A new study has found that anorexia nervosa, a serious eating disorder that can result in death, is more common among people born in spring months. Researchers from Oxford University said their study, the largest to date, provides clear evidence of a “season of birth” effect in anorexia.
The researchers, led by Dr. Lahiru Handunnetthi of the Wellcome Trust Centre for Human Genetics at Oxford University, compared the birth dates of 1,293 patients with anorexia to those of the general population. They found significantly more anorexia births between March and June, and a deficit between September to October.
Some previous studies have suggested an association between season of birth and eating disorders, the studies were much smaller and did not reach statistical significance.
Dr. Handunnetthi said that the researchers meta-analyzed four cohorts of anorexia nervosa patients from the United Kingdom, making this the largest study of its kind. The study found that the risk of developing anorexia is significantly influenced by an individual’s season of birth, with the risk higher among those born in the spring and lower among those born in the fall.
Dr. Handunnetthi added that many previous studies have found that mental disorders such as major depression, schizophrenia, and bipolar disorder are more common among those born in spring, so this finding regarding anorexia is not particularly surprising. However, the study provides the statistical evidence needed to further research the topic. The next step is to identify the factors that are increasing the risk of developing anorexia.
The researchers think environmental factors around the time of conception or development in the womb may be responsible for this increased risk. Seasonal change in temperature, increased sunlight exposure and vitamin D levels, maternal nutrition and exposure to infections are all possible risk factors, according to Dr. Handunnetthi, and identifying these factors is an important step in better understanding and preventing illnesses such as anorexia.
Source: Science Daily, Spring babies face anorexia risk, study suggests, May 5, 2011