Over the last few years, studies have described how the age at which a man has a child is related to the likelihood his child may develop schizophrenia or autism (NY Times described this last year). When we think about eating disorders, however, fathers are often left out of the discussion. Instead the focus is often on women and the relationship between mothers and daughters. A new study has just examined how paternal age is linked to the risk of eating disorders.
The study, released online last week in Psychological Medicine, was conducted by researchers at Michigan State University. They developed a set of questionnaires to give participants who were part of a larger twin study, the Michigan Twin Project. The researchers focused on twin girls who were going through puberty or were past puberty (ages 8-17). Parents were asked to answer questions about their daughters’ current eating behaviors and past history of eating disorder diagnosis.
It’s unusual that the study asked parents to report on their children’s current eating behaviors and attitudes. The researchers were faced with a difficult task of gathering responses from over 1,000 participants and wanted to give a short set of questionnaires to parents to increase the likelihood that they would participate. Nevertheless, it’s difficult to imagine that parents would have known the true extent of their teenage daughters’ eating behaviors and attitudes.
The researchers also assessed for paternal and maternal age and used statistical modeling techniques to see if age predicted symptoms of eating disorders. They found that the older a father was when his daughter was born, the more likely she was to show symptoms of eating disorders. This was true even after taking into account mother’s age, child’s BMI, and socioeconomic status. Men who were at least 40 years old when having their child were most likely to have a daughter with higher levels of eating disorder symptoms.
The researchers sought to understand if the fathers may have been contributing genetically or environmentally to their daughter’s eating disorder symptoms. The leading genetic theory in such a case is based on de novu genetic mutations, or mutations that occur spontaneously around the time of conception. However, the researchers did not find support for this theory when comparing identical twins to fraternal twins.
Speculating on why older fathers (but not older mothers) may uniquely affect their daughter’s environment, the researchers highlight the fact that men often experience more weight and diet concerns in older adulthood compared to young adulthood while women often experience the opposite. As fathers develop more concerns about their weight, they may be more likely to criticize or highlight weight in their children. This speculation is rather simplistic and we don't really have a solid explanation for why father’s age is correlated with eating disorder symptoms.
Given this study is the first to look at paternal age in relation to eating disorders, relied on parents to report eating disorder symptoms, and focused only on pre-teen and teenage daughters – we have to interpret the results cautiously. There are many reasons why a man may want to have a child before age 40, but doing so to prevent his daughter from having an eating disorder should not be one of them.
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Dr. Gupta is a professor at Barnard College of Columbia University and provides individual therapy at Tribeca Psychology
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