By Gloria Arminio Berlinski, MS
Reviewed by Vrunda Bhavsar Desai, MD, FACOG, Assistant Professor of
Obstetrics, Gynecology, and Reproductive Sciences, Yale School of
Medicine, New Haven, CT
Although cross-sectional studies indicate a possible association between pediatric attention-deficit/hyperactivity disorder (ADHD) and obesity in childhood, data linking pediatric ADHD with obesity in adulthood are relatively limited. According to Castaneda and fellow researchers, their study, newly published in Mayo Clinic Proceedings, is the first to use a longitudinal, population-based design to explore the impact of ADHD on obesity among patients with research-identified ADHD and non-ADHD controls from the same birth cohort.
The analysis included 336 patients with pediatric ADHD and 665 age- and sex-matched non-ADHD control subjects derived from a target population consisting of children born between 1976 and 1982, who subsequently remained living in Rochester, Minnesota, at or after age 5 years (N=5718). Medical records from birth through August 2010 were used to extract height and weight measurements, as well as history of stimulant medication use. Data were analyzed using Cox models.
A positive correlation among females
The authors’ research showed a significant connection between pediatric ADHD and the development of obesity during childhood and young adulthood among females--but not among males. In particular, a significantly higher percentage of female ADHD patients (41.6%) was observed to be obese after the age of 20 years compared with female non-ADHD control subjects (19.2%). In contrast, no significant difference in obesity rates was evident between male ADHD patients (31.7%) and male controls (27.8%).
Commenting on these observed sex-specific differences, study co-author Seema Kumar, MD, of the Mayo Clinic’s Department of Pediatric and Adolescent Medicine, in Rochester, explains, “Females with ADHD have a higher prevalence of the inattentive subtype, whereas the hyperactive-impulsive subtype is more prevalent among males. Boys with the hyperactive-impulsive type of ADHD may be protected against weight gain due to increased resting energy expenditure.”
“Additionally,” Dr. Kumar continues, “girls with ADHD tend to have higher rates of depression, anxiety, and eating disorders, along with lower self-efficacy and poorer coping strategies, all of which may contribute to habits that predispose to excess weight gain.”
The researchers, however, didn’t account for comorbidities common in both ADHD and obesity (such as behavioral, psychosocial, conduct, and neurodevelopmental disorders) to assess their possible influence on weight status.1 In addition, socioeconomic status, which may affect weight gain in both children and adults, wasn’t considered in the study.
Castaneda and co-authors also found that obesity rates weren’t significantly different between ADHD patients who were treated with stimulants for 3 months or more and those who were untreated. They note, though, that further study using an even longer follow-up period is needed to better assess any possible effect of stimulant use on weight status.
Possible mechanisms, and clinical implications
Common neurobiologic abnormalities, related to dopaminergic pathways and the disordered eating patterns or overeating due to symptoms of impulsivity and inattention in ADHD, may contribute to the link between ADHD and obesity.1,2 ADHD-related sleep problems that result in behavioral and hormonal changes may also be involved.
To illustrate, a newly published study, using a behavioral genetic model, supports the notion that overeating and increased dopamine in the ventral striatum, which coordinates reward perception, may in part mediate the ADHD-obesity connection.3 Another example comes from a recent report which suggests that disruption in circadian rhythms, either from short sleep times or unstable eating patterns (missing breakfast or binge eating later in the day, for instance), contributes to the association between ADHD symptoms and obesity.
When asked about the clinical implications of the Mayo Clinic study, Dr. Kumar says that “there’s a need for greater awareness regarding the increased risk for obesity in females with ADHD among patients, caregivers, and healthcare providers.” Therefore, preventive measures targeting healthy eating and active lifestyle should be incorporated as part of routine care of all patients with ADHD, she adds.
The study also highlights the need to regularly evaluate the weight of children with ADHD, to monitor for any trend toward becoming overweight or obese.
Even with this recent research in hand, “the impact of persistence of ADHD during adult life on the risk of obesity needs further study,” Dr. Kumar concludes.
Castaneda RLA, Kumar S, Voigt RG, et al. Childhood attention-deficit/hyperactivity disorder, sex, and obesity: a longitudinal population-based study. Mayo Clin Proc. 2016;91:352-361.
Seymour KE, Reinblatt SP, Benson L, et al. Overlapping neurobehavioral circuits in ADHD, obesity, and binge eating: evidence from neuroimaging research. CNS Spectr. 2015;20:401-411.
Patte KA, Davis CA, Levitan RD, et al. A behavioral genetic model of the mechanisms underlying the link between obesity and symptoms of ADHD. J Atten Disord. 2016 Jan 21. [Epub ahead of print] Vogel SW, Bijlenga D, Tanke M, et al. Circadian rhythm disruption as a link between attention-deficit/hyperactivity disorder and obesity? J Psychosom Res. 2015;79:443-450.