Previous obesity is associated with worse current mental health and this may increase risk of dying early, regardless of current weight status, according to research presented at the European Congress on Obesity (ECO) in Dublin, Ireland. Dr I Gusti Ngurah Edi Putra, of the University of Liverpool, Liverpool, UK and colleagues used data from two nationally representative US studies to test whether a history of obesity is linked to current mental health, irrespective of current weight status and even in participants no longer classified as having obesity. They then looked at whether the psychological consequences of past obesity may explain why the condition is associated with premature death.
The data came from the National Health and Nutrition Examination Survey (NHANES) (29,047 individuals) and the Health and Retirement Study (HRS) (11,998 individuals). It included information on past and current weight, height, symptoms of depression and other psychological well-being indicators (in the HRS), and mortality.
"Some previous studies indicated that some people who lost weight and were no longer classed as having obesity still feared being stigmatised due to having previously had obesity. This led us to hypothesise that past obesity may have long-term psychological impacts that persist even after individuals are no longer classified as having obesity,” explained Putra. “We have tested this novel 'weight scarring' hypothesis and are presenting our preliminary findings at ECO."
They found that past obesity was associated with greater depressive symptoms. In both NHANES and HRS, individuals with a history of obesity scored more highly when asked about symptoms of depression than those without a history of obesity.
In the HRS, past obesity was associated with a range of psychological well-being indicators, including an index of impaired psychological well-being which combined some indicators (e.g. depressive symptoms, loneliness, anxiety, hopelessness), independent of current weight status.
The association between past obesity and psychological well-being across studies remained in participants who were no longer classified as having obesity, indicating that past obesity may be psychologically scarring. A history of obesity increased the risk of early death by around 30% (31% in NHANES and 34% in HRS), independent of current weight status.
This association was partly due to the poorer psychological health (e.g. high depressive symptoms, impaired psychological well-being) of the individuals with a history of obesity. This is consistent with the researchers' proposition that the shorter lifespan associated with past obesity is partly due to the psychological consequences of the condition.
"Our findings suggest that obesity may be psychologically 'scarring' and that these psychological 'scars' may increase the risk of an early death. Ensuring people with obesity receive psychological support, even after experiencing weight loss, may reduce the risk of subsequent ill health,” added Putra. "It is important to note that these preliminary findings, which are yet to be published, are based on observational data and so we cannot establish causation, only associations. Further research confirming our findings is now needed."