New research may help explain why multiple sclerosis rates have risen sharply in the U.S. and some other countries among women, while rates appear stable in men.The study could also broaden understanding of how environmental influences alter genes to cause a wide range of diseases. The causes of multiple sclerosis (MS) are not well understood, but experts have long suspected that environmental factors trigger the disease in people who are genetically susceptible. In the newly published study, researchers found that women with MS were more likely than men with MS to have a specific genetic mutation that has been linked to the disease.
Women were also more likely to pass the mutation to their daughters than their sons and more likely to share the MS-susceptibility gene with more distant female family members. If genes alone were involved, mothers would pass the MS-related gene to their sons as often as their daughters, said researcher George C. Ebers, MD, of the University of Oxford. Ebers’ research suggests that the ability of environmental factors to alter gene expression — a relatively new field of genetic study known as epigenetics — plays a key role in multiple sclerosis and that this role is gender-specific.
The theory is that environmental influences such as diet, smoking, stress, and even exposure to sunlight can change gene expression and this altered gene expression is passed on for a generation or two. “The idea that the environment would change genes was once thought to be ridiculous,” Ebers says. “Now it is looking like this is a much bigger influence on disease than we ever imagined.”
The study by Ebers and colleagues included 1,055 families with more than one person with MS. Close to 7,100 genes were tested, including around 2,100 from patients with the disease. The researchers were looking for MS-specific alterations in the major histocompatibility complex (MHC) gene region. They found that women with MS were 1.4 times more likely than men with the disease to carry the gene variant linked to disease risk. A total of 919 women and 302 men had the variant in the MHC region, compared to 626 women and 280 men who did not have it.
The study appeared in the Jan. 18 issue of Neurology.
Epigenetics is not evolution. Genetic alterations linked to environmental assaults can be passed down for a generation or two, but DNA usually rights itself over time, Ebers says. “This may explain why we hardly ever see MS in families over more than three generations,” he says. Earlier studies by Ebers and colleagues suggest that vitamin D deficiency may be the environmental stressor that triggers the MS-linked gene alterations. Rates of the disease are highest among people living farthest from the equator, and there is widespread speculation that lack of vitamin D due to low sun exposure may explain this. Other than Ebers’ research team, Orhun Kantarci, MD, of the Mayo Clinic in Rochester, Minn., is one of the few researches studying epigenetics as it relates to multiple sclerosis.
Kantarci calls the new research a potentially important piece of the puzzle to explain the gender difference in MS, but he adds that the research must be replicated. “This study provides more questions than answers, but it is very interesting,” he says. “We are learning that inheritance isn’t as simple as [Gregor] Mendel described.”
The more time adolescent girls spend in front of Facebook, the more their chances of developing a negative body image and various eating disorders, such as anorexia, bulimia and exaggerated dieting. This has been shown in a new study from the University of Haifa.
Eating disorders include a wide spectrum of abnormal mental and behavioral conducts related to food and body weight, such as anorexia nervosa and bulimia nervosa. This study, conducted by Prof. Yael Latzer, Prof. Ruth Katz and Zohar Spivak of the Faculty of Social Welfare and Health Sciences at the University of Haifa, set out to examine the effects of two factors on the development of eating disorders in young girls: exposure to the media and self-empowerment.
A group of 248 girls aged 12-19 (average age: 14.8) took part in the survey. These girls were asked to provide information on their Internet and television viewing habits. Regarding the latter, they were asked to give the number of popular shows related to extreme standards of physical image (the “Barbie” model) that they watched. The girls also filled out questionnaires that examined their approach to slimming, bulimia, physical satisfaction or dissatisfaction, their general outlook on eating, and their sense of personal empowerment.
The results showed that the more time girls spend on Facebook, the more they suffered conditions of bulimia, anorexia, physical dissatisfaction, negative physical self-image, negative approach to eating and more of an urge to be on a weight-loss diet. Extensive online exposure to fashion and music content showed similar tendencies, but manifested in fewer types of eating disorders. As such, the more the exposure to fashion content on the Internet, the higher a girl’s chances of developing anorexia. A similar direct link was found between viewing gossip- and leisure-related television programs (the likes of “Gossip Girl”) and eating disorders in adolescent girls. The study also revealed that the level of personal empowerment in these girls is negatively linked to eating disorders, such that the higher the level of empowerment, the more positive the physical self-image and the lower the chances of developing an eating disorder.
In this study, exposure to the media and the consequential sense of personal empowerment was found to be associated to parenting practices. Girls whose parents were involved in their media usage; who knew what they were viewing and reading and where they were surfing on the web; who watched, surfed or read along with them; and who conducted cooperative and critical discussions with their daughters about the content of their surfing habits, showed more personal empowerment, forming a protective shield against eating disorders.
On the other hand, parents who were not involved in their media exposure, were not aware of the content that their daughters were consuming, and instead of sharing and becoming familiar with that content chose to limit or prohibit exposure, led to lower self-empowerment in their daughters. This, in turn, has a positive link to various eating problems and negative body image.
“Significant potential for future research and application of eating disorder prevention lies in an understanding of how parenting decisions can have effect on an adolescent girl’s sense of empowerment and that enforcing a girl’s sense of empowerment is a means to strengthening body image. This study has shown that a parent has potential ability to prevent dangerous behavioral disorders and negative eating behavior in particular,” the researchers stated.