Excess body fat increases the risk of depression

A new study from Aarhus University and Aarhus University Hospital, Denmark, shows that ten kilograms of extra body fat increases the risk of depression by seventeen percent.

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Carrying ten kilograms of excess body fat increases the risk of depression by seventeen per cent. The more fat, the greater the probability of developing depression. This is the main conclusion of a new study carried out by researchers from Aarhus University and Aarhus University Hospital, Denmark.

"Our study also indicated that the location of the fat on the body makes no difference to the risk of depression. This suggests that it is the psychological consequences of being overweight or obese which lead to the increased risk of depression, and not the direct biological effect of the fat. If the opposite was true we would have seen that fat located centrally on the body increased the risk the most, as it has the most damaging effect in biological terms," says the study's last author Dr. Søren Dinesen Østergaard. 

He is professor at the Department of Clinical Medicine at Aarhus University and affiliated with the Department of Affective Disorders at Aarhus University Hospital. 

Prior studies in the field have predominantly used Body Mass Index (BMI) to measure obesity. BMI is calculated solely on the basis of body weight and height and is therefore a fairly crude measure, that does not, for example, take build and muscle mass into account.

"BMI is an inaccurate way of measuring overweight and obesity. Many elite athletes with a large muscle mass and a low body fat mass will have a BMI above 25, which is classified as overweight according to the common definition. This obviously doesn't make much sense. Therefore, one of the strengths of our study is that we've been able to zoom in and look at the specific relationship between the amount of body fat and the risk of depression," explains Dr. Østergaard.

In the study, which has been published in the journal Translational Psychiatry, the researchers have analysed data from two large genetic data sets: the UK Biobank, which contains data on the correlation between genetic variants and physical measurements (including body fat mass distributed around parts of the body); and the Psychiatric Genomics Consortium, which contains information on the correlation between genetic variants and depression.

Dr. Østergaard also highlights his research group's choice of the 'Mendelian randomization' method as the main reason why the study was successful. He also emphasises that the findings are particularly significant in light of the fact that almost 40 per cent of the world's adult population is overweight. 

"In addition to the known physical consequences of obesity such as diabetes and cardiovascular disease, there is also a significant and now well-documented psychological component, which needs to be dealt with as well. This is yet another argument for resolving the obesity epidemic," he says, before emphasising that it is important to have a balanced approach to the issue: 

"As it appears to be the psychological consequences of obesity, such as a negative body image and low self-esteem that is the main driving force behind the increased risk of depression, society's efforts to combat obesity must not stigmatise, as this will probably increase the risk of depression even further. It is important to bear this in mind so we can avoid doing more harm than good in the effort to curb the obesity epidemic," says Dr. Østergaard. 

FACTS ABOUT MENDELIAN RANDOMIZATION:

Mendelian randomization (named after the Austrian monk Gregor Mendel, who was the father of modern genetics) is a method which in recent years has helped researchers to overcome a major challenge associated with observational studies - namely that of making causal inference. In observational studies researchers often find correlations between two conditions - e.g. between obesity and depression - where it is difficult, or rather impossible, to determine whether there is indeed a causal effect going from obesity to depression - or vice versa. Mendelian randomization may solve this challenge.

Mendelian randomization can be described as nature's version of the randomised controlled trials that are carried out when testing whether a new drug has the desired (causal) effect in the treatment of a disease. In the clinical trials of drugs, lots are drawn to determine whether individual participants will receive the active drug or a placebo, without them knowing which treatment they have been assigned to. Instead, Mendelian randomization takes advantage of the fact that a completely natural randomization takes place during the formation of the sex cells (egg cells and sperm cells), which represent the origin of all human beings. When sex cells are formed, the parents' genetic variants - including those that give rise to increased body fat- are randomly distributed. Therefore, some individuals will have received many of these variants and others less. In the study in question, the researchers have utilised this natural and random source of variation to determine whether people who have received many genetic variants for increased body fat have an increased risk of suffering depression.

THE RESEARCH RESULT - MORE INFORMATION

Genetic epidemiological study utilising data from the UK Biobank (with information on the association between genetic variants and fat mass based on a study of 330,000 people) and the Psychiatric Genomics Consortium (with information on the association between genetic variants and depression based on a study of 135,000 people with depression and 345,000 control subjects).

The research group comprises Maria S. Speed, Oskar H. Jefsen, Anders D. Børglum, Doug Speed and Søren D. Østergaard - all from Aarhus University.

