruses and fungi found across the skin vary over time and how these changes might affect health.

Microbial signatures

In a study published in the journal, Cell, researchers took skin samples from 12 healthy people at three times over a period of one month to two years, encompassing 17 areas of the body. Heidi Kong, of the National Cancer Institute, and Julie Segre, of the National Human Genome Research Institute, found healthy individuals kept their own unique microbial signatures despite exposure to clothes, washing, other people and the outside world. However, the stability of skin bugs varied among individuals and microbial strains, with some showing more changes than others.

In the future, the scientists plan to study patients with eczema and other conditions to look at how microbes might vary with disease. "Future studies can use the knowledge of the relative stability of the skin microbial communities in healthy adults to understand how various exposures or disease state may alter these skin microbes," said Dr Segre. "For example, studies in acne patients could explore whether specific strains bloom during adolescent acne flares or change with medications such as antibiotics."

http://www.bbc.co.uk/news/health-36213697
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waltky · May 9, 2016

Youthful 'second skin' to hide wrinkles...

Scientists make 'second skin' to hide wrinkles
Mon, 09 May 2016 - Scientists say they have developed an invisible elastic film that can be applied to the skin to reduce the appearance of wrinkles and eye bags.

Scientists claim to have developed an invisible elastic film that can be applied to the skin to reduce the appearance of wrinkles and eye bags. Once applied, the formula dries to form a film that "mimics the properties of youthful skin", Nature Materials reports after a series of small trials. At the moment it is being explored as a commercial cosmetic product. But the US scientists say their "second skin" might eventually be used to deliver medicines and sun protection.

Second skin

The team from Harvard Medical School and the Massachusetts Institute of Technology have tested their prototype product on a handful of volunteers, applying the formula to their under-eye bags, forearms and legs. The polysiloxane polymer was made in the lab using molecules of silicone and oxygen as the building blocks. Although it's synthetic, it's designed to mimic real skin and provide a breathable, protective layer. According to the researchers, the temporary film locks in moisture and helps boost skin elasticity. They performed several tests, including a recoil test where the skin was pinched and then released to see how long it takes to ping back into position. As skin ages, it becomes less firm and less elastic and so performs less well in this sort of test. Skin that had been coated with the polymer was more elastic than skin without the film. And, to the naked eye, it appeared smoother, firmer and less wrinkly.

The researchers, who have a spin-off company that could eventually market their patented formula, say the film is essentially invisible, can be worn all day without causing irritation and can withstand things like sweat and rain. But more studies are needed before then. The polymer would also need safety approval from regulators. Dr Tamara Griffiths of the British Association of Dermatologists says bags under the eyes are caused by the protrusion of fat pockets associated with ageing. While entirely natural, some people see it as undesirable and seek ways to reverse it - sometimes resorting to surgery. Dr Griffiths said: "The results [with the polymer film] appear to be comparable to surgery, without the associated risks. Further research is needed, but this is a novel and very promising approach to a common problem. I will follow its development with interest."

Prof Robert Langer, who led the work at MIT, said: "Developing a second skin that is invisible, comfortable and effective in holding in water and potentially other materials presents many different challenges. "It has to have the right optical properties, otherwise it won't look good, and it has to have the right mechanical properties, otherwise it won't have the right strength and it won't perform correctly. "We are extremely excited about the opportunities that are presented as a result of this work and look forward to further developing these materials to better treat patients who suffer from a variety of skin conditions."

http://www.bbc.co.uk/news/health-36245728
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Study shows no SES/skin color correlation, and a SES/genetic ancestry correlation

mikemikev Banned

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Study shows no SES/skin color correlation, and a SES/genetic ancestry correlation

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