Men diagnosed with ADHD as children had higher rates of obesity and larger body-mass indices (BMI) than their peers not diagnosed with childhood ADHD, according to a study published online in the journal Pediatrics today. However, it's important to keep in mind that correlation does not imply causation, and the findings of this study do not go so far as to say ADHD causes obesity, or vice versa. "We did not evaluate physical activity, sedentary time, or sleep problems, any of which might affect weight," the researchers note in their paper. Nonetheless, the results indicate that for the children who were surveyed in this case, there was a statistically significant difference in the obesity rates between those diagnosed with childhood ADHD and those without.

The study focused on a group of 207 boys diagnosed with ADHD ages 6 to 12, who researchers described as "middle class, medically healthy" and caucasian, with English-speaking parents. They boys were surveyed by researchers years after they were first enrolled in the study, at about age 18 and again at around age 41. By that time, scientists were only able to track down and interview 111 of the original participants. Researchers asked for these 111 men to provide their height and weight, and compared the values provided to 111 men who were not diagnosed with ADHD.

"significantly higher" obesity and average body mass indices

Overall, the men in the study who had been diagnosed with ADHD as children were found to have "significantly higher" obesity and average body mass indices than the group without ADHD. The obesity rate in the ADHD group was 41.4 percent, compared to 21.6 percent in the other group — almost double. Meanwhile, average BMI among the ADHD group as adults was 30.1, compared to an average BMI of 27.6 for the other group without childhood ADHD.

Importantly, the error rate in the BMI values between the two groups overlapped at plus or minus 6.3 for the ADHD group, and plus or minus 3.9 for the other group, indicating that their BMI could have actually been the same. The study was also limited by the fact that it was focused on only white males, and researchers note that the results need to be replicated in order to be verified. Still, the researchers are confident in the veracity of the results and conclude that the study indicates "the long-term risk for obesity should be considered when managing children with ADHD."