Abusive parenting may have a biological basis

Research led by University of Oregon professor unveils a potential neurobiological trigger EUGENE, Ore. -- Parents who physically abuse their children appear to have a physiological response that subsequently triggers more harsh parenting when they attempt parenting in warm, positive ways, according to new research. Reporting in the quarterly journal Couple and Family Psychology: Research and Practice, a five-member team, led by Elizabeth A. Skowron, a professor in the Department of Counseling Psychology and Human Services in the University of Oregon College of Education, documented connections between the nervous system's ability to calm heart rate -- via electrocardiogram (ECG) measures of parasympathetic activation -- and the type of parenting mothers displayed during a laboratory interaction with their preschool child LCSW Continuing Education Studies of child maltreatment have consistently found that parents who physically abuse their children tend to parent in more hostile, critical and controlling ways. Skowron's team appears to have found evidence of a physiological basis for patterns of aversive parenting -- the use of hostile actions such as grabbing an arm or hand or using negative verbal cues in guiding a child's behavior -- in a sample of families involved with Child Protective Services. For the experiment, mothers and children were monitored to record changes in heart rate while playing together in the lab. Parenting behavior was scored to capture positive parenting and strict, hostile control using a standard coding system. What emerged, Skowron said, were clear distinctions between abusive, neglectful and non-maltreating mothers in their physiological responses during parenting. When abusive mothers were more warm and nurturing, they began to experience more difficulty regulating their heart rate and staying calm. This physiological-based stress response then led the abusive mothers to become more hostile and controlling toward their child a short time later in the interaction. The same was not the case for mothers who had been previously identified as being physically neglectful or for mothers with no history of neglectful or abusive parenting. Participants in the National Institutes of Health-funded study were 141 mothers -- 94 percent Caucasian with a high school degree or less and incomes at or below $30,000 -- and their children, ranged in age from 3 to 5 years old. The research focuses on tracking the effects of physiology on parenting in real time. "Abusive mothers who try to warmly support their child when the child faced a moderate challenge displayed a physiological response that suggested they're stressed, on alert and preparing to defend against a threat of some kind," said Skowron, a researcher at the Child and Family Center/Prevention Science Institute at the UO. "This kind of physiological response then led to a shift in an abusive mother becoming more hostile, strict, and controlling ways with her young child, regardless of how her child was behaving." The findings, she added, suggest that when physically abusive mothers experience being a nurturing parent they find it to be hard work. "It appears to quickly wear them out, perhaps because it challenges them in ways that lower-risk mothers don't experience," she said. "An abusive mother appears caught: When she does a good job with her child, it costs her physiologically, and it negatively affects her because it leads to more aversive parenting." The team's findings help to explain why abusive parenting is so resistant to most interventions, Skowron said. "Most parents who struggle with child maltreatment really love their children and want help improving their parenting skills. Our findings suggest that many are experiencing a biological response during parenting that actively interferes with their efforts to parent in warm and nurturing ways." The next step, she said, is exploring how to translate the new discovery into interventions specifically designed for parents struggling with child abusive. "We have to figure out how to help these high-risk parents calm themselves down more effectively and enjoy the experience of supporting their children in warm, positive ways. First, she noted, it will be important for other researchers to replicate the findings. "Researchers at the University of Oregon continue to yield critical insights that result in more effective prevention strategies," said Kimberly Andrews Espy, vice president for research and innovation and dean of the UO Graduate School. "This research by Dr. Skowron revealing a potential neurobiological trigger involved in abusive parenting may lead to new interventions that could help to improve the lives of children." ### Co-authors with Skowron were Elizabeth Cipriano-Essel and Aaron L. Pincus, both of Pennsylvania State University where Skowron conducted this research, Lorna Smith Benjamin of the University of Utah Neuropsychiatric Institute, and Mark J. Van Ryzin, research associate in the UO Child and Family Center and researcher at the Eugene-based Oregon Social Learning Center. NIH grant RO1 MH079328 to Skowron supported the research through the National Institute of Mental Health. Additional funding was provided by the Administration for Children and Families, through its Children's Bureau of the Administration on Children, Youth and Families, as part of the Federal Child Neglect Research Consortium. About the University of Oregon The University of Oregon is among the 108 institutions chosen from 4,633 U.S. universities for top-tier designation of "Very High Research Activity" in the 2010 Carnegie Classification of Institutions of Higher Education. The UO also is one of two Pacific Northwest members of the Association of American Universities. Source: Elizabeth A. Skowron, associate professor of counseling psychology, 541-346-0913, eskowron@uoregon.edu Links: Skowron faculty page: https://education.uoregon.edu/users/elizabeth-skowron Counseling psychology and human services: https://education.uoregon.edu/department/counseling-psychology-and-human-services Child and Family Center: http://cfc.uoregon.edu/ College of Education: https://education.uoregon.edu/ Audio: 1) Skowron on main finding, 20 seconds: http://uonews.uoregon.edu/sites/uonews.wc-sites.uoregon.edu/files/uploads/AbusiveParenting-Response.mp3 2) Skowron on the challenges of intervention, 66 seconds: http://uonews.uoregon.edu/sites/uonews.wc-sites.uoregon.edu/files/uploads/Intervention%20Challenges.mp3 Follow UO Science on Facebook: http://www.facebook.com/UniversityOfOregonScience UO Science on Twitter: http://twitter.com/UO_Research More UO Science/Research News: http://uoresearch.uoregon.edu Note: The University of Oregon is equipped with an on-campus television studio with a point-of-origin Vyvx connection, which provides broadcast-quality video to networks worldwide via fiber optic network. 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